The Cloacal Kiss & other Curiosities

2010-04-13T03:47:00.000-07:00

Attraction & Olfaction

2009-11-29T18:46:00.000-08:00

The fact human females would want sex at all outside of their monthly 6-day window of receptivity is an evolutionary problem. What practical purpose does it serve? Don't females have better things to do?

Well, of course we do - but even so, those females who prescribe to a "dual sexuality" (conceptive and not conceptive) mating strategy are actually more likely to reap both the genetic and material benefits in their mate(s). There have been studies that suggest when a female is not receptive she prefers males who exhibit strong paternal and supportive attributes. These are the "nice" guys who are often pitied because they don't "get the girl." This isn't entirely true - except perhaps from a male's perspective. It really depends upon how "getting the girl" is interpreted. All but six days of the month studies have shown females to show preference towards the devout paternal male, not the raucous bad boy who is well endowed (genetically).

I suppose I should pause here to explain an important concept in evolutionary biology that's relevant to this entry. I'm inferring that he who is considered of high genetic quality is the aggressive, eyebrow-pierced, pink polo-adorned male who is incapable of articulating anything that has two or more syllables. This is true to at least one extent explained by the sexy son hypothesis. The idea is that if a female mates with a male who is considered "attractive," she will have attractive male offspring who will be perceived as having the same appeal to the next generation of women. A vibrant example of this is the male peafowl (below).

image source

One can easily see why the dual sexuality strategy would be adaptive to our female ancestors. A female prefers the male with whom she can share parental duties and, when she's ovulating, the male who can maximize her reproductive success in the long run. In human and nonhuman monogamous animals, females engage in extra-pair copulations during ovulation if the benefits outweigh the costs (ie. if the extra-pair male is much more genetically compatible and of course, if they don't get caught).

Follow your nose...
There is mounting evidence that suggests female mate choices are made through cues that reflect genetic quality ("sexy son" indicators) and material benefits ("good dad" indicators). Sexy son indicators include vocal and facial masculinity, muscles, symmetry, and body scent intensity. Good dad indicators are passiveness and feminine facial features (eg. round face and eyes).

So... what does the pill have to do with how sexy a woman perceives a man's stench?

The reason the pill has such a strong effect on female mate preference is because it keeps a high level of progestin (a substitute for progesterone) and estrogen in the female's system. Progesterone is a mellowing hormone and the sister to estrogen, the controlling, all-powerful hormone that is responsible for feelings of aggression and seduction. The pill tricks the body into thinking it is in a pregnant state, during which estrogen and progesterone are peaking. When a female is pregnant she does not continue the uterine cycle because a fertile egg is already gestating.

So what do the two key components to hormonally-based birth control pills actually do?Progestin and estrogen prevent gonatropin-releasing hormone (GnRH) from being secreted by the hypothalamus. GnRH is the signal to the pituitary gland to produce follicle-stimulating hormone (FSH) and leutinizing hormone (LH). Once GnRH is blocked, the body does not secrete FSH, which prompts the body to grow a follicle, and LH, which triggers the release of the egg. The pill essentially freezes the natural cycle so it remains at a single stage for the entire month.

The data suggests that females who are on the pill (or pregnant) do not have the same sexual palette as the non-pill user. In a study that manipulated the facial features in 20 pictures of male faces to masculinize or feminize their attributes found normally cycling women prefer less masculine faces in a long-term context compared to more masculine faces in a short-term context. Pill-users had an inverse preference and a weaker preference.

Love at first smell and contraceptives

The Major Histocompatibility Complex (MHC) is a gene family that serves as an important component to a person's immune system. It creates molecules capable of identifying pathogens, or foreign invaders, so that the soldiers of the immune system can be called upon for combat. The MHC is so essential that the olfactory cues reflecting the genetic compatibility among two individuals are thought to be based off of it alone.

Mate choice is influenced by MHC diversity through olfactory cues. MHC–peptide complexes present at the cell surface carry information about our cellular genetic make-up. When these complexes are shed from the cell surface they dissolve in our bodily fluids. This releases the peptide ligand component of the complex, which is then free to interact with other receptors (such as olfactory sensory neurons). The relevance of this has to do with the patterns of sensory neuron activation, which are unique to the structure of distinct peptide ligands. A person's distinct body odor reflects their MHC genotype, (drum roll) thus allowing us to assess the genetic compatibility of prospective mates!

This is where contraceptive pills come into play: natural selection has played a large role in making sure individuals with similar genetic material - siblings, for instance - do not breed because the resulting offspring will have weaker immune systems and be more likely subject to a whole suite of genetic faults. The cost of mating with someone who has a similar set of MHC alleles is large for the same reason. The idea is that with lots of diversity in our MHC genes, the body is ready to take on a lot of different invaders. This diversity can only be maintained by sexual outbreeding which leads to different combinations of MHC alleles representing a richer defense strategy.

Then the brilliant stinky t-shirt experiment was conceived:

In summary, (naturally cycling) women found the odors of MHC-dissimilar males more pleasant. These results yielded a negative correlation between number of shared alleles and pleasantness ratings.

Note, however, this test examined the preference of exclusively normally cycling women. When the same sweaty t-shirt test was performed on women who are taking contraceptives they found surprising results. These women didn't show a preference for the scent of males with dissimilar MHC genes. In fact, these women showed a higher preference for males with MHC genes similar to their own. If your body believes you to be in a pregnant state, this odor preference could be advantageous. Our primitive brains yearn to be surrounded by genetic similarity (ie. relatives) during this stressful and dangerous part of our life cycle.

Past studies suggest there are consequences to females preferring genetically similar males as long-term partners. Couples with dissimilar MHC genes are more satisfied and more likely to be faithful to their mate. Those who have similar MHC genes report less satisfaction and more wandering eyes. There are also fertility problems encountered by MHC-similar couples, who have a much higher probability of recurrent spontaneous abortions (RSA). There have also been studies that highlight the importance of odor perception as it plays a significant role in maintaining attraction within relationships.

So if a female acquires her male counterpart after beginning the pill, what happens when the woman goes off of it? Something I personally will never know. I'll take my sweaty man stench without the extra hormones, please.

Thornhill, R., Gangestad, S. W., Miller, R., Scheyd, G., McCollough, J. K., and M. Franklin. Compatibility complex genes, symmetry and body scent attractiveness in men and women. The Research & Education Division of The Fragrance Foundation.

Havlicek, J. and S. Roberts. 2009. MHC-correlated mate choice in humans: A review. Psychoneuroendocrinology 34: 497 - 512.

The adaptive benefits of producing non-functional sperm

2009-08-23T11:03:00.000-07:00

Scientists were scratching their heads while looking for the evolutionary explanation as to why the males of a butterfly species possessed predominantly non-fertile sperm.

What the heck is going on?

(image source)

Promiscuous mating regimes are great to research if you're interested in the coevolutionary arms race between male and female reproductive interaction. Usually it is evident that males will have evolved to manipulate female receptivity and females to resist the manipulation. An interesting example lies in the green-veined white butterfly (Pieris napi). Male butterflies transfer fertile and non-fertile sperm to their female. The non-fertile sperm requires less energy to produce and is used because females possess a sperm-storage organ that, when full, switches off the receptivity of the female. This enforces female monogamy because she cannot successfully mate with another male until she finishes the period during which she is not receptive (due to the full sperm storage organ). This period of time is called her refractory period.

However, females have also evolved to combat the standard lengthy refractory period by shortening it significantly. It is advantageous because it allows females to mate more and therefor have a higher reproductive output. Researchers found a positive genetic correlation between non-fertile sperm transfer and female refractory period. In other words, in the context of a promiscuous mating system, sexual conflict yeilds short female refractory periods and high proportions of non-fertile sperm in males. They also found that these traits were heritable and when the mating system was manipulated, the traits would also fluctuate.

This finding is consistent with previous findings related to male-female sexual conflict: selection on female reproductive traits directly affects male traits and vice versa.

Source:
Nina Wedell, Christer Wiklund, and Jonas Bergström. 2009. Coevolution of non-fertile sperm and female receptivity in a butterfly. Biology Letters.

Matt Ridley on the Evolution and Biology of Sex

2009-07-24T18:22:00.000-07:00

Mating Systems 101

2009-07-22T15:55:00.001-07:00

In a monogamous mating system, consistent pair bonds are formed between two individuals with sexual exclusivity. Polygamy is a general term used to describe a system in which an individual mates with 2 or more partners of the opposite sex. Two subsets exist within this definition. In a polygynous system, one male mates with two or more females. In a polyandrous system, one female mates with two or more males.

Polygynandry is a mating system defined by the sexual sharing among two or more females and two or more males. This term is often used interchangeably with promiscuity, but it differs because pair bonds form among specific individuals. In a promiscuous regime, no pair bonds are formed.

Across the board, mating systems develop to optimize the reproductive success of individuals. Monogamy will prevail when it is most fitness enhancing for those involved. For example, if females are dispersed, which is the case in some mammal and many bird species, monogamy will likely be the dominant strategy observed. If females are forced into a small area, such as female elephant seals cramped along a shoreline, males will use the opportunity to sequester females and maximize their reproductive output.

Monogamy will also prevail if the fitness of the offspring is dependent upon biparental care. In many bird species, the male and female are both fully capable of incubating the eggs and feeding hatchlings. If only one parent is involved, the probability of the chicks’ survival is compromised. Female-enforced monogamy is when a female eliminates the risk of other competing females from copulating with her chosen mate. A deep-sea angler fish male is born as a small, helpless sperm packet who lacks a digestive system and is entirely dependent upon his destine host female. He swims though the deep ocean in search of her, and has specialized mouth parts that assist in him in his permanent attachment to her.

Polygyny is by far the most commonly observed mating system in Animalia, and its presence is based on the extent to which males can monopolize females. This model applies to species in which the territory of a male contains useful resources for the female and her offspring. The environment plays a significant role in this mating system because females are easier to sequester when resources are spatially clumped. For example, female elephant seals in the Falkland Islands typically rear offspring and feed along the shoreline. Males fight one another in an effort to establish a more dominant hierarchy ranking which allows them access to the largest territory of shoreline. Once established, he is considered a harem holder, and mates with all the females who nest in his territory (a heram group). In polygynous mating systems, male reproductive success is a function of pre-copulatory strategies such as fighting in the example above. Males aim to mate with as females as possible, and females choose the male based on the quality of the territory he protects. A very small percentage of alpha males are successful harem holders among polygynous populations. The remaining male elephant seals roam the periphery of the territories, and are called satellite males.

Polyandry has been considered an evolutionary problem because it was thought to challenge one of the major underpinnings of sexual selection. It is the assumption that the disparity between male and female gamete investments (anisogamy) has favored the selection for diverging mating habits between males and females. Females are thought to be the “choosier” sex because they invest more energy into generating eggs, while males tend to favor quantity over quality and their fitness will not be lowered if they mate with a female of low genetic quality.

This line of thinking has gone under extreme scrutiny recently, as there has been accumulating molecular evidence revealing multiple paternity (polyandry) to be a common practice in animals. Multiple hypotheses have developed to explain this. The material benefits hypothesis predicts females who mate with more than one male are privileged to access more resources, parental care, and a limitless sperm supply. The genetic benefits hypothesis broadly predicts females who are mated with multiple males will produce offspring who are the result of superior ejaculates. If the offspring are males, they potentially have the same high quality sperm and will be able to heighten the fitness of the mother.

There are unique cases that do not fit in the categories described above. For example, we see an investment role reversal in Red Phalaropes of Alaska. Females exhibit traditionally masculine qualities. They are bigger and more colorful than males and play no role in incubating or caring for the young. The female spends about a week courting a single male and laying her eggs in his nest. Females of this species are able to generate eggs quickly, and after a week the female begins searching for another mate. Males incubate the eggs and nurture the chicks alone.

Polygynandry and promiscuity are similar yet distinctly different mating systems. Polygynandrous females regularly form pair bonds and copulate with several males at the same time as males form pair bonds and copulate with several females. The polygynandrous European badger lives in social groups with as many as five mothers and five fathers that produce multiple-paternity litters. It is thought the primary reason for this is described by the resource dispersion hypothesis: polygynandrous groups may arise because limited optimal resources may force more than one breeding pair within a territory. There is usually a dominant pair and a number of subordinates within a social group. In some species the subordinates do not mate, but in many cases subordinate females produce litters of mixed paternity.

Promiscuous species are those in which pair bonds do not form and males and females are likely to copulate with more than one individual of the opposite sex. It is a unique system because subordinate males have the opportunity to access females and male reproductive success is a function of post-copulatory strategies such as sperm competition and cryptic female choice. For example, when brown headed cowbirds live in areas with abundant resources, territorial lines are not well defined and promiscuity is often reported. The brown headed cowbird is a nest parasite that lays its eggs in other birds’ nests and provides no parental care for its young. Promiscuity may be the obvious choice given the birds’ behaviors and their lack of parental care.

Traumatic Insemination in aptly named 'Harpactea sadistica' spider

2009-07-14T20:23:00.000-07:00

A violent but evolutionarily effective mating strategy has been spotted in spiders from Israel. Males of the aptly-named Harpactea sadistica species pierce the abdomen of females, fertilising their eggs directly in the ovaries. This has been described as a "traumatic insemination strategy," in which insemination wounds are created by male genitalia in areas outside the genital orifice of females. It is practiced because it gives the first male a reproductive advantage by bypassing structures in the females' genitalia.

These tactics have been observed in insects such as mites, bedbugs, and flies, but this study was the first time that it was documented in spiders. Typically, spider males deliver their genetic package via sperm that manually inserted using a pair of appendages called pedipalps.

The sperm are then held in a receptacle between the ovipore and ovary known as a spermatheca until an egg is released. However, the spermatheca is a "last in, first out" structure, so that if any further males inseminate a female, the last mate's sperm is the first in line to fertilize an egg.

Milan Rezic, an entomologist at the Crop Research Institute in Prague, has spotted a spider circumventing this problem by delivering sperm directly to the ovaries via holes that the males bore directly in the females' abdomens. The male possesses a pair of emboli, appendages modified for piercing females.

The way in which the male H. sadistica inseminates the female is choreographed and complex. The male taps the female, subdues her, and wraps himself around her to properly position the sex organs. He then alternates between the two organs, piercing and injecting the sperm on one side, then the other. The physical marks left are two neat rows of holes in her abdomen.

An analysis of the females of the species has shown that relative to other spiders, their spermathecae are atrophied, or shrunken. In an apparent case of co-evolution, they seem to be slowly shrinking into nonexistence now that their purpose is being bypassed by the males' more direct approach. This is yet another example of the co-evolutionary arm's race we see between many male and female species, in which males evolve to more efficiently inseminate the female and displace other males' seminal fluid, and females evolve to be able to control who inseminates her precious eggs.

Dr. Rezac foresees the race continuing. He suggests that a means to avoid the injury caused by the males might drive the evolution of secondary genitalia nearer to the ovaries, which have been observed in some spiders and butterflies.

Rezac, M. 2009. The spider Harpactea sadistica: co-evolution of traumatic insemination and complex female genital morphology in spiders. Proceedings of the Royal Society: Biological Sciences 276(1668):2697-701.

Women evaluate mate quality based on dancing ability

2009-07-12T11:34:00.000-07:00

As a human female, this seems painfully obvious. He who has two left feet and/or does the robot sleeps alone. However, to examine the question of human mate choice from an evolutionary perspective can be astonishingly revealing. Why do women prefer men who can dance?

A recent study from the journal Personality and Individual Differences suggests that women have evolved cognitive adaptations to visually evaluate intra-male dominance potential in men in order to select the highest quality mate. Humans are physically sexually dimorphic, such that males are usually stronger than women. Females developed a preference for stronger men because they tend to have had superior fighting and resource-holding potential. As a result, over the course of human evolution, those males subject to more prenatal and/or pubertal testosterone developed attractive physical and behavioral characteristics that facilitate the attainment of status and resources. There are certain honest signals that females find attractive because they serve as correlates indicating high quality mate potential. This study specifically investigated whether male physical strength is honestly signaled via dancing performance.

The study assessed physical strength by measuring the handgrip strength of the participating male subjects. They had a sample of 40 male dancers of equal body weight and height. They were instructed to wear the exact same outfit as the rest of participants, and a short digital video clip of their dances were taken with consistent lighting, a uniform background, and with the same beat playing. A blurring filter was applied to the video camera so the body shape of the dancers could not be distinguished. A sample of 50 females from a local university were recruited to judge the attractiveness of the male dancers on a scale of 1-7 (1 = low and 7 = high on the attribute).

The results support the hypothesis that male physical strength can be signaled through dynamic displays such as dance. Women found men who were physically stronger (i.e. those with higher hand-grip strength) more attractive and assertive.

Hugill, N., Fink, B., Neave, N., Seydel, H. 2009. Men's physical strength is associated with women's perceptions of their dancing ability. Personality and Individual Differences 47 (5): 527-530.

Drifters of the Deep

2009-05-30T20:30:00.000-07:00

Drifters of the deep from Eugenia Loli-Queru on Vimeo.

When most fertile, females choose the jerk

2009-05-24T14:19:00.000-07:00

This paper, entitled "Changes in Women’s Mate Preferences Across the Ovulatory Cylce," examined how women rated men displaying certain characteristic indicators of good genes and good investment throughout their ovulatory cycle. First, a sample of women rated men based on the following traits and characteristics: “intelligence, warmth, degree of social respect, ability to be a good father, sexual faithfulness, capacity for financial success, physical attractiveness, muscularity, confrontativeness with other men, and arrogance." The men participating in the study as subjects also rated themselves based on these characteristics. Next, a different sample of women rated the attractiveness of each man as a long-term or short-term mate.

Their hypothesis questioned if mate preference varies depending upon where the woman is in her ovulatory cycle. They predicted that women would prefer good gene indicators when they are most fertile and good investment indicators in other contexts.

These indicators are important from a female perspective for a number of reasons. Females are capable of yielding a limited number of gametes in her lifetime. Gestation and lactation are also incredibly energy-consuming and required years of commitment before a woman is able to mate again to successfully rear another child. For these reasons, it is argued that women are the choosier sex.

Examples of good gene indicators are those phenotypes that correspond to good health and developmental stability. Particularly when women seek partners as short-term mates (ahem one night stands), it is predicted that she would prefer indicators of heritable fitness, or genes that will most likely yield successful offspring. Facial symmetry and masculinized physical features are examples of good gene indicators. They reflect good health and high testosterone levels, respectively. From an evolutionary standpoint, these indicators are advantageous because they will lead to fitness-enhancing characteristics passed on to the next generation.

They recognized that some traits, namely paternal investment indicators, had not been tested to empirically support the hypothesis that fluctuation in female preference does not extend to traits such as warmth, kindness, and faithfulness. They hoped to examine a wider variety of physical and behavior characteristics in men that serve as indicators of good genes and good investment.

Women’s ratings of men’s attractiveness were analyzed using a multilevel regression. The analysis described how women’s attraction to men as long-term or short-term mates related to the men’s characteristics (that both sexes were able to identify). They found that nine out of ten male traits were more preferred in the context of choosing short-term mates rather than long-term mates, including arrogance, muscularity, confrontativeness, etc.

They also analyzed women’s preferences for male characteristics as it relates to their degree of conception risk. In other words, they were looking for characteristics of men that women found attractive when they were most fertile, or at risk of producing a conceptus. They did find significant evidence that women preferred six traits of men for short-term mate interactions more when they were most fertile! These traits include confrontativeness, arrogance, muscular physical features, social respect, and physical attractiveness.

This supports the notion that women’s mate preferences predictably shift throughout their ovulatory cycle. When they are most fertile, women tend to preference indicators of good genes.

When they tested for fluctuations in female preference for long-term mates in good parental investment indicators across the ovulatory cycle, they found none. Women did not prefer parental investment mate qualities more when they were ovulating than when they were not.

These findings provide further support for the good genes hypothesis, which predicts women will prefer indicators of heritable genetic quality more when they are most fertile and assessing men as short-term mates.

Gangestad, S. W., Garver-Apgar, C. E., Simpson, J. A., and A. J. Cousins. 2007. Changes in Women’s Mate Preferences Across the Ovulatory Cylce. Journal of Personality and Social Psychology 92(1): 151-163.

High emotional intelligence linked with high orgasm frequency

2009-05-12T14:37:00.000-07:00

According to a study in the Journal of Sexual Medicine, "variations in emotional intelligence--the ability to identify and manage emotions of one's self and others--are associated with orgasmic frequency during intercourse and masturbation."

In short, the study found:

Emotional intelligence was not associated with ... age and years of education, nor did we find a significant association between emotional intelligence and potential risk factors for [female orgasmic disorder] FOD such as age, body mass index, physical or sexual abuse, or menopause. We found emotional intelligence to be positively correlated with both frequency of orgasm during intercourse ... and masturbation .... Women in the lowest quartile of emotional intelligence had an approximate twofold increased risk of infrequent orgasm ... Low emotional intelligence seems to be a significant risk factor for low orgasmic frequency. Consideration of this behavioral risk factor may need to be incorporated into research into FOD and possible treatment approaches.

This is interesting, and probably a valid finding in that it appears to be statistically demonstrable that there is a correlation between measured emotional intelligence and orgasm frequency. The correlation is positive, modest (between 0.13 and 0.23 Spearman's, and confirmed with logistical regression), and statistically significant.

They also found through a study using matched pairs of twins a statistically significant difference in both emotional intelligence measured by standard tests and patterns of orgasm frequency.

A worthy consideration with which to read this article is that contributers to emotional intelligence come from both environmental and genetic variables. To assume this correlation is entirely due to genetics is presumably not entirely true.

Original Source:

Burri, A., Cherkas, L., & Spector, T. (2009). Emotional Intelligence and Its Association with Orgasmic Frequency in Women Journal of Sexual Medicine DOI: 10.1111/j.1743-6109.2009.01297.x

Homosexual and masturbatory behavior observed in flour beetles

2009-05-10T07:21:00.000-07:00

This behavior in the 0.13-inch-long (three-millimeter-long) Tribolium castaneum, which can be found infesting flour in most temperate areas, has been observed for decades

They found that homosexual encounters did not improve a male's sexual success with females, as measured by the number of offspring carrying his genes. There was also no connection between homosexual activity and social dominance—male beetles that had many sexual encounters with other male beetles did not earn more attention from females.

What the team did find was that males were dribbling sperm onto each other. This suggested that males might be trying to get rid of old sperm, lining up fresher sperm for their next female encounter.

The team also found that if one male leaked semen on another male and the semen-covered male later bred with a female, the female's eggs could become fertilized with the sperm of the male she had never encountered. That a male could inseminate a female without directly breeding with her came as a big surprise.

It reveals that the flour beetles' homosexual behavior yields a direct reproductive benefit, allowing males to inseminate females without expending time or energy having sex with them.
"We could not believe these results when we first saw them, so we ran the experiment over and over again to make sure it was actually happening," Lewis said.

Levan, K. E., Fedina, T. Y.; Lewis, S. M. 2009. Testing multiple hypotheses for the maintenance of male homosexual copulatory behaviour in flour beetles. Journal of Evolutionary Biology. 22(1):60-70.

Same-sex mating observed in fungal species

2009-05-10T07:12:00.000-07:00

Cryptococcus neoformans is a major cause of fungal meningitis in predominantly immunocomprised individuals.

Recently it was discovered that C. neoformans can undergo same-sex mating under laboratory conditions, especially between α isolates. Whether same-sex mating occurs in nature and contributes to the current population structure was unknown.

In this study, natural αADα hybrids that arose by fusion between two α cells of different serotypes (A and D) were identified and characterized, providing definitive evidence that same-sex mating occurs naturally. A novel truncated allele of the mating-type-specific cell identity determinant SXI1α was also identified as a genetic factor likely involved in this process.

In addition, laboratory-constructed αADα strains exhibited hybrid vigor both in vitro and in vivo, providing a plausible explanation for their relative abundance in nature despite the fact that AD hybrids are inefficient in meiosis/sporulation and are trapped in the diploid state. These findings provide insights on the origins, genetic mechanisms, and fitness impact of unisexual hybridization in the Cryptococcus population.

This study provides the first evidence of this and sheds light on the genetic and environmental factors that play important roles in the evolution of the current population structure of this pathogenic fungus.

Lin X, Litvintseva AP, Nielsen K, Patel S, Floyd A, et al. (2007) áADá hybrids of Cryptococcus neoformans: Evidence of same-sex mating in nature and hybrid fitness. PLoS Genet 3(10): e186. doi:10.1371/journal.pgen.0030186

Virtual Heart Video

2009-05-08T10:37:00.000-07:00

Ugly Bugs!

2009-04-30T20:05:00.000-07:00

I sort of stumbled upon the Oklahoma Microscopy Society's Ugly Bug Contest Homepage.
What a discovery!
Check it out: The 2007 Winners

Flora and Fauna Photography

2009-04-25T10:39:00.000-07:00

These were taken during my recent trip to Key Biscayne, FL.

Portuguese Man-O-War

Tricolored (Louisiana) Heron

Northern green anole

Bar close - not beer goggles - affects perceived attractiveness in prospective mates

2009-04-25T10:03:00.000-07:00

People often assume that alcohol consumption plays a significant role in a person's perception of attractiveness in the opposite gender, but research performed at North Dakota State University may suggest there is another reason for the increased attraction. Male and females were asked to rate the attractiveness of members of the opposite gender in a bar throughout an evening. They were also asked to record the type and amount of alcohol consumed.

What they found was surprising. Attractiveness ratings of opposite-gender individuals increased over time, but these increased ratings were not due to alcohol consumption, data suggests. As the hour grew late, opposite-gender patrons grew more attractive.

"...we found that men and women increase their attractiveness ratings of the opposite gender throughout the evening at a so-called pickup bar. And we have an answer about the involvement of alcohol in these ratings: There is none. Estimated blood alcohol concentrations for both genders did not correlate with attractiveness ratings of the opposite gender."

Gladue, B.A. and Delaney, H. J. 2004. Gender Differences in Perception of Attractiveness of Men and Women in Bars. Personality and Social Psychology Bulletin: 378 - 390.

Volcano Eruption in Galapagos National Park

2009-04-12T14:31:00.000-07:00

La Cumbre volcano in the Galapagos Islands started spewing lava, gas and smoke on the Fernandina Island. The most recent volcanic activity on Fernandina Island occurred in May 2005. I was fortunate to attend a course that focused on the biology and evolution of the Galapagos last summer - I never stepped foot on Fernandina because my group explored the eastern portion of the archipelago.

It still breaks my heart that this eruption may have a detrimental effect on the wildlife endemic to the island. The following excerpt was taken from the Glob Gazette News Blog.

In a statement it said the eruption is not a threat to people living on nearby Isabela Island. But it added that lava flowing to the sea will likely affect marine and terrestrial iguanas, wolves and other fauna.

The iguanas we encountered on the islands were unlike any reptile I've ever seen. They also were oblivious to our presence - or mildly annoyed at worst.

This picture (left) features the Galapagos marine iguana. One of their interesting and diagnostic features was the little white cap that each wore atop their heads. Due to the high salt content in their diets, they have evolved a mechanism to maintain an internal osmotic equilibrium. They sneeze to expel excess salt from salt glands that are located above the eye. This in combination with the wind results in an accumulation of white salt on their head. When I was in the Galapagos, an ongoing pursuit among group members was to photograph a marine iguana mid- sneeze, as they expelled excess salt every few minutes. Sadly, no one was successful. I will say that there is nothing cuter than a sneezing iguana.

The majority of land iguanas we saw were on Santa Fe Island. They were visible because the island had low-growing vegetation that surrounded a sparsely distrubuted Opuntia cactus forest.

The land iguanas were quite visible, startlingly large, and usually munching on yellow purslane flowers (Protulaca lutea).

I hope the population of critters who were affected by the recent eruption are able to quickly rebound. I don't know the impact's severity at this point, but I can't say enough about the importance of conserving the Galapagos Archipelago. It represents a thriving pristine wilderness as untamed territories elsewhere - everywhere - are increasingly being forced to share resources with fatal human co-inhabitants.

Wishing you a Joyous Estrus!

2009-04-11T12:37:00.000-07:00

This here is informative. Thanks Tom Riddering from MN Atheists.

Quick! What do eggs, flowers, the East, maidens dancing around phallic symbols, the vernal equinox, fecund rabbits, chicks, flowers, Mardi Gras, estrus cycles, and Christianity all have in common? SEX!

Well, Christians actually call it Easter, named after Eastre, the Germanic fertility goddess, which comes from the same origin as the word "east." Why east? That's where the sun rises! The same spring sun that shines on those brightly colored chicken ova and brings new life to the earth -- flowers, chicks, bunnies, and the occasional god. Jesus wasn't the only god allegedly reborn around the vernal equinox. There was also Adonis, Osiris, Perseus, and Orpheus.

Spring is when we have the licentious festivals of Mardi Gras, Carnival, and the ancient Roman fertility festival of Lupercalia. It's when the Kanamara Matsuri (Festival of the Steel Phallus) is celebrated in Japan. Nothing subtle about those Buddhists and Shinto! It's when pre-Christian pagans all over the earth celebrated the return of life after the dark death of winter and propitiated their gods for a successful growing season by celebrating their fertility. The early Christian church couldn't eradicate this popular festival, so they hijacked it and assigned new theological meaning to it. But under all that sanctimonious piety, Easter is nothing but the spring fertility rites. Now that's something even atheists can celebrate!

2009-04-07T04:58:00.000-07:00

David Attenborough: Evolution from Sea to Land

How to Define an Open Mind

2009-04-06T11:02:00.000-07:00

"Science promotes and thrives on open-mindedness because the advancement of our understanding about the reality in which we exist depends upon our willingness to accept new ideas."

Temperature-dependent Sex Determination in Humans!?

2009-04-03T07:53:00.000-07:00

This is some wonderfully strange new research. Girls are more likely to be born at tropical latitudes than in temperate or subarctic climates. This study provides the first global look at human sex ratios and could shed light on how temperature and day length influence human reproduction. This article reminded me of temperature-dependent sex ratio of reptiles, and I'm not at all surprised that the length of day and temperature would induce a change in sex ratio.

Strangely, in reptiles there is polar variation in the effect temperature has on the outcome of the offspring among taxonomic groups. In crocodiles and alligators, for example, eggs incubated in temperatures below 30 °C produce female offspring and eggs incubated above 34 °C produces male offspring. In turtles, however, at cooler temperatures ranging between 22.5°C and 27 °C mostly male turtles are produced and at warmer temperatures, around 30°C, only female turtles arise. Many other animals adjust the sex of their offspring based on environmental cues such as temperature, but to confirm whether humans do to some extent is difficult to measure. There are multiple variables that have been confirmed to also affect the human sex ratio, such as stress imposed on the mother during pregnancy. How would one overcome this obstacle?

Reproductive endocrinologist Kristen Navara of the University of Georgia in Athens analyzed global sex ratios over 10 years, enough time to be sure that short-term social or economic crises weren't driving the results. Navara had previously found that Siberian hamsters raised with fewer hours of daylight produced more male offspring, and she wondered if the same might be true for humans. Navara gathered sex ratio data for every nation within a decade of uninterrupted statistics. She then analyzed the figures from 202 countries based on latitude, average temperature, day length, and socioeconomic status.

She found that humans living in areas with long, dark winters have more boys: 51.3% of babies born in temperate and subarctic regions are male, compared with 51.1% in the tropics. No one knows exactly when or how sex selection happens, but Navara says that some animals skew sex ratios as early as fertilization. "I suspect that all of this has something to do with melatonin," a hormone that regulates sleep-wake cycles and the production of female reproductive hormones, says Navara, noting that melatonin release varies in response to day length and season.

Navara, Kristen J. 2009. Humans at tropical latitudes produce more females. Biology letters.

When animals attack our morals

2009-03-23T11:09:00.000-07:00

The Colbert Report

Mon - Thurs 11:30pm / 10:30c

When Animals Attack Our Morals - Chimps, Lizards & Spiders

comedycentral.com

Colbert Report Full Episodes

Political Humor

Mark Sanford

Sex bias is entirely controlled by the females in Gouldian Finches

2009-03-22T05:49:00.000-07:00

The birds, which have either red or black heads, prefer to mate with males with the same head colouring, as this signifies a better genetic match. A report in the journal Science says that the birds compensate for this by having more male chicks in their brood. Colourful Gouldian finches can judge if a mate is genetically compatible just by looking at its head.

This new study has found that, when the female finches mate with a male that has a different head colour, they select the sex of their offspring - giving their chicks a better chance of survival.

In birds, the sex of an egg is already determined before it is fertilised by the male.
Sarah Pryke, a biologist from Macquarie University in Sydney, led this study. She found that when female finches mate with mismatched males, 70% of their chicks are male.

Dr Pryke's team disguised some of the male finches to show that this "sex bias" is entirely controlled by the females. They blackened the head feathers of red males, using a non-toxic dye, and paired them to both red and black females to allow them to breed.

The birds were fooled, and the team found that black females that mated with the "disguised" red males produced an equal ratio of male and female chicks. "This is the clearest and perhaps most extreme example of sex biasing that has been found," said Dr Pryke. "It's really black and white - or in this case black and red."

"It is pretty amazing to think that the female herself has so much control - subconsciously of course - over this basic physiology," said Dr Pryke.

The results were particularly striking because colour-matched matings, which result in much healthier broods, always produce roughly equal numbers of male and female chicks. "Females really don't want to mate with a male with a different head colour. But there simply aren't enough compatible males, so later in the mating season they seem to use this control to make the best of a bad situation."

From BBC News

The Fish-Tetrapod Transition

2009-03-19T17:24:00.000-07:00

With the vertebrate comparative anatomy lab quickly approaching in my Animal Diversity class, I was excited to fall upon a paper that appears well-tailored to the content of my own teaching schedule (for once! geesh). This is spankin' new, published March 17, 2009, from the journal Evolution: Education and Outreach.

This paper is paricularly interesting because it outlines both the history of tetrapod evolution and the history of human's perception of the animal transition from aquatic to terrestrial habitats. It highlights the helpful fossils unearthed that helps us trace this vertebrate history, such as Icthyostega spp., and those fossils, such as the Eryops cephalus, that hindered the pursuit. In the case of the latter organism (pictured below), despite its anatomy being characteristic of an early trasitional tetrapod, its ancestral origin was found to exist much later in tetrapod evolution.

This paper also describes the reason for the recent fame of the Tiktaalik transitional fossil, as it is known from several nearly complete specimens. Its excellent preservation and diagnostic transitional tetrapod features have made it an important tool for understanding the origin of the phylogenetic tree of Tetrapoda.

"In a nutshell, the 'fish–tetrapod transition' usually refers to the origin, from their fishy ancestors, of creatures with four legs bearing digits (fingers and toes), and with joints that permit the animals to walk on land. This event took place between about 385 and 360 million years ago toward the end of the period of time known as the Devonian. The Devonian is often referred to as the 'Age of Fishes,' as fish form the bulk of the vertebrate fossil record for this time."

This paper is a great read for eager young biologists like myself searching for readable scientific papers on phylogenetics and evolution. I recommend it!

The Fish–Tetrapod Transition: New Fossils and Interpretations

More Coleopterans Coitus

2009-03-16T20:19:00.000-07:00

A new study has revealed the painfully scandalous anatomy of C. maculatus seed beetles. The C. maculatus have a series of spikes and barbs on their members that, during sex, become embedded in their mates, acting as anchors of sorts.

"They literally injure females internally in their copulatory duct. They're pretty mean," Goran Arnqvist, the lead author of the study, said to National Geographic.

After looking at a large group of diverse, virgin beetles after copulation the study concluded that the beetles with the "largest and most damaging" phalluses had the most reproductive success. The injury to the females was simply an "unfortunate side effect" of the process.

At this point, I will use what little class I have to bite my tongue.

Above: a seed beetle's jaw-like spine structure on its appendage.

2009-03-16T14:51:00.000-07:00

A Sea Biscuit's Life

2009-03-10T14:03:00.001-07:00

I'm teaching about Echinoderms this week in Animal Diversity lab. They exhibit pentaradial symmetry as adults, but are actually born with bilateral symmetry. Put a beat to that concept, and you have a dance party (below).

A Sea Biscuit's Life from Bruno Vellutini on Vimeo.

Sand lizards find excuse for being lazy lovers

2009-03-06T10:35:00.000-08:00

Sand lizards engage in what are called serial copulation events. A single female copulates with multiple males in a sequence: male one, male two, male three, etc. In response to selective pressure exerted by mating with more than one male, the first male will insert a copulatory plug to serve as a barrier so the next male's sperm does not fertilize his female. We see this elsewhere in Animalia - namely, in humans! (Think "flowback")

Scientists noticed something peculiar was resulting from the serial copulation events. Sand lizards yield a disproportionate number of offspring that are sired by the multiple partners with whom the female mates. We would expect that the first male sire the majority of offspring, but that was not the case. There appeared to be something going on with the sperm or reproductive tract, but what?

Mats Olsson of University of Wollongong observed the male lizards exerting variable amounts of effort when copulating with a female. The amount of effort was positively correlated with clutch size (Figure 1 and 2, above). He sought to find what determined the time investment.

He and his team studied the second male and his ejaculation tactics. The second male would approach a female and obtain information about the prior male's relationship to her. If his rival was more genetically similar to the female than the second male was to the female, the second male stands a better chance of passing on his genetic material. The male sand lizards are able to sense an MHC (major histocompatibility compex)- related odor of the copulatory plug. With this information, the second male could ascertain the relatedness of the first male and female, and would spend more time in copula with the female if the first male was more related to her than he was to her. (Figure 3, below)

If his nemesis was less related to the female than the second male, the second male would engage in an informal "quickie" and then move on.

Olsson, M., T. Madsen, B. Ujvari, and E. Wapstra. 2004. Fecundity and MHC affects ejaculation tactics and paternity bias in sand lizards. Evolution 58: 906-909.

Pepto-Bismol-Pink Dolphin in Louisiana

2009-03-06T08:11:00.000-08:00

This is a peculiar find. (Thanks to Dr. Melissa Palmer for the tip)

The pink color and reddish eyes indicate albinism, an inherited condition that results in individuals lacking normal pigmentation. This special aquatic mammal drew quite a crowd when it first surfaced in Lake Calcasieu, an inland saltwater estuary north of the Gulf of Mexico in Louisiana.

The dolphin was first identified by charter boat captain Erik Rue, who said it was swimming with a pod of four other dolphins. I hope this special critter makes it despite its strange coloration.

Is this first pink dolphin observed in nature?

Actually, there are pink dolphins that reside in South America in the Amazon. The boto is the largest of the river dolphins. They have different color patterns, varying from bright pink to deep grey, depending upon their age and the geographical area where they are found. In the Arauca River in Colombia, dolphins are very pink (pictured below) and very active at the surface. They tend to become more "pink" with age because their skin becomes more translucent and the blood circulating beneath their skin becomes visible. These Amazon River Botos are close relatives to the dolphins with which we are familiar from the states. However, there are a few significant morphological differences.

In addition to the higher frequency of pink coloration among populations, the Amazon River Botos have specialized teeth that are used to crush fish and heavily armored benthic organisms such as crustaceans. They also have a big hump on their head and a ridge on their back in place of a defined dorsal fin.

da Silva V (1994) Aspects of the biology of the Amazonian dolphins Genus Inia and Sotalia fluviatilis. PhD Dissertation, University of Cambridge, Cambridge, 327 pp.

Science Fare

2009-03-03T22:21:00.000-08:00

A student introduced me to this fine tribute to science. Bad Astromony guy, you inspire!

In April, I was asked to give a short speech to a group of local students who participated in a science fair. I wasn’t sure what to say to them, until I saw a newscast the night before the fair. The story was some typically inaccurate fluff piece giving antiscience boneheads “equal time” with science, as if any ridiculous theory should have equal time against the truth.

I sat down with a pad of paper and a pencil and scribbled down this speech. I gave it almost exactly as I wrote it.

I know a place where the Sun never sets.

It’s a mountain, and it’s on the Moon. It sticks up so high that even as the Moon spins, it’s in perpetual daylight. Radiation from the Sun pours down on there day and night, 24 hours a day — well, the Moon’s day is actually about 4 weeks long, so the sunlight pours down there 708 hours a day.

I know a place where the Sun never shines. It’s at the bottom of the ocean. A crack in the crust there exudes nasty chemicals and heats the water to the boiling point. This would kill a human instantly, but there are creatures there, bacteria, that thrive. They eat the sulfur from the vent, and excrete sulfuric acid.

I know a place where the temperature is 15 million degrees, and the pressure would crush you to a microscopic dot. That place is the core of the Sun.

I know a place where the magnetic fields would rip you apart, atom by atom: the surface of a neutron star, a magnetar.

I know a place where life began billions of years ago. That place is here, the Earth.

I know these places because I’m a scientist.

Science is a way of finding things out. It’s a way of testing what’s real. It’s what Richard Feynman called "A way of not fooling ourselves."

No astrologer ever predicted the existence of Uranus, Neptune, or Pluto. No modern astrologer had a clue about Sedna, a ball of ice half the size of Pluto that orbits even farther out. No astrologer predicted the more than 150 planets now known to orbit other suns. But scientists did.

No psychic, despite their claims, has ever helped the police solve a crime. But forensic scientists have, all the time.

It wasn’t someone who practices homeopathy who found a cure for smallpox, or polio. Scientists did, medical scientists.

No creationist ever cracked the genetic code. Chemists did. Molecular
biologists did. They used physics. They used math. They used chemistry, biology, astronomy, engineering. They used science.

These are all the things you discovered doing your projects. All the things that brought you here today.

Computers? Cell phones? Rockets to Saturn, probes to the ocean floor, PSP, gamecubes, gameboys, X-boxes? All by scientists.

Those places I talked about before? You can get to know them too. You can experience the wonder of seeing them for the first time, the thrill of discovery, the incredible, visceral feeling of doing something no one has ever done before, seen things no one has seen before, know something no one else has ever known.

No crystal balls, no tarot cards, no horoscopes. Just you, your brain, and your ability to think.

Welcome to science. You’re gonna like it here.

Parasitizing caterpillar tricks ants into service

2009-03-03T03:01:00.000-08:00

A kind of European caterpillar can garner royal treatment from ants by mimicking the ch-ch-ch-ch of their queen, says an international research team.

Ants of the species Myrmica schencki can be fooled into carrying certain caterpillars into the colony nurseries where the fakers enjoy full care and five-star dining, explains Jeremy Thomas of the University of Oxford in England. An interloper caterpillar gains most of its body mass while luxuriating in ant care, and then turns into a Maculinea rebeli butterfly.

Chemical camouflage alone will let the caterpillars game their way into the ant colony. Now experiments show that the noises the caterpillars make get them the premium treatment, Thomas says. The rhythmic caterpillar purring has the effect of the queen ant’s noises, not those of a worker, Thomas and his colleagues report in the Feb. 6 Science.

It’s news that a queen sounds different from workers in an ant colony, Thomas says. Ants have such remarkable chemical messaging systems that their noises haven’t received much scientific attention.

“I haven’t been this excited about a paper in a long time,” says tropical butterfly ecologist Phil DeVries of the University of New Orleans. He made the first recordings of caterpillar calls, which he says occur only in groups that have some kind of relationship with ants.

M. rebeli caterpillars make a mini version of the brrrrrr of a woodcock or snipe, Thomas says. Recent work has suggested that caterpillar noises may come from repeated muscle spasms. And when caterpillars become enclosed pupae, they make noises by rubbing a scraper, or plectrum, on their abdomen against a patch of fine grooves called a file. “Actually they can wriggle their abdomen quite a bit,” Thomas says.

Adults of four of the 11 ant subfamilies also make noises by rubbing plectrum and file, Thomas says. “It’s rather like strumming a guitar.” In a quiet room of ants, he can just manage to hear “quite a scratchy sound,” he says.

Advances in miniature electronics made the new study possible. Specially built ant-scale microphones and speakers allowed researchers to record both queen and worker ants under normal conditions and then play back the noises and observe ant behavior.

To a human ear, queens and caterpillars don’t sound at all similar, Thomas warns. Yet ants perceive noises differently, picking up vibrations with sensors in the legs. “There is a debate about how well, if at all, they perceive airborne sounds,” he says.

Alternative mating tactics and female mimicry as post-copulatory mate-guarding behavior in the parasitic wasp Cotesia rubecula

2009-02-26T16:43:00.000-08:00

In species where there exists intense competition among males for females, we often see elaborate modification to what we would consider normal courtship to increase an individuals' chance of a successful copulation.

A peculiar example of this is seen in the solitary larval endoparasitoid of the cabbage white butterfly. The male parasite, Cotesia rubecula, displays post-copulatory female mimicry in the hopes of copulating with a desired female with whom he and another male are competing.

When the female is ready to mate, she exhibits a characteristic colulatory position by lowering her antenna (see graphic, Figure 2). This serves as a signal to males that she is ready to mate. If two males are present and competing for the same receptive female, it is not uncommon for "male one" to trick the other by assuming the same pre-colulatory pose. "Male two," confused and randy, may attempt to copulate with guised male one. Male one quickly unveils his identity by quickly scurrying over to the female and copulating with her, leaving a disapointed male two in his dust.

Though I have never observed this mating strategy among humans - and I can't say I think it would result in a sucessful copulation - it's a pretty clever behavior adaptation in a competitive intra-sexual environment.

Published in Animal Behavior

Flora and Fauna Photography

2009-02-23T11:29:00.001-08:00

Redpoll, originally uploaded by amplexus.

This picture was taken in sub-zero temperatures as the sun rose in Two Harbors, MN.

Sex Is Thirst-quenching For Female Beetles

2009-02-21T14:00:00.000-08:00

ScienceDaily (Aug. 29, 2007) — Female beetles mate to quench their thirst according to new research by a University of Exeter biologist. The males of some insect species, including certain types of beetles, moths and crickets, produce unusually large ejaculates, which in some cases can account for around 10% of their body weight. The study shows that dehydrated females can accept sexual invitations simply to get hold of the water in the seminal fluid.

Dr Martin Edvardsson, whose research is published in the journal Animal Behaviour (August 2007), studied the bruchid beetle Callosobruchus maculatus, a serious pest in warmer parts of the world. Some females were given unlimited access to water while others were not. All females were free to mate with males and the study found that thirsty females mated 40% more frequently than those with free access to water.
Female bruchid beetles can absorb the water in the seminal fluid through their reproductive tracts and need to mate less frequently the more water they take from each mating. This is to a male's advantage because the longer the female goes without mating with another male, the greater his chance of successful fertilization. By transferring a large amount of water with the sperm, a male can help ensure his sperm has more time to fertilize the eggs without having to compete with the sperm from future matings. Dr Martin Edvardsson of the University of Exeter says: 'The large ejaculates may have evolved because males can make it less beneficial for females to remate by providing them with a large amount of water.'

From morsels of food to less useful offerings like dried leaves or balls of silk, insects' nuptial gifts are thought to perform the role of enticing a female to mate or investing in the resulting offspring. However, this study shows that males can also prevent females from mating with other males by giving them a valuable nuptial gift. Dr Edvardsson says: 'This research offers an alternative theory on the function of 'nuptial gifts', which are an important part of insect courtship and mating.'

Dr Edvardsson argues that the trade-off between the costs and benefits of mating is essential to the mating behaviour of female bruchid beetles. The males have spines on their genitalia that puncture the females' reproductive tract as they mate. Because of the damage this causes, females must carefully trade off the costs and benefits of mating, and limit the number of times they mate depending on their need for water and sperm.

Because there are always costs as well as benefits associated with mating, similar trade-offs are likely to be important in many species where males provide their mates with material resources. 'The key thing' says Dr Edvardsson 'is that the resource provided by males is less beneficial to females the more of it they already have, like water or food for example.'

Though Dr Edvardsson believes these findings may be relevant to many other animal species, he does not think the study has any implications for our understanding of sexual behaviour in all other animals. He concludes: 'This is unlikely to occur in say, mammals and birds, because it is impossible for a male to give a female a gift that would fulfill her needs for food or water for such a long period of time. Also, while many female insects can store live sperm inside for long periods of time, females of these species need relatively fresh sperm to fertilize their eggs.

Thanks, sciencedaily!

The Loom Science Tattoo Emporium

2009-02-20T23:23:00.000-08:00

This is so adorable I can hardly take it.

The Loom Science Tattoo Emporium

When I find a passion that strongly wills me to ink myself, I aspire to be posted on that emporium, too.

Gay penguins steal eggs from straight couples

2009-02-20T14:14:00.001-08:00

The two penguins have started placing stones at the feet of parents before waddling away with their eggs, in a bid to hide their theft.

But the deception has been noticed by other penguins at the zoo, who have ostracised the gay couple from their group. Now keepers have decided to segregate the pair of three-year-old male birds to avoid disrupting the rest of the community during the hatching season.

A keeper at Polar Land in Harbin, north east China explained that the gay couple had the natural urge to become fathers, despite their sexuality.

"One of the responsibilities of being a male adult is looking after the eggs. Despite this being a biological impossibility for this couple, the natural desire is still there," a keeper told the Austrian Times newspaper.

"It's not discrimination. We have to fence them separately, otherwise the whole group will be disturbed during hatching time," he added.

There are numerous examples of homosexuality in the animal kingdom, but gay penguins have captured the public's attention more than any other species.

A German zoo provoked outrage from gay lobby groups after attempting to mate a group of gay male penguins with Swedish female birds who were flown in especially to seduce them. But the project was abandoned after the males refused to be "turned", showing no interest in their would-be mates.

In 2002 a couple of penguins at a New York zoo who had been together for eight years were "outed" when keepers noticed that they were both males.

Found in the Weird News

Richard Dawkins: Seven Wonders of the World (Parts 1-3)

2009-02-19T03:57:00.000-08:00

(Could I BE more excited for his presentation at Northrop March 4th?)
Part 1. The Spider's Web

I think not...

Part 2. The Bat's Ear
The Digital Code

Part 3. The Digital Code Cont.
The Parabolic Reflector
The Embryo
David Attenborough

Happy Birthday Darwin!!

2009-02-12T04:48:00.000-08:00

Jim Cotner created this brilliant masterpiece.

I've listed some science events happening in/around the month of February below.

Other events going on this month?

1. LIFE: A Journey Through Time
Thursday, February 12, 2009, 7 to 9 p.m.

Bell Museum Auditorium
The event will feature top University biologists using Lanting's photographs as a springboard to deliver a rapid-fire presentations relating their research on evolution to the images. From the big bang to the human genome, hear the newestI theories on how life evolved and enjoy the North American premiere of one the world's most celebrated photography exhibits.

Keith Olive

Mark Decker

Sehoya Cotner

Greg Laden

Mark Borrello

Lynn Fellman

2. Cafe Scientifique: A Romance with Spiders
Tuesday, February 17, 2009, 7 p.m.
Bryant-Lake Bowl

Spiders, one of the most important terrestrial predators on the planet, are primarily solitary, often cannibalistic, and always voracious. However, one percent of spiders are highly social, living in large groups characterized by tolerance and cooperation. Even in the most social spider species, individuals must balance the benefit of group living and the strong compulsion to eat irritating siblings. Linda Rayor, a senior lecturer and senior research associate who teaches spider biology and insect behavior at Cornell University, will discuss how she came to combine romance with spiders and aspects of their unusual sex and predatory lives.

3. The Purpose of Purpose: A Lecture by Richard Dawkins
Wednesday, March 4, 2009, 7:00pm
Northrop
(I just bought my tickets and I'm psyched! This fellow will surely be in your F1's textbooks)

Interesting new study

2009-02-11T09:41:00.000-08:00

"I'm a Neurosurgeon, and an Ignoramous"

2009-02-06T15:38:00.000-08:00

A Neurosurgeon, Not A Darwinist

This commentary in Forbes really made me cringe. People can wave around their PhDs in whatever subject they like, but it does not protect them from being completely ignorant in another.

"The fossil record shows sharp discontinuity between species, not the
gradual transitions that Darwinism inherently predicts. Darwin's theory offers
no coherent, evidence-based explanation for the evolution of even a single
molecular pathway from primordial components"

Oh, wow! Is the Tiktaalik, who shares anatomical features with both primitive fish and the first tetrapods, mean nothing to this neurosurgeon? Or the fact whales have floating pelvic bones that are remnants of their tetrapod ancestry? Or the transitional archaeopteryx bird-reptile?!Or the long list of others that is far from complete...?

Above: Tiktaalik roseae

Bottlenose dolphin shows off her butchering skills

2009-01-28T16:20:00.000-08:00

Considering they can't wield a knife or cleaver, dolphins make impressive butchers. Researchers in Australia recently observed a bottlenose performing a precise series of manoeuvres to kill, gut and bone a cuttlefish.

The six-step procedure gets rid of the invertebrate's unappetising ink and hard-to-swallow cuttlebone.

The procedure begins when the dolphin shoos a cuttlefish out of an algal forest into an open patch of the seabed. Next, she pins the cuttlefish down, ramming it into the ground. To rid the body of ink, she uses her snout to pick up the cuttlefish, and then shakes it several times until a black cloud streams out.

Let's walk through that again:

The dolphin begins the routine by shooing a cuttlefish out of hiding

She proceeds to pin it to the sand to kill it

Next, she nudges the invertebrate off the seafloor with her snout

To remove the cuttlefish's ink, which can slow digestion, the dolphin shakes it back and forth

Rubbing the inkless corpse against the sand breaks and releases its indigestible cuttlebone

The filleted cephalopod is now ready to eat!

Success!

Article from NewScientist

Oral sex gene helps male fish fake it

2009-01-28T16:13:00.000-08:00

Men may be intrigued to hear that researchers have pinpointed a gene that makes females suck up sperm through their mouths.

The gene was found in the cichlid fish, where the males have evolved a way to lure females close so that they can squirt sperm into their mouths.

As is the case in many fish species, the sight of a brightly coloured male somehow triggers females with ripe eggs to start releasing them. But in cichlids, there is a twist. Females hold their eggs in their mouths and incubate them there after fertilisation - a behaviour that is thought to have evolved to protect the eggs from predators.

As soon as a female has spawned her eggs, she collects them up in her mouth. Normally, sperm released into the water by a male nearby will then fertilise the eggs.

But males of certain cichlid species in east Africa have evolved a way to increase the odds that females take up their sperm. Oval yellow markings resembling the eggs are found on the anal or pelvic fins. When a female approaches the male, she thinks she sees an egg on its fin, so tries to vacuum it up in her mouth - and get a mouthful of sperm from the canny male in the process.

'Turned on'

Salzburger's team believes it has now identified the gene that makes this bizarre mating behaviour possible.

They suspected a gene called csf1ra - short for colony-stimulating factor 1 receptor a, was responsible - because they knew that zebrafish lacking this gene failed to produce a yellow pigment similar to the shade of the cichlid fin spots.

The researchers extracted DNA samples from 19 cichlid species - nine that had egg spots on their fins and 10 that did not. They found the species that had evolved most recently had a mutation in the csf1ra linked to the egg spots.

Salzburger says this shows that the dummy egg spots are a genetic trait that provides a selective advantage because they encourage females to participate in oral mating.

Thanks, NewScientist!

Golden Tortoise Beetle

2009-01-02T16:51:00.001-08:00

This Coleopteran is named the golden tortoise beetle because of the resemblance the "shelf" that skirts the outside of the wings and thorax bares to a tortoise. These critters are able to alter their vibrant color within a short time period, turning from brilliant gold to a dull, spotty reddish color. When disturbed, they become orange with black spots. Pretty ferocious.

Inter-taxonomic Romance

2008-12-29T05:19:00.000-08:00

"Lull" - Andrew Bird

Bernard meets Santa!

2008-12-16T05:17:00.000-08:00

Tiktaalik your Inner Fish

2008-12-13T07:11:00.000-08:00

Descent of the testicle

2008-12-11T03:52:00.000-08:00

This is an odd thing about mammalian testicles: they're often in a peculiar and very exposed place, bouncing about uncomfortably and dangerously, hanging out of the body in a scrotal sac. Other animals don't do anything so foolish; why mammals?

A couple of hypotheses have been proposed that might explain what advantage we derive from this peculiar arrangement.

The display hypothesis. Males are flaunting their strength and health and virility and ability to protect a delicate package. Some species do make a show of it; some baboons have bright blue scrota, for instance. Most do not, however, and the idea seems unlikely to explain why this trait is preserved in mammals with widely diverse mating strategies.
The cold storage hypothesis. It may not be so much the testis that is maintained at a cooler temperature outside the body core, but the epididymis. The epididymis is a storage organ for sperm. It may boost the longevity of the stored sperm if they are kept cool, maximizing the quantity of sperm that can be delivered. There are some good reasons that support this idea—some mammals do have internal testicles, but keep them organized so the epididymis is superficial—but personally, this hypothesis seems unlikely, and if it is sufficient to keep just the epididymis cool, it doesn't explain how the testicles ended up exposed in a bag.
The training hypothesis. This one seems a bit of a stretch to me: the idea is that the testicle and epididymis are like boot camp, a tough, difficult environment that will weed out the unfit and allow only the strong to go on. Cool temperatures, more variable temperature, restricted blood flow...all prepare the sperm for the hostile environment they will confront upon ejaculation. There are many untested assumptions in this hypothesis, and it seems particularly improbable in species that practice sperm competition that they would sacrifice quantity for hypothetical quality, or that they would need to do something as risky as descensus and scrotal exposure to create an unpleasant cellular environment.
The temperature hypothesis. The most likely explanation is that there is something in the function of the testis that is optimized for a lower temperature, and that the clumsy kludge that evolved to reduce that temperature was to let the organ hang out in the breeze. This seems reasonable, since fertility can be directly affected by temperature—a difference of a few degrees can be the difference between fecundity and sterility. The specific constraint in the process of sperm development that imposes this limitation hasn't been identified, however; one contributing factor (but definitely not the sole factor) may be that mutation rates increase with temperature, and the male germ line, which undergoes many more cell division than the female line, is much more sensitive to small changes in the mutation rate.

Werdelin and Nilsonne (1999) have taken a phylogenetic approach to examine this question. It may surprise some of you to learn that not all mammals have a scrotum. Many, like us people, have fully descended testicles contained in an external sac, the scrotum. Some have descended testicles, but no scrotum; the testicles are imbedded in the body wall. And some don't bother with that descensus nonsense at all, and keep their testicles high up in the dorsal body wall, near the kidneys, a condition called testicondy. If you'd asked me before I read this paper which animals have scrota and which do not, I wouldn't have had a clue (it really does seem like a rather personal thing, don't you think?), nor would I have had much of an idea of the distribution of scrota across the Mammalia. Werdelin and Nilsonne have peeked under the kilts, though, and summarized the distribution. Here is the abstract of the paper:

The adaptive significance of the scrotum and the evolution of the descent of the testicles and epididymis have been a focus of interest among biologists for a long time. In this paper we use three anatomical character states of the scrotum and descensus: (1) testicles descended and scrotal; (2) testicles descended but ascrotal; (3) testicles not descended (testicondy). These states are then mapped on an up to date phylogeny of the Mammalia. Three main points arise out of this mapping procedure: (1) the presence of a scrotum is either primitive in extant Mammalia or primitive within eutherian mammals except Insectivora; (2) evolution has generally proceeded from a scrotal condition to progressively more ascrotal; (3) loss of testicular descensus is less common in mammalian evolution than is loss of the scrotum. In the light of these findings we discuss some current hypotheses regarding the origin and evolution of the scrotum. We find that these are all incomplete in so far as it is not the presence of the scrotum in various mammal groups that requires explaining. Instead, it is the reverse process, why the scrotum has been lost in so many groups, that should be explained. We suggest that the scrotum may have evolved before the origin of mammals, in concert with the evolution of endothermy in the mammalian lineage, and that the scrotum has been lost in many groups because descensus in many respects is a costly process that will be lost in mammal lineages as soon as an alternative solution to the problem of the temperature sensitivity of spermatogenesis is available.

What they see in the phylogenetic distribution of scrota is that our common, ancestral proto-mammal had probably evolved a scrotum as a solution to its fertility requirements, and really, probably the best answer to why we have this odd scrotal arrangement is that that is the way great-great-greatⁿ-grandpa did it. It is the primitive condition, inherited from mammal-like reptiles of the Permian, and mammalian lineages have been independently ditching the idea as fast as they can...which isn't very fast. Here's one of their summary diagrams:

Results of mapping the three character states onto a phylogeny of the Mammalia. Testicle position unordered: red, testicond; gray, descended and ascrotal; black, descended, scrotal; blue, marsupial; white, equivocal.

The black bars are us, the species that let it all hang out. The most parsimonious explanation for their distribution, the one that requires the smallest number of novel adapations, is that they represent the ancestral condition. Some lineages, such as rhinos and tapirs and bats and whales (whales and seals, by the way, still keep their gonads cool by shunting blood vessels that pass through the skin back to the testicles—they essentially have water-cooled balls), still have descended testicles but don't have scrota; these are in gray. And the rare red lineages, elephants and manatees most prominently, have dispensed with the whole silly arrangement and keep their testicles safe and deep in the body cavity. (This is very useful knowledge to have if you ever get angry at an elephant and are tempted to kick him in the nads...don't bother. He'll just laugh at you.)

Here's the rough history of the mammalian testicle, in summary:

Studies of the origin of endothermy in mammals indicate that incipient endothermy may have evolved in mammalian ancestors as early as the middle Late Permian, at least 260 million years ago, which is some 40 million years before the origin of the Mammalia and 130 million years before the origin of crown group mammals, i.e. those for which we have here demonstrated that the scrotum may be primitive. A plausible, though at present untestable, scenario is that in the course of the evolution of mammalian endothermy, core body temperatures eventually reached levels at which spermatogenesis was disrupted. At this point, the testicles had to be cooled, and descensus into a scrotum was one way of achieving this result. However, because of the various costs of descensus the evolution of the male reproductive system of mammals since then has revolved around finding alternative solutions to the original cooling problem. This means that testicondy probably evolved only once among Eutherians, strengthening the conclusions herein.

Source: The evolution of the scrotum and testicular descent in mammals: a phylogenetic view.

Opinions from Pharyngula

Basic Male Tool Kit is Under Threat

2008-12-10T14:33:00.000-08:00

The male gender is in danger, with incalculable consequences for both humans and wildlife, startling scientific research from around the world reveals.

The research shows that a host of common chemicals is feminising males of every class of vertebrate animals, from fish to mammals, including people.

Backed by some of the world's leading scientists, who say that it "waves a red flag" for humanity and shows that evolution itself is being disrupted, the report comes out at a particularly sensitive time for ministers. On Wednesday, Britain will lead opposition to proposed new European controls on pesticides, many of which have been found to have "gender-bending" effects.
It also follows hard on the heels of new American research which shows that baby boys born to women exposed to widespread chemicals in pregnancy are born with smaller penises and feminised genitals.

"This research shows that the basic male tool kit is under threat," says Gwynne Lyons, a former government adviser on the health effects of chemicals, who wrote the report.
Wildlife and people have been exposed to more than 100,000 new chemicals in recent years, and the European Commission has admitted that 99 per cent of them are not adequately regulated. There is not even proper safety information on 85 per cent of them.
Many have been identified as "endocrine disrupters" – or gender-benders – because they interfere with hormones. These include phthalates, used in food wrapping, cosmetics and baby powders among other applications; flame retardants in furniture and electrical goods; PCBs, a now banned group of substances still widespread in food and the environment; and many pesticides.

The report – published by the charity CHEMTrust and drawing on more than 250 scientific studies from around the world – concentrates mainly on wildlife, identifying effects in species ranging from the polar bears of the Arctic to the eland of the South African plains, and from whales in the depths of the oceans to high-flying falcons and eagles.

It concludes: "Males of species from each of the main classes of vertebrate animals (including bony fish, amphibians, reptiles, birds and mammals) have been affected by chemicals in the environment.

"Feminisation of the males of numerous vertebrate species is now a widespread occurrence. All vertebrates have similar sex hormone receptors, which have been conserved in evolution. Therefore, observations in one species may serve to highlight pollution issues of concern for other vertebrates, including humans."

Fish, it says, are particularly affected by pollutants as they are immersed in them when they swim in contaminated water, taking them in not just in their food but through their gills and skin. They were among the first to show widespread gender-bending effects. Half the male fish in British lowland rivers have been found to be developing eggs in their testes; in some stretches all male roaches have been found to be changing sex in this way. Female hormones – largely from the contraceptive pills which pass unaltered through sewage treatment – are partly responsible, while more than three-quarters of sewage works have been found also to be discharging demasculinising man-made chemicals. Feminising effects have now been discovered in a host of freshwater fish species as far away as Japan and Benin, in Africa, and in sea fish in the North Sea, the Mediterranean, Osaka Bay in Japan and Puget Sound on the US west coast.
Research at the University of Florida earlier this year found that 40 per cent of the male cane toads – a species so indestructible that it has become a plague in Australia – had become hermaphrodites in a heavily farmed part of the state, with another 20 per cent undergoing lesser feminisation. A similar link between farming and sex changes in northern leopard frogs has been revealed by Canadian research, adding to suspicions that pesticides may be to blame.
Male alligators exposed to pesticides in Florida have suffered from lower testosterone and higher oestrogen levels, abnormal testes, smaller penises and reproductive failures. Male snapping turtles have been found with female characteristics in the same state and around the Great Lakes, where wildlife has been found to be contaminated with more than 400 different chemicals. Male herring gulls and peregrine falcons have produced the female protein used to make egg yolks, while bald eagles have had difficulty reproducing in areas highly contaminated with chemicals.

Scientists at Cardiff University have found that the brains of male starlings who ate worms contaminated by female hormones at a sewage works in south-west England were subtly changed so that they sang at greater length and with increased virtuosity.

Even more ominously for humanity, mammals have also been found to be widely affected.
Two-thirds of male Sitka black-tailed deer in Alaska have been found to have undescended testes and deformed antler growth, and roughly the same proportion of white-tailed deer in Montana were discovered to have genital abnormalities.

In South Africa, eland have been revealed to have damaged testicles while being contaminated by high levels of gender-bender chemicals, and striped mice from one polluted nature reserved were discovered to be producing no sperm at all.

At the other end of the world, hermaphrodite polar bears – with penises and vaginas – have been discovered and gender-benders have been found to reduce sperm counts and penis lengths in those that remained male. Many of the small, endangered populations of Florida panthers have been found to have abnormal sperm.

Other research has revealed otters from polluted areas with smaller testicles and mink exposed to PCBs with shorter penises. Beluga whales in Canada's St Lawrence estuary and killer whales off its north-west coast – two of the wildlife populations most contaminated by PCBs – are reproducing poorly, as are exposed porpoises, seals and dolphins.

Scientists warned yesterday that the mass of evidence added up to a grave warning for both wildlife and humans. Professor Charles Tyler, an expert on endocrine disrupters at the University of Exeter, says that the evidence in the report "set off alarm bells". Whole wildlife populations could be at risk, he said, because their gene pool would be reduced, making them less able to withstand disease and putting them at risk from hazards such as global warming.
Dr Pete Myers, chief scientist at Environmental Health Sciences, one of the world's foremost authorities on gender-bender chemicals, added: "We have thrown 100, 000 chemicals against a finely balanced hormone system, so it's not surprising that we are seeing some serious results. It is leading to the most rapid pace of evolution in the history of the world.

Professor Lou Gillette of Florida University, one of the most respected academics in the field, warned that the report waved "a large red flag" at humanity. He said: "If we are seeing problems in wildlife, we can be concerned that something similar is happening to a proportion of human males"

Indeed, new research at the University of Rochester in New York state shows that boys born to mothers with raised levels of phthalates were more likely to have smaller penises and undescended testicles. They also had a shorter distance between their anus and genitalia, a classic sign of feminisation. And a study at Rotterdam's Erasmus University showed that boys whose mothers had been exposed to PCBs grew up wanting to play with dolls and tea sets rather than with traditionally male toys.

Communities heavily polluted with gender-benders in Canada, Russia and Italy have given birth to twice as many girls than boys, which may offer a clue to the reason for a mysterious shift in sex ratios worldwide. Normally 106 boys are born for every 100 girls, but the ratio is slipping. It is calculated that 250,000 babies who would have been boys have been born as girls instead in the US and Japan alone.

And sperm counts are dropping precipitously. Studies in more than 20 countries have shown that they have dropped from 150 million per millilitre of sperm fluid to 60 million over 50 years. (Hamsters produce nearly three times as much, at 160 million.) Professor Nil Basu of Michigan University says that this adds up to "pretty compelling evidence for effects in humans".
But Britain has long sought to water down EU attempts to control gender-bender chemicals and has been leading opposition to a new regulation that would ban pesticides shown to have endocrine-disrupting effects. Almost all the other European countries back it, but ministers – backed by their counterparts from Ireland and Romania – are intent on continuing their resistance at a crucial meeting on Wednesday. They say the regulation would cause a collapse of agriculture in the UK, but environmentalists retort that this is nonsense because the regulation has get-out clauses that could be used by British farmers.

Sniped from The Independent

"An atheist before Darwin could have said...

2008-12-01T17:07:00.000-08:00

'I have no explanation for complex biological design. All I know is that God isn't a good explanation, so we must wait and hope that somebody comes up with a better one.' I can't help feeling that such a position, though logically sound, would have left one feeling pretty unsatisfied, and that although atheism might have been logically tenable before Darwin, Darwin made it possible to be an intellectually fulfilled atheist."

Richard Dawkins.

Weird sex: Giant squid do it deeper

2008-11-17T19:40:00.000-08:00

VIGO, Spain (25 Sep 2005) -- RESEARCH by marine scientists has shed startling new light on the secret sex life of the giant squid, one of the most mysterious monsters of the world's deepest oceans.

The breakthrough came after a recent spate of strandings on the Atlantic coast of Spain when five of the huge invertebrates - one of them 12 metres long - were washed ashore in a single week on beaches on the Bay of Biscay.

One of the two males washed ashore was found to have been accidentally inseminated - backing the findings of research in previous strandings.

And scientists now believe the males had either accidentally inseminated themselves during "violent" lovemaking sessions with females or been inseminated by other males after "bumping" into them in the dark depths of the ocean.

The new discovery is reported by a team of Spanish scientists at the Institute of Marine Research in Vigo in the latest edition of the monthly magazine of the International Council for the Exploration of the Seas.

The researchers state: "The giant squid, Architeuthis, is not only a cultural and media icon, but also a scientific enigma. Although it is among the largest living invertebrates ... most of our knowledge of its biology and ecology is still fragmented. So each time a giant squid is washed ashore or gets brought up in a fishing net, it provides a gold mine of information. A recent spate of strandings along the Spanish Atlantic coast has shed new light on their unique sexual behaviour in the ocean depths."

The report goes on: "Although mating has never been observed in giant squid, it is thought that what happens is that the male injects his sperm packages into the female's arms. The process is likely to be a fairly violent affair as the female is probably not that keen on being injected. This is a problem for the amorous male as females are normally a third bigger than they are.

"But males get round their inferior size by being endowed with a particularly long penis, which means they can inject the female without having to get too close to her chomping beak. The male's sexual organ is actually a bit like a high-pressure fire hose and is normally nearly as long as his body - excluding legs and head.

"But having such a big penis does have one drawback: it seems that co-ordinating eight legs, two feeding tentacles and a huge penis, whilst fending off an irate female, is a bit too much to ask, and one of the two males stranded on the Spanish coast had accidentally injected himself with sperm packages in the legs and body. And this does not seem to have been an isolated incident since two of the eight males that had stranded in the north-east Atlantic before had also accidentally inseminated themselves.

"It is also possible that the sperm packages had come from other males that they had 'bumped' into, in the dark depths of the ocean. However, the sperm packages ended up in the squid - it is just another part of the mysterious lives of these creatures of the deep sea."

Fewer than 600 specimens of giant squid have been recorded around the world since the 16th century, with the majority of landings and strandings in the north-east Atlantic and off the coasts of New Zealand and Australia. The giant squid can reach up to 18 metres in length and weigh up to 900kg.

The researchers state: "For many years the race has been on to try to film a giant squid going about its business in the ocean depths, and many marine scientists are vying to get the first video footage. So far all expeditions have been unsuccessful, but a new Spanish expedition is currently being planned and maybe this time we will be lucky."

Animal instincts

GIANT squid are not the only members of the natural world to display unusual sexual behaviour. In Australia, the male Yellow-footed Antechinus - a mouse-like marsupial - goes through such a frenzy of mating that they die of sexual stress. The female praying mantis often eats her partner during or after sex, while homosexual behaviour is also known in geese, ostriches, cichlid fish, rats and monkeys.

From CDNN

Embryo Development of a Frog

2008-10-28T18:20:00.000-07:00

Radial cleavage! Morula! Blastula! Gastrulation! The blastopore became the anus! Deuterostomy!

This video is amazing.

Thanks, A Blog Around the Clock!

Enhanced Partner Preference in a Promiscuous Species by Manipulating the Expression of a Single Gene

2008-09-17T16:17:00.000-07:00

(http://images.livescience.com/images/monogamous_Prairie_Vole_03_10.jpg)

A team of scientists observed the arginine vasopressin receptor 1a gene in prairie voles (Microtus ochrogaster) who are socially monogamous animals. This is a largely unique behavior among rodents. Prairie voles form long-lasting pair bonds and both parents partake in raising their young. It is thought that two hormones, oxytocin and vasopressin, are essential in the development of monogamy. The scientists observed a gene that regulates vasopressin output in the brain to see if, when transplanted into a close promiscuous relative species, the meadow voles (Microtus pennsylvanicus), it would have the same effect in forming pair bonds. The scientists genetically modified meadow voles by transferring the viral vector V1aR gene into test subjects’ forebrain. Additionally, they isolated adult males for 24 hours with a receptive female and sought to find out whether the males preferred to return to the female with whom he had spent the previous day. After male meadow voles were given the opportunity to access new partners, would they prefer to return to the old one? They measured this empirically by timing how long affected males huddled with the female with whom they had previously been isolated. They also hoped to show that by changing a single gene they would be able to provide “a potential molecular mechanism for the rapid evolution of complex social behaviour.”

They found that males possessing the V1aR gene would go back to the females with whom they were isolated for 24-hours and huddle. Males who hadn't been genetically modified were found uniformly distributed among females after the 24-hour isolation with one female.

Monogamy is a rarely observed phenomenon in mammals. Unlike birds that lay eggs, parental investment can just as easily come from the mother as it can from the father. Female mammals, on the other hand, tend to have long gestation periods followed by long lactation periods before they can mate again. From a male perspective, if the objective is to pass your genes on to as many offspring as possible, it seems maladaptive to stay with one female when there are many other females you could potentially inseminate.

If females are the limiting factor, from an evolutionary perspective mammals should be largely polygynous. Polygyny is a mating system where one male mates with many females. From a female perspective, it may be in her best interest to be polygynous because “loser” females, or those with unattractive genetic material, would be able to mate with high quality males. Polygyny may also ensure superior habitat and resources supplied by the male.

Promiscuity is another viable option for mammals. It may be in males’ and females’ best interest to be promiscuous like the meadow voles and let sperm competition and cryptic female choice determine which males are successful in providing the gamete for the female’s egg. Given the severity of the many negative aspects of monogamy- and the advantages of other mating systems - why do certain species still engage in this behavior?

Polygyny and promiscuity favor few “winner” males, and the many “loser” males do not mate at all. This is not an argument for group selection, but if a loser male can hook a female into mating with him, it is in his best interest to invest all of his time and resources into her and not attempt to sequester many females. From a female perspective, monogamy may be the best choice because it provides ensured support for the female and her offspring. Gestation and lactation are incredibly energy-consuming and difficult if pursued solitarily.

Olivia Judson wrote about this paper in her blog, The Wild Side, and concluded with "it does raise the tantalizing prospect that, one day, it might really be possible to concoct love potions or pills that would alter brain chemistry and enhance the odds of a man forming a strong attachment to his lover." A tantalizing prospect, indeed!

Lim, M. M., Wang, Z., Olazabal, D. E., Ren, X., Terwillinger, E. F., Young, L. J. 2004. Enhanced Partner Preference in a Promiscuous Species by Manipulating the Expression of a Single Gene. Nature: 429.

Why do Giraffes have such long...

2008-08-27T20:16:00.000-07:00

NECKS!?

Well, it appears to be for sexual selection. The standard story about why giraffes have evolved their incredibly long necks states that this trait has helped them in reaching to higher leaves. This story, however, is probably wrong. Observations of giraffes have shown that over 50 percent of the time, they feed with their necks horizontal and that during the food-scarce dry season, they feed in low bushes rather than in tall trees. The giraffes are obviously capable of feeding on higher leaves than other animals but this advantage doesn't seem to be sufficiently great to justify the costs of having such a long neck.

The giraffes' head is about 3 meters above the heart which makes it very difficult for the heart to pump blood to the brain. The giraffe has the highest blood pressure of all mammals and its heart weighs up to 10 kg. The largest giraffe on record was almost 6 meters tall and weighed about 2 tons. In spite of their size, the giraffe can run very fast, up to 60 km/h (aprox. 35 mph). Their heart seems to cope with such effort. Their front legs are 10 percent longer than the back legs which might also help them run.

Another reason why it is unlikely that the giraffe's neck has evolved due to feeding habits is that its closest relatives, although big, had short necks. The discovered fossils reveal large animals with long legs rather than long necks. The largest giraffe relative discovered insofar had legs almost twice as long than those of modern giraffes but a short neck. Other giraffe relatives have had impressive horns - while the giraffes have only two small horns. The giraffe evolved around 1 million year ago in the African savannah at the time when our ancestor Homo Erectus had already spread from Africa throughout Asia. The giraffe ancestor was significantly smaller in size and had a shorter neck than today's giraffes. So, what favored the growth of that incredible neck in a relatively short time?

One proposal is that the neck helped the giraffe spot predators from the distance, but most biologists reject this explanation as being much too ad hoc. Instead, the most widely accepted hypothesis is that the neck evolved under the pressure of sexual selection. Thus, the giraffe's neck is similar to the peacock's tail or to the moose's horns.

This explanation is in no way obvious, especially because the female giraffes also have long necks, while sexual selection usually favors such "wild" traits only in males. Nonetheless, observations of giraffes' behavior seem to support this view.

The first clue is quite direct: male giraffes, unlike female giraffes, use their necks to fight each other. Moreover, before an actual fight, they point their noses upwards as if they are trying to create the impression that their necks are higher. Researchers have discovered that this is indeed a sign of domination as some males run away from a dominant bull that does such a sign.

"An average male giraffe's neck weighs 90.72 kg. and can stretch 1.83 meters long. Giraffes fight over females by swinging their necks and heads like a medieval ball and chain. The longer and heavier the neck, the more momentum behind the often bone-shattering head slams," Kathy Wollard remarked.

A study in the 1980s by Pratt and Anderson had shown that the main criterion that determines the dominance among bulls is neck size. They classified the giraffes in three classes, A, B, C according to neck size and horns lengths and discovered that neck length is what counted. "The larger-necked A bulls were consistently dominant over B and C bulls, and they courted females significantly more often than B or C did. Ranking also appeared to be important in female mate choice: females allowed themselves to be urine tested (a test of their sexual receptiveness) by A bulls more often than B bulls, and they refused to be urine tested by C bulls in two-thirds of all encounters," wrote Robert Simmons and Lue Scheepers who first argued in favor of the sexual selection theory in the 1990s.

But why do female giraffes also have long necks? Simmons and Scheepers argued that the neck, unlike the tails or the horns, is a trait much too heavily integrated in the organism to be controlled only by a small number of genes. Therefore, the females necessarily inherit the same "neck genes" as the males.

There are however differences between males and females - exactly as one would expect from the theory of sexual selection. Female giraffes do have smaller necks than the males because their necks stop growing in their "adolescence", when they are around 6 years old. This probably happens because females have a gene that silences the neck-growing genes. The males' necks on the other hand grow constantly throughout their lives (giraffes live about 20 years). The largest males are about 53 percent heavier than the largest females.

The fact that the neck is a hindrance and has a large survival cost has been demonstrated by other studies, conducted since the late 1960s, which have shown that male giraffes were about twice as likely as females to be killed by a predator - mostly lions. This kind of difference, again, is a hallmark of sexual selection.

Finally, there is another interesting fact that can explain the long necks of female giraffes. The male giraffes are among the most homosexual mammals. Bruce Bagemihl has discovered that in some areas, 94% of mounting incidents were between two males. Males don't just fight with their necks - in one in 20 cases they engage in affectionate behavior. On the other hand, female giraffes engage in homosexual behavior only in one percent of the time. It thus seems that female giraffes have sexually selected males with longer and longer necks, but the males themselves find long necks sexy. So, in order to still get males, females also had to grow long necks.

Male Angolan giraffes neckingGranada Wild

Everyone is Narcissistic

2008-08-01T17:00:00.000-07:00

Here's Looking at Me, Kid

This article generated some question marks for me. I tend to see the world and observe human behavior from a evolutionary perspective, so the content of this article seemed obvious. Of course we are narcissists!

Within the spheres of ethics that exist in individuals, the very first is that of self-love. How are we to pass our genes on to subsequent generations (arguably the purpose of life) if we are more concerned about others? Does altruism exist in nature? Not likely. Most cases in which one could argue selflessness as a motive for an organism to act in the interest of another have been proved wrong. Ultimately, these "altruistic" behaviors benefit the seemingly thoughtful animal in the long run, as opposed to the alternative route that would appear to benefit it in the short-term.

An obvious example of misdiagnosed altruism can be found in male anubis baboons (Papio anubis) who may willingly assist other males in copulating with sexually receptive females. And does this really surprise you? I have heard countless laments from our own male species about a "friend," or one with whom he has formed an alliance, who exploits friendships only to bolster his own chances of mating with the opposite sex.

While the helper baboon appears to willingly eliminate his own chances of mating with the female of interest, the act is not necessarily altruistic. This mating strategy can subvert the normal age and size sexual dominance hierarchy. As males patiently scale the hierarchy, they heighten their own chances of mating successfully by using this behavior. The assumption is that the helper baboon will eventually become the helpee. By assisting another with whom he has formed an alliance, he will in the long run be rewarded with a better chance of mating successfully than had he not helped at all.

Male Anglerfish can be 'Clingy'

2008-05-08T10:55:00.000-07:00

Anglerfish, a deep sea fish named for the spiny appendage on its head that it uses as bait to "fish" its prey, has an unusual mating habit. As it spends its time in the bottom of the ocean, finding a mate is a problem - but the species solved this evolutionary challenge beautifully.

At first, scientists were perplexed because they’ve never caught a male anglerfish. Also, all female anglerfish have a lump on their body that looks like a parasite. Only later did scientists discover that the lump is the remain of the male fish.

The tiny male anglerfish are born without any digestive system, so once they hatch, they have to find a female quickly. When a male finds a female, he quickly bites her body and releases an enzyme that digests his skin and her body to fuse the two in an eternal embrace. The male then wastes away, becoming nothing but a lump on the female anglerfish’s body!

When the female is ready to spawn, her "male appendage" is there, ready to release sperms to fertilize her egg.

Taken from Journal of Ichthyological Research

Evolutionary Oddity: Lungless Frog Found on Island of Borneo

2008-04-21T10:51:00.000-07:00

The first recorded species of frog that breathes without lungs has been found in a clear, cold-water stream on the island of Borneo in Indonesia. The frog, named Barbourula kalimantanensis, gets all its oxygen through its skin.

Previously the only four-limbed creatures known to lack lungs were salamanders.

A species of earthwormlike, limbless amphibian called a caecilian is also lungless.

Tetrapods, or four-limbed creatures, that develop without lungs are rare evolutionary events, Bickford and colleagues write.

The researchers suggest lunglessness in B. kalimantanensis may be an adaptation to the higher oxygen content in fast-flowing, cold water.

"Cold water can hold more dissolved oxygen than warm water," Bickford explained.

The frog also has a low metabolic rate, which means it needs less oxygen.

What's more, the species is severely flat compared to other frogs, which increases the surface area of the skin.

"Along with the fact that having lungs makes you more likely to be swept away in a fast-flowing stream—because you would float—this [is] a very strong context for the evolution of loss of lungs," Bickford said.

(taken from google images)

(Article from National Geographic Website)

New Flat-Faced Fish Sighted Off Indonesia

2008-04-03T18:25:00.000-07:00

Divers have spotted a new type of fish off Ambon Island in Indonesian waters. The striped fish, which is about the size of a human fist, is believed to be an anglerfish because it crawls along the ground and into crevices using leglike pectoral fins. But unlike most anglerfish, this species does not have a "lure" dangling from its head to attract prey, so it probably represents a family of fish previously unknown to science, says Ted Pietsch, a professor of aquatic and fishery sciences at the University of Washington.

Three scuba divers first spotted and photographed one of the fish in late January. In search of international experts to identify the fish, they found Pietsch, who says the fish is unmistakably an anglerfish because of the leglike fins on its sides. Anglerfish are also known as frogfishes and toadfishes.

The fish's most unusual feature is its flat face. Most fish have eyes on either side of their head, and Pietsch says he has never seen a fish with two forward-facing eyes in his 40 years of studying fish.

The new fish appears to be fleshy with tough skin, because it is able to squeeze itself into very small cracks in coral reefs without getting scratched. That may be how it has escaped human attention for so long.

The divers who discovered the fish kept quiet about it for a while. But now that another adult, two juveniles, and a mass of eggs have been seen, the word is out.

(Article from PopularScience)

No Admission for Evolutionary Biologist at Creationist Film

2008-04-02T16:18:00.000-07:00

Two evolutionary biologists — P. Z. Myers of the University of Minnesota, Morris, and Richard Dawkins of Oxford — tried to go to the movies at the Mall of America in Minneapolis Thursday evening. Dr. Dawkins got in. Dr. Myers did not.

On those facts, everybody agrees. After that, things break down.

The movie the two scientists wanted to see was “Expelled,” whose online trailer asserts that people in academia who see evidence of supernatural intelligence in biological processes — an idea called “intelligent design” — have unfairly lost their jobs, been denied tenure or suffered other penalties as part of a scientific conspiracy to keep God out of the nation’s laboratories and classrooms.

Dr. Myers asserts that he was unfairly barred from the film, in which both he and Dr. Dawkins appear, and that Dr. Dawkins would have been, too, if people running the screening had realized who he was — a world leader in the field of evolutionary biology.

But Walt Ruloff, a partner in Premise Media, the film’s producer, said the screening was one of a series the producers have organized for the film, which opens April 18, in hopes of building favorable word-of-mouth among people likely to be sympathetic to its message. People like Dr. Myers and Dr. Dawkins would not have been invited, he said.

Mark Mathis, a producer of the film who attended the screening, said that “of course” he had recognized Dr. Dawkins, but allowed him to attend because “he has handled himself fairly honorably, he is a guest in our country and I had to presume he had flown a long way to see the film.”

Actually, Dr. Myers and Dr. Dawkins said in interviews that they had long planned to be in Minneapolis this week to attend a convention of atheists. Dr. Dawkins, an vocal critic of religion, is on the convention program.

And both had earlier complained that they originally agreed to appear in the movie — then called “Crossroads” — because producers told them it would be an examination of religion and science, not a defense of intelligent design, an ideological cousin of creationism. People who have seen the movie say it also suggests that there is a link between the theory of evolution and ideas like Nazism, something Dr. Dawkins called “a major outrage.”

In an interview, Dr. Myers said he registered himself and “guests” on a Web site for the film’s screening. A security guard pulled him out of the line but admitted his wife, daughter and guests — including Dr. Dawkins, who, Dr. Myers said, no one seemed to recognize. Dr. Dawkins, who like everyone was asked to present identification, said he offered his British passport, which lists him as Clinton Richard Dawkins.

Mr. Mathis said in an interview that he had confronted Dr. Dawkins in the question and answer period after the screening and that Dr. Dawkins withered. “These people who own the academic establishment and who have great friends in the media — they are not accustomed to having a level, open playing field,” Mr. Mathis said. “I watched a man who has been a large figure, an imposing figure, I watched this man shrink in front of my eyes.”

That is not how Dr. Dawkins recalls it. He said Mr. Mathis said “enemies” were attempting to interfere with the film.

“It is impossible to imagine what Mathis is afraid of,” Dr. Dawkins said. “It is impossible to credit such bungling and inept public relations.”

Eugenie Scott, director of the National Center for Science Education, a group that opposes the teaching of creationist ideas in public school classrooms, said in an interview that her organization was setting up a Web site to counter the arguments made in the film.

Dr. Scott said she and other supporters of the teaching of evolution have been having “a horselaugh” over the events as Dr. Myers recounted them, immediately, on his blog, Pharyngula.

She said it was “just tacky” that the producers barred Dr. Myers from the screening, but added, “I don’t think it’s inappropriate for us to have a good laugh at the creationists’ expense.”

Dr. Dawkins said the hoopla has been “a gift” to those who oppose creationism. “We could not ask for anything better,” he said.

This article was taken from The New York Times

Meyers responded to what he deemed a "hilarious" experience. Understandably!

"There is a rich, deep kind of irony that must be shared. I'm blogging this from the Apple store in the Mall of America, because I'm too amused to want to wait until I get back to my hotel room.

I went to attend a screening of the creationist propaganda movie, Expelled, a few minutes ago. Well, I tried … but I was Expelled! It was kind of weird — I was standing in line, hadn't even gotten to the point where I had to sign in and show ID, and a policeman pulled me out of line and told me I could not go in. I asked why, of course, and he said that a producer of the film had specifically instructed him that I was not to be allowed to attend. The officer also told me that if I tried to go in, I would be arrested. I assured him that I wasn't going to cause any trouble.

I went back to my family and talked with them for a while, and then the officer came back with a theater manager, and I was told that not only wasn't I allowed in, but I had to leave the premises immediately. Like right that instant.

I complied.

I'm still laughing though. You don't know how hilarious this is. Not only is it the extreme hypocrisy of being expelled from their Expelled movie, but there's another layer of amusement. Deep, belly laugh funny. Yeah, I'd be rolling around on the floor right now, if I weren't so dang dignified.

You see … well, have you ever heard of a sabot? It's a kind of sleeve or lightweight carrier used to surround a piece of munition fired from a gun. It isn't the actually load intended to strike the target, but may even be discarded as it leaves the barrel.

I'm a kind of sabot right now.

They singled me out and evicted me, but they didn't notice my guest. They let him go in escorted by my wife and daughter. I guess they didn't recognize him. My guest was …

Richard Dawkins.

He's in the theater right now, watching their movie.

Tell me, are you laughing as hard as I am?"

(Taken from his blog: Pharyngula)

The following is a trailer for the film:

Creationist Museum

2008-03-31T13:57:00.000-07:00

"The Bible speaks for itself at the Creation Museum. We’ve just paved the way to a greater understanding of the tenets of creation and redemption. Our exhibit halls are gilded with truth our gardens teem with the visible signs of life. We invite you to visit the Creation Museum. Your life may change forever."

This quote is taken from the website of the Creationist Museum.

The following is taken from our friend, Wikipedia:

"The Creation Museum is a 60,000 square foot museum in the United States designed to promote young Earth creationsim. The museum presents an account of the origins of the universe, life, mankind, and man's early history according to a literal reading of the book of Genesis. Its exhibits reject evolution and assert that the earth and all of its life forms were created in 6 days just 6000 years ago and that man and dinosaurs once coexisted. These views disagree with well in excess of 99% of the scientists in relevant fields. Also, the museum exhibits are at odds with the vast majority of scientists who accept that the Earth is approximately 4.5 billion years old, and that the dinosaurs became extinct 65.5 million years before human beings arose.The museum has generated criticism by the scientific community, several groups of educators, Christian groups opposed to young Earth creationism, and in the general press.

The museum, which is said to have cost $27 million, is privately-funded through donations and opened its doors to the public on May 28, 2007. Based on projections, the museum anticipated 250,000 paying visitors in its first year of operation.Total attendance at the museum surpassed 100,000 visitors on July 21, 2007 and 200,000 visitors on September 20, 2007. Visitor attendance also exceeded first year expectations only 5 months and 5 days after opening, with a total of 250,000 visitors on November 2, 2007."

The BBC covered the grand opening of this facility:

Complex Eye Evolution

2008-03-31T13:44:00.000-07:00

MORE AT ATHEISTNATION.NET

This is a video about the evolution of a complex eye structure. It explains how a group of light-sensitive cells could be favored in primitive animals and, over time, develop into the complex eye we now possess (though it pales in comparison to many other critters like raptors). Given millions of years, I think it's pretty feasible.

Maternal Qualities of Metopaulias depressus, a reddish-brown crab from the bromeliads of Jamaica

2008-03-24T17:54:00.000-07:00

"The magic of the microscope is not that it makes little creatures larger, but that it makes a large one smaller. We are too big for our world. The microscope takes us down from our proud and lonely immensity and makes us, for a time, fellow citizens with the great majority of living things. It lets us share with them the strange and beautiful world where a meter amounts to a mile and yesterday was years ago."
-From the book “Mites of Moths and Butterflies”

This is an animal I wouldn’t want to meet if I were tiny. Though they are small — a fully-grown adult has a shell just 2 centimeters (three quarters of an inch) across — they can see off a lizard that intrudes on their plant, and they can kill large centipedes, so they’d make mincemeat of little me.

All the same, I like them because they are unusual in two ways. First: their habitat. Most crabs live in the ocean or, if they’re really adventurous, in burrows they dig on a beach; a few live in (or near) streams and lakes. But M. depressus has evolved to exploit the bromeliad pools, and as far as anyone knows, they do so exclusively.

And here’s the other oddity: in this species, mothers look after their young.

Crabs aren’t famous for paying attention to their offspring. In most species, the female carries her eggs until they are ready to hatch, then releases the larvae into the ocean, where they fend for themselves. The numbers can be enormous — female blue crabs (Callinectes sapidus), for instance, can release two million larvae in one go. (After fertilizing all those eggs, the male needs 15 days to replenish his sperm supplies, poor fellow.)

M. depressus is different. The female lavishes attention on her young. She chooses her plant carefully — she prefers plants with larger volumes of water — and then prepares the pool that will be the nursery. She fishes out any dead leaves that may have fallen in, and drops them onto the ground. (If a sneaky experimenter puts leaves back in, she’ll remove them.) And she drops empty snail shells into the water, often after capturing and feasting on the owners.

These behaviors have two effects. Removing the leaves increases the amount of oxygen in the water; crab larvae need high levels of oxygen in order to breathe. The added snail shells increase the levels of calcium, a mineral without which baby crabs can’t make shells of their own. Unimproved pools can’t sustain baby crabs.

And the hard work doesn’t stop there. For several weeks, the mother feeds her young — perhaps as many as 90 of them (which sounds a lot — but is a lot less than two million) — on cockroaches and millipedes that she catches. And she protects them from being eaten by predators, especially hungry damselfly larvae.

Damselfly larvae generally live in streams, ponds, and lakes; but some have evolved to inhabit bromeliad pools. Among them: Diceratobasis macrogaster. Given a chance, one of these larvae will eat as many as five baby crabs a day. The mother crab does not give them that chance; but an orphaned brood will perish quickly.

Even more unusual, the young crabs don’t disperse immediately, but remain with mom; sometimes you’ll find a couple of generations living together. This is probably because small crabs are more vulnerable to attack as they search for plants of their own, and so it makes sense to grow up before leaving. But whatever the reason, living in family groups is the first evolutionary step towards complicated social arrangements, such as those common among termites and the ants, bees and wasps, but rare for other insects or crustaceans. Perhaps one day, if the evolutionary pressures are right, crabs might join the list of highly social creatures.

-Taken from Olivia Judson's Blog

The Eye of the Mantis Shrimp

2008-03-22T14:33:00.000-07:00

Mantis Shrimp: Photo by DNR

The mantis shrimp (which oddly is neither a mantis nor a shrimp, but a crustacean that resembles both) has arguably the most complicated visual system of any animal on Earth. Its compound eyes sit on independently moving stalks and can see colors ranging from ultra-violet to infra-red. Each eye is divided into three regions for tracking motion, forms, depth, and color. All of this, it is theorized, is done without the aid of its tiny brain. (It’s also got claws that can smash through glass, but that we’ll save for another article). Now add to this an entirely new kind of vision previously unknown: the mantis shrimp can see circular polarized light.

We humans can see the effects of linear polarized light when we put on polarized sunglasses and go out on a boat. Linear polarization is observed when transparent materials reflect light, so on a sunny day, the ocean’s surface will look glassy to us. Put on polarized sunglasses and the glare is eliminated. Circular polarization is a bit more complicated. It has to do with out-of-phase stereo imaging, which can best be explained by the effect you get when you put on 3-D glasses and watch a movie in 3-D. That’s circular polarization.

Why the mantis shrimp has the ability to, in effect, put on 3-D glasses is still a mystery. But Professor Justin Marshall (the researcher who discovered it), from the Queensland Brain Institute, surmises it has something to do with sex. Only the males are able to see this way, so his theory is it is some as of yet unknown communication for mating. "[We] humans only have three color channels," he said. "These little guys have 12, and can see both linear and circular polarized light—it is remarkable."

Peacock Mantis Shrimp

(Article by PopSci.com)

Sunflower Sea Star (Pycnopodia helianthoides)

2008-03-12T11:14:00.000-07:00

Sunflower sea stars are large predators of the sea floor, reaching arm spans of up to three feet. They are surprisingly fast, voracious hunters for clams, urchins, snails, abalone, sea cucumbers, and other sea stars. Adult sunflower sea stars can move at the astonishing speed of one meter per minute using 15,000 tube feet which line the undersides of their bodies.

The following video uses time-lapse photography to capture this beautiful animal in hot pursuit of lunch. Sea stars have two stomachs - one is used for digestion, and the other stomach can be extended outward to engulf and digest prey. The latter is highly specialized, and uses digestive enzymes to liquefy its prey before complete digestion. After protruding from the mouth, the stomach can be stretched so thin that it can fit into the thin opening of a mussel or clam shell! Once the stomach has entered the shell, the digestive enzymes liquefy the prey within its own shell. The liquids are fully digested when the stomach retracts back into the body of the sea star.

The Human Penis is a Bore

2008-03-05T11:54:00.000-08:00

In Kingdom Animalia, penises are for more than just sperm delivery. If females mate with a number of males, each subsequent suitor will sire a larger proportion of her children if his sperm are the ones that do the trick. A male who can stimulate his mate to take up more of his sperm, or who can somehow get rid of the sperm of his rivals, will spread more of his genes than less artful fellows. Thus, the first consequence of female promiscuity is that males are under greater pressure to outdo one another in all aspects of love. For this task, the penis is an important tool.

Bushbabies and many other primates have monstrous penises – many of them look like medieval torture instruments. They have spikes and knobs and bristles and are often twisted into weird and sinister shapes. By comparison, the human penis is dull, notable only for its girth.

Among primates as among insects, it is a rule of thumb that in species where females consort with one male at a time, penises are small and uninteresting. Take the gorilla – a huge guy with a little teeny weenie. A male gorilla can weigh 210kg (460lbs), but his penis is a measly 5cm (2in) long and entirely devoid of knobs and spikes. The Argentine lake duck puts him to shame. The duck is small, but his penis, which rivals that of the ostrich, is 20cm (8in) long – and it has spines. But then a male gorilla generally presides over a small group and does not often have to worry about other fellows’ sperm.

Damselflies, on the other hand, have evolved some of the fanciest penises around. A typical damselfly penis has a balloon – an inflatable bulb – and two horns at the tip, plus long bristles down the sides. In the black-winged damselfly, Calopteryx maculate, the male uses this device to scour sperm from inside a female before depositing his own. But in the related Calopteryx haemorrhoidalis asturica, he uses his penis as an instrument of persuasion: by stimulating her in the proper manner, he can induce her to eject sperm from previous lovers.

Meanwhile, the moth Olceclostera seraphica has genitals that resemble a musical instrument: the male rubs one part of his privates against another, producing vibrations with which to thrill his mate.

In contrast, among termites the female typically mates with only one male – and male termites have plain, unadorned genitalia that do not differ much from one species to the next.

Survival of the Loosest: the Myth of Monogamy

2008-03-05T11:45:00.000-08:00

Bar the doors and break out the chastity belts, boys, because girls of most species sleep around, and it's for their own good, if not yours.

For generations, biologists had assumed females to be naturally chaste, while males were renowned for their promiscuity. Even Charles Darwin, who invented the idea of sexual selection, didn't dare challenge the Victorian morals of his day. Man evolved from ape, fine. But an immodest and lustful Mother Nature? Heaven forbid!

Now, hundreds of studies and a spate of books are challenging that conventional wisdom. Females of many species, it turns out, have evolved strategies for passing on their genes that involve copulating with multiple males -- and recognition of that fact is literally changing our view of the birds and the bees.

"Natural selection, it seems, often smiles on strumpets," says evolutionary biologist Olivia Judson, author of "Dr. Tatiana's Sex Advice to All Creation," the most recent and entertaining book exploring the variety of female harlotry.

"As a rule, loose females have more and healthier children."

To be sure, biologists are examining these questions in the dispassionate light of scientific inquiry. In describing their theories, they prefer the more neutral term "polyandry," meaning many males, instead of "promiscuity." And they caution laypeople not to look to nature's own apparent infidelities for any justification of their own behavior.

The misbegotten idea that males evolved to make love and females to demur gained scientific currency in the late 1940s in fruit fly experiments by Angus Bateman, a British scientist who reached his erroneous conclusions in part because his experiments lasted only three or four days.

Had he run his experiments longer, he might have discovered that male black- bellied fruit flies secrete an anti-aphrodisiac in their semen that's relatively short lived. As soon as it runs out, females become interested in copulating again.

On the surface, the conventional view made sense. Sperm seemed to come cheap to males, while eggs were expensive to females, which have to invest the time to raise offspring. Scientists could not fathom any possible benefit of multiple partners of females, and they could come up with plenty of potential costs, such as sexually transmitted diseases.

BIRDS DO IT

Then came DNA paternity testing. In one species after another, it turned out that biologists were as cuckolded as the males they had been observing. The first and most extensive examples of polyandry were found among avian species, which was quite a shock to scientists because birds had appeared to be paragons of traditional family values.

"The way the male and female rush back and forth to their demanding brood of chicks seems like nature's model of good parenting," says Marlene Zuk, biology professor at UC Riverside and author of "Sexual Selections: What We Can and Can't Learn About Sex From Animals."

"Now, we find that they're actually in the same situation as millions of modern-day husbands and wives, eyeing a child warily and making uneasy jokes about the milkman," she says.

DNA testing in chicks of seemingly monogamous females showed a wide range of extra mates. In one study, for example, as much as 90 percent of the offspring of the brilliantly colored Australian fairy wren were from mates other than the presumed father.

Biologists have struggled to come up with broad theories for why females benefit from playing the field, but so far the reasons seem to vary widely according to species. A lot of complex theory boils down to this: A gal's got to do what's necessary to ensure the survival of her genes.

In some cases, females may get more help around the home. Among bronze- winged jacana, for example, harems of up to four males do all the child care, enabling a female to have four times as many broods. Male greater rheas, flightless South American birds that resemble ostriches, receive eggs from several females, incubate them and rear all the chicks, while females go off to mate and lay other clutches.

In other cases, females swap sex for food -- the more sex, the more food and the healthier their offspring.

Among green-veined white butterflies, for example, a virgin male ejaculates a sperm packet roughly 15 percent of his weight that also contains nutritious substances. Females that have sex with several virgins lay more and bigger eggs than those that do it with only one or with males that have lost their virginity and consequently make sperm packets only half the size of their virgin glory.

SURVIVAL OF THE LOOSEST

In other cases, promiscuity is simply a matter of survival. Male chimpanzees, for example, have been known to kill infants not their own. Frequent sex with several males -- in one 15-minute period, a female was observed having sex with eight males -- can heroically confuse paternity and act as insurance against harm to her offspring.

But while females are busy ensuring their genetic survival by sleeping around, males have not been idle. After all, female promiscuity puts the genes of males at risk. It's no good being Don Juan, seducing all the females in sight, if none of them uses your sperm, Judson says. So males have developed counterstrategies to ensure their genetic survival.

"This is perhaps the most significant discovery of the past two decades, that male and female attributes coevolve," writes Tim Birkhead, professor of behavioral ecology at the University of Sheffield in Britain and author of "Promiscuity: An Evolutionary History of Sperm Competition."

(From the San Francisco Chronicle)

Rule number one: Never get eaten during foreplay

2008-03-03T19:49:00.000-08:00

Dear Dr. Tatiana,

I'm a European praying mantis, and I've noticed I enjoy sex more if I bite my lovers' heads off first. It's because when I decapitate them they go into the most thrilling spasms. Somehow they seem less inhibited, more urgent - it's fabulous. Do you find this too?

I Like 'Em Headless in Lisbon

Males of your species are boring lovers. Beheading them works wonders: whereas a headless chicken rushes wildly about, a headless mantis thrashes in a sexual frenzy. Why can't he be that way when he's whole? Well, it's hard to have wild sex if you're trying to keep your head.

A male praying mantis is in danger during his approach and his departure, but while he's actually on your back-the position in which intact males have sex- you cannot attack him. However, you do not need him intact to have sex with him. If you rip his head off on the approach, his body will go into spasms that allow his genitalia to connect with yours. Unsurprisingly, though, he does not want to have his head removed. Put yourself in his place - you'd be trembling to the tips of your antennae.

(From Dr. Tatiana's Sex Advice to all Creation)

The Complex Eusocial System of the Naked Mole Rat

2008-03-01T11:12:00.000-08:00

Eusocial animals are an anomaly within Kindgom Animalia because an individual will put its energy towards helping another reproduce instead of placing that energy towards the perpetuation of its own genes. Within a colony of naked mole-rats, only one female will mate with her few chosen consorts, and the young from previous litters maintain and defend the colony and assist in rearing newborns. They essentially sacrifice their own opportunities to survive and reproduce for the good of other colony members.

The naked mole-rats are the only known mammal to display this odd behavior. We see eusocial systems in Class Insecta, Order Hymenoptera: bees, wasps, and ants. Why be eusocial? The reason is that by helping the queen reproduce offspring, it may contribute more to future generations of the species than actually reproducing themselves.

Is eusociality altruistic? Certainly not. Guidelines governing eusociality are as follows:

1. Reproductive division of labor

2. Overlap of generations

3. Cooperative care of young

Naked mole-rats’ native range is in Kenya, Ethiopia and Somalia. They are exclusively fossorial, or underground, rodents that eat primarily the succulent tubers that are formed by many of the plant species that grow in arid areas. They obtain all the water they need through their food- they do not drink! When a group of mole-rats finds a large tuber, which may be more than a foot in diameter, they generally bore through it, eating mainly the interior flesh while leaving the thin epidermis intact. This behavior may allow the plant to remain healthy for some time- even to continue growing- thereby providing a long-term food resource for the colony.

(They also regularly practice coprophagy, the reingestion of feces, which allows them to maximize their uptake of nutrients from their food.)

"When the rains come, the eusocial mole rats cooperate and teams of animals dig like the fury," said Dr. Paul W. Sherman, a behavioral ecologist and Cornell professor of neurobiology and behavior. "Together, they are more likely than a solitary mole rat to find a bonanza of tubers to sustain the colony until the next rain. Alone, individuals would starve in that environment. And with a 'super mom' to produce more helpers, individuals willingly give up personal reproduction for indirect reproduction through relatives."

This video feature this odd rodent: hairless, with sensory hairs on their nose and tail (which allows them to move deliberately backwards and forwards) . Their large incisor teeth sit outside their lips so they can gnaw comfortably through the toughest tuber. They are adorable. Enjoy!

The Zombie Snail

2008-02-26T19:23:00.000-08:00

“A shade-loving snail has been invaded by worms. These parasites take over the snail’s brain, and push into his tentacles, transforming them into swollen, colorful, pulsating targets…”

This parasite is apparently called Leucochloridium paradoxum.

There are many other “mind-controlling” parasites such as the Spinochordodes Tellinii which infect grasshoppers and forces them to drown themselves. The animal develops inside land-dwelling grasshoppers and crickets until the time comes for the worm to transform into an aquatic adult. Somehow mature hairworms brainwash their hosts into behaving in way they never usually would – causing them to seek out and plunge into water.

Once in the water the mature hairworms – which are three to four times longer that their hosts when extended – emerge and swim away to find a mate, leaving their host dead or dying in the water.

The Scotch-tape Test

2008-02-24T08:38:00.001-08:00

The adult worms live in the colons (large intestines) of human children and apparently feed on human fecal matter.

When adult male and female worms copulate, each female pinworm produces about 10,000 fertilized eggs. At night, the pregnant female migrates from the colon, out through the child's anus and onto the skin of the buttocks. There she violently expels all of her eggs and dies. Some of the eggs become airborne and land elsewhere in the child's room, but the great majority of the fertilized eggs stay on the skin of the child's buttocks. The eggs mature within six hours of being laid.

The adult worms and the eggs on the skin of the buttocks can cause intense itching in the child. When the sleeping child scratches, the eggs often get on the fingers and under the fingernails. If the child sucks his or her thumb or otherwise brings his or her hand to the mouth (perhaps while eating breakfast), the pinworm eggs are swallowed. They usually hatch within the small intestine and mature there. When they become adults, they move to the colon where they take up residence. The entire life cycle lasts four to six weeks.

NEJM -- Enterobius vermicularis -- Data Supplement - Video

How did sex begin?

2008-02-24T08:26:00.000-08:00

We've seen that sex is central to evolution, that it generates diversity, that despite the trouble it causes, it's something most of us can't live without, that abstinence almost always leads to extinction. But how did sex begin?

One idea is that gene exchange [among early microbes similar to our modern day bacteria] facilitated the repair of damaged DNA: an intact string of DNA received from a partner could perhaps be used to replace or repair genes that had been broken.

A second, more exotic idea is that sex was simply infectious. In other words, it arose because a segment of DNA promoted gene exchange in order to spread itself through the population. To use an analogy, it's as though the common cold caused humans to be promiscuous - an effect that would clearly enhance its transmission. One reason a modern bacterium will be moved to have sex is because it's become infected with a particular segment of DNA known as the F plasmid. An individual who's got the F plasmid is then driven to mate with an individual who hasn't, and so spreads the sex habit around.

Why do Males Exist? An Unanswered Question in Science

2008-02-24T08:21:00.000-08:00

Mysteries of the male

Why do males exist? If you look at any standard biology textbook,you will probably read that the point of having males as wellas females is to promote variation by the exchange of differentmutations, and hence to increase the chances of species survival.Unfortunately, most evolutionary biologists stopped believingin this explanation over 20 years ago. From a reproductive pointof view, no individual is interested in anything beyond donatinggenes to the next generation, while species survival happensmore or less at random, according to the whims of climate andgeology. You don't actually need sexes in order to mutate andproduce variation. In any case, most mutations have no effect,or mainly deleterious ones. John Maynard Smith talks of ‘thetwofold cost of males’. Firstly, it is incomprehensiblethat any female should want to chuck away half her genome. Secondly,the males of many species are useless at doing anything exceptsitting around, getting fat at the females’ expense, and—inthe words of Richard Dawkins—duffing up other males. Among some animals, such as elephant seals, the vast majoritydie as wasteful, disappointed virgins.

Given the cost of males, it is perhaps not surprising that thereare at least 40 species where the female kills the male duringor after sex. In the case of the praying mantis, she literallybites his head off as part of foreplay, and he carries on ina delighted reflex of posthumous orgasm. Females of other speciesare equally imaginative: male scale insects have been demotedto microscopic excrescences on their females’ legs, whilefemale angler fish carry their mates on their backs as tinydwarves. More pertinently, there are many effective ways ofreproducing apart from sex as we understand it. These includesimple division and gene exchange, which have served prokaryotesso well that they have produced the longest-enduring of allspecies on the planet, as well as comprising the greatest numberof species, and probably constituting most of the biomass aswell.

Among other organisms, alternative methods of reproduction includebudding, hermaphroditism and isogamy (i.e. two individuals,not distinguished as males and females, combining their genes).There are asexual variants among all sorts of creatures, includingjellyfish, dandelions, lichens and lizards. Of the creatureswho do reproduce sexually, some species have two sexes, butothers have three, or thirteen, or 10 000, if you are a fungus.Many species alternate between sexual and asexual reproduction,either on a regular basis or occasionally, as the circumstancesrequire. Bdelloid rotifers—tiny invertebrates who livein drains and puddles—went off sex about 80 million yearsago, and have cheerfully diversified into several hundred speciessince then, without regaining the inclination. Maynard Smithdescribed them an ‘an evolutionary scandal’.

The various current theories about why males evolved and stillremain in existence are nicely set out in Matt Ridley's book‘The Red Queen’. They are also covered in OliviaJudson's racy and wonderfully informative book ‘Dr Tatiana'sSex Advice to All Creation’. Different theories rejoicein names like Muller's ratchet, Kondrashov's hatchet, and theeponymous red queen of Ridley's book (named after the characterin Alice in Wonderland who perpetually runs without gettingvery far because the landscape moves with her). This last theoryseems to be the front runner at the moment. It is based on W.D.Hamilton's idea that sex is part of a continual race to outwitexternal pathogens. What is clear, however, is that the consensusthat existed on this topic from Darwin until the 1980s has totallybroken down. The purpose of males has instead become one ofthe biggest unanswered questions in science. My guess is thatwe will eventually come to understand fertilization by malesin a similar way to how we now understand the appearance ofancient autonomous organisms such as mitochondria or chloroplastsin the eukaryotic cell. In other words, we will see it as anevolutionary compromise poised half way between invasion andalliance, parasitism and symbiosis, or genetic rape and informedconsent. There is already much evidence to show how femalesresist the process physiologically (for example by strippingmale gametes of all extra-nuclear DNA) and how males try tocontrol reproduction against their females’ will (forexample, by killing off competitor sperm or genetic materialin the female genital tract, or alternatively killing the competitorsand their offspring directly).

If the status of males in evolutionary terms is an equivocalone, the consequences of sexual dimorphism are not reassuringfor males either. In a review of the evidence relating to humanmales, my colleague and mentor Sebastian Kraemer has set outthe scale of the problem. Throughout life, men are more vulnerablethan women on most measures. This starts with the biologicalfragility of the male foetus, leading to ‘a greater riskof death or damage from almost all the obstetric catastrophesthat can happen before birth’. If they survive these catastrophes,boys then have a far greater susceptibility to developmentaldisorders than girls. These are magnified in turn by our culturalassumptions about masculinity, and by our low expectations ofmales. The toxic interaction of biological and social ingredientsshows itself in far higher rates of suicide and deaths throughviolent crime. Males also do worse in (among other things) scholasticachievement, emotional literacy, alcoholism, substance abuse,circulatory disorders, diabetes, and of course in longevity.Kraemer looks at how male disadvantage is ‘wired in’from infancy and persists to the grave, but he suggests thatwe shouldn't necessarily conclude that maleness is a geneticdisorder. Instead, he argues, we should show more curiosityabout the reasons for boys and men being so vulnerable, andshould pay more attention to redressing this in child-rearingand in medicine.

It may be no coincidence that questions about the ‘raisond’etre’ for males, and concerns about their relativedeficiencies, should have arisen at this point in history; enoughof the relevant information behind them would probably havebeen available to an observer in Darwin's time. The recent appearanceof these scientific preoccupations may well be the consequenceof understandable male anxiety. In the last few generationsof our species, female control over fertility has developedat a rate so phenomenal that it may justify comparison withthe sudden emergence of male-female reproduction itself, arounda thousand million years ago. In evolutionary terms, it hastaken only the twinkling of an eye from the introduction ofthe vaginal diaphragm and the contraceptive pill in the middleof the last century, to the widespread use of frozen sperm andextracted eggs, and hence to the actualization of human oocytecloning. Within the span of just one lifetime, women have advancedthrough several enormous stages of biological liberation andhave reached the threshold of elective parthenogenesis.

Assuming that the minor technical problems of gene damage duringcloning can soon be overcome, and that legal constraints willin time be removed—assumptions that seem reasonable byany standard—it is possible that the women of our specieswill soon have the overall choice of doing with very few men,or with none at all. If, in the mean time, they can preventmales from destroying any environment in which to survive, theymight be forgiven if they choose to follow the path that hasalready been pioneered by the bdelloid rotifers. Attempts tounderstand maleness or to redress its difficulties will thenbecome entirely academic.

QJM: An International Journal of Medicine

Forsten's tortoise (Indotestudo forstenii)

2008-02-24T08:10:00.000-08:00

Forsten`s tortoise courtship

Really, really funny.

Hermaphroditic Penis Fencing

2008-02-24T07:56:00.000-08:00

We often think of animals hunting and fighting for food, but many flatworms appear to hunt and fight for mates. Each worm is hermaphroditic, containing both ovaries with eggs and testes with sperm. Some even have two penises and one or more genital pores for receiving a unique, two-tailed sperm delivered during copulation.

Using new camera technology, Marine Biologist Leslie Newman of Australia's Southern Cross University participated in filming the marine flatworm Pseudobiceros hancockanus engaging in some odd reproductive behavior -- referred to as penis fencing.

During penis fencing, each flatworm tries to pierce the skin of the other using one of its penises. The first to succeed becomes the de facto male, delivering its sperm into the other, the de facto female. For the flatworms, this contest is serious business. Mating is a fight because the worm that assumes the female role then must expend considerable energy caring for the developing eggs.

The Shape of Life . The First Hunter | PBS

(Article found at The Shape of Life)

Gay Penguins! Hide the Children!

2008-02-24T07:49:00.000-08:00

Remember the infamous gay penguin scare of 2006, when it was revealed that gay mating behavior among penguins was not at all unusual? It wasn't just the two male penguins at the Central Park Zoo taking care of an egg and acting as a family, it turned out that this sort of thing was commonly observed in penguin populations in captivity all over the world. Well a couple of authors wrote a children's book about it and people are trying to ban it from libraries all over the country.

The latest instance is in Loudon County, Virginia, where a parent is complaining and trying to get the book removed from an elementary school library, presumably on the theory that if their child happens to stumble upon the fact of the existence of gay penguins, they will turn out to be interior decorators or gym teachers.

"And Tango Makes Three" by Peter Parnell and Justin Richardson is based on the true story of two male penguins who took turns sitting on an orphaned egg at the Central Park Zoo. In the story, the penguins, Roy and Silo, start their family when the chick, Tango, is hatched.
A parent at Sugarland Elementary in Sterling filed a request with the school principal that the book be reviewed. The principal and several staff members deemed the book appropriate for general circulation.

The parent appealed the school's decision with the Loudoun County Public Schools administration. According to David Jones, the LCPS library media supervisor, a district-level committee was formed with teacher, parent, school librarian and administrative representatives who reviewed the book and offered a recommendation to Superintendent Edgar B. Hatrick III, who ultimately decided on the book's status.

Dr. Hatrick determined that "And Tango Makes Three" should be taken out of general circulation at the elementary level and placed in each school's professional library. Teachers may reference and share the book with students at their own discretion. Children and parents may not check the book out of the library.

The American Library Association says that this book is one of the most challenged books of the last couple years all over the country. All because there are people ridiculous enough to believe that if you even acknowledge the existence of gays, whether human or some other species, their kids will turn out to be gay. I love the smell of irrationality in the morning.

(Article found at Science Blogs)

(Roy and Silo, a now famous same-sex penguin couple who successfully raised a penguin chick, Tango)

Experimenting with a Four-headed Penis

2008-02-24T07:34:00.000-08:00

A new paper about the reproductive behaviour of the spiny anteater, to be published in the December issue of American Naturalist, makes for fascinating - if slightly disturbing - reading.

The spiny anteater (Tachyglossuss aculeatus) is a primitive mammal with an unusual four-headed penis. The animal is difficult to observe in the wild, and does not readily copulate when in captivity, so exactly how the male uses its penis was a mystery.

Stephen Johnston of the University of Queensland and his colleagues obtained a male spiny anteater which regularly produced erections when handled during public viewing sessions at a zoo, and had been "conditioned to develop an erection to the point where it would ejaculate." Johnston's team were therefore able to make the first observations of the animal's erection and ejaculatory mechanism.

They discovered that the anteater's ejaculatory mechanism is very strange - it is unique among mammals, and actually cloesly resembles the form of ejaculation observed in some reptile species. Further, they found that the anteater's sperm forms bundles which consist of up to 100 cells (above right).

The spiny anteater's penis is bilaterally symmetrical, and the glans is subdivided into four "rosettes", all of which remain displayed during the early stages of an erection. But as the erection continues, the two rosettes on one side become engorged with blood, and the two on the opposite side retract.

Because the two unused rosettes retract, the erection is symmetrical in appearance (right). The erect penis - which is one-quarter the anteater's body-length - is therefore fully compatible with the female, which has only two reproductive tracts.

Observation of consecutive ejaculations showed that the left and right sides of the penis are used alternately. But it remains whether or not ejaculation becomes restricted to one side of the penis during copulation; it is possible that sperm travels to the vas deferens on the unused side of the penis without being discharged.

When semen samples were examined using a scanning electron microscope, they were observed to contain bundles of up to 100 spermatozoa. This apparently increases the motility of the cells - although the precise velocities were not measured, large sperm bundles were found to swim more quickly than smaller bundles or individual cells.

Female anteaters sometimes copulate with up to 11 males in quick succession, so bundling may have evolved as a form of sperm competition. Alternatively, it could be a means of storing sperm within the female reproductive tract, or of preventing the cells on the inside of the bundle from maturing before fertilization can occur. A better understanding of sperm bundling should be possible now that the researchers have the ability to collect semen samples regularly.

This is the first time such ejaculatory behaviour has been described in a mammal. The ejaculation mechanism of the spiny anteater is reminiscent to that of the squamate reptiles (lizards and snakes), which have two alternately-used hemipenes that otherwise remain inverted inside the tail.

This study therefore supports the theory that monotremes (the mamalian order to which anteaters belong) have a close evolutionary relationship with reptiles. And further studies of the spiny anteater's reproductive behaviour may provide useful information about how all mammals evoloved.

(Article from Science Blog)

Did T.rex have a penis?

2008-02-24T06:20:00.000-08:00

Evolutionary biologist Olivia Judson is my hero. She is the author of “Dr. Tatiana’s Sex Advice to All Creation: The Definitive Guide to the Evolutionary Biology of Sex,” and also writes a blog for the New York Times. The following article is from her blog called "The Wild Side," and asks the burning question, "did dinos have penises?"

First, she describes why we have not yet answered this question based on good 'ol fossil evidence:

"The reason we don’t know whether T. rex had one is that the organ is generally too soft to leave a fossil trace. (There’s an exception to this: some mammals have a bone in their penis, the os penis or baculum. This can fossilize. Humans are unusual among primates in not having one; in case you’re wondering, it’s not clear whether the bone plays a role in maintaining erections.)"

To summarize the article: yes, she thinks they did. She bases her opinion on a few key evolutionary pieces of evidence. First, the two extant groups most closely related to dinosaurs are the crocodiles and birds.

Male crocs (of Class Reptilia) have a penis they keep tucked inside their cloacae. Unlike mammalian penises, that of the crocodile transports the sperm along an external groove, as opposed to through an internal tube.

The other group related to dinosaurs is the birds (of the violently disputed Class Aves). Birds can be divided into two main groups: those of the palaeognathous and those of the neognathous.

"The palaeos comprises the big flightless birds such as ostriches, emus, rheas, and cassowaries, as well as kiwis and an obscure (but flying) group of south American birds, the tinamous; the neos covers everything else. The palaeos have penises; like crocodiles, they keep them tucked into their cloacae. Again like crocodiles, the organ has an external groove for sperm. What’s more, the lineage leading to the other endowed birds, the ducks, geese, and swans, appears to have split off from that of the other neos relatively early."

All of this informations points to the conclusion that the ancestor of all birds in fact had a penis. At some point early in the evolution of neognathous birds, the penis was lost (and regained in many types of waterfowl in what probably was an independent event. Waterfowl often mate in the safety of the water, and a penis assists in steering the sperm and balance). So crocodiles have one, and ancestral birds probably did, and since the two groups have a very similar genital morphology - it may be safe to infer that T.rex probably had one too!

The Sex Lives of Birds

2008-02-24T06:07:00.000-08:00

Boy sees girl, girl sees boy. Boy and girl meet, date, and become a pair. They may eventually go on a honeymoon and raise a family.

As it is with people, birds also go through similar steps to ultimately produce offspring. Some species of birds remain together after copulation (sex), sharing in the incubation of the eggs, feeding and raising of the young birds, as well as staying together after the breeding season. Other types of birds are briefly attracted to each other only for the purposes of fertilizing the eggs, with the female incubating and rearing her family by herself.

During breeding season, it is usually the female birds who are wooed and courted by the males. These males have established their territories and work hard to attract a mate.

The male Mockingbird will sing his verses to all who can hear, sometimes into the night, advertising that he is certainly available as a husband. American Robins are another bird that will sing love songs to woo the females.

Male Peacocks strut about, fanning their gorgeous multicolored tail feathers. As gorgeous as peacocks are, the male Bird of Paradise is even more spectacular! They grow long iridescent tails that look as though they would impede his flight. When a female comes closer to hear his song better, he will clutch his perch tightly and hang upside down so his prospective mate can better see his tail.

The male Bowerbird builds his lady a room of sticks and leaves, furnishing it with objects that he feels a female will love, such as a pretty stone, flower petals, shells, pods, and other love items.

During breeding season, the male Magnificent Frigatebird's throat turns bright red. When a female comes near, he puffs it up, showing her his very sexy throat which she may find very alluring!

The Great Egret grows long wispy feathers that he fans and displays to any female who saunters by. Male hummingbirds perform swooping aerial dances for the females watching. Northern Harrier males will perform dances in the sky consisting of huge U-shaped swoops.

The male Prairie Chickens meet in a clearing, called a lek, where they raise the feathers on their neck and head to resemble ears, fan their tails, drop their wings to the ground and parade around. They fill air sacs located on either side of their head, then force out the air, producing booming love songs, while they strut around for the ladies' benefit and approval.

Once a female bird has shown that she is interested, the male may do a bit of courting to further entice her.

Just as a human male may take his girlfriend out to dinner, quite a few male birds, including the Northern Cardinals and Blue Jays, feed tender morsels of food to their ladies. Sometimes the females will assume a fledgling begging posture while being fed. Other birds, such as the Roadrunner, may bring food to the female just before mating. Species of birds that feed their girlfriends usually are the guys who stick around to help feed and raise the young chicks.

After dinner, what about going dancing?? Whooping Cranes and Sandhill Crane pairs perform dances together, bowing, jumping, turning and perhaps even presenting a twig to the other. Other pairs of cranes may join in this contagious and joyful dance. Roseate Spoonbills may grasp each other's bill in an amorous clench. And don't forget the Western Grebes who dance across the water, side-by-side, with their wings outstretched.

Pairs of Red-winged Blackbirds fly through the air together, with the male singing, raising his red epaulet feathers, and chasing the female in this courtship ritual. He may even grasp her rump and cause both to crash to the ground, hopefully unhurt, all in the name of love.

Many species of birds, once bonded as a pair, will perch close together, preen each other, and rarely leave each other's side. Ah, love is in the air!

The Honeymoon

Mr. Bird has found his season's love, and she loves him back. What causes these birds to form these bonds in the spring and summer, not when it is cold and snowy, nor while they are migrating?

Hormones from the pituitary gland are the answer. During breeding season in response to the hormones, the male's testes become several hundred times larger than normal to produce sperm, with the left testis usually larger. The female bird's ovaries also enlarge during breeding season to produce the ovum. Female birds usually only have one functional ovary, the left one.

In birds, an ovum is fertilized in the female bird's oviduct by a sperm cell from the male bird. Once fertilized, the ovum becomes the nucleus of the egg. The egg, that has its own food source, the yolk, will be laid by the female into her nest, incubated, and then the baby bird will hatch.

But how does the sperm from the male bird get into the female? How can they have intercourse without any external male organs, such as a penis? The male's sperm, produced in the testes, passes to the cloaca where it is stored until copulation (act of sex). The female also has a cloaca that leads from the ovaries. The female bird unfans her tail, moves it to one side while the male climbs up onto her back or gets close to her. Their cloacas are pressed together and the sperm moves from the male to the female. This act is called a cloacal kiss.

The sperm is stored by the female for at least a week, in some species over a hundred days. Then as each ovum from the ovary moves into the oviduct, it gets fertilized with the stored sperm, producing a clutch of many eggs, all with the sperm from that one cloacal kiss.

There are a few species of birds where the males do possess a retractable penis that can be pulled back into the bird. These birds include ostriches, cassowaries, kiwis, swans, geese, and ducks. Since waterfowl sometimes make love while in the lake or pond, the penis helps ensure that the sperm is not washed away by the water.

Sperm can be transferred from male cloaca to the female in a blink of an eye - less than a second. Some birds seem to want to linger longer though, sometimes having sex for more than an hour! And, although it is not necessary to copulate frequently since the sperm is stored within the female, remember those hormones are still making the birds excited. Many pairs of birds will mate numerous times within a few days.

Mating Variations

Most of the birds you see in your backyard are monogamous, at least for that breeding season. The cardinals, the jays, the robins stay together as a pair, helping with the nest building, the feeding of the young and perhaps even with the incubation of the eggs.

Some birds enjoy having more than one spouse. Polygyny is when a male bird has multiple wives, such as the Northern Harrier and the Eastern Meadowlark. It occurs in species where there is abundant food (male does not need to help the female feed the young.) Polyandry is when the female has multiple husbands, such as the Spotted Sandpiper who may have four husbands. And then there is is polygynandry where both the female and male have multiple spouses.

The Red-winged Blackbird male has an avian harem with up to 15 females in his territory. These females find that nesting close to each other helps deter predators as long there is a sufficient food supply for all of them.

Although two birds may be paired together for the season and may have already produced a clutch of eggs, either spouse could have wandering eyes and commit adultery. Tree Swallows, the Red-winged Blackbird females, some woodpeckers, some buntings, and even Baltimore Orioles are only a few species that have extra-martial flings now and then.

Some males just entice a female for sex, then leave to find another female to mate. In these cases, the female builds the nest, incubates the eggs, and raises the chicks by herself. Species of birds that follow this pattern include the hummingbirds. However, to feed hungry young birds and defend them from predators it usually takes both parents. Therefore, most birds work with their spouse to ensure that the greatest number of their chicks survive.

Hummingbirds usually allow no other hummer within their territory. They will chase off all other hummers, male or female, who try to feed at "their" flowers or feeders. However, female hummingbirds have been observed being allowed to feed within a male's territory before or after having sex with him.

And then there are the Galapagos Hawks who live in threesomes, one female with two attentive males. She mates with both, although one at a time, and both help her with raising the young hawks. Harris' Hawks threesomes have one male with two females. These threesomes find that life is easier and the chick survival rate higher with three parents.

Divorce and Death

Troubles do arise occasionally in bird pairings, and divorce is not unheard of.

A frustrated pair of birds who are unable to produce any eggs, may "divorce" and go in search of new mates, hoping that with their new lover, a nest full of healthy babies can be raised.

Most birds remain with the same mate throughout the breeding season, although they might have a few extra-marital flings.

Some birds such as raptors, swans and geese, live their entire lives with the same spouse. These birds remain together for years, both migrating back to the same territory each year. Even in species that don't migrate, staying with the same spouse, year after year can be beneficial. The territory is familiar and sources of food are known. Each bird knows the other's habits as well they know their mating will produce offspring.

Once a spouse dies or fails to return to the territory, the remaining spouse will eventually attempt to find a new mate. It is an old wives' tale that the remaining spouse will die of a broken heart.

(Article found at About.com:Birding/Wild Birds)

Zoological Curiosities.

2008-02-24T05:59:00.000-08:00

There are just too many fun facts floating around Kingdom Animalia. This blog's purpose is to act as a electronic cavity in which I may pool my findings.

Enjoy.