Thursday, February 26, 2009

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

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

Monday, February 23, 2009

Flora and Fauna Photography

Redpoll, originally uploaded by amplexus.

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

Saturday, February 21, 2009

Sex Is Thirst-quenching For Female Beetles

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!

Friday, February 20, 2009

The Loom Science Tattoo Emporium

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

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

Thursday, February 19, 2009

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

(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

Thursday, February 12, 2009

Happy Birthday Darwin!!

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
(I just bought my tickets and I'm psyched! This fellow will surely be in your F1's textbooks)

Wednesday, February 11, 2009

Friday, February 6, 2009

"I'm a Neurosurgeon, and an Ignoramous"

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