Wednesday, January 28, 2009

Bottlenose dolphin shows off her butchering skills

Rubbing the inkless corpse against the sand breaks and releases its indigestible cuttlebone. The filleted cephalopod is now ready to eat (Image: Julian Finn et al)

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 hidingThe dolphin begins the routine by shooing a cuttlefish out of hiding (Image: Julian Finn et al)

She proceeds to pin it to the sand to kill it
She proceeds to pin it to the sand to kill it (Image: Julian Finn et al)

Next, she nudges the invertebrate off the seafloor with her snout
Next, she nudges the invertebrate off the seafloor with her snout (Image: Julian Finn et al)
To remove the cuttlefish's ink, which can slow digestion, the dolphin shakes it back and forth
To remove the cuttlefish's ink, which can slow digestion, the dolphin shakes it back and forth (Image: Julian Finn et al)

Rubbing the inkless corpse against the sand breaks and releases its indigestible cuttlebone
Rubbing the inkless corpse against the sand breaks and releases its indigestible cuttlebone (Image: Julian Finn et al)

The filleted cephalopod is now ready to eat!
The filleted cephalopod is now ready to eat (Image: Julian Finn et al)






Success!


Article from NewScientist

Oral sex gene helps male fish fake it





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!

Friday, January 2, 2009

Golden Tortoise Beetle


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.