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Gene fools female cichlid fish into sucking up male sperm

Researchers in Switzerland and Canada have pinpointed a gene that makes females suck up sperm through their mouths.

Lucky you, there's even a video of the discovery:

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 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.

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 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.

The scientists believe they have identified the gene that makes this bizarre mating behaviour possible.

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