If you like to take the cynical view on things, all lifeforms are just squishy machines programmed to do basically one thing: get it on and make new little lifeforms. Evolution has given various lifeforms a whole host of crazy body parts, characteristics and behaviors to make sure that that happens. Guppies maybe take the cake, though - females can hold onto males' sperm inside their bodies for months to ensure a genetically diverse brood, and by the time some of those little fishes' are born, their fathers might be long dead.
At its most posthumously successful, stored ghost sperm sired about one in four of the offspring among wild guppies released into a stream, evolutionary biologist Andrés López-Sepulcre of École Normale Supérieure in Paris and his colleagues report June 5 in Proceedings of the Royal Society B.
Biologists have long known that female Poecilia reticulata guppies store sperm. The cells clump in little pockets in a female’s ovarian cavity and feed on sugars released by ovarian tissue. Storage in itself isn’t unusual, López-Sepulcre says. Some crabs, turtles, lizards, bats and other creatures preserve sperm for later use.
Posthumous reproduction by stored sperm also isn’t unheard of. “The fun part of our study,” López-Sepulcre says, “is that you have males who are alive and males who are dead competing with each other.” [ScienceNews]