Science!: Hammerheads, Fly Sex and Evolution

Lauren Admire | 30 Nov 2009 17:00

Female Flies Do Chores After Sex

After a quick round of raunchy fly sex, the female fruit fly doesn't want to cuddle, and she doesn't want to sleep. No, the only thing this chica wants to do is some fly chores. And it's not because she wants to, it's because there's a special enzyme in the male fruit fly's sperm that compels her to do so.

Professor Elwyn Isaac from the University of Leeds made this discovery after comparing the sleeping patterns of virgin fruit flies and mated female flies. Typically, flies forage around rotting food at dawn and dusk. They then take a nice afternoon nap and catch a deep sleep a night. However, mated females ditched the siesta and spent their post-copulation time foraging in rotting food for suitable places to lay eggs. "Our research findings suggest that this change is not by choice." says Isaac. "Females who mated with males that produced sperm without the sex peptide continued to take their siesta. So we're certain that this change of behavior is chemically induced by the male."

The sex peptide is attached to the end of the sperm's tail and also encourages the female to lay 100 eggs a day, as compared to the 1-2 eggs laid by a virgin female. Although preventing the female from taking her afternoon nap increases her chances of being eaten for lunch, it also increases the chances that the male will have successful paternity. Talk about marital compromises.

Source: Science Daily

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