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Tuesday, December 1, 2009

Fruit Fly Sperm Makes Females Do Housework

Don’t tell men about this…..
Fruit flies have a sleep/wake pattern similar to humans. They forage for fruits and vegetable during the day, and sleep at night. Their most active times are dawn and dusk. In the hottest hours of the afternoon, they take what has been likened to a ‘siesta’.
A team lead by Elwyn Isaac from the University of Leeds has discovered that after mating, females spent 70% less time resting during the day. Presumably, the extra hours were used to search out proper egg-laying sites and to gain fuel for egg-laying. The surprising thing was that this change in behavior was brought about by a chemical in the male’s sperm. This ‘sex peptide’ is made by the fly’s equivalent of the prostate gland and attaches to the sperm’s tail. When this particular peptide was removed, the females resumed their afternoon napping.
In addition to making female flies work harder, this same peptide has previously been shown to drastically increase egg production (from 1or 2 per day to up to a hundred), and discourage the female from mating with other males. In other words, by mating with her, the male turns the female into his personal baby-making zombie.
Or maybe she feels it’s worth giving up her siesta to find the perfect rotting banana for her little ones.
Photo of Drosophila melanogaster by André Karwath