Human parents who force alcohol down their children's throats will find themselves in jail, but a new study shows that among fruit flies and other fly species, liquoring up the kids is just good parenting.
Biologists at Emory University studied the reproductive behavior of fruit flies in the presence of parasitoid wasps. These wasp species lay their eggs in fruit fly larvae, effectively using the young fruit flies as incubators.
The biologists divided fruit flies into two separate cages: one containing a parasitoid wasp, the other without. Both cages contained two petri dishes of food, one with a 6 percent alcohol content and the other alcohol free. The results were unambiguous; in the cage with the wasp, fruit flies laid their eggs in the dish containing the alcohol 90 percent of the time, whereas in the other cage only 40 percent of the eggs were laid in the alcohol containing dish.
Fruit flies have adapted to tolerate highly alcoholic environments, while the wasps that prey on them have not. Fruit fly larvae that hatch in more alcoholic environments are essentially medicated against the was larvae, as the wasp young cannot tolerate the high alcohol content inside the fruit fly larvae's body.
Other interesting results from this study reveal that fruit flies identify wasps by sight, showing that flies' compound eyes impart sharper vision than previously thought. These were lab bred fruit flies, who had never been exposed to the parasitoid wasps before.
Finally, the sight of female wasps induce a stress response in fruit flies, which causes them to seek out alcohol. That's right; when stressed, fruit flies turn to booze. Who would have thought flies would act so, well, human?