Another cool article from Science Daily. Kind of a long article, but very interesting! It is about a fruit fly study showing that adult fruit flies can anticipate a parasite infection and lay their eggs in an alcohol-soaked environment to give their young a better chance of survival. Fruit fly larvae eat the rot that grows on overripe, fermenting fruit. The larvae have developed the ability to withstand reasonably high levels of alcohol toxicity. Parasitic wasps are major killers of fruit fly larvae. The female wasps deposit their eggs and some venom into the fly larvae. If the flies cannot fight off the infection, the wasps larvae will mature and eat their way out of the fly larvae. The researchers discovered that when wasps are present and flies are given the choice of an alcoholic or non-alcoholic environment, 90% of the time the flies lay their eggs in the alcoholic environment. If no wasps are present, the likelihood drops to 40%. The idea is that since the flies can tolerate higher levels of alcohol than the wasp larvae, the alcohol can be used as a “medicine” and improve the chances of the fly larvae surviving if infected.
The other surprising facts from these studies was that fruit flies can distinguish between male and female wasps and do so by sight. It was previously hypothesized that the flies were using smell rather than sight to determine the gender of the wasps. Another neat thing is that the flies who exhibited this “alcoholism” had never seen a wasp before. The flies used in this study had gone through hundreds of generations without being exposed to a wasp, yet the females still registered a threat at the sight of wasps! The article goes into a few other aspects of related research, like how this behavior is also seen in other species of flies or what neuropeptides are correlated to this behavior. I recommend reading the whole thing and not just my summary! Researchers believe that flies are not the only animals to exhibit this “medication” behavior, and think it could apply to other animals as well. I think it is cool that insects we find as a nuisance can have such well evolved behaviors. Maybe I’ll appreciate them more? Additionally, I like that flies are still model organisms. With how many science articles are out there about fruit flies, I would’ve thought we would almost be out of things to research on them!