When fruit flies hover in your kitchen, you may think, as the name suggests, that they're simply attracted to fruit.
It's not exactly fruit that the tiny flies crave. That hovering cloud of party-goers is actually after the yeasts that produce alcohol in old, fermenting fruit, as well as the alcohol itself.
That's right, fruit flies hold their liquor better than just about any other member of the animal kingdom. What makes the little critters such professional tipplers? Ethanol, the kind of alcohol that makes you woozy, is toxic to most living creatures. Many animals are able to produce tiny amounts of an enzyme that helps convert toxic ethanol into compounds they can use for energy. However, fruit flies produce a whole lot of this enzyme, which can be found throughout their bodies and even in their eggs. In one study, fruit flies lived happily on alcohol fumes as their only source of food!
Fruit flies' penchant for alcohol makes them particularly pesky wherever fruit ferments, including in wineries and tomato processing plants. Although their favorite food is the yeasts that produce alcohol, they're easy to please and will gobble up bacteria and fungi in a pinch.