Why Do Fruit Flies Love Beer?

Fruit flies love beer!

Actually, they love yeast aromas. That's why I sometimes find drowned fruit flies in my fermenter airlocks.

The fruit flies are attracted to the almost fruity aroma of yeast. Bioengineer Kevin Verstrepen published a paper in Cell Reports. In it, he demonstrated that if he turned off the yeast gene that produces the fruit smell, more fruit flies are attracted to the fruitier smelling yeast. They eat the yeast, and the yeast sticks to their legs. When the flies leave, they spread the yeast to other environments. After all, yeast don't have legs.