D: How did so many fruit flies get in here, Yaël?

Y: Where there’s a will, there’s a way.

D: Do fruit flies have wills? They definitely don’t have any manners, flying inside when I make it pretty clear they’re uninvited guests.

Y: Maybe not manners, but they do have culture, Don—or cultural traditions, which are socially learned behaviors that animals pass down across generations. A team of researchers wondered if we could observe the kinds of cultural traditions we’ve seen in some apes, whales, and birds in much smaller animals, like insects.

The researchers set up an experiment where observer female fruit flies observed demonstrator female fruit flies choose between artificially colored pink or green males. When the observers later chose mates of their own, over seventy percent of the time they chose a mate that was the same color picked by the demonstrator they’d watched. That showed that fruit flies transmit mating preferences amongst themselves. Next, scientists wanted to test whether the fruit flies would pass this preference down to subsequent generations, so they had the fruit flies that had been the observers become the demonstrators in a new trial for a number of rounds. The mating preferences— picking either a green or a pink mate— were passed down for eight generations before a generation of fruit flies started selecting mates randomly again. The groups of flies were small, but by using computer simulations, scientists found that when a group of flies was over thirty per generation, the cultural traditions could, in principle, be passed down for thousands of generations.

D: I wish staying outdoors could be one of their traditions. Maybe someone can teach them to pass down that.