Female Fruit Flies Charm the Pants Off Otherwise Hostile Males

Recent research published in the journal Nature Neuroscience indicates that male fruit flies that spend time with female fruit flies are less aggressive with other males. Like, the male fruit fly can be a total sweetheart when it’s just him and the female, but—like—sometimes he acts totally different when he’s around his bros. It’s like the male fruit fly can’t even be himself around his friends, you know?

Researchers at the University of California San Francisco collected a number of virgin male fruit flies in a Virgin Male Fruit Fly “Bachelor Pad” (the next hit show on TLC) for nearly a week, and then introduced half of them to female flies.

Male fruit flies that had spent time with females were far less aggressive than their counterparts who 1) had no interactions with the females and 2) were still virgins. The calming effect also happened whether the male (regardless of V-card status) and female flies actually mated or just hung out for a few days. On top of that if a female fly was taken away right after mating, the male was just as aggressive. This baffled researchers who believed this “calming down effect” was mating-related, when really it was about contact.

It turns out that male flies pick up on a certain pheromone that is on the body of female flies. The region of the brain that corresponds with these pheromones contains neurons “responsible for dampening aggression.” The study gave new insight into how a certain neurotransmitter (GABA) is involved in aggression, previously thought unrelated in humans. So this could potentially help researchers more fully understand human aggression. As researcher and UCSF professor Yuh Nung Jan explains, “This is really an entry point to study how aggression can be modulated.”