Are female behaviours just variants of those in males? Apparently not

A recent discovery in Amanda Moehring’s lab in the Department of Biology, at Western University, may be giving scientific credence to the old saying that “men are from Mars and women are from Venus.” By hyperactivating a cluster of nine brain cells, the group has managed to elicit entirely different responses between males and females, showing fundamental differences between the sexes in brain development. “The neurons that we’ve been able to hyperactivate, cause females to become really aggressive,” tells Moehring. Interestingly, hyperactivating those same nine nerve cells in the male brain induces them to courtship, rather than aggression – showing a significant difference between males and females when it comes to the way their brains respond.

The Moehring group focuses on mapping nerve cells; their connections help determine behavioural traits like aggression. Not only does the new evidence suggest a major divergence in brain development between the sexes, it also upsets long-standing assumptions of certain female behaviours being a subset of variants present in males. Instead, female behaviours, even though they look similar to male behaviours, can be developed entirely separately, changing the way we approach studying female behaviour, all the way down to the genetic level.

Video Transcript: Female fruit flies aggressively interact and move around an enclosed area.

The Moehring group’s next steps are to better characterize the brain circuitry which forms female aggression, including which chemical compounds are involved. “If the same nerve connections hold sway over both male mating behaviour and female aggression, there are a lot of new research areas to explore in the female brain that we never thought of before,” explains Moehring. These findings also open new avenues to understanding how female and male traits have evolved and diverged.