Everybody knows that males tend to be more aggressive than females.  But why is that the case?



In a recent New York Times article, a study on fly aggression by neuroscientists from the California Institute of Technology revealed that male flies, just like humans, tend to be more aggressive than female flies.  And their findings may provide an insight as to why male humans are more aggressive than female humans.

Doctor David J. Anderson set up a fight club for flies and found out that a tiny cluster of neurons only found in the brain of male fruit flies control aggression.  These neurons, active only when the males were fighting each other, released tachykinin, a neuropeptide linked to aggression                                                                                                                                                                                 .

Humans have a different kind of tachykinin, called substance P, which is associated with inflammatory processes and pain.

The few neurons that caused an increase in aggression in the flies were only found in males.  They found that the levels of aggression in flies is directly associated with the amount of tachyninin produced by the neurons.  From these studies, it appears that humans and flies have more in common than we think.  And the flies can teach us about the neurology of own aggression.