Check out this article about this recent study on aggression in fruit flies that seems to demonstrate what strutures in the brain of male fruit flies contribute to their greater aggression than females AND the gene (which codes for a brain chemical) that seems to control this aggressive behavior.
It is some top-notch research. Of course it is also a bit eerie to the extent that flies maty be models for mammalian (and human behavior). Why say this? Because the reporter James Gorman (and I'm sure the resaerhcers as well) point out this gene is also found in humans, reaising the question as to whether one might be able to "tweak the gene" or brain chemistry, and thus tweak the behavior.
Of course there are very important medical reasons to do this, but also some potentially oversimplifying conclusions one might try to draw. After all, does this gene then simply "do the same thing" in humans in such simplistic a fashion? That is what reporter James Gorman seems to imply in the video which seems sloppy and overstepping of what this experiment can tell us about human behavior. Some dee questions here. Either way, some real nice scientific work.
The VIDEO is a fascinating synopsis of the behavior as well as fruit fly brain scans that show the nuerons in question!