because pris so la breed very rapidly and are cheap to maintain you can screen through essentially a haystack of many mutant strains which has a higher level of aggression than normal flies have. dro so la. and the next shows an example of a hyper aggressive fly strain. so this is the genetic equivalent of the hess experiment where these flies have been made hyper aggressive by a manipulation of their genes and this promises in the future some insight into how genes control aggression. but i also think it's important not to assume that environment doesn't affect aglegs the spez species just because genes do. in fact, environment affects aggression in fruit flies almost as much as genes. so you can show that if you socially isolate flies. you just let one fly grow up from its pew pa in a vial and then test its aggressiveness, those isolated flies are more aggressive than flies housed in groups. and this is also true throughout the animal kingdom. >> rose: so if you're isolated you're going to be more aggressive? >> you're going to be more aggressive. >> rose: i knew that. (laughter) >> i'd like to show you a video of what's cutting edge in robotics just to give you a feel of how cl