The latest Deep Look video explores a curious experiment using fruit flies. In the lab, neuroscientist Eric Hoopfer makes fruit flies fight. The flies have been genetically altered to respond to red light. A zap from the light makes the pair of males aggressive, and they go to battle.

What's odd is that by changing the intensity of the light, Hoopfer gets very different results from the flies. With increased light intensity, they begin courtship behavior. Hoopfer is studying this phenomenon, with an eye toward better understanding how human brains work at the neuron level.

Come for the incredibly closeup video of fruit flies...stay for the science! (Note: This video is presented in 4K Ultra HD, so it looks great in fullscreen mode.)

For more (or if video isn't your thing), check out this KQED article.