Figure 2

Swarm structure in single-sex male and female swarms. The superimposition of 2700 images from one of the cameras, clearly shows a gross difference in swarm structure. Male swarms (left panel) are stable and have a roughly cylindrical form, while non-participating males remain stationary on the cage walls. In contrast, female swarms (right panel) comprise two distinct zones, a dense, relatively ordered aggregation near the ground marker, and a second zone, at some distance from the ground marker, characterized by much more disordered female motion.