Insect behaviour: migratory bands give crickets protection.

Mormon crickets and juvenile locusts form huge migratory bands--millions of individuals march in unison across the landscape and devastate vast agricultural areas, but little is known about why these bands form. Here we use radiotelemetry to show that band membership benefits these insects by greatly reducing the probability that they will become victims of predators. It is likely that migratory banding has evolved because it gives substantial protection to individuals within the group.