Submitted to: Nature
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/23/2004
Publication Date: 2/17/2005
Citation: Sword, G.A., Lorch, P.D., Gwynne, D.T., 2005. Migratory bands give crickets protection. Nature. 433(7027):703 Interpretive Summary: Massive outbreaks of locusts and Mormon crickets are currently afflicting people in North America, Africa, Asia, and Australia. A common characteristic of these insects is that they form huge groups called migratory bands that can contain millions of insects all traveling together in the same direction. Using Mormon crickets tagged with tiny radiotransmitters, scientists recently discovered that individuals in migratory bands are much less likely to be eaten by predators than those that are not in bands. These findings suggest that migratory bands, which can be devastating when they enter agricultural fields, have evolved as a defense against insect predators.
Technical Abstract: Locusts and Mormon crickets can be devastating agricultural pests that form huge migratory bands with millions of individuals moving in unison, but little is known about why these bands form. Anti-predator benefits such as early detection, predator confusion, and dilution of risk (selfish herd effect) have been proposed to account for the evolution and maintenance of group living in animals. Although predation has been discounted as an explanation for migratory band formation, our results reveal that migratory band membership does, in fact, confer major benefits by greatly reducing predation on individuals.