The scientists report hunger for protein and salt, and a fear of cannibalism, drives the mass migration of Mormon crickets in western North America.
Throughout their seasonal migration, millions of Mormon crickets (relatives of locusts and grasshoppers) cover more than 50 miles of ground, destroying farmland and causing hazardous driving conditions along the way.
The research team, led by Dr. Stephen J. Simpson, conducted field observations and experimentation to determine that two driving forces are behind the migration: a need for protein and a fear of cannibalism.
Their results reveal a different model for collective motion, with the crickets' migration in effect a forced march. The constant threat of cannibalism from the rear appears to push the crickets' movement as much as the need to find protein and salt pulls it, researchers say.
The team's findings could lead to more environmentally friendly tactics for controlling large swarms of insects.