What drives the relentless march of Mormon crickets across the landscape is both a craving for food and a reluctance to be cannibalized, says an international research team.
The swarms loom large in the lore of the American West, but scientists hadn't worked out the dynamics of what keeps the insects on the move, says Stephen Simpson of the University of Sydney in Australia. He and his colleagues now report that swarming Mormon crickets are deficient in protein and salt. They march over the countryside in quest of the missing nutrients, but the laggards provide excellent dining for their fellow crickets. Simpson and his colleagues propose in the March 14 Proceedings of the National Academy of Sciences that hunger and danger co