Mormon crickets aren't crickets but rather katydids, their close relatives. (They're not Mormon, either.) While scientists have generally attributed their swarming mass migrations to food shortages, there's a darker side of that hunger that keeps these insects on the march: If one stops marching, the others will devour it, as seen here.

Starving Mormon crickets need protein and salt, and it turns out that other Mormon crickets are great sources of both.