Interacting Gears Synchronize Propulsive Leg Movements in a Jumping Insect

Abstract

Joint Action Many small insects are impressive jumpers, but large leaps and small bodies pose biomechanical challenges. Burrows and Sutton (p. 1254 ) show that the nymphal planthopper Issus has interlocking gears on their hindleg trochanters that act together to cock the legs synchronously before triggering forward jumps. At the final molt, the gears are swapped for a high-performance friction-based mechanism because the risk of breaking a gear is high, the options for repair during molting are gone, and, moreover, the animal is bigger and stronger.