Kinematics of jumping in leafhopper insects (Hemiptera, Auchenorrhyncha,Cicadellidae)

Abstract

SUMMARYThe jumping movements and performance of leafhopper insects (Hemiptera,Auchenorrhyncha, Cicadellidae) were analysed from high-speed sequences of images captured at rates up to 5000 frames s–1. The propulsion for a jump was delivered by rapid and synchronous movements of the hind legs that are twice the length of the other legs, almost as long as the body, and represent 3.8% of the body mass. The wings were not moved before take-off, but the jump frequently launched a flight. The front and middle legs set the attitude of the body in preparation for a jump but were usually raised from the ground before take-off. The movements of the hind legs occurred in three distinct phases. First, a levation phase of 15–30 ms, in which both hind legs were moved forward and medially so that they were positioned directly beneath the body with their tibio-tarsal joints pressed against each other. Second, a holding phase lasting 10–200 ms, in which the hind legs remained stationary in the fully levated position. Third, a rapid jump phase,in which both hind legs were simultaneously depressed about their coxo-trochanteral joints and extended at their femoro-tibial joints. This phase lasted 5–6 ms on average, with the fastest movements accomplished in 2.75 ms and involving rotations of the coxo-trochanteral joints of 44 000 deg. s–1. In the best jumps by Aphrodes, a peak take-off velocity of 2.9 m s–1 was achieved by an acceleration of 1055 m s–2, equivalent to 108 times gravity. This jumping performance required an energy output of 77 μJ, a power output of 28 mW and exerted a force of 19 mN, or 100 times its body mass.