Modelling jumping in Locusta migratoria and the influence of substrate roughness

Locusts are widely recognized for their jumping performances. Jumping allows locusts to avoid predators and initiate flight. In this study, jumping performances of Locusta migratoria were modelled with a lumped-parameter theoretical model. Results showed that L. migratoria can reach a maximum take-off velocity of 1.83 m/s and maximum acceleration of 66.72 m/s2, with take-off angle of about 36°. While carrying out such a high performance, locusts are prone to slip when taking off from a smooth ground, especially for locusts with only one hind leg. Experiments have been therefore conducted to test the influence of ground roughness on jumping performance. There was no significant relation between ground roughness and jumping success, and this was due to combined action of rigid claws and adhesive pads ensuring static contact between tarsus and ground. It was noted that large take-off angles might help locusts to jump successfully with only one hind leg left, as well as to achieve better performance on smooth surfaces. The excellent contact ability on surfaces with different roughness gives meaningful insights for jumping robot design.