Kinematic and biomechanical analyses in Drosophila suggests that most legged locomotion in insects can be understood within a single framework.

Abstract

Despite the fact that all insects have six legs, they display considerable differences in their legged locomotion. Are these differences irreconcilable, or simply different domains of the same system? In this study, we investigate walking in Drosophila. We find that despite the fact that flies walk extremely slowly relative to their size, they predominantly employ an alternating tripod gait, a gait typically associated with high-speed locomotion. The kinematics of their center of mass (CoM) is diametrically opposite to the CoM kinematics observed in insect runners such as cockroach. We resolve this tension between similar gaits, and differing kinematics in slow and high-speed locomotion by showing that the mechanics of a tripod gait naturally reduces to a simple biomechanical model which can support a range of kinematic patterns including both fly-like and cockroach-like patterns. These findings suggest that legged locomotion in different insects might represent different domains of the same system.