Figure 1. Gait optimization in an insect model.

(a) A ventral view of a D. melanogaster female. Each leg is labelled as belonging to the right (R) or left (L) side and the prothoracic (1), mesothoracic (2) or metathoracic (3) leg pair. Scale bar, 0.4 mm. (b) A ventral view of the in silico insect model used in this study. A vector of five numbers encodes a single gait: each number represents a leg's phase of motion relative to the left front leg whose phase is fixed at 0°. Scale bar, 0.4 mm. (c) A side view of the insect model in its in silico environment. (d) The classic tripod gait has two power strokes per locomotor cycle. During each power stroke three legs are on the surface (stance phase, black circles), whereas the other three legs are off the surface (swing phase, grey circles). Grey arrowheads point in the direction of motion. (e) An idealized gait diagram of stance (black) and swing (white) phases for each leg during two cycles of tripod locomotion. The phase of motion for each leg is indicated. Each power stroke is numbered.