Thermal pulse induced escape behavior. (A) Thermal avoidance response. An infrared (IR) laser with a beam width larger than the worm body (1/e = 1.5 mm) heats the entire worm. The worm typically will response with a reversal (red), perform an omega turn (green), and then move forward (blue). (B) Temperature increase versus laser current. The maximum temperature increase caused by a 0.5 s laser pulse at various currents was measured using a thermal camera.