Response of beetle No. 1 to strong IR radiation.

Change of direction caused by IR radiation extracted from 10 s video files. After the beetle had flown in zero direction for 3 seconds, the heated IR emitter was swiveled towards the beetle (black bar indicates onset and duration of the stimulus). Mean values (solid line) and standard deviations (stippled lines) of angles of flight direction are shown for 6 exposures to IR radiation from left or right, respectively. If IR radiation was applied from left, beetles turned right (positive angles, red line), if radiation was applied from right, beetle turned left (negative angles, green line). Beetle icons show IR irradiation and the resulting rotation of the beetles.