Behavior with blocked and unblocked IR organs.

The IR organs of 3 beetles which clearly had responded to strong IR radiation were covered with Tipp-Ex and aluminum foil. No reactions could be discovered (black traces, threshold criterion not reached). After removal of the covering beetles were tested again and responded to IR radiation as before (red traces, threshold criterion reached). n = 6 stimulus applications per body side. In all beetles significant differences exist between the means of the angles (calculated according to the second evaluation process, t-test, p ≤ 0.05). (A) Responses of beetle 4. No significant difference in strength of response was measured compared to the earlier results shown in Fig 4 (t-test, p > 0.05). (B) Responses of beetle 15 (not included in Fig 4). (C) Responses of beetle 8. No significant difference in strength of response was measured compared to the earlier results shown in Fig 4 (t-test, p > 0.05). Bar indicates exposure to IR radiation.