The ability of Rhodnius prolixus (Hemiptera; Reduviidae) to approach a thermal source solely by its infrared radiation

The ability of the haematophagous bug Rhodnius prolixus to approach a pure IR source only by its long-wave infrared radiation (IR) was investigated. T o exclude any heated air from reaching the bug a cooled IR-transmitting win dow was placed between the IR-source (a Peltierelement heated to 35 degrees C) and the bug. Starved bugs were tested under invisible short-wave IR ill umination (lambda<1 mu m) in order to exclude also any visual cues. The num ber of bugs approaching the IR-source was significantly increased compared to the controls in which the IR-source was turned off (chi(2)-test, P<0.01) . Our results show that Rhodnius prolixus can use infrared stimuli to find a host. (C) 2000 Elsevier Science Ltd. All rights reserved.