Olfactory perception of live hosts and carbon dioxide by the tsetse fly Glossina morsitans orientalis Vanderplank

Abstract

Laboratory investigations of olfactory perception in the tsetse fly Glossina morsitans orientalis Vanderplank, were carried out by measuring the modulation of the spontaneous rate of activity by sudden olfactory stimulation. Marked responses were obtained to emanations from guinea-pig, chick, crocodile and the human hand and forearm. Emanations from human skin despite the absence of expired carbon dioxide induced a strong response compared to the other host types. The stimulus was removed by rinsing the skin with acetone solvent. Air passed over material impregnated with human sweat and odour was ineffective. Responses to guinea-pig odour and guinea-pig expired air were approximately equal. Carbon dioxide was the important factor in expired air. The quantitative relationship between stimulus and response was non-linear, responses increasing with approximately exponential increases in stimulus intensity. The existence of an airborne sexual stimulus could not be demonstrated.