Sensory Mechanisms of Host Recognition and the Action of Repellents in the Bed Bug Cimex lectularius and the Mosquito Aedes aegypti

Abstract

Mosquitos and bed bugs use blood of humans and other species as a source of nutrition. When searching for hosts, both insects express a host-seeking behavior in order to find the source. So far, literature on host recognition supports evidence that bed bugs and mosquitos are able to sense warmth of the host due to convection. Furthermore, temperature-sensitive sensory structures responding to warm air (convection) have been found on the two insects’ antennae. However, heat is generally transferred in three ways: convection (warm currents), conduction (heat transfer through contact) and radiation (transfer of energy by electromagnetic waves). We have been able to obtain evidence that mosquitos have a directional infrared sense used in host-seeking. The results show that mosquitos are strongly attracted by a warm, IR-emitting source, whereas bed bug did not appear to use IR-sensing for host-seeking. Furthermore, three repellents (DEET, cinnamaldehyde and citronellal) were tested and found to disrupt infrared-guided thermotaxis in mosquitoes at low spatial concentrations in air.