What’s been bugging you, Chemosensory behaviors of parasites.
Many multicellular parasites seek out hosts by following trails of host-emitted chemicals. Host seeking is characteristic of endoparasites such as parasitic worms as well as ectoparasites such as mosquitoes and ticks. Many of these parasites use carbon dioxide (CO2), a respiration byproduct, in combination with host-specific chemicals for host location. Recent work has begun to elucidate the behavioral responses of parasites to CO2 and other host chemicals, and to unravel the mechanisms of these responses. Here we discuss recent findings that have greatly advanced our understanding of the chemosensory behaviors of host-seeking parasites. We focus primarily on well-studied parasites such as nematodes and insects, while also noting broadly relevant findings in a few less well-studied parasites.