Gene expression profiles of chemosensory genes in Calliphoridae species

Abstract

Gustatory and olfactory stimuli are important for the behavior of insects, influencing decisions to initiate courtship and copulation, select hosts and oviposition sites, locate nutrient-rich foods, and avoid toxic substances. Both, smell and taste begin with the reception of semiochemicals on the periphery of the olfactory and taste systems, with important roles played by receptors expressed in olfactory receptor neurons (ORN) or in gustatory receptor neurons (GRN). Different peripheral proteins are involved in smell and taste. Three families of antenna receptor proteins are expressed in ORNs and ligate odor molecules: olfactory receptors (ORs), taste receptors (GRs) and ionotropic receptors (IRs). In addition to the receptors, other proteins are also involved in smell and taste. Odor-binding proteins (OBPs) make the connection between the external environment and the ORs. OBPs bind and solubilize odors that reach the pores of a sensillum, and transport them through the lymph in the cavity around the dendrites. Considering the dependence of blowflies on semiochemical tracks for choosing oviposition sites, the importance of smell and taste for insect behavior, and also the importance of peripheral proteins for smell and taste, the investigation of these proteins can help elucidate the behavior of blowflies and their lifestyles. Mutations in OR, GR, IR, and OBP genes (or on their regulatory sequences) may underlie the different lifestyles. We will study chemosensory genes (ORs, GRs, IRs, and OBPs) in seven blowfly species, comparing their expression in necrophagous species, obligatory and facultative parasites. (AU)