EFFECTS OF FENVALERATE ON THE DEVELOPMENT OF OLFACTORY PERCEPTION IN A BEETLE

LOW doses of fenvalerate (a Type II pyrethroid) were applied to the be etle Tenebrio molitor at pupation, to ascertain its effects on the dev eloping olfactory system. Doses of fenvalerate that prevent the format ion of glomeruli in the primary olfactory neuropil (antennal lobes) al so inhibit olfactory orientation behavior for different odors, despite the fact that sensory neurons developed responses to these odors. Eve n when lower amounts of fenvalerate that allowed glomeruli to develop were applied to pupae, the olfactory behavior was affected. Therefore, the formation of glomerular structures within the antennal lobe is no t sufficient to establish olfactory behavior. A possible reason for th is developmental effect of fenvalerate is a change in the odotopic arr angement of sensory axons within the glomeruli. (C) 1998 Lippincott Wi lliams & Wilkins.