Meeting Abstract
Males of the hawkmoth species Manduca sexta are able to track plumes of female pheromone in flight using their olfactory systems, which receive input directly from sensory cells on their antennae. To do this they use two possible odorant comparison strategies: spatial and temporal. If using spatial comparison, unilateral removal of an antenna should greatly diminish their ability to locate an odor source. If using temporal, unilateral antennectomy should have less of an impact, as the moths could still compare odor cues over time using one antenna. To determine which of these underlies plume tracking behavior, we antennectomized moths in three ways: (1) surgical removal of an antenna from adult males prior to flight, (2) surgical removal of the imaginal discs responsible for development of the adult antenna during the last larval stage, (3) surgical restriction of growth of the odor-detecting sensory cells on the antennae in stage 1 pupae while preserving the mechanosensors at the antennal base. In the last treatment group, a donor antenna was attached to the stump on the base of the antenna effectively “re-loading” the large mechanoreceptors at the base prior to flight. Though 97% of control animals find the odor source, only 43% of type 1 antennectomies and 26% of type 2 are able to perform this behavior. With mechanosensation preserved, the type 3 antennectomies perform at a rate of 86%. These results show that, while two antennae are certainly ideal for tracking an odor source, for M. sexta one is sufficient. It also reveals the importance of bilateral antennal mechanosensory inputs for flight control. We thank Jen Milligan and Sean Copley for their assistance. AES and MAW were supported by NSF grant IOS-1121498.
