Meeting Abstract
The hawkmoth Manduca sexta uses odors to find mates, food and egg-laying sites. Odor molecules are distributed by moving air into a non-uniform, patchy cloud known as a plume. While tracking an odor plume, M. sexta drive their antennae through the odor plume along a zigzagging flight track in a relatively narrow range of flight speeds. Their flapping wings also draws air and odor through their antennae. These behaviors could work together to sample the odor environment both in space and time and this information may be used to alter steering maneuvers to maintain contact with the plume. One element of this spatial odor information could come from bilateral comparisons between the two antennae. The prerequisite for this strategy to work is that the moth must be able to discriminate which antenna is being stimulated. To address this question, we designed an odor arrival side discrimination task based on the proboscis extension reflex conditioning. Proboscis extension was monitored by recording electric potentials generated by the cibarial pump muscle that is involved in drawing nectar up the moths’ proboscis. Initially, the moths were presented 10-12 trials of conditioning stimuli i.e., odor stimulation to one of the antennae was associated with sucrose reward. Following this, moths were tested for cibarial muscle activity when odor was presented from either the associated or unassociated side. The moths were expected to generate cibarial muscle potentials when presented with odor on the associated side and remain relatively quiet during odor presentation to the other side. Moths discriminated the odor arrival side with an accuracy of >70%. These results show that moths may be able to determine the odor plume location in 3D space, and use this information to control the turning maneuvers used during plume tracking.
