Meeting Abstract
The visual identification of externally moving targets allows animals to locate and track predators, mates, and food sources. Insects that routinely track small targets have dedicated neurons in their brain and ventral nerve cord (VNC) that selectively respond to targets of various size. The moth flower tracking behavior, where a feeding moth tightly tracks the 3D motion of a swaying flower, relies on acquiring and acting upon both self-motion (wide field visual movement of the background) and the external motion of a flower. Emerging evidence suggests that some descending neurons in the moth VNC selectively respond to wide field or small target cues while others respond generally. It is unknown which class(es) of moth VNC neurons are responsible for encoding flower motion. To answer this question, we recorded the response of descending VNC neurons to wide field motion (WFM), small target, and flower stimuli using multielectrode arrays in tethered hawkmoths, Manduca sexta. We find that VNC neurons respond to moving flowers, and some neurons can have directional selectivity. Over 80% of the recorded neurons have a large overlap in response to the three classes of stimuli presented; neurons that are sensitive to flowers can also respond to either WFM, target, or all three types of stimuli. Not all cells are universally responsive and some show selectivity to flower stimuli, being silenced by or unresponsive to either wide field or small target stimuli. These results show that descending neurons of the moth VNC can have overlapping and unique selectivity to both target and flower stimuli, suggesting that the visual system of insects can be evolutionary tuned to the life history and ecologically relevant stimuli of a given species.
