Meeting Abstract
73.4 Monday, Jan. 6 09:00 Fusion of proboscis mechanoreception and vision contributes to flower tracking in a freely flying moth HALL, RW*; SPONBERG, S; DANIEL, TL; Univ. of Washington; Univ. of Washington; Univ. of Washington rhall9@uw.edu
How do organisms in challenging sensory environments integrate independent information from multiple sensory modalities in order to improve performance? The crepuscular hawkmoth, Manduca sexta, hovers and tracks moving flowers during natural foraging behaviors. Prior experiments have shown that tracking performance depends on luminance, with an 30% increase in processing delay as light levels drop from dusk (300 lux) to moonlight (.3 lux). While vision is clearly involved, the role of mechanosensory information from the proboscis may also contribute to tracking performance. We tested this hypothesis with freely flying hawkmoths feeding from a robotically actuated artificial flower. The front face of the flower provided visual motion cues, while the concealed nectar reservoir provided independent mechanical motion cues. The face and nectary were decoupled so that one or the other could be moved in isolation. Movement was generated by a signal composed of a superposition of multiple sine waves (.2-20Hz). We reconstructed the moths’ frequency response to determine the gain, phase, and error of its tracking performance. Results show that there is significant tracking to both modalities, providing strong evidence for the use of the proboscis as a sensory feedback system. At low frequencies, there was a significant phase lead when tracking the visual-only reference suggesting predictive filtering, such as velocity estimation. However, the gain of the mechanical system was much greater at low frequencies before trading off with vision at higher frequencies. Tracking error was reduced at low frequencies when both modalities were present indicating positive sensory fusion. The integration of multiple independent sensory modalities enhances performance of difficult behaviors in sensory deprived environments.
