Meeting Abstract

84.4  Friday, Jan. 6  Odor-gated rheotaxis and sensory integration by the rhinophores during navigation in the nudibranch, Tritonia diomedea MCCULLAGH, Gregory*; BISHOP, Cory; WYETH, Russell; St. Francis Xavier Univ. gregory.mccullagh@stfx.ca

Neuroethological studies of navigational behaviors have progressed in the mollusc, Tritonia diomedea, due to their easily observable behaviors, and accessible nervous system. T. diomedea navigates using odor plumes, crawling upstream towards prey and downstream to avoid upstream predators. The mechanism by which T. diomedea integrates odor and flow cues to create these behaviors is likely odor-gated rheotaxis, but a bilateral comparison of odors alone has not been ruled out. The rhinophores detect odors during navigation and the oral veil has been shown to detect flow direction in flow alone. However, within odor plumes, the rhinophores or the oral veil may detect flow stimuli. Our goals were to determine 1) whether T. diomedea uses a bilateral odor comparison between rhinophores and, 2) whether flow is detected by the rhinophores or the oral veil. Prey and predator odor plumes were generated in a non-recirculating flow tank and we tested navigation performance in animals with either unilateral rhinophore lesions, a bilateral denervation of their oral veil, or unilateral rhinophore lesions and a bilateral denervation of their oral veil. Our results show that in each case, experimental slugs orient similarly to control slugs, suggesting that within odor plumes, T. diomedea does not sample odor cues using a bilateral comparison across their rhinophores and the oral veil is not the principal flow detecting organ. This study is consistent with previous research suggesting that T. diomedea navigates using odor-gated rheotaxis and thus that the rhinophores may detect bulk flow direction as well as odors. Future studies will evaluate the cellular components of the peripheral nervous system within the rhinophores and further explore the functional relevance of T. diomedeas’ oral veil during navigation.