A comparative analysis of the remote touch mechanism in birds


SOCIETY FOR INTEGRATIVE AND COMPARATIVE BIOLOGY
2021 VIRTUAL ANNUAL MEETING (VAM)
January 3 – Febuary 28, 2021

Meeting Abstract


P36-4  Sat Jan 2  A comparative analysis of the remote touch mechanism in birds Spriggs, SN*; Cost, IN; Albright College; Albright College suzanne.spriggs001@albright.edu

Touch is an integral sense in the development of all animals. Birds and crocodiles have similar anatomical plans and thus should have similar facial innervation. Crocodilians are covered with dome pressure receptors (DPRs) that send signals of pressure changes to the brain via the trigeminal nerve, which has three branches (V1, V2, and V3). Bird remote touch sensation effected through Grandry and Herbst corpuscles, is also transmitted to the brain via the trigeminal nerve. In remote touch sensitive birds, mechanoreceptor abundance is highest in the bill tip organ. The bill tip organ is known to exist in four families of birds; Apterygidae, Scolopacidae, Anatidae, and Threskiornithidae. We conducted a review of current literature and known trigeminal nerve maps for birds and crocodilians. Based on the literature, we predict that probing birds will have more branched trigeminal nerve (V1 and V2) divisions. We created nerve maps (V1 and V2) of a Black-crowned Night-heron (Nycticorax nycticorax) and a Virginia Rail (Rallus limicola) by using manual dissection. Photographs and measurements were taken during dissection. Measurements of overall trigeminal nerve and segment length were taken by using calipers and scale bars associated with photographs. These were used to compare overall trigeminal nerve distribution in species of birds that utilize spearing (N. nycticorax) and species of birds that utilize probing (R. limicola) when finding food. Preliminary examination of the trigeminal nerve in birds appears to support our prediction. Our study provides more complete nerve maps of shorebirds and provides connections between degree of trigeminal nerve branching and the ability to use remote touch. Our nerve maps offer a more complete understanding of remote touch sensation which is essential to conservation of shorebirds.

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