Meeting Abstract

61.4  Thursday, Jan. 6  The neuromuscular bases of vocalization in X. borealis and X. boumbaensis: insights into the evolution of simple advertisement call patterns in Xenopus LEININGER, E.C.*; KELLEY, D.B.; Columbia University; Columbia University ecl2107@columbia.edu

Comparative examinations of the neuromuscular mechanisms responsible for generating behavior can lead to insights regarding the evolution of behavioral phenotypes. In this study, we examined the neuromuscular bases of vocalization in two species of Xenopus, X. borealis and X. boumbaensis. These species, despite diverged ancestry, both produce advertisement calls with a simple but evolutionarily derived ‘click type’ temporal structure. We used two isolated preparations, the fictive singing brain and the isolated larynx, to determine whether the neuromuscular basis of click type vocal production is shared in these two species, with particular interest in the relative roles of central (hindbrain central pattern generation) and peripheral (laryngeal) contributions to the vocal pattern. We report that X. borealis and X. boumbaensis have achieved a click type advertisement call via different modifications of central and peripheral components of the vocal circuit. X. borealis isolated brains produce fictive vocal patterns consisting of single compound action potentials presented in temporal patterns that closely resemble two call types: the advertisement call and the approach call. The larynx is capable of converting single stimuli faithfully into muscle tension transients and sound. In contrast, X. boumbaensis brains primarily produce a fictive burst type advertisement call pattern consisting mostly of doublets of compound action potentials. The isolated larynx requires doublets to produce a single tension transient and click of sound, a consequence of a highly potentiating EMG.