Social and Acoustic Behavior of the Leaf-Roosting Bat Thyroptera Tricolor

• Main Author: Montero, Bianca Karina
• Format: Others
• Published: North Dakota State University 2018
• Online Access: https://hdl.handle.net/10365/27843

The limited availability of refuges may represent an important factor promoting the evolution of sociality, particularly in bats. Spix’s disc-winged bats (Thyroptera tricolor) show highly specialized morphological adaptations that enable individuals to roost inside furled musoid leaves. This roosting ecology presents major challenges, as leaves rapidly unfurl, forcing bats to locate new roosts on a daily basis. Despite the reliance of T. tricolor on such ephemeral roosting resources, bats form stable group associations. The purpose of this study was to characterize the behavioral patterns associated with assessing roosts and any accompanying communication strategies of Spix’s disc winged bats. In the first chapter, I used video and acoustic monitoring to test the hypotheses that finding a high quality roost involves the regular assessment of leaf suitability within a group’s rooting range and that acoustic signals facilitate group interactions during nightly activity. The second chapter examines the patterns of geographic variation in two contact calls regularly emitted by T. tricolor. I evaluate the congruence of geographic variation in the acoustic features of contact calls with genetic differentiation of two populations in Costa Rica separated by a geographic barrier. In the third chapter, using an automated telemetry system, I examined the nocturnal movement patterns of all group members within the limits of the roosting range. I determined that bats regularly monitor furled leaves within their roosting range, during which they emit a number of distinct social calls. Among the acoustic signals produced by these bats, two calls are particularly common near furled leaves. When examining the relationship between genetic distance and acoustic divergence of these two contact calls I found discordant patterns of variation, suggesting the presence of distinct modes of vocal transmission within populations. The continuous assessment of movement patterns during foraging bouts provided evidence that in general, bats remain within close proximity of a group’s roosting range and the occurrence of dyadic encounters during the course of the night. This study contributes to our understanding of the behavioral strategies used by free-ranging bats providing valuable insight into the role of shelter stability in the evolution of the T. tricolor social system. === North Dakota State University. Graduate School === North Dakota State University. Department of Biological Sciences