Do physiological and environmental factors influence vocal communication and associated behaviors in Peromyscus?

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Radmila Petric (Creator)
The University of North Carolina at Greensboro (UNCG )
Web Site:
Matina Kalcounis-Rüppell

Abstract: Vocal communication is an integral component of animal behavior and individuals rely on vocal signals to mediate a myriad of daily activities. Despite valuable work from the laboratory, we do not understand how physiological and environmental factors alter vocal communication and activities in complex field settings where multiple competing stimuli occur simultaneously. The goal of my research is to understand how transient testosterone (T) pulses, a physiological factor, and anthropogenic noise, an environmental factor, alters the allocation of time and energy to influence vocal output, signal structure, and other reproductively related behaviors in free-living animals. Physiological Factor: T-pulses naturally occur after social interactions in a variety of species and can modulate call production and alter animal preferences for the physical location at which the T-pulse occurred (conditioned place preference; CPP). Manipulation of T-pulses has been conducted under controlled laboratory conditions; here, I ask how multiple T-pulses alter time allocation in complex field setting and influence future vocal behavior. H1: T-pulses reinforce behaviors in the area where the experience occurred in the form of conditioned placed preference (CPP) that in turn alter call production and the allocation of time and energy spent towards specific social interactions. To determine whether T-pulses induce CPPs and alter call production in the wild, I used a monogamous, territorial, and vocal rodent, the California mouse (Peromyscus californicus). California mice are well studied both in the laboratory and the wild, and in this species, males must balance mate attendance, offspring care, and territory defense with T being an important mediator of these social behaviors. I assessed the effects of three exogenously administered T-pulses or saline (control; C) on the following: 1) spatial preference 2) number of calls produced, and 3) spectral and temporal characteristics of calls (frequency, amplitude, and duration). I found that in the field, environmental location dictates the effects of T injections, suggesting that T-pulses are highly context dependent. At the nest, T-males spend more time at the nest and their noninjected mates spent less time at the nest. At the territory boundary, T-males and their non-injected mates spent less time at the boundary, but T-males traveled further outside their original territory than C-males. At the nest, T-mice produced more calls with a lower mean bandwidth whereas at the territory boundary T-males produced more short duration calls than C-males. In free-living and pair-bonded males, T-pulse induction of CPPs is based on the physical environment and the interactions that occur in that space. Together, these results suggest there is behavioral plasticity in inducing CPPs and that it is context dependent. Lastly, I found that independent of treatment type, the acoustic properties within a pair were more similar than among pairs, providing evidence for vocal convergence in pair-bonded California mice. Environmental Factor: Anthropogenic noise is a global pollutant that alters the natural soundscape which animals rely on for communication, foraging, navigation, exploring, and predator avoidance. Anthropogenic noise is pervasive in the audible range during the day, but it also extends into the ultrasonic range and into the night. Here, I ask how broadband (audible and ultrasonic) anthropogenic noise influences behaviors of free-living and nocturnal mammals. H2: Broadband anthropogenic noise alters the allocation of time and energy to influence activity, foraging, and vocal communication. To test my hypothesis, I broadcasted anthropogenic or familiar noise to examine 1) activity, 2) foraging and 3) call production of the deer mouse (Peromyscus maniculatus) and woodland jumping mouse (Napaeozapus insignis). I found that deer mice and woodland jumping mice spent less time at sites with anthropogenic noise compared to familiar noise. I also found that deer mice were less likely to approach food than woodland jumping mice during broadcasts of anthropogenic noise, however, both species spent less time foraging and vocalizing in the presence of anthropogenic noise. My results show species-specific responses to noise in nocturnal rodents that vocalize in the ultrasonic range. Overall, my data are consistent with previous research from other taxonomic groups, which demonstrate that anthropogenic reduces activity, foraging and vocalization production of animals.

Additional Information

Language: English
Date: 2020
Behavior, Mice, Noise, Spatial preference, Testosterone, Vocalization
Peromyscus $x Vocalizations
Peromyscus $x Behavior

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