Date of Award

Spring 2023

Project Type

Dissertation

Program or Major

Biological Sciences

Degree Name

Doctor of Philosophy

First Advisor

Michelle Fournet

Second Advisor

Jennifer Miksis-Olds

Third Advisor

Jeff Garnas

Abstract

For acoustically oriented species, elevated levels of ambient sound can interfere with an organism’s ability to detect and assess acoustic signals and cues needed for making important decisions. Ambient noise, defined as any unwanted or non-focal acoustic signal, can impact behavior and decision-making by disrupting auditory sensory perception. As a result, noise in the context of this dissertation can be further delineated as excess sound that hinders a receiver's ability to detect and distinguish acoustic signals. Noise consists of either airborne or substrate-borne modalities or both. While many studies focus on the impact of airborne noise, many species have evolved the ability to detect both airborne and substrate-borne sounds. This bias towards airborne stimuli has left researchers with only a partial understanding of the impact of noise on animal behavior. Taking an integrative approach, this dissertation identifies the impacts of multisensory noise on the behavior of the Australian black field cricket (Teleogryllus commodus). First, I established the sensitivity of the auditory system to airborne sonic (1-20 kHz), airborne ultrasonic (>20 kHz), and substrate-borne stimuli (50-1600 Hz). I also determined that noise regardless of modality or bandwidth (sonic, ultrasonic, and substrate vibrations) has a significant impact on female phonotaxis. Finally, I tested how each noise type influences female choice regarding male calling phenotype and found that all noise types and bandwidths disrupt the mate choice process. I identified two possible causes for these shifts in behavior: energetic and informational masking. Energetic masking occurs when noise energetically overlaps with the signal and prevents detection of the signal. Informational masking occurs when the noise does not energetically overlap with the signal but still interferes with the female’s ability to extract information. The findings of this dissertation demonstrate the complexities of noise and its impacts on animal behavior, emphasizing the need to consider the sensory sensitivity of animals in studying the effects of noise. By furthering our understanding of how different noise types inform how animals interact with their environment, we can better determine the constraints and adaptations of living in an increasingly noisy world.

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