Date of Award
Fall 11-21-2025
Document Type
Dissertation
Degree Name
Ph.D. in Biological Sciences
Organizational Unit
College of Natural Science and Mathematics, Biological Sciences
First Advisor
Robin Tinghitella
Second Advisor
Erica Larson
Third Advisor
Jonathan Velotta
Fourth Advisor
Shannon Murphy
Copyright Statement / License for Reuse
All Rights Reserved.
Keywords
Anthropogenic change, Noise pollution, Species interactions, Pacific field cricket, Sexual signals
Abstract
Anthropogenic change forces organisms into new environments, and they can respond through rapid adaptive evolution and/or plasticity. Understanding such responses has direct applications (i.e. conservation) and provides an opportunity to learn about basic evolutionary and ecological processes. I focus on two consequences of anthropogenic change: introduced species interactions and noise pollution. I capitalize on the recent radiation of novel sexual signals (purring, rattling, smallwing, curlywing) in Hawaiian populations of the Pacific field cricket, Teleogryllus oceanicus. These signals attract mates while protecting males from an introduced and deadly parasitoid fly. In chapter one, I investigate how relaxed receiver preferences facilitate novel signal evolution. I probe the mechanistic underpinnings of relaxed preferences (are they evolved or plastic) with sound preference trials conducted across the crickets’ range from Australia (no fly) to Hawaii (fly present) and in the field and lab. In the field, Hawaiian females responded more positively to the novel rattling song than Australian females. In the lab, however, differences across regions disappeared, driven primarily by increased responsiveness of Australian and French Polynesian females. This pattern points to a loss of plasticity in Hawaiian female preferences, resulting in heightened responsiveness to all songs—likely giving novel signals a foothold. In chapter two, I investigate the molecular underpinnings of two novel attenuated signals with convergent functions and fitness consequences (attracting mates while avoiding the fly), asking whether convergent signals have similar genetic architectures. Purring and rattling were associated with different mutations in similar regions of the genome, suggesting that even on short timescales, convergent evolution of function may involve similar genomic regions. However, genome FST outlier scans identified additional candidate regions of potentially elevated differentiation among morphs. Third, I test how traffic noise amplitude influences fitness-related traits and whether that depends on the life stage (juvenile or adult) of noise exposure. Noise did not impact most of the thirteen measured fitness traits. Instead, this chapter points to the importance of the detailed acoustic content of noise pollution; when noise exposure is relatively constant, as here, animals may be able to habituate to these conditions, regardless of amplitude.
Copyright Date
11-2025
Publication Statement
Copyright is held by the author. User is responsible for all copyright compliance.
Rights Holder
Gabrielle T. Welsh
Provenance
Received from ProQuest
File Format
application/pdf
Language
English (eng)
Extent
173 pgs
File Size
8.5 MB
Recommended Citation
Welsh, Gabrielle T., "Novel Signal Evolution in a Rapidly Evolving Field Cricket" (2025). Electronic Theses and Dissertations. 2677.
https://digitalcommons.du.edu/etd/2677