Date on Honors Thesis

Spring 5-9-2023

Major

Biology

Minor

Chemistry

Examining Committee Member

Oliver M. Beckers, PhD, Advisor

Examining Committee Member

Laura Sullivan-Beckers, PhD, Committee Member

Examining Committee Member

Kevin M. Miller, PhD, Committee Member

Examining Committee Member

Warren Edminster, PhD, Honors Advisor

Abstract/Description

Many animals communicate with one another in the context of reproduction, utilizing different modalities. In some cases, more than one modality is used by the sender and receiver. Each modality can provide different sets of information, or function in a different context. Importantly, no matter the modality, the signals should be clearly distinguishable between males and females and need to be reliable even in the face of environmental changes.

In field crickets, there are two major modes of communication. For long-range communication, the males produce acoustic signals to attract females. At short-range, chemical communication involving cuticular hydrocarbons (CHCs) in males and females are added as a communication modality to acoustic signals. The cricket Gryllus rubens has a spring and a fall generation in Kentucky and the long-range acoustic signal shows substantial differences between the generations as the result of seasonal temperatures during development (phenotypic plasticity). Even though much is known about acoustic signals and their plasticity, very little is known about chemical communication in crickets and if these short-range signals display phenotypic plasticity related to seasonal temperatures.

I hypothesized that CHCs differ between males and females to allow for distinction between the sexes and that the CHC signature is also affected by environmental changes. I collected CHCs from the body surface of male and female Gryllus rubens crickets and analyzed the chemical composition of each individual. My results showed substantial differences in chemical composition of CHCs of males and females and between generations, indicating phenotypic plasticity. More specifically, I detected differences in the range of CHC compounds as well as peak abundances in my sex and generation specific comparisons. I discuss potential explanations and ramifications of this plasticity in the context of natural and sexual selection.

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