Date of Award
2024
Document Type
Thesis
Degree Name
Master of Science (M.S.)
Department
Biological Sciences
First Advisor
Zachary Stahlschmidt
First Committee Member
Ryan Hill
Second Committee Member
Paul Orwin
Abstract
Glyphosate (GLY) is the most used pesticide worldwide, and GLY-based herbicides (GBHs) can affect animals’ microbiomes and, in turn, their physiology and morphology. Environmental stressors can be mitigated by flexibility in life-history strategies, which can also dictate animal physiology and morphology. However, we lack an understanding of how GBH influences life-history strategies and stress tolerance, in addition to its effects across generations. Thus, I exposed the variable field cricket, Gryllus lineaticeps, to GBH within- and across-generations to examine the role of GBH in developmental plasticity and evolution. Specifically, I measured its effects on life-history traits (e.g., developmental duration and a life-history tradeoff between investment into reproduction and flight), stress (heat and desiccation) tolerance, and the gut microbiome. One generation of exposure to GBH reduced desiccation tolerance. However, after 11 generations of exposure to GBH, this cost of GBH disappeared, and GBH exposure instead increased body size and mass in flight-incapable individuals. The effects of flight capacity and GBH on the gut bacterial community were also greater in Generation 1 relative to Generation 11. Together, my results indicate that GBH exposure may have minimal long-term effects on stress tolerance and the gut microbiome, but GBH may facilitate the evolution of flightlessness given its benefits to flight-incapable individuals.
Pages
42
Recommended Citation
Whitlock, Jacob R.. (2024). Effects of Glyphosate-Based Herbicide Exposure on Life History, Stress Tolerance, and Microbiome—From Plasticity to Evolution. University of the Pacific, Thesis. https://scholarlycommons.pacific.edu/uop_etds/4275
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