Defense Date

5-1-2026

Document Type

Thesis

Degree Type

Master of Science

Degree Name

Biological Sciences

First Advisor

Christopher A. Blanar

Second Advisor

Eloy Martinez

Third Advisor

David W. Kerstetter

Keywords

Temperature, Survival, Metabolism, Activity, Media

Abstract

Rising global temperatures are likely modulating parasite-host interactions, yet the direction and magnitude of these changes remain uncertain. Rarely are these interactions viewed from both a host and parasite perspective. Using both CTmax, or Critical Thermal Maximum, and Clark-type polarographic oxygen microelectrodes, the physiological metabolic effects are investigated. CTmax is examined in Common Shiners, Luxilis cornutus, and is shown to be modulated by parasitism: uninfected fish had the highest CTmax average of 37.0°C, whereas heavily infected fish had decreased CTmax averaging 35°C. Prior to the parasite metabolic investigation, a suitable medium was determined, as parasitic helminthes such as digeneans possess a general inability to survive outside of their host for more than a few days. Bivesicula cercariae were exposed to either Fetig’s Medium, Mitochondrial Isolation Medium or Mitochondrial Respiration Medium. Survival and cercarial activity was assessed on a daily basis thereafter; showing Fetig’s Media to be the most suitable medium. This medium was used in determining Bivesicula cercariae metabolism. Oxygen consumption increased from 3.3 ± 0.96 nL of oxygen consumed per individual to 29.3 ± 8.5  nL of oxygen consumed at 35°C and declined to 11.8 ± 2.2 nL of oxygen at 40°C, indicating a clear thermal optimum around 35°C. These combined results show at higher temperatures, endoparasites will benefit more than their hosts will. At extreme temperatures, neither host nor parasite will be able to withstand temperatures at 40°C.

ORCID ID

0009-0009-3914-4793

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