Electronic Theses and Dissertations

Date of Award

1-1-2020

Document Type

Thesis

Degree Name

M.S. in Biological Science

First Advisor

William J. Resetarits

Second Advisor

Chris J. Leary

Third Advisor

Jason D. Hoeksema

School

University of Mississippi

Relational Format

dissertation/thesis

Abstract

Habitat selection by pond breeding amphibians and insects is often critical for larval survival, performance, and resulting parental fitness, since there is typically little parental care beyond oviposition site choice. Numerous axes of patch quality have been identified and quantified, but species with varied life histories may differently shift perception of habitat quality as changes in global climate increase water temperatures and rates of eutrophication. Three outdoor mesocosm experiments were conducted using two species with complex life cycles and very different life histories; Hyla chrysoscelis, or Cope’s Gray tree frog, and the mosquito (Culex restuans). Two mesocosm experiments were conducted to test the oviposition preference of each species by establishing gradients of temperature and nutrients in a completely crossed design. Additionally, a third mesocosm experiment testing larval performance of H. chrysoscelis was conducted by measuring frog metamorph body metrics of individuals reared in each temperature and nutrient combination. The temperature and nutrient treatments showed no significant effect in any of the three experiments, but each experiment had significant covariate predictors. The temperature difference from control pools in each block had a significant positive linear relationship with the number of H. chrysoscelis eggs laid per mesocosm, and metamorph mass increased with higher nitrate levels. C. restuans laid more egg rafts in mesocosms with higher levels of nitrate, and nitrate was driven significantly by temperature. Both species choose to oviposit in treatments that may ultimately benefit their offspring through increase rate of development and survival. The environmental variables that influence oviposition choice and offspring performance are crucial to understanding species distributions, abundances, and community structure as global warming and eutrophication affect the quality of freshwater systems.

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