Date of Completion

2019

Document Type

Honors College Thesis

Department

Biology

Type of Thesis

Honors College, College of Arts and Science Honors

First Advisor

Brent Lockwood

Keywords

Developmental plasticity, thermal tolerance

Abstract

Drosophila melanogaster live across a wide latitudinal range, thus resulting in divergence in thermal adaptation between populations. Despite differences in thermal tolerances, the effects of an embryonic thermal stress on development have not been studied. The goal of this experiment was to determine the effects of a brief embryonic heat shock on larval and adult performance in tropical versus temperate genotypes of D. melanogaster. Larval and adult performance were measured through pupation height and walking speed, respectively. I predicted that as embryonic thermal shock temperature increased, performance values would decrease, showing a physiological cost in response to the heat shock. Additionally, I expected that the tropical genotype would exhibit less of a plastic response to the thermal shock compared to the temperate genotype due to having a higher embryonic thermal tolerance. In response to increasing embryonic shock temperature, performance values decreased similarly in both genotypes. Given the tropical flies only walked at a slightly faster pace, it can be concluded that the thermal shocks resulted in a comparable plastic response in both genotypes. With global temperature rising and an increasing number of days reaching thermal extremes, these results suggest a possible decrease in survival and performance of D. melanogaster in the natural environment. Although there is a possibility of natural selection resulting in a less severe plastic response to embryonic thermal stress, based on these data, there may not be significant phenotypic variation among populations of this species on which natural selection can act.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.

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