Murray State Theses and Dissertations

Abstract

The objective of this study was to determine if Roundup (active ingredient: Glyphosate) causes negative effects on behavior, growth, and mortality of larval Pachydiplax longipennis. Larvae were captured from rainwater-filled mesocosms at Hancock Biological Station in Murray, KY. Larvae were exposed to one of four concentrations of Roundup (0mg/L, 2.5mg/L, 5mg/L, or 10mg/L). Daphnia consumption, seek refuge, and anti-predator trials were conducted at 7 and 14 days post-exposure. Growth and survival trials were carried out for eight weeks using different larvae. There were no significant differences among treatments for whether or not larvae ate offered Daphnia for Day 7 (c2 =1.915, df =3) or Day 14 (c2 =1.283, df =3). For the trials on Day 7, Roundup concentration did not have a significant effect on the time the larvae took to consume 1, 2, or 4 Daphnia; however, exposure significantly increased the time the larvae took to consume three Daphnia (P=0.036). For the trials on Day 14, concentration did not have a significant effect on the time the larvae took to consume 1 or 2 Daphnia; however, Roundup significantly increased the time the larvae took to consume 3 (P=0.050) or 4 Daphnia(P=0.029). In the seek refuge trials, there were no significant differences among treatments for the number of pokes required to elicit a behavioral response to hide during Day 7(c2=9.458, df =6) or Day 14 (c2 =5.759, df =6). In the anti-predator trials, there were no significant differences among treatments for the number of pokes required to elicit a fleeing response during Day 7 (c2 =1.336, df =3) or Day 14 (c2 =1.976, df =3). The behavioral response variables measured in the seek refuge and anti-predator trials were not significantly influenced by Roundup concentration, trial day, or size of the larvae. Roundup concentration and exposure week had a significant effect on growth (head width and body length) (P

Year manuscript completed

2018

Year degree awarded

2018

Author's Keywords

Roundup, Pachydiplax longipennis, behavior

Thesis Advisor

Claire A. Fuller

Committee Chair

Claire A. Fuller

Committee Member

Timothy W. Spier

Committee Member

Laura Sullivan Beckers

Committee Member

Howard H. Whiteman

Committee Member

David Roach

Document Type

Thesis

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