Date of Award

5-2024

Document Type

Open Access Thesis

Degree Name

Master of Science (MS)

Department

Biology

First Advisor

Joseph Staples

Second Advisor

Rachel Lasley-Rasher

Third Advisor

Chris Maher

Keywords

Thesis, Biology, Imidacloprid, Respiration, Common Flesh Fly

Abstract

Neonicotinoid pesticides are used worldwide due to their effectiveness in protecting crops from pests like aphids, thrips, moths, flies, and beetles. These insecticides are applied on surfaces or absorbed systemically by plants, where insects encounter them through contact or ingestion. While beneficial for agriculture, they also negatively impact nontarget species. Numerous studies have reported the inhibitory effects of sublethal exposure to neonicotinoid-based insecticides on nontarget insects, especially pollinators such as bees, flies, and beetles. While research has demonstrated the toxicity of neonicotinoids, most studies have focused on low-energy activities such as walking or resting. In this research, I examined the respiratory responses of the Common

Flesh Fly, Sarcophaga bullata, to sublethal levels of imidacloprid during low- and high- energy activity. To do this, I developed a method that allows for repeated measurement of

the respiratory responses in individual flies at rest and high activity levels. Results revealed a significant difference in respiratory quotient (RQ), based on relative CO2 production and O2 consumption, between control (non-treated) and imidacloprid-treated flies during high-energy activity, a difference not observed during low-energy activity. I also observed that moderate levels of imidacloprid (50 ppb) impaired fly behavior and mobility. Several flies treated with 50 ppb displayed an inability to walk properly and lost the ability to right themselves after flipping over. Food consumption rates also decreased, suggesting possible behavioral resistance. These findings indicate that field-relevant levels of imidacloprid impair S. bullata respiration and behavior. Future studies should consider utilizing methods developed in this study to further enhance our understanding of chemical and environmental stressors on insect pollinators.

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