Degree

Doctor of Philosophy (PhD)

Department

Entomology

Document Type

Dissertation

Abstract

Honey bee colonies have perished at an alarming rate for over 15 years. Among the multitude of threats to bee health, virus infections and agrochemical exposure appear to be major drivers of colony loss. As virus infection is among the most damaging influences on bee health, we first investigated a putative target for antiviral immunity, termed KATP channels. We previously demonstrated that pharmacologically activating KATP channels induces the production of reactive oxygen species and increases survival during infection with Israeli Acute Paralysis Virus. Here, we demonstrate that KATP modulation and ROS induction reduce virus replication and enhance markers of immune function, strongly supporting the linkage between KATP activation, reactive oxygen species, and antiviral immunity in honey bees. We then translated these results to a field setting, showing that KATP activation reduces replication of Deformed Wing Virus-A, Deformed Wing Virus-B, Black Queen Cell Virus, Lake Sinai Virus-1, and Lake Sinai Virus-2. Importantly, our data represent the first evidence of pharmacological reduction of virus infection in honey bee colonies under field conditions. As deformed wing virus infection is known to affect foraging and homing behaviors, we next investigated the role of deformed wing virus on honey bee vision. Our data demonstrate that deformed wing virus infects the compound eye to a high degree and alters color preference under laboratory conditions. Our data indicate that deformed wing virus may physiologically alter vision among infected bees, potentially leading to a reduced pollination efficacy and colony health. Finally, we investigated interactions between classes of agrochemicals commonly encountered by honey bees during crop pollination. Our data show that the acute toxicity of the insecticide chlorpyrifos is enhanced by exposure to the herbicides atrazine and alachlor. We further demonstrate that atrazine likely enhances chlorpyrifos toxicity through increased oxidative activation by cytochrome P450 monooxygenase enzymes. Our data indicate that these commonly encountered classes of agrochemicals may interact to the detriment of commercial crop pollinators. In summary, this dissertation fills critical knowledge gaps regarding two of the major drivers of colony loss and may provide the foundation for future studies aimed at enhancing honey bee health.

Date

1-11-2023

Committee Chair

Swale, Daniel R

DOI

10.31390/gradschool_dissertations.6034

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Available for download on Saturday, January 10, 2026

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