Honey bees are economically important pollinators of a wide variety of crops that have attracted the attention of both researchers and the public alike due to unusual declines in the numbers of managed colonies in some parts of the world. Viral infections are thought to be a significant factor contributing to these declines, along with exposure to agricultural and apicultural pesticides, but viruses have proven a challenging pathogen to study in a bee model and interactions between viruses and the bee antiviral immune response remain poorly understood. Recent studies have demonstrated an important role for inwardly-rectifying ATP-sensitive potassium (KATP) channels in the cardiac regulation of the fruit fly antiviral immune response, but no information is available on their role in the heart-specific regulation of bee immunity. The results of this work demonstrate that KATP channel modulators have an observable effect on honey bee heart rate that supports their expected physiological role in bee cardiac function. Here, it is also reported that the entomopathogenic flock house virus (FHV) infects adult bees, causing rapid onset of mortality and accumulation of viral RNA. Furthermore, infection-mediated mortality can be altered by pre-exposure to KATP channel modulators. Finally, this work shows that exposure to environmental stressors such as commonly used in-hive acaricides can impact bee cardiac physiology and tolerance to viral infection. These results suggest that KATP channels provide a significant link between cellular metabolism and the antiviral immune response in bees and highlight the significant impact of environmental stressors on pollinator health. / Ph. D. / Honey bees are economically important pollinators of a wide variety of crops that have attracted the attention of both researchers and the public alike due to unusual declines in the numbers of managed colonies in some parts of the world. Viruses are thought to be an important contributor to these declines, along with exposure to pesticides used in farming and beekeeping, but viruses have proven challenging to study in honey bees, and the bee immune response remains poorly understood. Recent work using fruit flies has shown an important role for a type of ion channel known as the inwardly-rectifying ATP-sensitive potassium (K<sub>ATP</sub>) channel in the insect heart and regulation of virus infection, but this ion channel has not been studied in honey bees. The results of this work demonstrate that drugs targeting K<sub>ATP</sub> channels affect honey bee heart rate and support their expected role in the function of the honey bee heart. Here, it is also shown that a model insect virus can be used to study viral infections in bees, which helps to overcome several major challenges to the study of how honey bees respond to such infections. This model system provides evidence that K<sub>ATP</sub> channel drugs can be used to improve the survival of bees that have been infected with a virus. Finally, this work demonstrates that exposure to pesticides, such as those commonly used to treat for pests in the hive, can impact bee cardiac function and tolerance to viral infection. These results suggest that K<sub>ATP</sub> channels provide a significant link between cellular metabolism and the antiviral immune response in bees, highlighting the significant impact of environmental stressors on pollinator health.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/78344 |
| Date | 14 July 2017 |
| Creators | O'Neal, Scott T. |
| Contributors | Entomology, Anderson, Troy D., Brewster, Carlyle C., Bloomquist, Jeffrey R., Swale, Daniel Robert, Kuhar, Thomas P. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Dissertation |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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