Ecology of Bee Viruses

Author:

Mcmenamin, Alexander James

Graduate Program:

Entomology

Degree:

Master of Science

Document Type:

Master Thesis

Date of Defense:

April 13, 2015

Committee Members:

Christina M Grozinger, Thesis Advisor/Co-Advisor
Diana Lynn Cox Foster, Thesis Advisor/Co-Advisor
Cristina Rosa, Thesis Advisor/Co-Advisor

Keywords:

Honeybees
bees
agriculture
viruses
Deformed Wing Virus
Apiculture
ecology
epidemiology
colony losses
management

Abstract:

Throughout much of human history honey bees have provided pollination services crucial to our economy and human survival. Thus, in yet more recent history humans have developed a keen interest in the health of honey bees and how it relates, directly and indirectly, to their effectiveness as pollinators. Furthermore, other pollinator species have also become of interest to humans due to their own contributions to pollination services. Here we seek to add to a global understanding of bee health by taking a closer look at viruses known to negatively impact honey bee health and suspected to impact the health of other bees, as well. In Chapter 1, we review the literature incriminating viruses as a cause of honey bee colony losses. This includes a breakdown of the different kinds of evidence collected, including correlative evidence, experimental evidence verifying viral pathology, experimental evidence of therapeutic techniques, and the impact of a vector. In Chapter 2 we take a look at the seasonal variance of viruses in Kenyan honey bee colonies and the effect of hive type (Langstroth, Log or Kenyan Top Bar) on colony health as well as swarm preference for 3 different hive types. Briefly, we found that viral infection is higher in the dry season, when the bees are nutritionally stressed, though there seems to be no effect by hive type. Furthermore, swarms preferred the Langstroth hive, and secondly the Log hives. After giving considerations to costs and hive productivity, we recommend a modified Kenyan Top Bar hive may present the best course of action for beekeepers in the Mwingi District of Kenya. Lastly, in Chapter 3, we take a preliminary look at the role that a Bombus impatiens plays in the ecology of a honey bee virus (Deformed Wing virus, DWV). Our results suggest that individuals of this species may not be effective or competent transmitters of this virus. Further studies that improve upon our study design would need to be done to confirm or deny our result. It is our hope that this thesis provides an impetus for other scientists to look more closely at current apicultural practices used in the West, with a particular focus on how these practices impact the epidemiology of known honey bee pathogens.