Examining the factors influencing Varroa destructor host selection of Apis mellifera larvae

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Taylor Danielle Reams (Creator)
The University of North Carolina at Greensboro (UNCG )
Web Site: http://library.uncg.edu/
Olav Rueppell

Abstract: The European honey bee, Apis mellifera, is a vital species for agriculture, providing pollination for crops all around the world. Recent declines in honey bee health have been concerning, and the spread of the ectoparasitic mite Varroa destructor is thought to be one of the leading causes of this decline. Examining how Varroa destructor finds its larval host for reproduction is important for understanding how Varroa destructor can ultimately lead to the death of the colony. Investigating the factors that guide Varroa destructor host seeking is also an important step for developing tools to control Varroa destructor within the Apis mellifera hive without the use of toxic acaricides. While early studies showed promising results of identifying Varroa attractants, an adequate in-hive trap has not been developed. I investigated the influences of three factors on Varroa destructor host selection of Apis mellifera larvae in two sets of experiments: caste, nurse bee visitation rate, and larval weight. I also investigated gene expression and virus titers as possible consequences to mite invasion. Overall, we found complex interaction among the tested factors. My comparison among worker and drone cells showed that with increasing nurse bee visitation rates there is an increased chance of cell invasion by Varroa. However, drone larvae did not have a significantly higher chance of invasion compared to worker larvae, despite higher visitation rates. Worker larvae manipulated through starving and feeding did not exhibit altered nurse bee visitation rates, although some weight changes were observed. Larvae with increased weight did not to have a higher chance of cell invasion. Interactions between visitation rates and molecular variables, such as immune activity and virus titers were studied. The immune gene Dicer-Like and deformed wing virus-A were both associated with Varroa cell invasion. These results provide insight into how physical, behavioral, and chemical factors influence Varroa destructor. This study shows how Varroa destructor acts and interacts within Apis mellifera hives, that can be used to develop methods of control in the future.

Additional Information

Language: English
Date: 2018
Honey bee, Apis mellifera, Varroa destructor, Visitation rates, Nurse bees
Varroa destructor
Honeybee $x Larvae
Honeybee $x Health

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