Graduate Studies, UNL
Embargoed Master's Theses
First Advisor
Judy Wu-Smart
Committee Members
Jeffrey Bradshaw, Leslie Rault
Date of this Version
12-2025
Document Type
Thesis
Citation
A thesis presented to the faculty of the Graduate College at the University of Nebraska in partial fulfillment of requirements for the degree of Master of Science
Major: Entomology
Under the supervision of Professor Judy Wu-Smart
Lincoln, Nebraska, December 2025
Abstract
The European honey bee (Apis mellifera L.) plays a critical role in agroecosystem productivity by providing pollination services essential to global food security. Despite this importance, honey bee health continues to decline due to interacting biological, chemical, and environmental stressors, a pattern intensified by climate change and increasing weather variability. This thesis examines how pesticide exposure and pests jointly influence honey bee health and evaluates sustainable management strategies to mitigate these pressures.
Chapter 1 reviews the primary stressors affecting honey bee colonies, with emphasis on Varroa destructor mites, associated viral pathogens, and pesticide exposure. This chapter synthesizes current research on how biological and chemical stressors interact with management practices to shape colony resilience, highlighting the need for integrated, field-realistic approaches to pollinator health within IPPM frameworks.
Chapter 2 presents a case study investigating pesticide contamination associated with the AltEn ethanol facility in Mead, Nebraska, and its effects on honey bee colonies monitored from 2019 to 2023. Sentinel hives placed at varying distances from the facility experienced elevated mortality during periods of active processing of pesticide-treated materials, consistent with chronic pesticide exposure. Following the facility’s closure, colonies showed improved overwintering survival. These findings provide real-world evidence of chronic pesticide pollution impacts on pollinator health and demonstrate the potential for recovery once contamination sources are removed.
Chapter 3 evaluates drone brood trapping as a mechanical method for managing Varroa destructor under varying pesticide exposure risk during 2024-2025 field seasons. Two approaches were compared: the industry-standard plastic drone comb and a novel wooden frame design that allows bees to construct natural wax comb using skewer supports. Experiments were conducted across two apiaries with contrasting exposure risk. By monitoring colony strength, brood development, and mite loads, this chapter assesses interactions between mite pressure and chemical exposure and evaluates the efficacy of alternative mechanical control strategies.
Together, this thesis highlights the importance of integrative, field-based approaches that address combined pest and pesticide pressures on honey bee colonies while supporting sustainable, non-chemical management practices.
Advisor: Judy Wu-Smart
Comments
Copyright 2025, Jade (Jae) C. Horn. Used by permission