Date Available

10-1-2023

Year of Publication

2023

Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation

College

Agriculture, Food and Environment

Department/School/Program

Entomology

First Advisor

Dr. Clare C. Rittschof

Abstract

An organism’s ability to respond to changing conditions can be vital to its success. Indeed, plasticity is a common feature of living organisms. Much of the research in this area, though, has focused on effects caused by environmental conditions. What has received relatively less attention is how social experiences and broader features of an organism’s social environment can lead to long-lasting changes in health and behavior. This knowledge gap exists despite the well-documented existence of health and behavioral effects after social interactions in certain taxa such as humans.

Social insects such as honey bees provide an excellent opportunity to better understand this phenomenon due to their well-characterized behavioral repertoire, complex social dynamics, and experimental tractability in natural and semi-natural settings. This project examines multiple aspects of honey bee behavior and health to determine how they are affected by a bee’s previous experiences. Additionally, this project aims to uncover how elements of the social environment (such as colony-level aggression) lead to different outcomes in adult behavior, physiology, and health in these insects.

I first documented the existence of high colony-level variation in the nutritional profile of “worker jelly.” Worker jelly is a nutritional secretion that is synthesized by adult nurse bees and comprises the entirety of the nutritional resources available to a honey bee larva, making it a critical feature of the early-life development period for bees. Next, I examined the social interaction element of nurse bees inspecting and feeding larvae. I determined that this vital interaction can be affected by social pheromones such as the honey bee alarm pheromone. This effect was dependent on the colony-level aggressive social environment, however, despite these nurses not being specialized for aggressive nest defense. I then followed up on the previous results by using electrophysiology to determine that colony-level aggression differentially affects the peripheral detection of some social pheromones in nurses but not in bees of a typically more aggressive task specialization, foragers. Finally, I turned the lens to the adult social interaction of allogrooming. Allogrooming is a key component of a honey bee colony’s health-promoting “social immunity.” I tested how an acute allogrooming event affects the expression of key immune genes from multiple pathways as well as deeply conserved genes implicated in social responsiveness across taxa.

This work demonstrates how early life experiences and social interactions can affect the health and behavior of a highly social organism. Additionally, given the recent challenges faced by these important pollinators, this research provides key foundational knowledge on the importance of social factors in maintaining the overall health and vitality of honey bees and honey bee colonies.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2023.412

Funding Information

These studies were supported by:

  • Animal Behavior Society Student Research Grant (awarded 2018)
  • Richards Graduate Student Research Activity Award through the University of Kentucky (awarded 2019)
  • University of Kentucky Presidential Fellowship (2020-2021)
  • Sigma Xi Society Grant in Aid of Research (awarded 2020)
  • United States National Science Foundation grant (IOS-2045901, 2021-2023)

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Dissertation Data.xlsx (188 kB)
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