In partial fulfillment of the requirements for the degree of

Doctor of Philosophy in Biology

In the

School of Biological Sciences

Carl J. Dyson

Will defend his dissertation

The Genetics and Epigenetics of Plasticity in Social Insects

14, April 2022

12:00 PM

https://bluejeans.com/415983512/2805

 Thesis Advisor:

Michael A. D. Goodisman, Ph.D.

School of Biological Sciences

Georgia Institute of Technology

Committee Members:

Soojin Yi, Ph.D.

Department of Ecology, Evolution and Marine Biology

University of California, Santa Barbara

I. King Jordan, Ph.D.

School of Biological Sciences

Georgia Institute of Technology

William C. Ratcliff, Ph.D.

School of Biological Sciences

     Georgia Institute of Technology

Joseph R. Mendelson, Ph.D.

School of Biological Sciences

Georgia Institute of Technology

Zoo Atlanta

ABSTRACT:

Highly social (eusocial) insects, in particular, comprise some of the most successful species on Earth due in large part to their high levels of cooperation and division of labor. However, these behaviors are subject to evolutionary pressures from abiotic conditions such as environmental changes and the loss of natural habitats. When faced with such disruptions, social insects display a remarkable capacity for phenotypic plasticity and behavioral alterations. I examined the evolutionary trajectory of this plasticity in eusocial insects from both a population genetics and a molecular perspective. First, at a population level, I investigated changes to the social form and life cycle of the southern yellowjacket Vespula squamosa and found polygynous colonies representing plasticity in changing environmental conditions. Next, I probed the evolution of duplicated genes in the honeybee Apis mellifera and uncovered strong correlations between gene body methylation and gene duplication in several contexts that could represent a significant molecular pathway to the plasticity of gene expression in highly social insects. Finally, to further understand the molecular underpinnings of plasticity, I examined the distribution of DNA methylation within multiple insect genomes to explore its possible mechanistic role in eusocial systems. These projects provide insight into the evolution of eusocial organisms from both a population and a molecular level. The results of this research contribute to a greater understanding of the population dynamics of insect societies and the evolution of plasticity across eusocial insects.