Genomic studies of social evolution in bees

Woodard, Sarah

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https://hdl.handle.net/2142/30928 Copy

Description

Title

Genomic studies of social evolution in bees

Author(s)

Woodard, Sarah

Issue Date

2012-05-22T00:16:00Z

Director of Research (if dissertation) or Advisor (if thesis)

Robinson, Gene E.

Doctoral Committee Chair(s)

Robinson, Gene E.

Committee Member(s)

• Cameron, Sydney A.
• Hudson, Matthew E.
• Robertson, Hugh M.

Department of Study

School of Integrative Biology

Discipline

Biology

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Social evolution
• eusocial insects
• natural selection
• bumble bees
• Bombus
• genomics
• microarrays
• behavior

Abstract

The eusocial insects (ants, termites, and some bees and wasps) are paragons of social complexity, with their highly organized societies comprised of primarily sterile workers, headed by one or a few reproductives. Despite a rich body of theoretical, empirical, and natural history research on social insects, relatively little is known about how the insect societies evolved at the molecular level. Here, I employ techniques from genomic biology to shed light on the molecular basis of social evolution in the bees, a group of socially diverse species that encompasses multiple, independent evolutions of eusociality. In Chapter 1, I provide a detailed overview of the chapters contained in this dissertation. In Chapter 2, I review current progress in molecular evolutionary analyses of the social insects and outline some common themes emerging from this area of research. In Chapter 3, I use a comparative genomics approach to identify hundreds of genes that are rapidly evolving in eusocial bees. Additionally, I highlight biological processes, such as carbohydrate metabolism, which may have been important targets of natural selection during the evolution of eusociality in these bee lineages. In Chapter 4, I combine a behavioral analysis with a microarray experiment to explore how changes in maternal traits in queens of the bumble bee Bombus terrestris are regulated by workers during the nest initiation phase of the Bombus life cycle. Here, I provide evidence that workers socially regulate both brood-feeding and egg-laying behavior in queens, and may also influence patterns of brain gene expression in queens. Lastly, in Chapter 5, I use a microarray experiment on B. terrestris to identify patterns of brain gene expression that are shared by brood-feeding bumble bee queens and workers, as well as genes that appear to be associated with brood care in bumble bees and in other eusocial insect lineages. These shared patterns of brain gene expression may provide insights into how sibling care evolved in the bumble bees, as well as how convergent evolution of cooperative brood care occurred across multiple eusocial insect lineages.

Graduation Semester

2012-05

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http://hdl.handle.net/2142/30928

Copyright and License Information

Copyright 2012 Sarah Woodard

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