Date of Award:

12-2010

Document Type:

Dissertation

Degree Name:

Doctor of Philosophy (PhD)

Department:

Biology

Committee Chair(s)

James P. Pitts

Committee

James P. Pitts

Committee

Terry Griswold

Committee

Carol D. von Dohlen

Committee

Steven R. Larson

Committee

James A. MacMahon

Abstract

For centuries, scientists have been intrigued by the high amount of biodiversity that is found in the deserts of North America. Recently, several studies have investigated the causes of the high diversity found in desert-dwelling mammals, reptiles, and amphibians. These studies have found that many of these organisms seem to have diversified in response to the same historical events. Little work has been done, however, on diverse desert-dwelling insect groups. In this dissertation, I investigate the patterns of genetic diversity in four groups of nocturnal wasps called velvet ants. I compare the patterns of genetic diversity to the historical events like mountain building and climate changes to determine which historical events were responsible for driving diversity in these groups of wasps. I obtained DNA from numerous velvet ant specimens and analyzed two non-coding regions of their DNA using Bayesian statistical methods implemented in several computer programs. These programs allowed me to determine if a consistent pattern could be found across species and populations of these wasps. I used other computer programs that analyze the patterns in the DNA to estimate a date when the different species evolved. These analyses showed that some of the species-level diversification events occurred about five million years ago, during a time when many of the western mountain ranges were being formed, and other species-level evolution events occurred in the last two million years, during the most recent ice ages. Many of the recent studies investigating evolution in mammals and reptiles have suggested that most species-level evolution events occurred in response to the geologic changes that were happening about five million years ago. My research, however, shows that both the mountain-building events and the most recent ice ages influenced the evolution of velvet ants.

Checksum

a2715de15294a55d3d090bedfd9fe361

Comments

This work made publicly available electronically on October 1, 2010.

Download

Share

COinS

Copyright for this work is retained by the student. If you have any questions regarding the inclusion of this work in the Digital Commons, please email us at .