UC Riverside

Biologists have long been interested in using population parameters not only to assess species’ growth trajectories, but also to make inferences about the processes underlying animal behavior. One parameter of considerable contemporary interest, fluctuating asymmetry, is characteristic of all bilaterally symmetrical animals. In the first chapter of this thesis, fluctuating asymmetry is defined in empirical terms and by how it relates to organism stress. Its importance to biologists is briefly reviewed, and some potential limitations to its utility are outlined. The second chapter is a report of a laboratory experiment designed to detect fluctuating asymmetry in wing traits of the model butterfly Vanessa cardui, and to test whether fluctuating asymmetry varied with the degree of environmental stress to which larvae and pupae were exposed. Finally, the third chapter critiques the author’s experiment and evaluates the likely usefulness of fluctuating asymmetry as an indicator of changing environments in nature. Recommendations are made for those interested in studying fluctuating asymmetry further.