Date of Award

Fall 12-2017

Degree Type

Dissertation

Degree Name

Ph.D.

Degree Program

Conservation Biology

Department

Biological Sciences

Major Professor

Lailvaux, Simon

Second Advisor

Husak, Jerry

Third Advisor

Anthony, Nicola

Fourth Advisor

Howard, Jerome

Abstract

Performance is key to survival. From day-to-day foraging events, to reproductive activities, to life-or-death crises, how well an organism performs these tasks can determine success or failure. Selection, therefore, both natural and sexual, act upon performance, and performance demands on individuals shape a population’s morphological and physiological trait distributions. While studies of morphological adaptations to ecological pressures implicitly center on the idea that responses to selection improve performance via changes in morphology, the relationships between morphology, performance, and fitness are not always well understood. In this dissertation, I investigate these relationships explicitly, as well as determine the effects that different ecological and genetic contexts have on selection and how populations respond to performance pressures.

Using a model of lizard locomotor performance, I address three issues that may impact selection on performance that are often overlooked in performance studies. First, performance is not a static trait. Rather, individuals possess a range of performance abilities or intensities that can be expressed as needed. Using a novel, individual-based, quantitative genetic simulation model, I demonstrate the effects of variable performance expression and genetic constraints on how a population experiences and responds to selection on sprint and endurance performance. Second, sex differences in performance are expected in sexually dimorphic species, but empirical evidence for this is lacking. To this end, I measured and analyzed multivariate morphology and performance in Anolis carolinensis to identify sex-specific patterns in functional morphology and functional trade-offs within a broad suite of performance traits. Third, intralocus sexual conflict should constrain the evolution of the multivariate performance phenotype in both sexes. By extending the simulation model to include correlated trait inheritance between sexes and sex-specific selection on certain performance traits, I demonstrate the extent to which this sexual conflict constrains performance evolution. In combining studies of natural populations with simulation studies of selection, this dissertation embraces the complexity of performance to address the multiple contributing factors and constraints on performance evolution, and demonstrates the importance of accounting for such complexity when studying animal performance.

Rights

The University of New Orleans and its agents retain the non-exclusive license to archive and make accessible this dissertation or thesis in whole or in part in all forms of media, now or hereafter known. The author retains all other ownership rights to the copyright of the thesis or dissertation.

Download

Share

COinS