Doctoral Dissertations

Date of Award

8-2008

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Ecology and Evolutionary Biology

Major Professor

Christine R.B. Boake

Committee Members

Gordon Burghardt, Ben Fitzpatrick, Susan Riechert

Abstract

Phenotypic correlations between traits are thought to reflect genetic correlations. However, traits related to a central function, like reproduction, need not all be genetically correlated. Identifying genetic correlations between behavioral traits can help identify the evolutionary relationship between different behaviors, as well as provide initial information on the number of genes involved in behavioral variation and the rates and direction of evolution. This body of work describes the phenotypic and genetic relationship between mating traits in the parasitoid wasp genus Nasonia. Chapters 2 and 3 describe behavioral differences among the three species of Nasonia. Two of the species, N. vitripennis and N. giraulti, show extreme differences for several behavioral traits. Nasonia vitripennis females mate almost exclusively after emergence from the host puparium and show a strong propensity to remate, and males of this species show strong site fidelity after emergence. Conversely, N. giraulti females mate almost exclusively inside the host (called within-host mating; WHM), show a low frequency of remating, and males show no site fidelity and disperse after emergence. The third species, N. longicornis, is similar to N. vitripennis for male site fidelity, but shows between line variation for WHM and female remating. I used the between line variation to create divergent recombinant inbred lines (RILs), 24 of which were screened for ten different behavioral traits (Chapter 4), including WHM, male site fidelity, remating, components of male courtship, and male and female developmental traits. Three behaviors were genetically correlated; WHM was positively correltated with remating frequency and remating frequency was negatively correlated with male courtship duration. The relationship between WHM and remating frequency could not be explained in terms of timing of female receptivity. However, remating frequency was directly correlated with when females became sexually receptive as early female receptivity was found in lines with high remating frequencies. I also address the evolution of these behaviors in an ecological context (Chapter 5). WHM is thought to have evolved as a byproduct of selection against hybridization in nature, and the ecological distribution of Nasonia,a both within nests and host pupae, is consistent with this hypothesis.

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