I present a thorough investigation of the meaning of fitness variance in the context of conditional sex expression, followed by a comprehensive analysis of a weak maternal effects model of conditional sex expression. This includes a consideration of the effects of different sex expression strategies on the population genetics and conservation ecology of species. I focused on three questions: What is the meaning of fitness variance in the context of conditional sex expression? Under what conditions can conditional sex expression evolve? How can we detect conditional sex expression in natural populations, given new findings on its population genetics and the significance of fitness variance? Findings include the following: 1. Fitness variance is not a useful metric to detect conditional sex expression. 2. Conditional sex expression evolves when selection is greater on one sex than the other; this holds true for a wide range of parameter values. This corroborates existing theory. 3. In the first known model including sexual selection and conditional sex allocation, this combination is shown to produce faster adaptation than sexual selection alone. 4. Conditional sex expression has the potential to increase population longevity, and may additionally spread through clade (or group) selection. 5. Conditional sex expression can be reliably detected using a combination of allele frequency trajectories through time and cross-sectional allele frequency data from polymorphic loci; this combination is necessary to avoid false positives from loci under balancing selection.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:663654 |
| Date | January 2008 |
| Creators | Wesche, Philipp L. |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/11543 |
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