Sexual selection and sexual conflict in Anolis lizards: From molecules to populations

Sexual selection is a driver of biodiversity and creates spectacular forms of variation. However, only recently have we begun to understand how this variation operates on the postcopulatory level and how cryptic mechanisms affect male-male competition and female choice. Whenever a female mates with and stores sperm from multiple males, there is potential for fertilization to be biased. Brown anoles (Anolis sagrei) are exceptional in that females exhibit a fertilization bias with a known ecological basis. When mated multiply, females produce a higher proportion of sons from larger sires. This bias is adaptive in that sons from larger sires have higher survival in the wild. However, the mechanisms that underlie this bias are not known.;Here, I take a three-pronged approached to exploring this cryptic fertilization bias. First, I develop an Approximate Bayesian Computational model to investigate effects of male mating order on their reproductive success. Second, I use a functional genomic approach to investigate the female genetic response to mating and uncover potential genetic candidates involved in postcopulatory sexual selection. Third, I use a three-year parentage dataset of a wild population of brown anoles to determine whether selection is acting antagonistically on male and female body size at the population level, which might further highlight the importance of cryptic processes for fertilization bias.;Using Approximate Bayesian modeling, I find that the first male to mate has an advantage in Anolis sagrei. I also find that the model sometimes outperforms other statistical methods at detecting mating order biases. Secondly, I find that the female genetic response to mating in Anolis is complex; many genes are differentially expressed after mating. These genes show convergence to the genetic response to mating in Drosophila based on Gene Ontology. Additionally, I describe one serine protease gene (Stejnibrase) that shows evidence of positive selection. Lastly, I report evidence for sexually antagonistic selection on body size in Anolis sagrei based on a reproductive component of fitness. These results indicate that sexual conflict is a persistent force in this system and that mechanisms that resolve this conflict should be promoted by selection.