PhD project: the effect of social environment on sexual selection in an invasive fish species

Gambusia (Mosquito fish). Photo: Andrew Kahn

Description

PhD project

Individuals are affected by those around them: social environment can play a critical role in shaping not only individual phenotypes but also selection pressures, the expression of genetic variance, and hence how traits evolve. Ultimately, some genotypes may have highest fitness in one social environment and others in another – providing a neat intuitive explanation for the persistence of genetic diversity, but one for which there is surprisingly little support from empirical data. Furthermore, by definition individuals’ social environments are themselves genetically determined by the genes of the conspecifics with whom they interact (be these competitors, or potential mates, or even just their parents). There is now increasing awareness of the potential impact of these “indirect genetic effects” on evolutionary processes, but, to date, relatively little data with which to test the theoretical expectation that IGEs may provide important contributions to variance in fitness.

The project will use laboratory and semi-natural pond populations of the mosquitofish Gambusia holbrooki to explore the effects of social environment and varying levels of competition on sexual selection and evolutionary dynamics in males and females, and to determine the contribution of indirect genetic effects to the multivariate phenotype and fitness. Gambusia is an excellent model organism for studies of sexual selection. The project will combine analyses of a suite of phenotypic traits, including sperm, morphological and behavioural characteristics, with SNP genotype data. It will provide training in evolutionary ecology, and quantitative genetic and genomic statistical analyses. It will be supervised Loeske Kruuk, Michael Jennions and Megan Head; between us, we have a wide experience of work on life history evolution, sexual selection and quantitative genetics.

If you are interested, please contact me: Loeske.Kruuk@anu.edu.au

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