Research Projects

Rationale: Sexual selection, an evolutionary process that acts through the competition for mates, is known to strongly affect animal traits by selecting for large body size, costly striking weapons, ornaments and signals, particularly in males. Sexual selection also has important consequences for ecological traits such as species interactions, and evolutionary traits, such as lifespan. The action of sexual selection is keenly sensitive to environmental conditions. These conditions are now changing rapidly as a result of human actions. How will human-related factors modify the action of sexual selection and what are the consequences of animal traits and populations? This question is crucial to predict how animal populations will cope in the anthropocene, but studies are severely lacking. Research objectives: This study aims to investigate the impact of anthropogenic factors on sexual selection processes and their action on animal traits and the cascading effects on animal populations. We focus on wild populations of the agamid lizard Psammophilus dorsalis. This species is ideally suited to examine the impact of sexual selection in the anthropocene since it is found in dry rocky hillocks, a habitat that is highly human-modified; it shows conspicuous sexual displays; it is short-lived and thus its response to recent human-driven environmental change can be studied. Our objectives are to (1) to quantify variation in traits under sexual selection in males and females in wild populations experiencing varying levels of anthropogenic factors; (2) To test the relationships between variation in sexually selected traits and key ecological variables hypothesized to affect the strength of sexual selection, namely animal density and predation risk; to test the trade-offs underlying these relationships; and to compare these relationships between males and females; (3) investigate the impact of anthropogenic factors on the key ecological variables (density and predation risk) and therefore the strength of sexual selection, namely the strength of direct competition and mate choice; and (4) investigate the impact of anthropogenic factors on sexually selected traits (through the impact on density and predation risk), and the cascading effects on populations, specifically demography, effective population size and genetic diversity. Hypothesis: We propose to test the hypothesis that anthropogenic factors affect ecological and demographic conditions and thereby affect the strength of selection, resulting in rapid changes in phenotypic traits and downstream effects on population parameters, with implications for trait diversity and population persistence. Methodology: We propose to use a combination of behavioural, ecological and genomic approaches with in-depth studies in select populations and cross-population measurements. In select wild populations varying in human disturbance, individually tagged males and females will be monitored over their lifetime and a suite of morphological, behaviour and life history traits will be measured in relation to sexual selection processes. The impact of anthropogenic factors on selection pressures that affect the action of sexual selection will be measured. The link between modified environments, the strength of sexual selection and animal traitswill be tested. The impact on genetic diversity and effective population size will be estimated. Outcome: By using the rare approach of combining in-depth studies of tagged individuals over multiple generations in select wild populations differing in human disturbance, together with large-scale sampling of multiple populations varying in anthropogenic factors, this study hopes to yield conceptual breakthroughs in how sexual selection processes are likely to change in the anthropocene. This study will produce a predictive framework of how animal phenotypes are likely to respond to rapid human-driven environmental change and the links to population responses.