Understanding variation in fitness conferring traits

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How genetic variation is maintained in traits that enhance fitness remains a fundamental dilemma in evolutionary biology. Several major theories have been put forth to explain the persistence of genetic variance. These theories include genic capture, fluctuating selection, genotype-by-environment interactions, genotype-by-genotype interactions, heterosis, and antagonistic pleiotropy. My students and I are testing some of these theories using an animal behaviour approach that incorporates tools from statistical genetics and ecological physiology. Our laboratory and field based empirical research quantifies the phenotypic and genetically based variation in condition, life-history, and sexually selected traits and determines how this variation is influenced by diet and the social environment. Specifically, our research examines (1) how dietary variation in essential and limited elements (nitrogen and phosphorus) influences the genetics of condition (including growth rate, development time, adult size, body fat content, and nutrient retention in the body), and (2) how diet and condition interact to influence sexually selected and life-history traits (attractiveness of male long-distance mate advertisement signals, female mating preferences, lifetime reproductive success, anti-predatory behaviours, and survival of both parents and their offspring). Our short-term research goals are to determine whether the interactions between these traits act to maintain high genetic variance. We will also conduct an artificial selection experiment with the short-term goal of ascertaining whether temporally fluctuating selection can maintained the genetic variance in sex-limited and sexually selected traits. Overall, our research will explicitly test two of the above theories for the maintenance of high genetic variance - genic capture and temporally fluctuating sex-limited selection. Long-term, the overarching goal of my research program is to contribute to a more complete understanding of how high genetic variance is maintained in traits that enhance fitness.