| dc.description.abstract | Condition-dependent sexual selection has the potential to align natural and sexual selection and accelerate adaptation. When the expression of a sexually selected trait is constrained by the condition of the bearer, it offers a reliable signal of quality on which females can base mate choice decisions. Individuals with highly expressed sexually selected traits are therefore expected to possess advantageous genes given the prevailing environmental conditions. Such genes can then spread by their naturally selected benefits as well as their sexually selected advantages, thereby accelerating adaptation. I investigate the effect of condition-dependent traits on mating and signalling behaviour to explore the potential for alignment between natural and sexual selection in the wild. By studying a wild population of the field cricket, Gryllus campestris, I explore condition-dependent sexual selection in a natural context. This avoids some limitations of laboratory studies, which may overestimate effects in the absence of natural and environmental variation. I employ a direct experimental test of the effect of condition on sexually selected traits and mating success, finding that while male acoustic signals are condition-dependent, modest increases in calling effort do not result in increased mating success. I investigate the effect of body size on mating success and find mating success to be independent of body size. I explore the possibility of condition- and context-mediated flexibility in mate-searching tactics, finding that while population density influences tactic choice, individual condition is unlikely to predict which tactic a male will adopt. Finally, I consider the role of female condition in sexual selection and find that mating latency in females is not condition-dependent, but that mating history has an important effect on female choosiness. | en_GB |
