Uncoupling direct and indirect components of female choice in the wild.

Abstract

One of the most controversial debates in evolutionary biology concerns the fitness consequences of female choice in nature. Discriminating females may benefit from high-quality territories and/or sires with high-quality genes. Here we experimentally dissociate female preferences for high-quality territories and male body size in a wild population of side-blotched lizards, Uta stansburiana. Females preferred experimentally improved territories but still chose high-quality sires for their progeny. High-quality territories were associated with earlier egg-laying dates and larger eggs. These maternal effects, evidently stimulated by high-quality territories, have been shown to enhance competitive ability and therefore the likelihood that philopatric offspring will capitalize on the direct benefits of superior territories, previously shown to promote progeny growth rate and survival (most offspring do not disperse from their natal area). Paternity analysis within clutches co-sired by two males revealed that female preferences for large males were also adaptive in terms of indirect benefits. Females used sperm from large sires to produce sons and sperm from small sires to produce daughters. Differential allocation of resources and progeny sex was adaptive and demonstrates a high degree of female control in the mating system.