Data from: Frequency-dependent and correlational selection pressures have conflicting consequences for assortative mating in a color-polymorphic lizard, Uta stansburiana

Abstract

Genetically determined polymorphisms incorporating multiple traits can persist in nature under chronic, fluctuating and sometimes conflicting selection pressures. Balancing selection among morphs preserves equilibrium frequencies, while correlational selection maintains favorable trait combinations within each morph. Under negative frequency-dependent selection, females should mate (often disassortatively) with rare male morphotypes to produce conditionally fit offspring. Conversely, under correlational selection, females should mate assortatively to preserve coadapted gene complexes and avoid ontogenetic conflict. Using controlled breeding designs, we evaluated consequences of assortative mating patterns in color-polymorphic side-blotched lizards (Uta stansburiana), to identify conflict between these sources of selection. Females who mated disassortatively, and to conditionally high quality males in the context of frequency-dependent selection, experienced highest fertility rates. In contrast, assortatively-mated females experienced higher fetal viability rates. The trade-off between fertility and egg viability resulted in no overall fitness benefit to either assortative or disassortative mating patterns. These results suggest that ongoing conflict between correlational and frequency dependent selection in polymorphic populations may generate a trade-off between rare-morph advantage and phenotypic integration, and between assortative and disassortative mating decisions. More generally, interactions among multiple sources of diversity-promoting selection can alter adaptations and dynamics predicted to arise under any of these regimes alone.Mating outcomes from controlled crosses of side-blotched lizards (Uta stansburiana)This data set was created from a controlled laboratory breeding study of wild-caught side blotched lizards (Uta stansburiana), conducted in 2004 and 2006. Each dam is mated to a single sire, and data on their throat colors and mating outcomes are provided.Lancaster data for DRYAD.xls