Data from: Phenotypic assortment mediates the effect of social selection in a wild beetle population

Social interactions often have major fitness consequences, but little is known about how specific interacting phenotypes affect the strength of natural selection. Social influences on the evolutionary process can be assessed using a multilevel selection approach that partitions the effects of social partner phenotypes on fitness (referred to as social or group selection) from those of the traits of a focal individual (nonsocial or individual selection). To quantify the contribution of social selection to total selection affecting a trait, the patterns of phenotypic association among interactants must also be considered. We estimated selection gradients on male body size in a wild population of forked fungus beetles (Bolitotherus cornutus). We detected positive nonsocial selection and negative social selection on body size operating through differences in copulation success, indicating that large males with small social partners had highest fitness. In addition, we found that, in low-density demes, the phenotypes of focal individuals were negatively correlated with those of their social partners. This pattern reversed the negative effect of group selection on body size and led to stronger positive selection for body size. Our results demonstrate multilevel selection in nature and stress the importance of considering social selection whenever conspecific interactions occur nonrandomly.,deme-statsData used to generate Figure 3 and related statistics. Data collected from the wild and managed with JMP V.7male-male-interactionsFile used to calculate covariances, described as Cii and Cii (prime). Data collected in the wild and managed with JMP v7. Data used to generate figure Table 2 and used in calculation of Table 5.Social-selection-gradientData collected in the wild and managed with JMP v7. Data used in the calculation of Table 3, Table 4, and Table 5. These are the data used to calculate selection gradients. Also used to generate Figure 4.