Different proxies, different stories? Imperfect correlations and different determinants of fitness in bighorn sheep

Measuring individual fitness empirically is required to assess selective pressures and predict evolutionary changes in nature. There is, however, little consensus on how fitness should be empirically estimated. As fitness proxies vary in their underlying assumptions, their relative sensitivity to individual, environmental, and demographic factors may also vary. Here, using a long-term study, we aimed at identifying the determinants of individual fitness in bighorn sheep (Ovis canadensis) using seven fitness proxies. Specifically, we compared four-lifetime fitness proxies: lifetime breeding success, lifetime reproductive success, individual growth rate, and individual contribution to population growth, and three multi-generational proxies: number of granddaughters, individual descendance in the next generation, and relative genetic contribution to the next generation. We found that all proxies were positively correlated, but the magnitude of the correlations varied substantially. Longevi..., This dataset contains fitness proxies and their determinants for each female bighorn sheep used in the analyses in the manuscript. Details on data collection and processing can be found in the methods section of the manuscript.,