Inbreeding depression influences lifetime breeding success in a wild population of red deer (Cervus elaphus)

Evolutionary and conservation biologists have a long-standing interest in t he consequences of inbreeding It is generally recognized that inbred indivi duals may experience reduced fitness or inbreeding depression. By the same token, relatively outbred individuals can have greater than average fitness , i.e. heterosis. However nearly all of the empirical evidence for inbreedi ng depression comes from laboratory or domestic species. Inbreeding depress ion and heterosis are difficult to detect in natural populations due to the difficulties in establishing pedigrees. An alternative method is to correl ate heterozygosity, which is measured using genetic markers, with a trait r elated to fitness. The typically studied traits, such as juvenile survival and growth rates, either cover only early life or are weakly correlated wit h lifetime breeding success (LBS). In this paper we show: that heterozygosi ty is positively associated with male and female adult LBS in a wild popula tion of red deer (Cervus elaphus) on the Isle of Rum, Scotland. To the auth ors' knowledge, this is the first time that inbreeding depression and/or he terosis have been detected for a trail highly correlated with overall fitne ss in both sexes in a wild population.