Heritability of fitness in a wild mammal population

Classical population genetics theory predicts that selection should deplete heritable genetic variance for fitness. We show here that, consistent with this prediction, there was a negative correlation between the heritability of a trait and its association with fitness in a wild population of red de er (Cervus elaphus) and there was no evidence of significant heritability o f total fitness. However, the decline in heritability was caused, at least in part, by increased levels of residual variance in longevity and, hence, in total fitness: in this population, longevity is known to he heavily infl uenced by environmental factors. Other life history traits that were not as sociated with longevity, such as average annual breeding success, had highe r heritabilities. Coefficients of additive genetic variance differed marked ly between traits, but highly skewed measures, such as male breeding succes s, generally had greater coefficients of variance than morphometric traits. Finally, there were significant maternal effects in a range of traits, par ticularly for females.