Data from: Estimating selection on the act of inbreeding in a population with strong inbreeding depression

Inbreeding depression is widely regarded as a driving force in the
evolution of dispersal, mate choice and sperm selection. However, due to
likely costs of inbreeding avoidance, which are poorly understood, it is
unclear to what extent selection to avoid inbreeding is expected in
nature. Moreover, there are currently very few empirical estimates of the
strength of selection against the act of inbreeding (mating with a
relative), as opposed to the fitness costs of being inbred. Here, we use
data from the individual-based study of red deer on the Scottish island of
Rum, a strongly polygynous system which harbours a large inbreeding load,
to estimate selection against the act of inbreeding for each sex. We use
pedigree and genomic estimates of relatedness between individuals and
measure fitness using both lifetime breeding success (number of calves
born) and lifetime reproductive success (number of calves surviving to
independence), with the latter incorporating inbreeding depression in calf
survival. We find for both sexes that the repeatability of the act of
inbreeding was low (<0.1), suggesting little among-individual
variation for this trait on which selection can act. Using the genomic
measures there was significant selection against the act of inbreeding in
males, but not in females, and there was considerable uncertainty in the
estimate in both sexes. We discuss possible explanations for these
patterns and their implications for understanding the evolution of
inbreeding avoidance in natural populations.