Data from: Sex-specific effects of inbreeding on reproductive senescence

Inbreeding depression plays a significant role in evolutionary biology and
ecology. Yet, we lack a clear understanding of the fitness consequences of
inbreeding depression. Studies often focus on short-term effects of
inbreeding in juvenile offspring whereas inbreeding depression in adult
traits and the interplay between inbreeding depression and age is rarely
addressed. Inbreeding depression may increase with age and accelerate the
decline in reproductive output in ageing individuals (‘reproductive
senescence’), which could be subject to sex-specific dynamics. We test
this hypothesis with a longitudinal experimental study in a short-lived
songbird. Adult inbred and outbred male and female canaries were paired in
a 2x2 factorial design and survival and annual reproductive performance
were studied for three years. We found inbreeding depression in female
egg-laying ability, male fertilization success and survival of both sexes.
Annual reproductive success of both males and females declined when paired
with an inbred partner independent of their own inbreeding status. This
shows that inbreeding can have fitness costs in outbred individuals when
they mate with an inbred individual. Further, inbred females showed faster
reproductive senescence than outbred females, confirming that inbreeding
depression and age can interact to affect fitness. In contrast, there was
no evidence for an interaction between inbreeding depression and
reproductive senescence in male fertilization success. Our findings
highlight the importance of considering sex-specific effects and age to
determine the full range of fitness consequences of inbreeding and
demonstrate that inbreeding depression can accelerate reproductive
senescence.