Individual variation in age-dependent reproduction: fast explorers live fast but senesce young?

1. Adaptive integration of life history and behaviour is expected to result in variation in the pace-of-life. Previous work focused on whether “risky” phenotypes live-fast-but-die-young, but reported conflicting support. We posit that individuals exhibiting risky phenotypes may alternatively invest heavily in early-life reproduction but consequently suffer greater reproductive senescence.
2. We used a 7-year longitudinal dataset with >1200 breeding records of >800 female great tits assayed annually for exploratory behaviour to test whether within-individual age-dependency of reproduction varied with exploratory behaviour. We controlled for biasing effects of selective (dis)appearance and within-individual behavioural plasticity.
3. Slower and faster explorers produced moderate-sized clutches when young; faster explorers subsequently showed an increase in clutch size that diminished with age (with moderate support for declines when old), whereas slower explorers produced moderate...