Sources of variation in individual life-histories
Individual generation time in this metapopulation has a mean of 1.77 (SD=0.90) and ranged from 1 to 5.6 years. They were on average 0.20 years longer for males compared with females. Males also lived longer, started contributing to the adult population later in life than females and produced on average 0.10 fewer recruits per year (Table 1). Among-population differences and among birth year differences each explained around 5% of the variation in individual estimates of generation time (Table 1).
Quantitative genetic analyses estimated an additive genetic variance of 0.04 (SE=0.03) and a log-likelihood ratio test supported the hypothesis of non-zero additive genetic variance. Additive genetic variance explained around 4.8% (SE =3.2) of the variation in individual estimates of generation time, which translates into an evolvability (i.e. mean scaled additive genetic variance) of 1.27% (SE=1.29). See Table S2 for the full results of the animal model.