Covariations between life-history traits
Individuals with longer generation times started reproducing later,
lived longer and produced fewer recruits per breeding season compared to
individuals with shorter generation times (Figure 1A-C, Table 2). In
addition, individuals with longer generation times had higher lifetime
reproductive success, but not necessarily higher individual growth rates
(Figure 1D and E, Table 2). This is partly explained by individual
growth rate being a metric that puts more weight on reproduction earlier
in life (McGraw & Caswell 1996). Consequently, we found that
individuals with the same lifespan could have quite different generation
times, with different individuals reproducing much earlier or later
relative to their lifespan (Figure 1B). There was a negative covariance
between lifespan and reproductive rate, implying that individuals that
lived longer were unlikely to produce many recruits per breeding attempt
(Figure 1F). Individuals with greater lifetime reproductive success were
those that lived longer, produced more recruits per breeding attempt,
had longer generation times and had higher expected individual growth
rates (Table 2).