Figure 3.

Reproductive lifespan is correlated with offspring survival (A) but not with live interbirth interval (B). The regression lines in both panels represent visualizations of (G)LMMs. (A). Probability of offspring survival as a function of mother’s age at birth and reproductive lifespan. The trendlines show predicted values with 95% confidence intervals from a model that also includes maternal parity, maternal death in the weaning period, and random effects of maternal identity and offspring birth year. The model indicates a statistically significant relationship between offspring survival and maternal age, as well as between offspring survival and maternal reproductive lifespan (which is depicted as categorical but modeled as continuous). The small vertical lines show our actual offspring survival data. (B) Live interbirth interval as a function of mother’s age and reproductive lifespan. The trendlines show predicted values with 95% confidence intervals from a model that also includes maternal parity, offspring death in the weaning period, and random effects of maternal identity and offspring birth year; the model indicates no statistically significant relationship between live interbirth interval and maternal age, or between live interbirth interval and reproductive lifespan. The points show our observed interbirth interval data.