Table 2.

Results of four ‘tradeoff models’ of the relationships between surviving interbirth interval and reproductive lifespan, and between surviving interbirth interval and offspring survival, controlling for individual quality (see fig 4; see also table S5 for tradeoff models including outliers and using alternative definition of reproductive lifespan).

Model description*	Predictor	Effect size (Std. Err.)	p value
1. Reproductive Lifespan ~ Surviving interbirth interval (fig. 4A)	IBIs	0.001 (0.004)	0.791
2. Reproductive Lifespan ~ Surviving interbirth interval + Quality score (fig. 4B)	IBIs	0.02 (0.007)	0.003
	Quality score	2.47 (0.69)	0.0006
3. Proportion offspring surviving ~ Surviving interbirth interval (fig. 4C)	IBIs	0 (1.89e-04)	0.815
4. Proportion offspring surviving ~ Surviving interbirth interval + Quality score (fig. 4D)	IBIs	0.001 (2.67e-04)	0.0001
	Quality score	0.13 (0.03)	5.4e-06

^*The tilde (~) in each model indicates that that model tests the dependence of the response variable on the predictor variables (which are listed after the tilde).