. Author manuscript; available in PMC: 2020 Dec 1.

Published in final edited form as: Am Nat. 2019 Oct 11;194(6):745–759. doi: 10.1086/705810

Table 1.

Summary of putative indicators of multivariate female quality from principal components analysis

Component	Variable loadings*	Variance Explained	Description	Correlation with measures of fitness
				LRS	λ_IND
PC1	AFLB: −0.87 IBI_s: −0.79 RL: 0.20 OS: 0.27	38%	Females with early ages at first reproduction and short interbirth intervals (fast birth rates) versus females with late ages at first reproduction and long interbirth intervals (slow birth rates). This axis represents a ‘quality’ axis.	0.31 p=0.005	0.36 p=0.0008
PC2	AFLB: −0.03 IBI_s: −0.39 RL: −0.70 OS: −0.69	28%	Females with short lives and low offspring survival but short interbirth intervals (fast reproduction) versus females with long lives and high offspring survival but long interbirth intervals (slow reproduction). This axis thus describes both tradeoffs with interbirth interval length and evidence of quality differences (seen in the covariation between offspring survival and reproductive lifespan).	0.54 p<0.001	0.33 p=0.003