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letter
. 2020 Jan 13;4(1):44–53. doi: 10.1002/evl3.156

Figure 2.

Figure 2

(A) Maturation bias is associated with polygamy bias in birds (mean [±SE] of 1000 phylogenetic generalized least squares (PGLS) models using different phylogenies: slope = 0.069 [<0.001], P < 0.001 [<0.001]; n = 201 species). Maturation bias was estimated as log(male age at maturation/female age at maturation). Polygamy was scored for each sex separately on a 5‐point scale, from 0 to 4, and polygamy bias was computed as male minus female polygamy score (see Methods section). Point size is proportional to the sample size of each data point showing 1–75 observations. (B) Maturation bias is associated with sexual size dimorphism in birds (slope = 0.129 [<0.001], P < 0.001 [<0.001]; n = 199 species). Sexual size dimorphism was estimated as log(adult male mass/adult female mass). Point size is proportional to the sample size of each data point showing one to five observations. (C) Maturation bias in relation to the adult sex ratio (slope = −0.081 [<0.001], P < 0.001 [<0.001]; n = 183 species). Adult sex ratio (ASR) was estimated as the proportion of males in the adult population (arcsine‐square‐root‐transformed). The regression (solid) lines show mean slope fitted by phylogenetic regressions using 1000 different phylogenies. In panel (C), second x‐axis labels correspond to the back transformed ASR (even ASR shown by vertical dotted line). Point size is proportional to the sample size of each data point showing one to five observations. Different colored points on all plots show where the exemplified species in photos appear in each plot. For further details of these relationships, see also Supporting Information Figure S1. Photo credits from left to right: Jacana spinosa © G. Friesen; Chiroxiphia lanceolata by © G. Friesen; Cisticola juncidis by Afsarnayakkan (https://bit.ly/2HnllT0), used under CC BY‐SA 4.0, cropped and rescaled from original; Tetrao urogallus by sighmanb (https://bit.ly/2Hnl1DM), used under CC BY 2.0, cropped and rescaled from original; Rostratula benghalensis by J. Thompson (https://bit.ly/2HjGg9x), used under CC BY 2.0, cropped and rescaled from original; Tympanuchus cupido by © S. Henkanaththegedara.