Fig. 2

Phylogenetic distribution of female promiscuity estimates for the 202 Passerides species. A maximum clade credibility tree, derived from 1 000 trees, is shown. Female promiscuity estimates were derived from two sources: molecular paternity studies and the coefficient of total sperm length variation (for further details see Methods). Bars at tips indicate female promiscuity estimates for each species, with branch colouring indicating ancestral estimates of female promiscuity as inferred using the contMap function in the R package phytools. For better visualization (because of highly skewed data), species were binned into ten promiscuity categories ranging from 1 to 10, with 20–21 species in each category