Fig. 1.—

Phylogenetic tree of 166 opsins obtained using Phylobayes and a GTR-Γ model. On each node, the three support values shown are (left to right): PP of opsin + outgroup data set, PP of opsin unrooted data set, ML bootstrap of the opsin + outgroup data set. All phylogenetic trees were performed under GTR-Γ. The lack of support for the UV + Blue opsin clade in the ML tree is caused by phylogenetic instability of a single opsin from the human ectoparasitic louse (compare supplementary figs. S1–S3, Supplementary Material online). The orphan sequence not assigned to a named clade derives from pea aphid (Acyrthosiphon pisum). The same tree with species names is given in supplementary figure S1, Supplementary Material online.