Fig. 1: The evolution of female-limited colour polymorphisms in Ischnura damselflies.
From: The genomics and evolution of inter-sexual mimicry and female-limited polymorphisms in damselflies
a, A previous phylogenetic study and ancestral state reconstruction28 proposed that the genus Ischnura had a sexually dimorphic ancestor, with O-like females (red circle). The O morph is markedly different from males, having a bronze-brown thorax and faint stripes, instead of the black thoracic stripes on a bright blue background of males. b, Male mimicry (A females, blue circle) has evolved more than once, for instance, in an ancestor of the (expanded) clade that includes the common bluetail (I. elegans, outlined with solid line) and the tropical bluetail (I. senegalensis, outlined with dashed line). c, I. elegans is a trimorphic species, due to the recent evolution of a third female morph, I (yellow circle). In I. elegans, morph inheritance follows a dominance hierarchy, where the most dominant allele produces the A morph and two copies of the most recessive allele are required for the development of O females. In contrast, the O allele is dominant in I. senegalensis106. Terminal nodes in the phylogeny represent different species. Grey triangles represent other clades of Ischnura, which are collapsed for clarity. Damselfly images adapted from ref. 25 under a Creative Commons licence CC BY 4.0.
