Evolutionary divergence in a non-genitalic sexual contact character in the beetle genus Choleva

It has been argued that non-genitalic contact characters display similar evolutionary patterns as genitalic characters. We studied the shape of the male metatrochanter in the beetle genus Choleva (Leiodidae). We used multi-locus molecular phylogenetics to reconstruct the phylogeny for 19 species-level taxa, and quantified their metatrochanter shape by applying spherical harmonics to microcomputed tomography scans. As a control, we did the same for the (undifferentiated) male mesotrochanter. Finally, we obtained maximum likelihood estimates for Pagel’s κ for 31 multiple aspects of shape to estimate the tempo of evolution. We found that, while the overall shape of the metatrochanters has evolved in a continuous fashion over time, specific aspects of the shape have evolved punctuationally with speciation events. Unexpectedly, in the undifferentiated mesotrochanter, we also found evidence for punctuated evolution, which may reflect developmental coupling of leg morphology for the middle and hind legs.