Systematics of the millipede assassin bugs (Heteroptera: Reduviidae: Ectrichodiinae): flaunting aposematism and extreme sexual dimorphism

Ectrichodiinae, the millipede assassin bugs, is a subfamily of Reduviidae with >600 species in ~120 genera. Many species are aposematic and potentially sequester millipedes’ secondary metabolites for defensive purposes. Several species also display metallic coloration, known to function as an aposematic signal in other Heteroptera. It is currently unknown if metallic coloration is independently evolved or derived from non-metallic aposematism. Several species also exhibit drastic sexual dimorphism that poses significant difficulty in associating sexes using morphology alone. Dramatic differences in adult phenotypes have been shown to evolve multiple times within other insects lineages and may have done so in Ectrichodiinae. Such phenomena make Ectrichodiinae attractive for ecological and evolutionary research. However, relationships among genera have not been tested cladistically beyond a phylogeny for Neotropical taxa. A molecular phylogeny is reconstructed and is used to investigate the evolution of coloration and extreme sexual dimorphism.