Testing relationships of the termite-assassins: A molecular phylogeny of Salyavatinae and Sphaeridopinae (Hemiptera: Reduviidae)

Salyavatinae is a subfamily of assassin bugs containing specialist predators of termites. They exhibit a unique prey-capture strategy of "fishing" with carcasses of recently-predated termites to capture surveiling worker termites one after another. Recently, a morphological analysis has found that Salyavatinae may be a paraphyletic assemblage and that the only Neotropical genus of this subfamily may be closely related to the small, Neotropical, termite-specialist subfamily of Sphaeridopinae.  In an attempt to clarify subfamily-level relationships, the first molecular phylogeny of Salyavatinae is constructed using four ribosomal gene loci (28S D2 region, 28S D3-D5 region, 18S and 16S) and two nuclear protein encoding genes (Wingless [Wg] and Deformed [Dfd]) from 20 morphospecies in five genera of Salyavatinae. In order to test the monophyly of Salyavatinae and the placement of Sphaeridopinae, molecular data from Sphaeridops amoenus (Sphaeridopinae) and two representatives from each major clade of higher Reduviidae are included in the analysis, for a total dataset of 52 taxa. Salient morphological characters as well as biographical distribution data are mapped onto the resulting phylogeny. The molecular dataset provides evidence that Sphaeridopinae and Salyavatinae together are monophyletic. It also shows a single origin for expanded fore tibiae in Salyavatinae, mysterious structures with unknown function for the insect. The problems associated with highly autapomorphic taxa and possible solutions are discussed in relation to the placement of Sphaeridopinae.