UC Riverside

Reduviidae (assassin bugs), the largest clade of predatory non-holometabolous insects (~6,800 species), display a range of prey specializations and members of one subfamily, the Triatominae, feed on vertebrate blood and are the vectors of Trypanosoma cruzi. A combination of phylogenetic analyses and taxonomic revisions of several target taxa are conducted to improve our knowledge of reduviid systematics. The emphasis is on resolving the highly polyphyletic Reduviinae, shedding light on the prevalence of trypanosomes in a species of endemic Triatominae in Southern California, revising a genus of Malagasy Reduviinae and the Indo-Pacific group of Physoderinae, a group once thought to be sister to the Triatominae.

A higher-level phylogeny of Reduviidae (178 taxa, 18 subfamilies) is reconstructed to investigate the relationships among subfamilies using five gene regions, with extensive sampling of the polyphyletic Reduviinae. Results indicate that Reduviinae fall into 11-14 separate clades and Triatominae may be paraphyletic. The evolution of blood-feeding may thus have occurred once or twice independently among predatory reduviids. Fossil-calibrated divergence time estimates show that Reduviidae originated in the Middle Jurassic (~178Ma), but the majority of extant lineages only emerged in the Late Cretaceous (~97Ma). Ancestral state reconstructions indicate bark-association as the ancestral microhabitat for Higher Reduviidae.

A survey on the infection rate of Triatoma protracta with T. cruzi in Southern California show relatively high rates (19-36%) with geographical variability but no clear temporal differences. A taxonomic revision of the Malagasy endemic reduviine Durevius is provided and 2 new species described.

A phylogenetic analysis of Physoderinae (57 taxa) based on 57 morphological characters (50 discrete, 7 continuous) indicate that the Neotropical Physoderinae are sister to all remaining Physoderinae except Porcelloderes. The morphologically diverse Malagasy physoderines are not monophyletic. Physoderine diversity in the Oriental and Australasian regions is here revised based on the most extensive collection of specimens (902) assembled to date. Based on the phylogenetic analysis, the generic classification of Old World Physoderinae is revised. Three new genera are created, 15 new species described, 11 new combinations created, and 14 synonyms established. Diagnoses and identification keys for Old World genera are provided and species illustrated.