UC Riverside

The current dissertation project integrates revisionary taxonomy, comparative morphology, molecular phylogenetics and comparative evolutionary analyses to investigate the diversity and evolution of assassin bugs, focusing on the Malagasy Bekilya group (Peiratinae) and the New World Harpactorini (Harpactorinae). Four objectives and research topics are addressed. (1) Association of dimorphic sexes in the Bekilya group and taxonomic revisions. Members of three genera of Malagasy Peiratinae, Bekilya Villiers, Hovacoris Villiers, and Mutillocoris Villiers, appear to be mimics of mutillid wasps. Mutillocoris was originally described only from female specimens, the two remaining genera from males. Molecular data demonstrate that species of Mutillocoris represent females of Bekilya and Hovacoris. Mutillocoris is therefore synonymized with Bekilya. The current project treats a total of 10 species as belonging to the Bekilya group, including 6 species that are described as new. (2) Investigation of the taxonomic distribution of sticky glands. Specialized glands have been known from species of Zelus Fabricius for more than 50 years. The current study examines 67 taxa of Reduviidae and finds sticky glands in 12 genera of Harpactorini. (3) Reconstruct a molecular phylogeny of Harpactorini and investigate the evolution of sticky trap predation and its relationship to accelerated morphological diversification. A molecular phylogeny of the Harpactorini is presented, sampling 198 taxa of Harpactorini and using 5 genes. Comparative analyses show that bugs exhibiting sticky trap predation have evolved more slender and longer fore femora than non-sticky bugs. Using phylogenetically independent contrast analyses, correlated evolution between femoral thickness and length is documented, thus providing support for the existence of a functional constraint on the fore femur and a trade-off between femoral thickness and length. It is argued that the novel sticky trap predation strategy may allow sticky bugs to alleviate functional constraints on the fore femur and thus to attain a higher rate of fore leg evolution than other Harpactorini or Reduviidae. (4) Taxonomic revision of Zelus Fabricius, 1803. The harpactorine genus Zelus is revised based on examination of 11,000 specimens, recognizing 70 species as valid. Twenty-four new species are described, 13 new synonymies proposed, and 5 previously synonymized names are returned to species status. Additionally, eight species that were previously treated as Zelus are removed from this genus.