Few studies have been conducted to test species limits in fungi used in insect biocontrol programs. One such group of ascomycete fungi is the Hypocrella and Aschersonia group, the former with sexual, ascospore producing phases and the latter with only or usually asexual spore forming phases, but shown with recent DNA sequence data to be likely close relatives of various sexual Hypocrella species. These fungi mostly infect Homoptera insects, usually scale insects and whiteflies, and some were used early in the 1900s to control pests of citrus groves in Florida. The taxonomic boundaries between species and the linkages between sexual and asexual forms remain poorly studied, which in turn has limited the development of improved biocontrol agents. Dr. Kathie Hodge of Cornell University will work with graduate students there to analyze species relationships in the critical Aschersonia aleyrodis and A. goldiana complex, with a focus on integrating data from morphology, mating trials, and multi-gene sequences to establish species circumscriptions that reflect biological properties of the organisms while providing practical tools for rapid identification from observable phenotypic features. Taxonomic data will be gathered from existing herbarium specimens and laboratory cultures, and from material newly collected during field work in Florida and elsewhere, augmented with material provided by colleagues around the world. New taxonomic identification resources and keys will be generated. Evolutionary relationships will be assessed through phylogenetic analyses of morphological characters and of DNA sequence data obtained from several nuclear ribosomal and protein-coding genes. A graduate student will be trained in collecting techniques and in modern phylogenetic systematics. Publications and Internet-based resources will be generated to transmit the results of the work to other biologists and to the public.
