Parasite-host interactions

Pest insects affect the profitability, production and sustainability of food and fiber production systems. The issues UGA entomologists study focus on three questions. How do insects that vector human and animal diseases develop and reproduce? How do parasites and microbes cause disease and how can they be used to control insect pests? How do microbial symbionts benefit insects that are used to control pest species? Studies during the past year have focused on three study systems: 1) vector mosquitoes that cause human disease, 2) parasites and microbes that control populations of pest insects, and 3) microbes that promote the survival of beneficial insects that are used to control pest species. Results in the first area this year identified the molecular mechanisms by which microbes in the digestive tract of mosquitoes regulate growth and molting. Studies indicated that gut microbes are required for egg production and affect transmission of Dengue virus and malaria parasites. In the second area, results identified a new bacterium from the field that kills mosquito larvae. Bacterial symbionts associated with aphids were successfully cultured for the first time and multiple strains were genetically characterized, while immune responses of shrimp in aquaculture systems against viral pathogens were characterized. The third study system focused on parasitoid wasps that are used in biological control of several pest insect species, and which rely on viral symbionts to parasitize hosts. Results included issuance of a patent for using genes from viral symbionts as tools for transforming insect cells. Expression studies identified features of viral symbiont genes that control expression in pest insects.