Title: Oviposition substrate selection by Florida mosquitoes in response to pathogen-infected conspecific larvae Authors
Submitted to: Journal of Vector Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 24, 2013
Publication Date: May 24, 2013
Citation: Zettel Nalen, C.M., Allan, S.A., Becnel, J.J., Kaufman, P.E. 2013. Oviposition substrate selection by Florida mosquitoes in response to pathogen-infected conspecific larvae. Journal of Vector Ecology. 38(1):182-187. Interpretive Summary: Mosquitoes are important vectors of arthropod-borne diseases with the most important species in Florida being Aedes aegypti, Aedes albopictus and Culex quinquefasciatus. While insecticides are most often used for mosquito control, the use of biological control agents such as insect pathogens is a promising and environmentally friendly approach for mosquito control. For these pathogens to kill larvae, however, it is important that mosquitoes lay eggs in the water containing the pathogens. In this study conducted at the USDA Agriculture Research Service, Center for Medical, Veterinary and Agricultural Entomology in Gainesville, FL, scientists infected three mosquito species with three insect pathogens and determined that two of the pathogens did not deter mosquito oviposition. This study supports the potential use of these pathogens as biological control agents as management tools for mosquito larvae.
Technical Abstract: The sustained presence of mosquito larvae in substrates containing larval pathogens is critical for the continued maintenance of these pathogens, despite the detriment to survival of the mosquito hosts. The impact of the presence of larval mosquito pathogens with potential for biological control on oviposition choice was evaluated for three mosquito species/pathogen pairs present in Florida. These included Aedes aegypti infected with Edhazardia aedis, Aedes albopictus infected with Vavraia culicis and Culex quinquefasciatus infected with Culex nigripalpus nucleopolyhedroviruis (CuniNPV). Two-choice oviposition bioassays were performed on each host and pathogen species with one oviposition cup containing infected larvae and the other cup containing uninfected larvae (control). Both uninfected and E. aedis-infected female Ae. aegypti laid significantly fewer eggs in oviposition cups containing infected larvae. Uninfected gravid female Ae. albopictus and Cx. quinquefasciatus oviposited equally in cups containing uninfected larvae or those infected with V. culicis or CuniNPV, respectively. Gravid female Ae. albopictus infected with V. culicis did not display ovarian development and did not lay eggs. The decreased oviposition by gravid Ae. aegypti in containers containing E. aedis-infected larvae may indicate that the infected larvae produce chemicals deterring oviposition.