Abstract

Behavioral and physiological ecology of mosquito disease vectors (Diptera: Culicidae) as a function of aquatic macrophyte invasions

by

Rakim Kareem Turnipseed

Doctor of Philosophy in Environmental Science, Policy, and Management

University of California, Berkeley

Professor George K. Roderick, Chair

To investigate the impact of invasive aquatic weeds on mosquito populations in the Sacramento-San Joaquin River Delta, field and laboratory experiments were conducted to test the impact of invasive aquatic plants (water hyacinth, water primrose, and Brazilian waterweed) on the behavioral ecology of Culex pipiens, a primary mosquito vector for West Nile Virus (WNV). In an outdoor caged experiment containing larval mosquitoes and predatory Mosquitofish, mosquito survival was significantly higher among high densities of the three plant species than vegetation-free water. In intermediate plant densities, mosquito survival was higher among water hyacinth than both Brazilian waterweed and water primrose. In low plant densities, mosquito survival was higher among water hyacinth than Brazilian waterweed and vegetation-free water. In another caged experiment containing mesocosms, mosquito larval development time was completed more rapidly in the presence of intermediate densities of water hyacinth than all other treatments. In an outdoor caged choice experiment, mosquitoes laid more eggs in mesocosms containing intermediate densities of water hyacinth than all other treatments. Laboratory choice tests and an olfactometer experiment revealed that mosquitoes were more attracted to water that contained plants or plant infusions than water alone. These results suggest that water hyacinth provides both physical and chemical cues to some species of mosquitoes. Effective management of invasive water hyacinth in waterways may thus reduce mosquito populations and reduce human health risk.