Dispersal and Survival of Field and Laboratory Strains of Culex Tarsalis (Diptera: Culicidae)1

Abstract

Mark-release-recapture studies were made in Kern County, California, of the field dispersal and survival of Culex tarsalis of laboratory-colony and field origin. Genetically translocated males from the laboratory generally were recaptured close to the points of release and did not appear to disperse well into the native population. Overall recapture rates for colony females were very high (27.4–41.0%) compared to rates for field females (3.4–13.1 %) and dispersal, in terms of distance or recaptures from release points, was significantly less lor colony than for field females. Regression estimates of daily survival, which reflect loss from mortality and emigration, ranged from 38% to 44% for colony females and from 60% to 72% for field specimens. Colony mosquitoes had the same or similar genetic background as translocation males that were released in experimental genetic control trials. Apparent behavioral differences between colony and field mosquitoes and a relative unfitness for survival of colony specimens could present major barriers to successful genetic control of Cx. tarsalis .