Studies on the Biology of Culiseta Inornata (Diptera: Culicidae) in Three Regions of Central California, USA1

Abstract

Indigenous adult and larval populations of Culiseta inornata (Diptera: Culicidae) were sampled in 3 regions, Suisun Marsh, Sacramento Valley, and the Sierra Nevada foothills, in central California, USA. Collection data demonstrated that Cs. inornata is predominately a rural species in those regions sampled. Adult and larval abundance and productivity were significantly higher in coastal salt marsh (Suisun Marsh) habitats and lowest in the Sierra Nevada foothills. Flight activity was optimal between 9 and 18 °C and decreased sharply below 6 °C and above 18 °C. Increasing seasonal rates of autogeny were correlated with reduced activity and indicated a possible homeostatic response to assure egg production during periods of minimal activity. Female populations gonotrophically aged by the Polovodova method were significantly older in rural areas and in the Suisun Marsh. The follicular resting stages of nulliparous females collected in CO2 light traps and reared from field pupae showed that more than 90% of the females examined exhibited primary follicles in stage II. The resting stages of parous females collected in CO2 light traps included a significant portion (35%) with primary follicles not developed beyond stages I or I–II.