BIONOMICS OF ANOPHELES-QUADRIMACULATUS AND CULEX-ERRATICUS (DIPTERA, CULICIDAE) IN THE FALLS LAKE BASIN, NORTH-CAROLINA - SEASONAL-CHANGES IN ABUNDANCE AND GONOTROPHIC STATUS, AND HOST-FEEDING PATTERNS

Larval and adult Anopheles quadrimaculatus Say (sensu lato) and Culex erraticus (Dyar & Knab) were collected at Falls of the Neuse Lake (Fal ls Lake) in North Carolina from May 1985 to December 1986. Adult mosqu itoes were aspirated weekly from shelters in woodlands adjacent to lar val sampling sites. An. quadrimaculatus and Cx. erraticus comprised >9 5% of the total number of mosquitoes collected. An. quadrimaculatus ad ults exhibited vernal and autumnal peaks of abundance during both year s. Cx. erraticus adults exhibited several peaks of abundance in summer and early fall of both years. An. quadrimaculatus initiated blood fee ding in May and April 1985 and 1986, respectively. Only unfed females were found in late fall and winter. Cx. erraticus initiated blood feed ing earlier than An. quadrimaculatus. In 1985, almost-equal-to 25% of the females in the first collection in May contained a blood meal, whe reas in 1986, almost-equal-to 10% of the females in the first collecti on in April were blood fed. Females of both species ceased blood feedi ng in late fall. Larvae were sampled on a weekly basis from lake edge, flood plain, and creek edge habitats. Generally, An. quadrimaculatus larvae were most abundant in lake edge and flood plain habitats, where as Cx. erraticus larvae were most abundant in the creek edge habitat. The population dynamics of An. quadrimaculatus were associated with se asonal changes in the level of Falls Lake. In 1985 and 1986, the level of Falls Lake gradually declined from May to mid-August until heavy r ainfall caused a 1-m rise in lake level. Populations of An. quadrimacu latus larvae and adults increased significantly following the rise in the level of Falls Lake. In contrast, the abundance of larval and adul t Cx. erraticus decreased with rising lake levels in late August. Wate r level management should be an effective method for controlling popul ations of An. quadrimaculatus but not for Cx. erraticus. Blood-fed mos quitoes were tested to identify bloodmeal hosts using both capillary p recipitin and enzyme-linked immunosorbent assays. An. quadrimaculatus (n = 941) predominantly (99%) fed on mammals, principally white-tailed deer and horses. Cx. erraticus (n = 348) exhibited an opportunistic h ost-feeding pattern; blood meals were taken from mammalian (49%), rept ile or amphibian (20%), and avian (31%) hosts.