Discovery, distribution, and abundance of the newly introduced mosquito Ochlerotatus japonicus (Diptera : Culicidae) in connecticut, USA

The earliest documented specimen of an exotic east Asian mosquito Ochlerota tus (Finlaya) japonicas japonicus (Theobald) in the Western Hemisphere is r eported along with the results of a state wide survey to determine the dist ribution and abundance of this mosquito in Connecticut. Ochlerotatus japoni cus was collected from 87 locations in eight counties. It is established th roughout the state and occurs in a variety of natural and artificial contai ner habitats including discarded tire casings, bird baths, wooden barrels, porcelain bath tubs (used for watering animals), plastic milk cartons, toys , vinyl tarpaulins (covering wood piles and swimming pools), exposed rock h oles in stream beds, tree holes, subterranean catch basins, surface water r ain pools, and spring-fed depressions. Larvae were particularly common in c ontainers with water, decaying leaves, and algae, in shaded and sunlit area s and, in rock-pool habitats along streambeds, in association with Ochlerot atus atropalpus (Coquillett). Adult females were collected in sod grass-inf used gravid and CO2-baited light traps, from early June through October, wi th peak collections in September. Biting females were collected by human ba it method augmented with CO2, verifying its capacity to feed on humans. The ovitraps used in this study were not effective for recovering this species . Our results suggest that Oc. japonicas was introduced into Connecticut be tween 1992 and 1998. Because of the ability of Oc. japonicas to transmit We st Nile virus, and because of the recent detection of this virus in field-c ollected specimens, the introduction of Oc. japonicas is considered a signi ficant public health development.