Behavioral and morphological aspects of the cattail mosquito, Coquillettidia perturbans (Walker) in relation to eastern equine encephalomyelitis virus in New Jersey.

摘要

In New Jersey adult cattail mosquitoes, Coquillettidia perturbans (Walker) typically begin emerging in early summer and continue through September. Oviposition occurs throughout the summer and larvae enter a winter quiescent period in several instars. The composition of overwintering larval instars varies from year to year and from site to site. Adult populations recorded through the summer show a correlation to the composition of the prior overwintering larval cohort. Sampling of overwintering larvae may be a useful tool in predicting summer adult emergence patterns.; Female Cq. perturbans mosquitoes emerge from permanent freshwater marshes and begin host-seeking shortly thereafter. Significantly more host-seeking mosquitoes were collected in forested habitats when compared to marshes. Forest and field collections did not differ significantly from one another nor did field and marsh collections. Host-seeking female Cq. perturbans did significantly more host-seeking during the night period when compared to evening or morning and tended to stay near the ground; at no time did they ascend to the forest canopy. Host-seeking Cq. perturbans and their apparent spatial disparity to roosting/nesting birds may act as a possible barrier to the transmission of eastern equine encephalomyelitis (EEE) virus.; Examination of the siphon and spiracular apparatus of Cq. perturbans revealed a specialized structure composed of the inner spiracular teeth, outer spiracular teeth, a saw, postabdominal spiracles and a spiracular apodeme. These structures act to pierce and then anchor larvae into the large air-filled aerenchyma channels found in the roots of emergent aquatic macrophytes.; Reverse transcriptase polymerase chain technique was used to test 3,491 Cq. perturbans larvae from three sites in southern New Jersey in 1996. Despite EEE virus circulating at all three sites the season prior to testing, no isolations were obtained. The absence of EEE virus from Cq. perturbans larvae in this study does not necessarily rule out the occurrence of transovarial transmission, but may reflect other factors such as small sample size and/or low minimum field infection rates. The results of this study, coupled with those of an earlier study indicate that the seasonal reintroduction of EEE virus by way of transovarial transmission in Cq. perturbans is unlikely.