COMPOSITION AND ADULT ACTIVITY OF SALT-MARSH MOSQUITOES ATTRACTED TO 1-OCTEN-3-OL, CARBON DIOXIDE, AND LIGHT IN TOPSAIL ISLAND, NORTH CAROLINA

By monitoring weekly for 3 months with Centers for Disease Control (CDC) light traps baited with carbon dioxide (CO2) and light, 12 species of mosquitoes were collected from salt-marsh areas in Topsail Island, North Carolina: Aedes vexaris, Anopheles atropos, An. bradleyi, An. crucians, An. ptmctipennis, Culex pipiens, Cx. restuans, Cx. salinarius, Ochlerotatus sollicitans, Oc. taeniorhynchus, Oc. iqfirmatus, and Urano- taenia sapphirina. The hourly activities of common salt-marsh mosquitoes, namely Oc. sollicitans, Oc. taenior- hynchus, An. atropos, An. bradleyi, and Cx. salinarius, were observed from 1700 to 0800 h by using a collection bottle rotator trap baited with l-octen-3-ol (octenol), CO2, and light. The mosquitoes exhibited different peaks of adult activity, with a significantly greater number of mosquitoes collected from 0600 to 0800 h than from Salt-marsh mosquitoes are a nuisance along the coastal areas of North Carolina and other eastern states. During peak season, they cause severe an- noyance to humans, and thus may affect the tourism industry along the coastal areas. These mosquitoes also might be important in the epidemiology of east- ern equine encephalomyelitis virus, West Nile virus, and other arboviruses (Rueda et al. 2001). Little is known about the ecology of these mosquitoes in eastern North Carolina. Knowledge of the compo- sition and biting habits of mosquitoes associated with salt-marsh areas is essential in establishing sound vector control programs. Furthermore, person- al protection measures such as repellents, tent bed- nets, and wearing of long-sleeved clothes, require information on biting and feeding behavior of salt- marsh mosquitoes. In this study, we determined the composition and hourly activity pattern of salt-marsh mosquitoes in Topsail Island, North Carolina. Mosquito collections were made in a salt-marsh area with the predominant plant species consisting of salt grass (Distichlis spicata L.), smooth cord grass (Spartiaa ahernifiora Loisel.), and black nee- dle grass (Juncus roemerianus Scheele) in the northern part of Topsail Island (34o27'N, 77o30'W), Onslow County, North Carolina. Margins of the salt marsh support dominant species such as marsh el- der (Ira imbricata Walt.), wax myrtle (Myrica cer- i{kra L.), yellow jasmine (Gelsemium semperviren,s