DR. GEORGE F. O'MEARA
Reproduced from Wing Beats of the AMCA, the official publication of the Florida Mosquito Control Association. Please use the following citation when referring to this article:
O'Meara, G. F. 1992. The eastern saltmarsh mosquito Aedes sollicitans. Wing Beats, Vol. 3(4):5.
The eastern saltmarsh mosquito Aedes sollicitans.
Importance
Aedes sollicitans is a major pest species in many areas on the eastern seaboard of the United States and Canada. Besides being a serious nuisance, the eastern saltmarsh mosquito is an important vector of Eastern equine encephalitis, Venezuelan equine encephalitis and dog heartworm. Numerous coastal mosquito control districts have been established primarily to combat the pest and disease problems caused by Ae. sollicitans.
Geographic DIstribution
Range extends along the Atlantic Coast of North America from New Brunswick to Texas with populations also occurring in the Bahamas and Greater Antilles. Although it is occasionally found at inland saline locations as far west as Arizona, Ae. sollicitans does not occur on the Pacific Coast.
Adult Description
Aedes sollicitans is a medium-sized species with a brightly colored scaling pattern. A conspicuous band of white scales rings the center of proboscis and the anterior portion of the hindtarsomers. The middle portion of hindtarsomere 1 has a distinctive band of yellow scales bordered by darker scales. Dark and pale scales intermixed on wings. A pale-scaled median, longitudinal stripe covers the top of the abdomen. The thorax is covered on the sides with dense patches of white scales and on the top with brown, yellow, golden and white scales.
Larval Habitat
Eggs are laid individually on moist substrate around depression at the upper reaches of grassy saltmarshes, especially in areas with salt meadow grass or saltgrass. Man-made habitats for this mosquito include, but are not limited to, disposal sites for dredged materials, mine tailings, or wastewater from food processing operations.
Associated Species
In the southern part of its range, immature Ae. sollicitans are often found associated with Ae. taeniorhynchus, Anopheles atropos and An. bradleyi; whereas to the north they are more commonly found with immature Ae. cantator.
Larval Behavior
Aedes sollicitans larvae develop in pools and puddles that are produced by exceptional high tides and/or heavy rainfalls. Since these aquatic systems tend to dry up quickly, survival to the adult stage often depends on rapid larval development. The duration of the larval stages in Ae. sollicitans is noticeable shorter than that of Ae. taeniorhynchus, a species more commonly associated with shaded aquatic habitats. Under optimal conditions emergence of adult Ae. sollicitans can occur in as little 4 to 5 days following egg hatch.
Most of the inland dispersal from coastal marshes seems to result from gradual searching flights for food or mates. The average distance that a brood moves inland before returning to the coast is influenced by the direction and intensity of the prevailing winds, but generally this distance is less than five miles. Under favorable environmental conditions, young Ae. sollicitans females move about 1 mile per day. Once they have laid their first egg batch, females tend to remain much closer to the saltmarshes.
Bloodfeeding
Host-seeking flights occur primarily during the twilight periods (more so in the evening than in the morning). Yet, resting females will readily attack hosts that enter their territory during the daytime. Chances for such opportunistic feeding are enhanced by the fact that this mosquito rests in relatively open areas. Essentially all Ae. sollicitans females require a blood meal for the production of each egg batch. Females obtain blood primarily from mammals and to a lesser extent from birds.
Seasonality
In the south, peak abundance of adults usually occurs in the spring and fall, although it is possible to have active adults at other times of the year. In the north, Ae. sollicitans adults are most abundant in the summer and by the beginning of fall, eggs laid by these females are in a diapause which lasts through the winter.
Dr. O'Meara is a Professor of Entomology at the University of Florida's Medical Entomology Laboratory in Vero Beach