A life cycle classification system has been proposed for mosquito
species that occur in New Jersey (Crans and McNelly 1997). Classification
is based upon four characteristics, including where eggs are laid,
the typical larval habitat, the number of generations per year,
and the stage in which overwintering takes place. These four characteristics
provide the framework for building life cycle Types, each of which
is headed by a common representative species. Developed for New
Jersey mosquito species, the system could be used to include classifications
for the entire northeastern region. The adoption of such a system
should be of benefit to those interested in mosquito biology and
Aedes sollicitans (Walker), the salt marsh mosquito, is
a common mosquito along the eastern coast of North America, from
the Gulf of Mexico to Nova Scotia. Throughout much of its range,
Ae. sollicitans is a serious nuisance. In New Jersey, a
recent poll of mosquito control agencies ranked Ae. sollicitans
as the second most important pest species statewide, and was ranked
number one by agencies in the southern half of the state (Crans
1996). Ae. sollicitans is also an efficient vector of eastern
equine encephalitis virus (EEEV) and is considered to be the probable
human vector in coastal New Jersey.
Ae. sollicitans eggs are deposited individually on the
moist substrate in and around depressions that occur on tidal
wetlands. Breeding sites are located in areas of the saltmarsh
not subject to daily tidal flushing. These sites tend to be slightly
higher in elevation than the surrounding marsh, and are thus flooded
only by exceptional high tides - storm, full moon, new moon tides.
Particularly in New Jersey, breeding depressions are associated
with Spartina patens (saltmeadow cordgrass).
Provided the female has obtained a full blood meal, as many as
200 eggs can be deposited. Eggs must dry for a period of 24 hours
before they are viable. The eggs are desiccant resistant, and
may remain viable for up to five years.
Once flooded, larval development is rapid within this transient habitat. In southern New Jersey, development (to the point of emergence) can take place in 4-5 days under optimal conditions. Development is subject to environmental conditions, and slows during the cooler temperatures of spring and fall.
Ae. sollicitans requires a blood meal for the production
of eggs. Host seeking typically occurs during the twilight periods
of dusk and dawn, however, resting females will actively bite
during the day if disturbed. Mammalian blood meals are most frequently
reported in the literature (Thompson 1963, Crans 1964), though
involvement with other hosts, particularly birds, may be underestimated
(Crans et al. 1996). Inland dispersal of Ae. sollicitans,
the result of searching flights for both food and mates, is influenced
by the direction and intensity of winds.
In New Jersey, Ae. sollicitans is most abundant between
the months of May to October. Egg production proceeds throughout
this time period; Ae. sollicitans is a multivoltine species.
In the fall, egg hatch diminishes with the reduction in light
and temperature. What eggs remain enter a true diapause for the
duration of the winter.
Ae. sollicitans is offered as the representative species
of the Aedes sollicitans Type. This Type includes four
Aedine species : Aedes cantator, Aedes dorsalis, Ae.
sollicitans, and Aedes taeniohynchus.
The proposed classification system actually includes two multivoltine Aedes Types, the Aedes vexans Type and the Aedes sollicitans Type. The Aedes
vexans Type includes fifteen Aedes and Psorophora species. These two Types require differentiation based upon the site of larval development. Aedes vexans Type larvae use a wide variety of
temporary freshwater habitats in which to develop. Larvae of species included in the Aedes sollicitans Type, however, develop in brackish and saline temporary pools associated with tidal wetlands.
The Aedes sollicitans Type can be characterized using the following life cycle characteristics:
* Eggs laid on substrate that will be flooded by exceptional high tides
* Larvae develop in brackish to saline temporary saltmarsh pools
* Multiple generations each year
* Overwinters in the egg stage
Crans, W.J. 1964. Continued host preference studies with New Jersey mosquitoes. Proc. N.J. Mosq. Exterm. Assoc. 51: 50-58.
Crans, W.J. 1996. The ten most important mosquito species in New Jersey. N.J.M.C.A. Newsletter Vol. 3, No.2 : 3.
Crans, W.J. and J.R. McNelly. 1997. Classification system for the life cycles of mosquitoes in New Jersey. Proc. N.J. Mosq. Control Assoc. 84: 42-48.
Crans, W.J., D.A. Sprenger and F. Mahmood. 1996. The blood feeding habits of Aedes sollicitans (Walker) in relation to eastern equine encephalitis virus in coastal areas of New Jersey. II. Results of experiments with caged mosquitoes and the effects of temperature and physiological age on host selection. J. Vec. Ecol. 21 (1):1-5.
Thompson, E.G., D.E. Hayes and K.W. Ludlam. 1963. Notes on the feeding habits of Aedes sollicitans in the Chincoteaque-Assateaque Island area of Virginia. Mosq. News 23:297-298.