LIFE CYCLE CLASSIFICATION
Aedes communis is one of several univoltine northern Aedes
found in New England. Its life style has been adapted for life
in the arctic where conditions only permit a single generation
per year. Though conditions in New England permit multiple generations
per year, these mosquitoes have genetic "safety" defenses
that prevent their eggs from hatching until the following spring.
GEOGRAPHIC DISTRIBUTION
Aedes communis is a true snowpool species that reaches
greatest numbers north of New Jersey. The species is common throughout
the northern United States and Canada into Alaska. Throughout
its range, the species is associated with heavily forested areas
at high elevations. Aedes communis is a major pest in the
Adirondaks in New York State and the Pocono Mountain range in
Pennsylvania. In New Jersey, suitable breeding habitat is limited
to the highest elevations of Sussex County and a few areas in
Passaic County during early spring.
SEASONAL DISTRIBUTION
Aedes communis is one of the earliest mosquitoes to appear
in the Northeast. Following mild winters early instar larvae can
be collected as soon as the ice melts in late February. These
snowpools will often freeze over with a thin layer of ice during
the colder evenings with little apparent effect on these larvae.
Larvae can often be collected in late March and most populations
begin pupating during the 3rd week of April. In the
northernmost areas of New Jersey where the species is found, Ae.
communis larvae reach their 4th instar before Aedes
canadensis eggs hatch. The species is also well ahead of Aedes
stimulans and Aedes excrucians in pools where the 3
species coexist. On a statewide basis, Ae. communis pupation
corresponds with that of Aedes grossbeckii populations
from the southernmost portions of New Jersey.
LARVAL HABITAT
Aedes communis larvae are most common in deep snowpools
filled with dark colored water in forested areas above elevations
of 1500 ft. In most cases, Ae. communis is the only large
mosquito in the pools although in some years, small numbers of
another northern species, Aedes provocans, may be intermixed.
Machlonyx midge larvae, fairy shrimp, spotted newts and
wood frog tadpoles frequently share the habitat. Aedes excrucians
breed in the same pools but are generally only in their 2nd
instar when Ae. communis is pupating. Aedes communis
larvae are particularly abundant in the numerous snowpools
within High Point State Park. The Sunrise Mountain area of Stokes
State Forest is another area that provides habitat for this northern
mosquito species. Many of the pools utilized by this species have
steep banks and are too deep to enter with hip boots. Larvae from
shallower pools develop more rapidly and may pupate as early as
the 2nd week of April.
COMMON ASSOCIATE SPECIES
Ae. excrucians, Ae. stimulans, Ae. provocans
LARVAL COLLECTION
The larvae of Ae. communis rarely congregate close to the banks of the deep pools that they inhabit. Oxygen requirements are minimal in this cold water habitat and the larvae usually remain below the surface at least several feet from the shoreline. Slowly moving the dipper below the water's surface provides a bright, white background to observe the aquatic life in the pool. The mosquito larvae, Machlonyx midge larvae and fairy shrimp that are feeding in the deeper recesses of the pool stand out clearly against the white background of the dipper. Subsurface larvae can be collected by slowly raising the dipper under swimming specimens. In most cases, the larvae sound when disturbed and swim directly into the body of the moving dipper. In shallower pools, filimentous algal mats can make collection difficult by tying up the subsurface dipper and disturbing the leaf litter. On bright, sunny days, late instar Ae. communis larvae congregate in tight masses near the water's surface. When this occurs, most of the larvae become concentrated in a relatively small portion of the pool. When the larvae exhibit this balling behavior, a single dip can yield as many as 1000 specimens.
LARVAL IDENTIFICATION
Aedes communis larvae resemble Ae. stimulans and confirmation of identification is difficult with living specimens. The two species occupy similar habitat, although Ae. stimulans are normally one or more instars behind in their development. Under the microscope, both species have either single or double head hairs, comb scales in a patch, evenly spaced pecten teeth and an incomplete saddle. The gills of Ae. communis larvae almost always have a characteristic rusty-red color which may be evident in the dipper. The gills retain their color after preservation but gills are fragile and more often than not, break off in preserved specimens. Most keys use the spicules on the saddle as the major character to separate these two species. Aedes stimulans has well developed spicules on the posterior portion of the saddle. The saddle of Ae. communis is almost smooth. Proper placement of the specimen, however, is essential to accurately assess the presence or absence of spicules. The spicules are tiny teeth that protrude from the saddle and, in most cases, cannot be seen by looking directly down on the saddle. If the specimen is positioned on a white background with the siphon pointing directly up, the spicules on the posterior margin of the saddle stand out as sharp little teeth. They are very obvious in Ae. stimulans and totally absent in Ae. communis. As a result, the posterior margin of the saddle is raggedly toothed in Ae. stimulans and completely smooth in Ae. communis. A number of spring Aedes have spicules on the saddle including, Ae. aurifer, Ae. fitchii. Ae. grossbeckii, Ae. implicatus and Ae. thibaulti.
ADULT COLLECTION
The adult female Ae. communis have been reported as being
serious pests in forests where swarms are encountered in the spring.
This has not been reported in New Jersey where suitable larval
habitat is limited to the highest elevations in the state where
relatively few people live. Females bite mostly after sundown
or during the day in shaded areas near the larval habitat. They
are opportunistic feeders and will readily attack persons taking
bite counts should they enter the habitat during the day. Ae.
communis females are relatively long lived with an occasional
adult being taken in carbon dioxide baited traps as late as July
in Sussex County. Throughout the season, their numbers usually
do not constitute a major portion of the adult collections.
ADULT FEMALE IDENTIFICATION
Adult female Ae. communis are similar to the many other
univoltine Aedes on the wing during the early spring in New England.
To the unaided eye, they are a medium sized, dark, pale scaled,
black legged Aedes, with broad basal bands of cream colored scales
on the abdomen.
(From Carpenter & LaCasse University of California Press 1955)
Medium sized species. Head: Proboscis dark scaled; palpi
short, lightly sprinkled with pale scales. Occiput with narrow
curved yellowish scales in a broad median patch; erect forked
scales dark, with a few yellowish ones intermixed; appressed broad
yellowish-white scales laterally. Tori brown to black, with white
scales on inner surface. Thorax: Integument of scutum dark;
scutum clothed with a varying pattern of yellowish-white to yellow
and dark-brown scales; the dark-brown scales are usually confined
to a pair of submedian strips and posterior half-stripes. Posterior
pronotum with rather narrow yellowish-white scales dorsally, becoming
somewhat broader and paler ventrally. Scutellum with pale scales
and dark setae on the lobes. Pleura with extensive, poorly defined
patches of broad grayish-white scales. Scales on sternopleuron
extending to anterior angle, narrowly separate from patch on prealar
area. Mesepimeron with scales extending to near lower margin.
Hypostigial spot of scales absent. Lower mesepimeral bristles
two to six. Abdomen: First tergite with a median patch
of white scales; remaining tergites each brownish black, with
a broad basal band of cream colored scales, widened laterally,
particularly on posterior tergites. Venter mostly pale scaled.
Legs: Femora dark brown, sprinkled with pale scales, posterior
surface yellowish white; knee spots white. Tibiae dark brown,
sprinkled with pale scales. Tarsi dark brown, first segment more
of less sprinkled with pale scales. The front tarsal claw is variable
but usually shorter than in A. pionips and bends just beyond
the lateral claw. Wing: Length 4.5-5.0 mm. Scales dark,
a small patch of pale scales usually present on base of costa
and occasionally on base of vein 1.
REPRESENTATIVE COLLECTION RECORDS
Northern New Jersey
Location: Stokes State Forest, Sussex Co.
Date : April 14
Habitat : Snowpool on road between Steam Mill Campground and Sunrise Mt.
Instar : 4th
Northern New Jersey
Location: High Point State Park, Sussex Co.
Date : April 14
Habitat : Snowpools at top of Ridge Road
Instar : 4th & Pupae
Northern New Jersey
Location: High Point State Park, Sussex Co.
Date : May 17
Habitat : Forest at top of Ridge Road
Adult female taken during the day (bite count)
Northern New Jersey
Location: Stokes State Forest, Sussex Co.
Date : June 5
Habitat : Forest area off Upper North Shore Road Culvers Lake (Sunrise Mt.)
Adult female taken with carbon dioxide bated trap
Although Ae. communis occurs in large numbers within its restricted range, the species is not regarded as a significant pest in New Jersey. The mosquito can be a significant pest in some areas of Northeast.
The mosquito is limited to mountainous habitat in New Jersey where State and National Parks have been established and or in areas where few homes exist. The adults do not range far from the breeding sites feeding in forested areas and fields bordering forested areas. Annoyance is most intense after dark in these areas. This
mosquito host-seeks in greatest numbers during May when few people
are out of doors in Ae. communis habitat. Aedes
communis may play a role in the maintenance cycle of Jamestown
Canyon virus. Virus isolations have been obtained from larvae
suggesting transovarial transmission of this California group
virus.