by Wayne J. Crans, Rutgers University
Subgenus : Ochlerotatus
Type of Life Cycle : Aedes sollicitans Type (Multivoltine floodwater Aedes with salt tolerance)
Typical Habitat : Salt marsh floodwater pools
Larvae Present : Early Spring through Fall
Head Hairs
Upper: 4-10 branched
Lower: 3-8 branched
Antenna
Length: About ½ as long as head
Tuft: Multiple, inserted before middle of shaft
Abdominal Hairs (Segments III-VI) : 2-2-2-2.
Comb Scales : Patch
Siphon
Index: 2.5-3.0
Tuft: 4-9 Hairs, inserted beyond pecten
Pecten: Evenly spaced
Anal Segment
Saddle: Incomplete
Precratal tufts: 2
Other : 1) Gills shorter than saddle and bud-like
2) Dorsal gills slightly longer than ventral pair
GEOGRAPHIC DISTRIBUTION: Aedes cantator has a distribution that extends from Labrador, Newfoundland and Nova Scotia south along the east coast of the U.S.A to Virginia. Isolated populations have been reported from some inland areas east of the Mississippi River. The mosquito reaches greatest abundance along the Atlantic coast of New Jersey and areas that border Delaware Bay. Lesser numbers are present in inland areas of New Jersey but the mosquito does appear on the checklist of nearly every county in the state.
SEASONAL DISTRIBUTION: Aedes cantator is a multivoltine species that occurs in greatest numbers during early spring. In southern New Jersey, the initial generation of larvae can be usually be found along the upland edge of salt marsh habitats during April. Larval populations from the spring brood generally peak by mid-May and become mixed with those of Aedes sollicitans. As the season advances, larvae appear in lesser numbers but become distributed over a wider range of salt marsh habitat. Larvae can generally be collected from both salt and brackish habitats well into the fall.
LARVAL HABITAT: Aedes cantator is recognized as a salt marsh species but the larvae can be found in a wide range of floodwater habitats. The species is most common in mixed stands of Spartina patens, Spartina alterniflora and Distichlis spicata along the upland edge of salt marsh habitats. Aedes sollicitans, Culex salinarius and Anopheles bradleyi are the most common associate species in salt and brackish water habitats but Ae. cantator larvae frequently invade habitats occupied by fresh floodwater mosquitoes. In early spring, Ae. cantator may share habitat with Aedes canadensis, particularly along the margins of freshwater impoundments. Later in the season, they may be mixed with Aedes vexans, Aedes atlanticus or Psorophora ferox. Inland populations are most common in floodwater habitats that receive runoff from highways that are salted during the winter for ice removal. The species has also been reported from roadside ditches, sanitary landfills and artificial containers far removed from salt marsh habitat.
COMMON ASSOCIATE SPECIES: Ae. sollicitans, Ae. canadensis, Ae. vexans, Cx. salinarius, An. bradleyi
LARVAL COLLECTION: No special collection techniques are required to locate Aedes cantator larvae in the primary breeding habitat. The mosquito is normally the first to appear on the salt marsh in spring and larvae are abundant in a variety of floodwater situations on the marsh. On a bright day, the larvae can be seen prior to dipping and collection can be selective. Under cloudy conditions, adequate samples can be obtained by random dipping. The salt marsh pools where Ae. cantator larvae develop are high in organic matter and the water is often infused with particulates. If larvae are preserved directly from the habitat water the specimens often develop a flocculate film that interferes with some of the characters used in identification. Some collectors take care not to disturb the bottom sediment and siphon off larvae only from relatively clear water in the dipper. Others, dip indiscriminately into a bucket and transfer larvae into clean water after the particulates have settled. If the preserved larvae show evidence of contamination, one or more washings with preservative may be necessary. If the specimens are to be reared through to the adult stage, it is advisable to take the time to bring back clear habitat water in a separate container.
LARVAL IDENTIFICATION: Aedes cantator larvae closely resemble Ae. canadensis, an upland floodwater species that is also common in early spring. Both have multiple head hairs, a siphon of moderate length, evenly spaced pecten, comb scales in a patch and an incomplete anal saddle. Major differences occur in the structure of the gills. The freshwater species, Ae. canadensis, has long tapered gills that are longer than the saddle. The brackish water breeder, Ae. cantator, has gills that are considerably shorter than the saddle and bud-like in structure. Although all four gills are short in this species, the dorsal pair is always slightly longer than the ventral pair. This is an excellent diagnostic character and can be used to quickly screen for Ae. cantator in mixed larval collections. Gills frequently break off in preserved specimens but the gills of Ae. cantator are so short that they remain attached after even rough handling. If the gills are missing in a species that keys out to the couplet that separates these two species, the specimen is an Ae. canadensis.
REPRESENTATIVE COLLECTION RECORDS
Central New Jersey
Location: Cheesequake State Park, Middlesex Co..
Date: May 18
Habitat: Salt Marsh potholes
Instar: 4th & Pupae
Southern New Jersey
Location: West Creek, Ocean Co.
Date: May 2
Habitat : Breeding Depressions in Spartina patens marsh
Instar: 4th & Pupae (mixed with Ae. sollicitans)
IMPORTANCE: Aedes cantator functions as a pest in coastal areas of New Jersey but is usually overshadowed by Ae. sollicitans. Like its sibling, Ae. cantator will bite during the day if its habitat is invaded but causes most nuisance at dusk when the majority of the population is actively patrolling for a blood meal host. Most of the control efforts directed against Ae. sollicitans have an impact on Ae. cantator. Rarely is control directed specifically against this species. The mosquito has an affinity for light and is well represented in light trap collections used to monitor mosquito populations. In many cases, the numbers of Ae. cantator in light traps give an over-estimation of the numbers that are actually causing nuisance.