NSW Arbovirus Surveillance & Vector Monitoring Program Ochlerotatus vigilax
Note that 'Ochlerotatus vigilax' prior to 2000, was known as 'Aedes vigilax'.
Female:A mid-sized mosquito of dark appearance with banded legs; proboscis with pale scaling on basal two-thirds underside; scutum with dark bronze and some golden scales; wings dark scaled with sparse mottling of narrow white scales mainly along front veins; hind legs with femur and tibia mottled, tarsi with basal bands; tergites dark with pale basal bands; sternites pale scaled with dark lateral apical or sub-apical patches (occasionally bands). (Click here for a large photograph of the adult).
Females may be confused with other species with mottled proboscis and banded legs, e.g. Oc. theobaldi (pale wing scales broader than dark scales), Oc. flavifrons (dark blotch on wing membrane), and Oc. alboannulatus, Oc. camptorhynchus, Oc. procax (with dark scaled wings).
NSW (coastline from north to south, and far southwest in saline areas of Murray), Vic (northeast of coastal Gippsland and saline areas in lower Murray Valley), SA (Gulf coastal and saline river areas in Murray valley), (also Qld, NT, WA); essentially coastal and associated with estuaries and mangrove zones, but it disperses for many tens of kilometres from larval habitats.
Ochlerotatus vigilax breed in saline habitats on mudflats usually behind mangroves. Hatching of eggs is in response to innundation of mudflats through extremely high tides, although rainfall can initiate hatching and breeding (click here for the lastest high tide values for the current mosquito season). Adults are most abundant in summer months and in NSW are active from mid-spring through autumn; they attack humans and other animals readily and bite during the day in sheltered areas (or full sunlight in larval habitats), but also at evening and night (Click here for a photograph of the larvae).
This is the major coastal pest species for NSW and more northern areas, and also for parts of coastal SA, where it may succeed and replace Oc. camptorhynchus as summer progresses; because it can disperse and be windblown for many kilometres it can create nuisance problems over large and diverse areas. It has been shown to be able to transmit Murray Valley encephalitis (MVE) and Ross River (and other) viruses in laboratory studies, but although it is unlikely to be of concern for MVE and Kunjin because of distribution, it is accepted as the major vector of Ross River and Barmah Forest (and others such as Gan Gan) virus in coastal areas of NSW because of repeated virus isolations from collections in north, central and south coast areas; it is also known to carry dog heartworm.