# Aedes notoscriptus

Aedes notoscriptus, commonly known as the Australian backyard mosquito, is a species of mosquito native to Australia, New Zealand, and the southwestern Pacific islands, including Papua New Guinea, the Solomon Islands, the Philippines, New Caledonia, and Indonesia. It has recently been introduced to Southern California, where it was first detected in 2014. This mosquito is recognized for its aggressive daytime biting behavior and its role as a vector for several diseases, such as dog heartworm (Dirofilaria immitis), Ross River virus, and Barmah Forest virus.

## Taxonomy

Aedes notoscriptus belongs to the genus Aedes within the subgenus Rampamyia. It was first described by entomologist Frederick A. Askew Skuse in 1889 based on specimens from New South Wales, Australia. Historically, it has been classified under the synonym Ochlerotatus notoscriptus due to taxonomic revisions within the tribe Aedini, though it is now widely recognized under its original name.

## Description

Aedes notoscriptus is a small to medium-sized mosquito distinguished by its "spotty" appearance. It features clusters of bright-white scales on the ends of its palps and across the lateral thorax. The proboscis is dark with a median pale ring, and the scutum displays lyre-shaped lateral silvery lines, narrow median silvery lines, and anterior sublateral golden lines of scales. Its wings are entirely dark-scaled dorsally, and the legs exhibit pale scale markings on the femora and tibiae. These morphological traits aid in its identification among other *Aedes* species.

## Distribution

Aedes notoscriptus is native to Australia, New Zealand, and the southwestern Pacific islands, including Papua New Guinea, the Solomon Islands, the Philippines, New Caledonia, and Indonesia. In Australia, it is widespread and commonly found in both urban and rural areas. In New Zealand, it is prevalent across the Wellington Province and beyond. The species has established invasive populations in Southern California since its detection in 2014, likely introduced via international trade or travel, and has spread across multiple counties.

## Behavior

Aedes notoscriptus is a diurnal feeder, exhibiting aggressive biting behavior, particularly in shaded areas during the daytime. It has a broad host range, feeding on humans, dogs, brushtail possum, birds, cats, and flying foxes, which enhances its capacity to transmit various pathogens across species. Its adaptability to urban environments and preference for shaded habitats make it a common nuisance in residential areas.

## Ecology

This mosquito breeds in container habitats, utilizing both natural and artificial water sources. Natural breeding sites include tree holes, bamboo stumps, and rock pools, while artificial sites encompass roof gutters, cement containers, and discarded items that hold water. Its life cycle—from egg to larva, pupa, and adult—varies with temperature, averaging 11 days in summer and 20 days in winter in Brisbane, Australia. This adaptability to diverse breeding sites contributes to its success in urban settings.

## Medical Importance

Aedes notoscriptus is a significant disease vector. It is the primary vector of dog heartworm (Dirofilaria immitis) in Australia, posing a threat to canine health. It also transmits Ross River virus and Barmah Forest virus, both of which cause notable human morbidity in Australia, characterized by fever, rash, and joint pain. Laboratory studies have demonstrated its competence to transmit additional viruses, including Japanese encephalitis, Rift Valley fever, West Nile, chikungunya, and yellow fever viruses, though its role in natural transmission of these pathogens is less clear. Conversely, it is an inefficient vector for dengue and Zika viruses, limiting its significance in their spread.

## Control Measures

Controlling Aedes notoscriptus populations involves eliminating standing water to prevent larval development, applying larvicides to breeding sites, and using adulticides to reduce adult numbers. Public health initiatives include surveillance to track its spread, particularly in invasive regions like Southern California, and community efforts to remove potential breeding sites, such as water-holding containers around homes. These strategies are critical in mitigating its impact on human and animal health.