Types of mosquitoes

The saltmarsh mosquito is Brisbane’s most significant mosquito pest due to:

• large numbers simultaneously hatching after trigger events such as heavy rain or high tides
• adults being highly mobile and dispersing inland at least five to 10 kilometres
• female mosquitoes having highly aggressive biting behaviour
• having the capacity to carry Ross River and Barmah Forest viruses.

Saltmarsh mosquitoes can be a particular problem during times of low rainfall as their eggs are conditioned to hatch in greater numbers after a period of drying out.

Generally, rain over 30 mm or high tides over 2.4 m can trigger a hatching event and biting activity can be expected approximately 10 days later. The adults live for about one to two weeks.

Larval mosquito treatments are targeted after each hatching event, where mosquito eggs hatch into larvae.

Saltmarsh mosquito lifecycle

Adult female and eggs

Adult female emerges and her first batch of eggs is laid. The females then disperse (at least 10 km) in search of a blood meal with the aim of returning to the saltmarsh to lay more eggs.

The female saltmarsh mosquito lays her eggs on damp soil at the base of saltmarsh vegetation around the high tide mark and at the edge of impounded pools in mangroves. These eggs dry and become dormant.

They hatch weeks to months later when submerged by tide or rainwater that refill the depressions.

Adult saltmarsh mosquitos only live for about 1-2 weeks.

Larvae

Larvae are aquatic and develop into pupae in as little as 5-6 days (in warmer months).

This is the only time the mosquito is vulnerable to Council’s eco-friendly treatments. Council needs to treat the saltmarsh mosquito larvae in their breeding pools before they emerge with either Bti (Bacillus thuringiensis israelensis) or methoprene.

1. Btionly effects larvae for the few days before they pupate and the larvae need to ingest it for Bti to work.
2. Methoprene works by disrupting larvae-to-pupae development, killing the larvae.

These products only target larvae and are safe for people, pets and the general environment. They are treated by helicopter, with ground support from our All Terrain Vehicle (ATV) teams.

There are usually only a few days available after a hatching event to successfully control the larvae with these products.

Pupae

If not treated, in 1-2 days pupae develop into flying, adult mosquitoes.

Eggs 

The female will begin life again by laying her first generation of eggs.

Freshwater-breeding mosquitoes breed in:

• shallow freshwater pools
• grassy drains and depressions
• rural areas or suburbs with open space, which includes most of Brisbane.

The common banded freshwater-breeding mosquito is a carrier of Ross River and Barmah Forest viruses in South East Queensland. Other freshwater breeding mosquitoes can also carry these viruses, as well as heartworm, which effects cats and dogs.

Council controls freshwater-breeding mosquitoes and other mosquitoes on public land, however private landowners are responsible for managing of the control of mosquitoes on their land. 

Container-breeding mosquitoes breed in:

• natural containers such as:
  • tree cavities
  • bromeliads
• made containers such as:
  • pot plant saucers
  • bird baths
  • discarded tyres
  • garden rubbish
  • gutters
• unmaintained, unchlorinated swimming pools
• poorly-maintained rainwater tanks.

Adult container-breeding mosquitoes lay their eggs above the water line in containers.

The eggs remain dormant until rain or watering fills these containers, triggering the eggs to hatch into larvae.

Adult mosquitoes will be abundant about a week after this happens.

This species also occurs in winter in well-watered gardens and can transmit heartworm to pets.

The Dengue mosquito (Aedes aegypti) and the Asian tiger mosquito (Aedes albopictus) are container-breeding mosquitoes which do not currently occur in Brisbane and it is vital we keep these mosquitoes out of Brisbane.

Help keep these mosquitoes out of our city and suburbs by remembering that anything around your property that can fill with water is a potential breeding site.

Control of this species requires property owners to be aware of breeding sites and remove or manage them.