Aggressive stinging wasps ‘flourish’ in Victoria’s humid summer

Victorians are reporting swarms of wasps nesting near their homes and of being chased, “attacked” and painfully stung multiple times.

Victorians in the state’s north east are reporting swarms of wasps nesting near their homes and of being “chased and attacked”, and painfully stung multiple times.

There have also been reports of the wasps “taking over” swimming pools on hot days, making it near impossible for residents to use.

Australian native paper wasps — that form colonies in inverted cone shaped nests, commonly under tree branches and house eaves — are among the wasp species bugging residents.

A spokesperson for the Victorian Department of Energy and Environment said higher-than-average rainfall over recent summers has created ideal conditions for insects such as paper wasps to flourish across the state.

Paper wasps are flourishing in Victoria.

The wasps can be aggressive when they feel their nest is threatened. Picture: Steve Cruickshank

“There are several commonly seen species of wasps that will nest around homes, and it is important to determine which wasp species it is before trying to remove them, with European wasps tending to be the more aggressive and problematic,” she said.

The Asian paper wasp (polistes chinensis) arrived in Victoria about five-years-ago and there had been an increased number of sightings since its introduction, the department spokesperson said.

As the end of summer approached the females started to mate and there was increased activity in the lead up to autumn, she said.

The introduced wasps (Asian and European) tended to be more of a nuisance and reach higher populations due to the lack of natural enemies in the introduced environment.

“Staying away from wasp nests where possible is advised and if required, removal of nests is best left to a pest controller to avoid being stung,” she said.

“All wasps are capable of stinging more than once and will sting if threatened. As with all bees and wasps, their sting contains venom that is painful and can cause localised swelling and, in some cases, an allergic reaction.”

A paper wasp nest. Picture: Supplied

Wasps on a swimming pool. Picture: Supplied

Australian paper wasps

Proper name: Polistes humilis

Found in: Australian (or common) paper wasps are found across the southern mainland of Australia including Victoria. You do not need to report this species.

Look like: Australian paper wasps are similar to the Asian hornet, only Australian paper wasps are much smaller and have reddish brown body colouring with distinct yellow face, abdomen and thorax. Their size ranges from 10–15mm.

How and where do they live? They are a social species and form small colonies. The nest of the paper wasp is a series of hexagonal cells shaped like an inverted cone made from saliva mixed with wood fragments. When it dries the mixture is quite paper-like, and gives these wasps their name. paper nests under tree branches and the eaves of houses. The wasp larvae are maggot-like and develop inside the papery cells of the nest.

A close-up of a paper wasp. Picture: Murray Nichol

An extreme close-up view of the head of a yellow paper wasp. Picture: Daniel Kariko

What do the wasps feed on? Adult paper wasps feed on nectar and collect caterpillars and other small insects to feed their brood. The Australian paper wasp is part of the Australian ecosystem and plays an important role in pollination services and population control.

Do they attack? They can be territorial if their nest is threatened or disturbed and can deliver a painful sting if they feel the need — but are not as aggressive as European wasps.

Can their stings be dangerous or deadly? If stings are multiple, a more severe systemic reaction may occur and can be very serious.

What is the worst that can happen if stung? If it causes an allergic reaction (anaphylaxis) this can be dangerous and deadly, but this is relatively uncommon. Only several deaths over 20 years have been attributed to wasp stings.

How do you treat a sting? A cold pack may be used to relieve the pain of the sting. If there is evidence of a more severe reaction or the sting victim is known to be allergic to wasp and bee venom, medical attention should be sought immediately.