European Wasps are exotic pests that have established themselves in the temperate regions of Australia. European wasps are black and yellow, usually slightly larger than a bee. Most of the time they will form nests up to the size of a soccer ball and occasionally even bigger! Nests are usually located under ground, with a single entrance hole approximately the size of a 50-cent coin. They can also form sizeable nests in wall and roof cavities or tree hollows.
Why are they a problem?
European wasps feed on meat and meat products, such as dog food and barbecue scraps. They are also like to scavenge sweet food and drinks and steal honey from beehives.
Nests are started in spring and by late autumn new queens are hatched, with the nest dying down over winter. With the fairly mild winters in Australia some nests survive over winter with multiple queens and flourish year round.
European wasp stings are not barbed like bee strings. This means a single wasp can sting repeatedly. The toxins in the sting will cause a painful reaction, and in some pets an allergic reaction. Because they are attracted to food, many wasp stings are in or around the mouth. These are the most dangerous places for a sting, as swelling can result.
Reactions range from small, painful swellings on lips to major swelling of the face and neck and back of throat, blocking the trachea (wind-pipe) and in the most severe cases leading to death. In some allergic animals a rapid anaphylactic reaction will occur, resulting in shock and respiratory distress.
10 % of people that are stung more than once will have an allergic reaction to following stings. It is unknown if this is similar with household pets.
What can I do?
Be on the look out for wasp nests and any accumulation of wasps, as there may be nest nearby that is not visible. If you find a nest contact the council or a pest control agent immediately. Do not try and eradicate the nest yourself. If their nest is disturbed, European Wasps are much more aggressive than native wasps.
Because wasps are attracted by their food, do not leave dog food or meat unattended in the back yard. Pick up any over-ripened or fallen fruit from the ground.
What if my pet has been stung?
Symptoms of a sting will vary depending on where. Bites around the mouth will cause pain, salivation and some degree of swelling. The amount of swelling will depend on how many times your pet has been stung and how allergic your pet is to wasp venom. If you notice severe, painful swelling around the face or any limb contact the vet and seek veterinary attention immediately. Antihistamines that are used to control beestings and minor allergic reactions may be effective for a minor reaction to a wasp sting, but will not act fast enough in anaphylaxis or if there are multiple stings around the mouth or back of throat, said Dr Alex Harrison of Hills Veterinary Centre.