ABOUT EUROPEAN WASPS

 

Wasps belong to the Order Hymenoptera. They are a diverse group of insects: in
Australia alone there are over 12,000 species, ranging from the tiny diapriid wasps,
which are barely visible to the naked eye, to the spider wasps and cicada-killer
wasps, capable of taking large prey. Most wasps have carnivorous larvae that feed
on other insects and spiders. The adults provide food for them by capturing prey or
by laying the egg on or near the food source, which might be an egg, larva or pupa
of another insect.
The European wasp (Vespula germanica) is native to parts of Europe, Asia and
North Africa. It is an introduced species and therefore does not have natural
predators in Australia to keep numbers of these wasps low. In Europe, the cold
winters ensure that only the Queen wasp can live, but the warmer climate of
Australia means the entire nest can survive.
European wasps are a pest because they are far more aggressive than native
wasps. Lack of predators and warmer weather conditions mean that the European
wasp is an increasing problem in Australia. This insect likes to live around humans
because of the ready supply of food and drink, particularly of the sweet varieties.

Appearance

Characteristics of the European wasp:
 Similar in size and shape to a bee
 12mm – 16mm in length (a queen is about 20mm long)
 Bright yellow body with black triangle-shaped markings
 Yellow legs
 Two long black antennae
 Wings folded when at rest.

 

Life cycle

 

Each nest usually lasts one year but in warmer climates the nest may survive and
expand. In Winter the males die off and the newly fertilised queen hibernates to build
a new nest the following spring.
The queen lays eggs in the cells of the nest and the larva hatch from each egg in
about 6-8 days. The larvae are tended to by the queen for a number of weeks.
The larva grows in a series of stages (instars). Five instars are completed before the
larva encases itself in a cocoon. The total larval development time is 9-22 days,
depending on the temperature and availability of food.

When fully fed, the larva spins a cocoon within its cell using silk secreted by its
salivary glands. Inside the cocoon this larva/pupa develops into an adult, this takes
7-9 days. They become the first batch of workers that take over the construction of
the nest and rearing of the larvae while the queen lays eggs.
In order for the colony to survive, the adult workers must perform a large number of
tasks both inside and outside the nest. Workers start as nurse wasps, they then
progress to collecting nesting materials and fluids and finally to foraging for solid
food for the larvae; the older wasps guard the nest entrance. Worker wasps live for a
number of weeks.
Towards the end of the season, in Autumn, the worker wasps build larger cells in
which the next generation of several hundred queens and males is reared. When
fully developed, these individuals mate and fly off to start new nests. In Europe the
nest then disintegrates, but in Australia's warm climate the nest can continue to grow
over a number of seasons. This can result in giant and potentially dangerous nests
of over 100,000 wasps.

Difference between European wasps and native
wasps

 

There are many harmless and beneficial native wasp species which are commonly
mistaken for European wasps. In particular the European wasp and the native yellow
paper wasp are very similar in size.
Native wasps, including paper wasps, are considered beneficial because they assist
in pollination by feeding on nectar, and they control pest populations, such as
caterpillars, by feeding them to their larvae. Paper wasps, however, should not be
allowed to develop in or near the home because they may attack if they feel their
nest is threatened.

Sundew VESPEX European wasp versus paperwasp

 
As the picture above shows, paper wasps are longer and thinner than European
wasps and they have orange-brown antennae (European wasps have all black
antennae). Paper wasps back legs dangle down during flight and they are often seen
hovering around bushes, over lawns and around water sources. European wasps on
the other hand have legs that are held close to their bodies during flight and they fly
very quickly and generally do not hover.
The great majority of Australian wasp species don’t live in colonies, being solitary
and nesting in the ground or in a crack or crevice, and they don’t attack humans. If
the nest is safely out of reach it should be left alone.
Paper wasp nests are usually above ground and are golf ball to side plate size while
European wasp nests are rarely seen and can be the size of a basketball or larger.
The diagram below shows the difference between European wasp nests and paper
wasp nests.

Life cycle

 

European wasps make their nests from chewed wood pulp and saliva giving the nest
walls a distinctive papery look. Nests constructed of mud are not European wasp
nests. Nests are usually built in sheltered locations.
About 80% of European wasp nests will occur in the ground with the remainder
usually found inside buildings. Nests will often resemble footballs.

Places you are most likely to find a wasp nest:

 

  • In the ground
    -Any concealed site
    -Holes dug in the ground
    -Around the base of trees or along hedges
    -Within retaining walls
    -In rockeries
    -In rubbish heaps or under disused rubbish (for example: old dog houses or pieces of furniture)
    -In an uncovered compost heap or grass clippings.
  • Above the ground
    -In the roof
    -In the wall cavity
    -In sheltered parts of a building

Discourage wasps

 

  • The following advice can be provided to people experiencing a wasp problem:
    -Do not leave fallen fruit or food scraps lying around the yard
    -Avoid leaving uneaten pet food or dog bones outside
    -Make sure rubbish bins have tight fitting lids
    -Keep compost covered at all times
    -Keep swimming pools covered when not in use
    -Cover exposed food at picnics and barbeques
    -Don’t drink out of cans or bottles, use clear containers or a straw

Places you are most likely to find a wasp nest:

 

Symptoms of stings will vary from person to person depending on their tolerance.
The majority of people without allergies to insect stings will show only minor
symptoms during and after a wasp sting. 
A wasp can call other colony members using a scent chemical (pheromone) to help
defend the nest from a potential threat. Unlike honeybees, which have a barbed
stinger and can only sting once, European wasps can sting multiple times. The
stinger contains several toxins, which may cause hypersensitive or allergic reactions
in some people.

Minor Symptoms

The initial sensations of a wasp sting can include sharp pain or burning at the sting site followed by a raised welt around the perimeter. A tiny white mark may be visible in the middle of the welt where the stinger punctured the skin. Usually the pain and swelling recedes within a few hours of being stung. The sting usually causes far more discomfort than a bee sting.

Major Symptoms

Larger local reactions to wasp stings can include extreme redness and swelling that increases for one or two days after being stung and subsides on their own, over the course of a week or so. If symptoms persist, it is recommended to seek further medical advice. A small percentage of people will experience anaphylaxis from wasp stings. For any life threatening symptoms such as anaphylactic shock immediately call emergency services on 000