Characteristics:
Up to 30mm long; eyes kidney shaped; two
pairs of membranous wings, the hind wings
smaller than the forewings and linked to them
by a row of hooklets; wings folded
longitudinally at rest; mouthparts adapted for
chewing and licking; dorsal surface of the first
thoracic segment extends back to a small lobe
which overlies the base of the front wing;
abdomen constricted at base giving appearance
of a waist; metamorphosis complete, with egg,
larval, pupal and adult stages; typically possess
complex social system (sub-family Vespinae).
Family: Vespidae
Species Characteristics:
Genus: Vespula and Vespa.
Similar in appearance. Distinguished by patterns
on the face and abdomen. The following species
are found in Northern Europe:
Common Wasp
(Vespula (Paravespula) vulgaris)
Nests underground and in cavities in trees and
buildings.
German Wasp
(Vespula (Paravespula) germanica)
Nests underground and in cavities in trees and
buildings.
Tree Wasp
(Vespula (Dolichovespula) sylvestris)
Nests suspended from the branches of trees or
constructed underground.
Norwegian Wasp
(Vespula (Dolichovespula) norvegica)
Constructs small nests on twigs e.g. on
gooseberry bushes and hawthorn.
Cuckoo Wasp (Vespula austriaca)
Worker caste lacking. It is parasitic usually laying
its eggs in the nests of the Red Wasp.
Red Wasp (Vespula rufa)
Nests underground.
Hornet (Vespa crabro)
The largest of the wasps but relatively
uncommon. Nests in hollow trees and
occasionally buildings.
Genus: Odynerus, Mason wasps.
Solitary wasps about 13mm long predominantly
black with yellow markings. The females
construct nests of a few cells each of which
contain an egg and is provisioned with food e.g.
caterpillars. The larvae which hatch from the
eggs feed themselves and live independently
from their neighbours. Nests will be constructed
in the ground and in soft mortar.
Significance
Wasps can be regarded as beneficial insects. As
the nests develop during the spring and early
summer the workers collect insect larvae, scraps
of meat and even fish to feed to larvae. They
therefore help to control insect pests and clear
carcasses. The workers prefer high energy
carbohydrates which they obtain from fruits and
the nectar of flowers. They could act as
pollinators although are unlikely to be as
efficient as honey bees.
In general, however, wasps are regarded as
nuisance pests or a threat to health.
They feed on fruits e.g. apples, pears and plums
although they are regarded as scavengers
extending the damage caused by other pests
and diseases. The need to collect wood to
construct nests means that wasps may damage
the wooden fabric of buildings, fences and even
perhaps garden furniture.
Wasps are a particular nuisance at the end of the
summer when the workers are freed of the need
to collect proteinaceous foods for their young
and can indulge their passion for sweet materials
e.g. jam and syrup. They cause a nuisance when
they enter kitchens, bakeries and other premises
handling sweet aromatic materials. Foodstuffs
can be contaminated and staff will be disturbed
or even stung. Where wasp densities are high
and a real threat is perceived, production in
workplaces can be halted.
It is the ability of wasps to cause painful stings
that concerns most people. Unexplained road
accidents have sometimes been attributed to the
distraction of drivers by wasps. They are not
regarded as particularly aggressive and the ability
to sting is employed by the social wasps to
defend their nests.
The sting is caused by the injection of venom
into the victim by means of the modified
ovipositor of the females. Unlike the sting of
bees the wasp sting can be withdrawn from the
victim. The venom is haemolytic, haemorrhagic
and neurotoxic. Histamine is also present which
causes the redness, flare and weal in skin.
