Wasps
Wasps are probably one of the most familiar and generally feared groups of
insects. They belong to the order of insects called Hymenoptera which also
includes bees and ants. Most of these posses stings which mainly used against
other insects but can be turned against man with unpleasant results.
Types of Wasps Found In U.K.
- Common Wasp (Brownish/Creamy colour nest* with whirls)
- German Wasp (Grey nest*)
- Tree Wasp, Very aggressive not common
- Norwegian Wasp, Not found in southern England.
- Cuckoo Wasp
- Hornet
* Nest colour only differs once the workers take over nest building.
Queen built nests are grey.
The common and German wasps are the two species likely to be found
during domestic treatments.
Life cycle
The queen wasp (somewhat larger than the worker), emerges from hibernation
in the spring and build a round nest 2-3 ins. in diameter from chewed
wood pulp which is obtained from dead trees, fences, etc. This nest
will contain a small number of cells into which the queen lays her
eggs, one per cell. The eggs hatch into larvae and are fed by the
queen fragments of insects (the Queen herself feeds on nectar). The
cells hang downwards and the larvae are prevented from falling out
by keeping part of their bodies in the egg cavity which was glued
to the ceiling of the cell when laid by the queen. After pupation
workers (sterile females) emerge and take over the running of the
nest from the queen who devotes the rest of her life to egg laying.
This occurs late June to early July. The nest can grow considerably
during this time and may at its peak, contain 10-15,000 wasps.
Towards the end of the summer, special larger cells are constructed
to provide drones and queens for the next season. In these are reared
drones (males) and the queens (fertile females). They fly outside
and mate (usually with drones/queens from other nests), the drones,
workers & original Queen die off with the approach of colder
weather, the new queens seek out sites for hibernation. It is not
hibernation as in the mammals sense as this can take place as early
as September when the weather is still quite warm.
The wasp community resembles that of the bumble bee in being annual
and never producing swarms. Nests are never recolonised the following
year, but a special favourable site may be used again and new nest
built each year.
Populations of wasps tend to be low in years when the weather is
cold and wet in May and June. This is attributed to queens being
unable to forage frequently enough to sustain themselves and the
brood, their small abandoned nests are a common site in lofts. Lofts
are ideal places for nests to thrive. A natural controlling factor
before man built buildings would have been the number of dry cavities
available for wasp nests to be built. Along came man and the availability
of these sites is now almost unlimited. |
Food
Unlike bees, wasps do not store food (honey) and so need to forage daily in order to meet the dietary requirements of the colony. Whereas the grubs require a largely protein diet to maintain healthy growth, the intensely active workers need mainly energy foods i.e., carbohydrates. It must be remembered that wasps do not grow once they have emerged from the pupa stage and their size is often determined by food type and amount of food fed to the grubs by the workers.
The food of the workers consists of the nectar of certain flowers, e.g.,cotoneaster
and ivy, and a variety of other sweet substances including fresh and
processed fruits. It is when seeking for sweet foodstuffs that wasps
into close contact with man and become a problem.
Very young grubs are fed the sweet carbohydrate diet to start with then
onto a diet mainly of other insects, portions of which are first? masticated
by the workers, but fresh and decaying meat and fish are also used. Workers
will also kill the grubs of other nests for food especially towards the
end of the year when some nests die out before others leaving them unprotected.
There is also an exchange of foods between the grubs and the workers
feeding them, as the grubs secrete a sweet fluid which is eaten by the
workers. This exchange may help to ensure that the workers tend the brood
adequately.
The Queens, when confined to the nest, are fed by the workers on a liquid
mixture of nectar, fruit and meat juices. Males in the nest also obtain
food from the workers but once outside, probably feed only on plant juices.
Wasps change their eating habits in August. The workers normally collect
protein, such as flies, and take it back to feed the larvae in the nest.
The larvae secrete a carbohydrate which the workers eat. In late August,
the queen stops producing larvae and the workers start looking for sugar
outside the nest, so it is usually at this time that wasps are of the
greatest nuisance, when their numbers are at their peak and searching
for sugary food.
They (the workers) have time on their hands and are consuming rotting
fruit which can lead to more aggressive behaviour. The time spent in
the nest is less as there are no grubs to feed. In the Autumn the nest
starts to die out.? |
