Wasps and Hornets, (Social).
In
France
there are six species of native social or colony forming wasp, one species
of native hornet and two species of introduced hornet. In addition
there are 5 or 6 species of Paper wasp, (Polistes) & 3 species of Polistes
kelptoparasites that use Paper wasp nests.
Geman Wasp -
Vespula germanica
-
La guêpe
germanique
Red Wasp - Vespula
rufa
-
La guêpe rousse
Common Wasp -
Vespula
vulgaris
- La guêpe commune
Median Wasp -
Dolichovespula media
-
La guêpe des
buissons
Saxon Wasp -
Dolichovespula saxonica
-
La guêpe saxonne
Tree Wasp -
Dolichovespula sylvestris
-
La Guêpe des bois
European Paper Wasps -
Polistes species
Oriental hornet
- Vespa orientalis -
Frelon oriental
Hornet - Vespa
crabro - Frelon or Guêpe frelon or Guichard
Asian Hornet - Vespa velutina nigrithorax - Frelon asiatique
The three Vespula
species, the three Dolichovespula
species and the three Vespa,
(Hornet), species share the same general biological features regarding their
life cycle which starts in the spring with fertile
Queens
that have over wintered in hibernation finding a suitable location to create
a nest.
Early in the year in the period following
hibernation the only source of energy for
them is nectar from flowers where they play an important role as
pollinators.
Having found a suitable location the Queen, (Foundresse),
makes a small nest starting with a central single hexagonal cell which is
suspended on a short central stalk around which are usually six more cells,
the Queen laying an egg and providing for it in each one as it is
constructed. Once these eggs have hatched out, gone through the development
stages and pupated into adult wasps they take over the nest construction and
provision of nutrition for the larvae and leave the queen solely to lay eggs
and control the nest which is now her primary function. At this stage and
until late summer all the worker hornets and wasps will be sterile females and there
will be no males. As the colony grows the workers feed the grubs and the
grubs exude a sweet liquid which the adult hornets and wasps consume to satisfy their
energy requirements. It is only later in the season when the quantity of
brood being reared reduces that we find the adult hornets and wasps searching for large
sources of sugars that are naturally available from fruits.
The nest itself is constructed using small pieces of
wood that they shave either from the bark of living trees or from dead wood
including fence posts, garden furniture and so on that is chewed into a
paste and moulded into place.
With the growth of the nest the size of the cells progressively increases
which leads to an increase in the size of the worker hornets and wasps. The final cells
to be constructed called Gyne cells are extra large for queen production
that takes place late in the season, (end August – September), when males
will also be produced using worker cells to mate with them. These newly
mated
Queens
will disperse and eventually find somewhere to hibernate where they will be
protected from freezing. All other hornets and wasps, workers and males will die before
winter and the nest will be abandoned and not reused.
All
hornet and wasp larvae,
(Workers, Males and Queens),
are fed with mashed up insects, the larvae of other species and even carrion
that provides them with the protein they require to grow. This is why we
find them taking small pieces of meat or fish when we eat outside, either
from our plates or from waste bins. The larvae are fed and checked by
nursery workers perhaps as often as 50 to 80 times each hour and go through
5 instars or stages of development shedding their skin at the end of each
instar. When fully fed, the larva spins a cocoon within its cell using silk
secreted by its salivary glands. Inside this cocoon the larva develops into
an adult. During this time (7–9 days) the pupa is not tended by adult
workers and when fully developed they chew away the cap of the cell to
emerge and start work.
Essentially as with Honey bees there is no genetic difference between an egg
that will produce a worker, (sterile or sexually inactive female), and a
Queen that is fertile, can mate and produce fertile eggs. In the case of
hornets and wasps the mechanism for producing new potential Queens, (Gyne), is not fully
understood and may be the result of one or more of a number of factors that
include Queen pheromone releases, larger cells, better nutrition, (increased
quantity and quality of larval food supply), and vibrational signals, (cell
rim tapping). I have provided some links regarding this subject.
(Gyne refers to potential or actual queens, whereas Queen refers to a
reigning gyne with a colony).
LINKS
The
Evolution of Social Wasps
Simplified hornet and social wasp life cycle.
March - April: Mated queens leave over wintering sites (under bark, in
log piles, even in folds in your curtains) to gather nectar and look for
nesting sites.
May - August: The nest is established. Worker wasps
an hornets take over the
duties of enlarging the nest and feeding the larvae, leaving the queen to
continue laying eggs. In the case of Asian
hornets this is a primary nest that is later abandoned when the colony moves
to a permanent location.
August - October: Towards the end of the season the worker wasps
and hornets build larger cells in which the next generation of several
hundred queens and males is reared. When they reach adulthood, these
individuals leave the nest and take part in mating flights although actual
mating takes place on the ground.
November - March:
With the onset of winter mated queens hibernate in safe sites. All other
hornets or wasps
die and the nest is abandoned.
Regrettably our native wasps and hornets are persecuted and are in overall
decline. This decline is being brought about by a number of factors many of
which are the same causes for the decline in other species of insect notably
bumble bees and a large number of solitary bee species. Pesticide use,
(insecticides, herbicides, fungicides etc), habitat loss and destruction of
nest sites and the widespread use of domestic insecticide sprays.
It's worth reminding ourselves that our native Wasps and
Hornets serve a multitude of important functions in a balanced eco system
and we should all try to avoid destroying them unless it is absolutely
necessary.
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