Life Cycle of the Wasp
Vespula Vulgaris | Vespula Germanica
Hibernation & spring emergence
The wasp’s year starts in the spring. As the days start to warm up the queen wasps come out from hibernation where they have spent the winter months in a deep sleep. At this time of year there are no active wasp nests, just queens which will begin to look for a suitable place to build their new nests.
It is mistakenly believed by a lot of pest controllers that hard cold winters will kill hibernating queen wasps. Most hibernating queen wasps do die over the winter but this mortality is not due to cold weather but predation by other insects such as spiders. Warm winters are more likely to affect queen wasps as they emerge from hibernation too soon and starve due to lack of food.
As you can see from the following photos, hibernating queen wasps protect their wings and antennae by tucking them under their bodies. Wings are vital for obvious reasons but the antennae are equally important to a queen wasp as she uses these to probe and detect the cells in the nest before laying eggs. (The white stuff over the wasp is just sawdust, as we found her in a wood cutting shed)
Note how she has tucked her middle legs over the top of her wings to protect them. Her hind legs are used to anchor herself in place over winter.
What do wasps eat?
Another common misconception is that wasps eat insects. This is not the case. Adult wasps do not have mouth parts that allow them to eat solid foods. They have mouth parts that are similar to a honey bee, a series of tubes for sucking liquid such as nectar.
Do not confuse the mandibles at the front of a wasps head for mouth parts. These mandibles (which are similar to a crabs claw) are used for catching and dissecting prey which they feed to their young. They are also used for stripping and pulping wood for nest construction. Mandibles are also used for biting other wasps, either in defence; if the nest is being attacked, or in attack; if another nest is being predated on. There is also a lot of biting and forcefulness used within the nest hierarchy.
When the queens emerge from hibernation, the only source of food for them is nectar from plants and flowers. They are responsible for plant pollination in much the same way as honey bees. Adult workers will also use nectar from flowers in the spring and early summer.
As nests start to grow and there are young wasp larvae to be nurtured, the adults catch insect food for the larvae to eat. In turn, the wasp larvae regurgitate parts of this insect food (chitin which make up insect exoskeletons) producing a sugary liquid which they feed back to the adult wasps.
Nest building and colony expansion
Once the queen has chosen a nest location (in a loft, shed or hole in the ground etc) she will start stripping wood from fence panels and shed walls etc (you can often see little white lines on shed walls and fences in the summer. This is a sign of a wasp nest nearby). The material collected for nesting is chewed, shredded and mixed with saliva and wax to make a paste material which is then used to construct the nest.
We have shared this video from our sister site to display how wasps strip wood.
The queen starts the nest off by attaching the first part of the nest to something sturdy; normally in lofts and sheds this will be a roof rafter or some other part of the roof structure. She builds a centre stalk called a petiole. Around this centre stalk she adds cells, these are similar to the cells that can bee seen within a beehive (although bees make their cells from wax).
The queen will start to lay eggs in these cells and once they have hatched she will forage for food to feed the larvae. Whilst in this initial stage she continues to build more cells. The larvae grow quickly due to their protein rich insect food.
How wasp larvea turn into adult wasps
When the larvae are ready to pupate into adult wasps, they spin a silk cap over the top of their cell as illustrated in the images below. Looking closely at the images you can see the maggot like wasp grubs within their uncapped cells. These grubs are still being fed by the adult worker wasps and are not yet ready to pupate into adult wasps. When they are at the right stage of development, they will spin their caps and pupate (just like a caterpillar into a butterfly). After a few weeks they have transformed into adult worker wasps and are sterile.
Adult worker wasps, which are all female, can sometimes lay eggs as well as the queen but these are not fertile and can only produce male wasps (drones). Once the first brood of adults has hatched, they take over the nest building duties and caring for the larvae. They are responsible for food collection. This leaves the queen free to do her job which now consists solely of egg laying and nest control.
As the amount of individuals increases, so does the nest size. Alot of effort goes into wood collection and nest building. The brood comb also grows to accommodate the young larvae. A lot of effort also goes into water collection for keeping the nest at the desired temperature. If the nest starts to become overheated the wasps use water along with fanning their wings to keep the nest temperature even.
How many eggs will a queen wasp lay?
A very good queen honey bee can produce around 2000 eggs per day but a queen wasp will not be anywhere near as prolific and will lay nearer to 100 eggs per day.
How do wasps reproduce?
As the nest reaches its maximum size towards the end of summer/beginning of autumn the queen will lay queen eggs and drone (unfertilized) eggs. Each nest will produce around 1000/1500 new queens.
Once these eggs have been laid, the existing queen will not lay any further eggs. These special eggs hatch out and when they have pupated they turn into virgin queens and male drone wasps. They leave the nest and navigate to special mating areas. It is believed that drones will not mate with queens from the same nest as they can visually recognise other individuals from the same nest/colony. This ensures that interbreeding does not occur and genes are evenly distributed.
Once mating has taken place, the now fertilised queens find somewhere to hibernate over the winter months and the drones die.
When will a wasp nest die off?
Once the wasp nest has produced new queens and these have spun their silk caps ready to pupate, the nest is then essentially on countdown to dying. The timing of new queen production varies from year to year but it is synchronised so all the nests do it at the same time. This is to ensure that there are enough drones and queens to successfully mate.
The adult worker wasps that are left in the nest now have no food source because there are no wasp larvae in the nest to feed the adults with the sugar solution. This is when wasps can become a problem as they go looking for other food sources and often cross paths with humans. These wasps are looking for any source of food that contains sugar, so for example a pub garden with pints of beer or other sugary drinks and food lying about will be a target for hungry wasps.
As the weather gets colder and autumn arrives, food diminishes and the remaining adult wasps and old queens die off due to starvation. By winter most average size nests have died but occasionally a large nest will survive longer if enough food can be found.