Wasps’ Nests In North West Britain 2015

Wasps' Nest

Wasps’ Nests In North West Britain 2015

Many people in Britain will have experienced a wasps’ nest at home, unfortunately it is not unusual to make the discovery of the nest in a painful manner, perhaps when entering the loft space or trimming the hedge.

They are often found by window cleaners and contractors doing work at gutter level and sadly often by children kicking a ball into a bush.

Although there are something in the order of 20,000 species of wasps worldwide only three species concern us as pests in the UK, The Common Wasp (Vespula vulgaris), The German Wasp (Vespula germanica) and a relative new-comer The Median Wasp (Dolichovespula media).

Although it is quite easy to identify each wasp species, to all intents and purposes it is not necessary as their behaviour and nest-building habits are pretty similar.

All three species are ‘social’ wasps which means that they construct a social nest as a working community and do not build individual nests like solitary wasps.

We do have solitary (non-nest building) wasps in the UK but they do not concern us as pest species as they are harmless.

The life-cycle of our pest species wasps are pretty much identical and commence with a wasp queen coming out of hibernation in the spring, typically once the temperature remains above ten degrees for a few days.

These early emerging wasp queens will feed on insects and small spiders before beginning to build a new nest, having already mated before going into hibernation the previous winter.

The queen will build a small structure about the size of a table tennis ball by chewing rotten would with saliva.

Wasp

The Wasp
Photo Courtesy of John Hastings

From this mixture she makes ‘wasp paper’ from which she builds the nest. Inside this small cocoon she constructs small egg chambers and into each one she lays an egg, around 15 – 20 eggs in total.

Wasps have a complete metamorphosis which means their life cycle is egg – larva – pupa – adult.

The queens tend to these new wasps as they pass through their various stages until they emerge as adults and are able to fly and feed themselves. She then remains inside the nest laying eggs as subsequent wasps enlarge the nest to accommodate the growing colony.

It is at this early nest siting stage where there is a slight difference between species, the Median Wasp tends to build its nest outdoors more so than the other two species, often in trees and bushes or under the eaves of the house, whereas the other species tend to build in lofts, attics and garden sheds.

Median Wasp

Median Wasp

This frequently brings the Median species into conflict with human beings as we are more likely to disturb its nest.

Every summer brings horror stories of children being badly stung, perhaps when kicking a football into a bush containing a nest.

These early worker wasps are all sterile females, they cannot start new nests or lay eggs, they are biologically tied to the nest they were born in and their sole function is the welfare of the new queens to come.

Neither can wasps’ nests ‘move’. We frequently get people who have a nest treated on the front of the house saying that the wasps have ‘moved’ to the back. This is just not possible and it simply means that there is a second nest which they had not spotted.

All of this process takes time and it is rare indeed in our area to see a live wasps’ nest containing flying workers before the beginning of June, often much later.

It is for this reason that we know that when people call us in April and early May claiming to have a wasps’ nest we know immediately that what they are seeing are bees of some description.

We have constructed a helpful chart of what you are likely to see at various months of the year.

Throughout this early part of summer, June, July and early August the larvae in the nest are being fed on grubs and aphids and the nests usually cause surprisingly little nuisance for the home owner on whose property it is built.

However the same cannot be said for all the neighbours.

Wasps can be surprisingly bad at navigating and when one house in a street has a nest it is common for all the houses in the row to have a few wasps entering at the same point.

They effectively go to the right spot on the wrong house and once inside are disorientated as there is no nest and are likely to sting.

This becomes worse later in the season and in bad weather, it is not uncommon for neighbours to find upwards of a hundred or more wasps in their homes per day and yet the nest is several doors down the road.

It can be very difficult to persuade someone experiencing such an ingress of wasps that they don’t in fact have a nest on their property.

The only thing which can be done in these circumstances is to locate the nest and persuade the neighbour to destroy it.

Last year we had a chap badly stung when entering his loft to retrieve his suitcases for his holidays and we located the offending nest six houses down the road, so it’s important to understand that before mid-September wasps in the house does not mean that you have a nest, just merely that there is one nearby.

The neighbour who actually has the nest can often be quite oblivious to the fact as the wasps come and go from the nest, doing what they need to do, and cause little problem.

All this changes as summer changes to autumn though, and not for the best!

When a worker wasp feeds a grub in the nest the grub secretes a sweet, sticky substance as a reward, this is the worker’s incentive to bring food to the nest.

As we approach the autumn the final batch of eggs will hatch and these will be males and virgin queens.

Queens are easy to spot being much larger

Queens are easy to spot being much larger

On average a wasps’ nest will produce around 2000 new queens at the end of summer, this is when they start to be really problematical.

The old queen has run out of eggs and the nest is no longer producing new wasps so the workers are no longer getting their ‘fix’ of sweet secretion and they start to crave sweet foods.

Up to now they have been the gardener’s friend by doing natural pest control on bugs and aphids but now they become a nuisance.

Their diet changes to rotting fruit which of course is often fermenting and contains alcohol.

It is now that the bulk of the stings tend to occur.

It is now also that the social structure of the nest starts to disintegrate. The queens will start to leave the nest and crawl out into surrounding areas looking for hibernating holes.

It is now that the householder with the nest has a problem, often with hundreds of queens a day appearing in adjacent rooms, and of course, as females the queens can also sting.

There is no complete cure at this point, destroying the nest alone will not solve the problem, the queens are no longer returning to it.

Treatments can be carried out such as fogging the loft, but inevitably some queens will survive.

This troublesome period can last up to two months usually mid-September to mid-November but can last throughout the winter in some cases.

This is why we always advise clients to get a wasps’ nest dealt with before September.

Once the life cycle is complete the workers and males die off with the first hard freeze and the queens feed, mate and go into hibernation to await the following spring to start the cycle all over again.

The survival of the queens has less to do with the severity of the winters but the weather in spring.

In hibernation the queens can survive the coldest of conditions but the weather in spring can bring disaster for them.

In 2012 in our area we had an unseasonably warm spell in late February and early March. This brought the queens out of hibernation too early, the weather cooled and they starved.

As a result the wasp population in the summer of 2012 was down around 90% in our area and is still recovering.

Only female wasps can sting, their stinger being a modified ovipositor (egg-laying tube) and people often ask us what is the best treatment for a wasp sting.

In these litigious times, not being medically qualified, we are unable to give advice but there are many over-the-counter products which it may be wise to have in the medicine cupboard on a ‘just in case’ basis.

We would certainly advise you to seek medical attention if you receive multiple stings which is quite possible if you inadvertently disturb a nest.

We also advise people to routinely check their properties for nests each year by walking round the house on a nice, sunny day in mid-July and if you have a nest you will clearly see large numbers of wasps flying in and out and around the entrance, it is quite easy to see, even at heights.

If you discover a nest we would advise you to get it treated as soon as you become aware of it.

Pest control companies do not physically remove the nest and nor should you.

The nest is injected with a small amount of insecticide which is then spread around the interior of the nest by the returning workers.

The nest then needs to remain in place for returning wasps to enter and be killed.

Normally all visible activity will cease within a couple of hours.

Even then we advise people against trying to remove a nest, even if it is easily accessible. Inside the nest the wasps in pupal cases are protected from the insecticide and will continue to hatch for some time. As soon as they do they will come into contact with the insecticide and die, but for the short time they are alive they are quite capable of stinging.

A wasps’ nest is a one year event, even if not treated with insecticide it will never be used again and being paper will quickly crumble away.

There is absolutely no need whatsoever to try and physically remove the nest and they should always be left in place.

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