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Your Guide to Wasps

Yellow Jacket Wasp
The common wasp (Hymenoptera apocrita) is something like a cross between an ant and a bee, and causes fear in most sane human beings. It’s important to note, however, that wasps are enormously important in natural biocontrol and are consequently used in agriculture as a natural means of controlling pests that damage crops. Wasps should also be welcomed in many gardens because their diet includes caterpillars and other garden pests.

Wasps are friends, not pests

While we might not think so when we’re being invaded, wasps aren’t pests; their function within the ecosystem is vital. Like all wild creatures, you have to exercise extreme caution when dealing with them. When they sense they’re under threat, wasps let off a pheromone which informs the rest of the nest of danger, and the next thing you know you might be facing an onslaught from some very angry stingers!  .

About wasps

There are over 100,000 species of wasps and the majority are parasitic. The majority of wasps are also non-pollinating wasps. There are some wasp species that are pollinators, such as the fig wasp which has a co-evolutionary relationship to fig tree species, so much so that they are mutually co-dependent. Interestingly, not all fig wasps are pollinator wasps, some of the fig wasps are also parasitic.

The wasp which is most familiar to humans belongs to the Aculeata group, a subdivision of the Apocrita group.  In the Aculeata group we find the stinging wasps, but there are also non-stinging wasps. In non-stinging wasps, the ovipositor is adapted for egg laying only, while in stinging wasps it also delivers the dreaded sting.

The  Bees, Wasps and Ants Recording Society  (BWARS) is an excellent resource for information, and so whether you’ve got visitors of the wasp variety this summer or not, it’s a good idea to make sure that you’re as well-informed as you can be.

There are two main categories of wasps: Social wasps and solitary wasps.

Solitary wasps

Solitary wasps spend their adulthood alone and the majority don’t build nests per se, instead they occupy natural cavities like rock crevices or small holes in twigs. Mud daubers and pollen wasps build nests from mud in sheltered places like the sides of walls. Potter wasps also build their mud nests attached either to the sides of walls or to twigs. The majority of predatory solitary wasps burrow into soil or into plant stems.

Social wasps

Social wasps, on the other hand, build nests and exist in large colonies. Typically, a wasp nest holds a population of around 5,000 wasps, but during particularly hot weather the average nest size is around 10,000 (wasp nests with a population of 50,000 has also been reported).  They build nests in trees, holes in the ground, sheds, loft spaces, roofs, eaves or wall cavities. The most common nests they build are made of a papery material which is made when wasps (initially the queen and then female workers) chew bark from trees or fence posts. Mixed with saliva, the chewed bark gets a papery consistence and is used to forms the outer shell of the nest.

Wasp nests and nest building

The first stage of a wasp colony is when the queen begins the process of nest building (using the process described above) after coming out of hibernation around the beginning of May. This nest is roughly the size of a walnut. She lays between 10 and 20 eggs which are fertilised using the stored sperm from the previous winter. Once the first eggs hatch the queen feeds the larvae until they become the first adult worker wasps. They’re all female and their function is two-fold; to expand the nest and to feed the immature wasps a diet of insect larvae.

The size of the nest at this point is roughly the size of a shot put ball, and can house between 100 and 300 workers. By July, the nest can reach the size of a bowling ball. At this stage, the queen wasp no longer engages in foraging or nest building activities; her only duty is to increase the population. She still has stored sperm and continues fertilising the eggs without needing to mate. Most of the nest population is made up of sterile female worker wasps.

By the time the queen’s stored sperm begins to run dry, which is towards the end of summer, the eggs she lays hatch into fertile males and fertile female queens. At this stage the nest population is in the thousands. The fertile males leave the nest in search of mates, continuing the reproductive cycle. The fertile male wasps travel further afield to find mating partners while the fertile queens stay within close proximity to their nests.

Wasps don’t return to old nests and most wasps die out towards the autumn.

How to treat a wasp sting

According to PiedPiper, you can treat wasp stings with ammonia, alcohol or cold poultices. If you’ve just been stung on your extremities or body, you can use an antihistamine ointment on the wound. If it remains sore and angry-looking then you should phone your GP for further assistance. However, if you’ve been stung on your neck or mouth, or if you experience dizziness and nausea or the swelling is unusually severe or you’re in extreme pain, make sure you get medical assistance immediately. Sensitive individuals can suffer from anaphylactic shock, which can be fatal.

You should also be aware of the link between wasp stings and heart attacks, following a discovery by Dr Nicholas Kounis, who found that some people have an allergic reaction to wasp stings that can cause acute myocardial infarction – heart attack. The phenomenon has been called Kounis Syndrome. The scary thing about Kounis Syndrome is that there are few (if any) symptoms that predict a reaction. What’s more, a reaction can occur up to two weeks after the sting, so don’t be afraid to get help for any signs of dizziness or nausea or anything else uncommon for up to a fortnight after an unfriendly encounter with a wasp.

How to remove a wasp nest from your garden

If you discover a wasp nest early on – it’s still very small and activity is sluggish because the heat of summer hasn’t quite hit – you may be able get rid of it simply by knocking it down with a shovel. If that sounds a little barbaric, you can get puffer packs with insecticidal powder, which you can dust over the nest. There are wasp traps and wasp sprays on the market.  Advice from a pest control expert is recommended first however.

Remember wasps play a beneficial role in your garden, so if you can keep a safe distance from the nest you might not even have to remove it. Just make sure that you know where the nest is and are aware of wasp activity, so you don’t cross their flight path, or give them a fright which will cause it to release the dreaded pheromone.

However, if the nest is large and there is a lot of activity, you are far better off calling in pest control experts and getting in touch with your home emergency insurance provider.

The sting in the tale

Wasps can be quite handy to have around, as police in West Yorkshire found in August 2014. The Leeds Inner South Neighbourhood Policing Team was investigating a man in connection with theft of a fish tank from a furniture store in Leeds. He attempted to hide from the police in a bush, but was unaware that he had made himself the target of angry wasps by disturbing their nest. The suspect was repeatedly stung and though charged and arrested, had to be taken to hospital for severe swelling.

Makes you wonder if wasps shouldn’t be encouraged to nest outside buildings vulnerable to theft.