Help! I think I have a wasp nest!

Honey bees in a chimney

It’s Spring – and the time of year the insect world starts to get busy. The weather is warming up and if you’re an insect, the things you feed on or collect are starting to become more available. This means pest controllers start to get an influx of calls about insect pests.

One of the most common queries at this time of year starts with “I think I have a wasp nest”. Entirely understandable: they’re black and yellow – like Bumble Bees – and can be mistaken for them at first glance. However, wasps are rarely seen before mid-May while Bumble Bees are one of the first insects we generally see in Spring. Because the Bumbles’ active season starts before the others we’ll look at them first.

Bumble Bees

They come in different varieties – the picture is of a very common Bumble – but yours might come with yellow and black fur or have darker colouring at the ‘bum’ end. The defining elements of these lovely creatures are their very fluffy body (it’s covered all over in hair) and their general shape: they look almost too fat to be able to fly! With all that hair, it must struggle to push through the air – and, indeed, they sometimes do!

Bumbles will usually nest somewhere in the garden and common spots are compost heaps, in the cracks between paving slabs, under garden sheds or decking. Their nest is just a collection of loose ball-shaped cells and they rarely nest in large numbers: 50 or so would be a big colony. Their season ends in mid-summer so they’re a short-term problem at best. Unfortunately, because their nest is so fragile, they generally can’t be moved unless the nests location is inside something that, itself, can be moved (we’ve relocated Bumbles nesting in bird boxes, bags of compost and – in one memorable occasion – a sports bag that had been left in a garden). If the nest is under a shed or decking, it’s generally not possible to move it without accidentally destroying the colony in the process.
We desperately need Bumble bees: they can pollinate flowers that Honey Bees simply can’t get their mouth parts into properly. They don’t ‘swarm’, they don’t generally come into a house (even if their nest is right nest to a window) and they don’t cause any damage so we far prefer to leave them alone if at all possible. While Bumbles can sting people, they generally don’t unless you are seen as a threat – so if you have Bumbles nesting somewhere and it can’t be moved then we will always try to talk you into simply taking the few extra steps to avoid them.
Contrary to popular belief, Bumbles are not protected (we think they should be given the same status as most wild birds) and, therefore, they can be legally destroyed – but you really shouldn’t find any self-respecting pest controller that uses that as their default response.

Honey Bees

Honey bees come in a range of shades but most of them are black-ish. They’re industrial little workers and their job is to collect nectar – this is found in flowers and they are guided to it by the ultra-violet light that flowers reflect. Because of this, they only ever go into a house by mistake; you won’t lots of them doing it, that’s for sure!
Nor will you find Honey Bees living on their own. A colony is generally counted in the thousands and they remain active (although much quieter in Winter) throughout the year – you won’t suddenly get one or two Honey Bees going into a hole in a garden shed because, when they do relocate to a new home, they move in a swarm of thousands – and it’s quite a sight to see! This is most common in May, June or July and generally fairly easy to deal with; a swarm of bees might look terrifying but they’re usually docile enough to handle. In the wild they usually nest in spots like hollowed-out old trees but they will sometimes use chimneys or holes left behind in buildings after pipework has been removed. On the very rare occasions we’ve had to relocate an active colony of Honey Bees, it almost always requires taking a building structure to bits in one way or another to get to them.
The risk presented by bees is that they can sting. They generally don’t (indeed, many bee keepers wear a veil over their face simply to prevent a bee flying into their mouth or eyes but are happy to work bare-handed) and being stung by one won’t mean others will come and ‘join in’. Honey Bee stings don’t generally cause a bad reaction or hurt too much, despite what you might read in social media!

Mason Bees

Not so common but this chap looks for all the world like a normal Honey Bee being generally black in colour and torpedo shaped. The name is the clue: the Mason – or Mortar bee – lives in small holes in brickwork (on occasion, sand banks or even garden lawns). They might live in clusters but each hole is home to a single insect so they’re classed as a solitary bee. Importantly, Mason Bees can’t sting so there’s no risk from Mason Bees at all (on one occasion, we’ve gone bare-foot across a lawn to prove their safety). Best advice: enjoy watching them and don’t worry about them at all. If they’re in a lawn, be grateful for the additional drainage holes they’ve provided!

Wasps & Hornets

The wasp – and its relation, the Hornet – are the only ones in this list that are classed as pests. By far the worst offenders are the two main wasp species, Vespula Gemanica and V. Vulgaris: both will sting at even minor provocation and, when they do, they give off a pheromone that signals to other wasps to join in the attack – they’re classed as ‘social wasps’ partly because of this group behaviour.
Sub-species differences aside, wasps and Hornets have very distinct black and yellow bands across their ‘back’ which also looks hairless. Nests start – always – with a single queen wasp building a ball shaped nest (about the size of a ping-pong) and laying eggs in it. Generally speaking, this process doesn’t get going until May and, because the initial population is small (tens of wasps), it goes unnoticed. Once she gets established, the queen will stay in the nest and becomes an egg-laying machine – producing up to 200 a day is not uncommon. It’s harder to miss the constant traffic once the population swells to the hundreds and, if it’s in a cavity wall or loft, there’s usually a noise associated with it: scratching or popping sounds are often attributed to wasps building their nest.
Hornet nests peak at a hundred insects or so while wasps can easily have 8,000 or more in a nest – but both will actively defend their territory: get to close to a nest and there’s a very real danger of being stung multiple times. While Hornets generally nest outdoors (we’ve seen a few up against the eves of a home but most have been in bird boxes, shed walls or wood piles), the wasp will happily enter a home’s loft or an air brick and build their nest ‘indoors’, making them – by far – the most likely species to encounter people.
Because their nests can’t easily be relocated (on the odd times we’ve been called early enough for the nest to be small enough to move we’ve tried relocating them but with very limited success), if the nest presents a risk to people then the only practical solution is to destroy it. This is usually done by injecting a powder directly into the nest ball or onto the surfaces the wasp walk on before entering their nest – their ‘landing zone’ if you like. Obviously, both these techniques require someone to get fairly close to the nest site so we’d advise leaving this to someone who’s suitably equipped with protective clothing, has the right products and knows how to deploy them safely.

Pictures courtesy Flikr/Wikipedia/Pestend