There are many flying insects in the British Isles. The only insect in the British Isles that swarms is the honey bee. If you see only a dozen or so insects flying at one time it may be bumble bees which are quite definitely black and yellow.
Bumble bees differ from wasps in that bumble bees tend to be short and stumpy and furry, whereas wasps tend to be long and sleek and not furry at all. Honey bees range in colour from yellow and brown to almost black.
If you see a LOT of insects flying at one time, i.e. hundreds, it may be honey bees. If you see them forming a cluster on a tree or a structure then it is honey bees you are seeing as bumble bees and wasps do not cluster.
If you see a swarm clustered on a branch or a structure, a local beekeeper will generally be happy to come and take it away for you. Contact your local Beekeeping Association. In Scotland you can find your local Association by checking the Scottish Beekeepers’ Association website.
If the bees are in an inaccessible spot, the beekeeper will perhaps only be able to advise you how to deal with the bees. If they are not a danger to you or the public they can generally be left where they are. If they do pose a danger, then you may have to contact your local authority or a pest control company to have the bees destroyed.
Bumblebees nest in the ground, in dry sheltered spots. They quite like under decking! Bumblebees are non-aggressive and are not at all interested in people, they very rarely sting. If you have a bumblebee nest and the bumblebees pose a danger to you or the public, their nest can be moved if it is accessible. For an excellent explanation of how to move a bumblebee nest, please see the Bumblebee Conservation Trust’s website
Why do Bees Swarm?
Swarming is the process by which a new honey bee colony is formed. A colony is considered to be a ‘super organism’ i.e. none of the individual members can survive without the others. For honey bees to increase in number, i.e. grow their population, they will increase the number of colonies, not the number of individual bees within a colony. The queen bee leaves the colony with a large group of worker bees. Only the older workers go with her, the younger ones remain behind to finish hatching what brood she has left behind and to care for the new queen. When she has hatched, the new young queen then begins laying and that colony will continue. The old queen and her accompanying workers will be looking for a place to set up a new home, thus two colonies result and the bees have multiplied.
What is a Swarm?
A swarm is made up of the old queen and up to 60% of the worker bees from the original hive. This swarm can contain from thousands to tens of thousands of bees. Swarming only happens in the warmer months, usually in Scotland between the end of May and the end of August. A swarm can be an awesome sight to see! The air will be filled with bees, humming and buzzing as they leave the original hive. They generally settle on a site only a few metres away from the original colony and then they cluster, forming a dense ‘ball’ of bees on the branch or structure they have chosen. This cluster then sends out scout bees to look for a new home. The scouts each come back and ‘dance’ to show other workers on the surface of the cluster where they think there is a good location. More bees then leave to check out these potential sites. Bees returning from scouting will either encourage the dances of sites they think are good or will head-butt bees dancing about sites that they think are not good to stop them dancing. Thus, eventually, a consensus is reached and the swarm will move to the site chosen, almost democratically, by the most bees. A swarm will cluster for about 3 days maximum before moving to a new site. While the bees are clustered they may look ‘dangerous’ but they are actually quite docile. Each bee has filled herself with as much honey as she can hold before leaving the old hive so the colony has food to tide them over until they set up their new home. Bees like this will very rarely sting, unless the cluster is poked with a stick or has stones thrown at it! All they want is to find a new home. The queen is protected at the centre of the cluster and they will not become aggressive unless she is threatened.
Stimulus to Swarm
Bees are stimulated to swarm when their colony becomes too large. Queen honey bees emit a pheromone that is passed from bee to bee throughout the hive, this chemical signal reassures the colony that all is well and encourages the bees to continue with their individual tasks. When a queen is removed from a colony it takes only 15 minutes or so before the bees will become anxious as they notice that this chemical signal is no longer there. Likewise, if a colony becomes very large, the chemical signal becomes diluted among so many bees which causes the bees to act differently. They begin by stopping feeding the queen. A queen cannot fly if she is too heavy, so they stop feeding her and she gradually stops laying. This then stimulates the queen to want to fly, to leave, to set up a new colony. By this time the worker bees will have selected some recently laid eggs and started treating them differently to ordinary worker eggs. They will have made a few special ‘queen cups’, deeper cells that the queen has laid eggs in. When the eggs in these queen cells hatch after 3 days, the nurse bees feed these chosen larvae with only royal jelly. (Worker larvae are fed bee-bread, a mixture of pollen and honey.) The worker bees elongate the queen cup into a queen cell, it looks like a peanut in its shell stuck onto the middle of the frame or near the bottom of the frame. These chosen larvae will develop into queens. Five days after the eggs have hatched into larvae, the queen larvae are ready to be capped over. This is the time the old queen is most likely to leave with the older workers. Beekeepers use these signs to try to avoid their bees swarming because if the older bees leave, the beekeeper loses a valuable honey making resource. The younger colony left behind will only begin to make a surplus of honey when the new queen starts to lay and there are enough older workers to go out foraging, which can take another 2-3 weeks. The Scottish summer is not long, so this is lot of time lost from honey making.
When the beekeeper sees signs that the bees intend to swarm there are a number of things he can choose to do. Most involve making an artificial swarm, which makes the older bees feel that they have swarmed so they settle down quickly in their new home and they get down to raising new brood and making honey to increase their chances of surviving the autumn and the winter. There is a wide variety of techniques the beekeeper can choose from – have a look on the web for information regarding artificial swarms, e.g. Snelgrove boards, Demaree, Pagden.