What the Buzz?

Why honey bees swarm and what we can do about it

Hello again! I’m sorry I’ve abandoned Bees, Trees and Curiosities for so long, it’s been a busy month meeting deadlines and sitting exams to complete my second year of university. With no more uni work to do for the next 3 months, blogging is now my top priority! From now on, I’ll be posting something new at least once a fortnight. No more long absences. I promise!

I wanted to start my summer of blogging with my first post (of many, I’m sure) about bees. Precisely, why honey bees swarm and what we beekeepers do about it. At this time of year, swarms start appearing all over the UK, clustering together in all manner of places. Often, the bees will stop to rest on tree branches, walls or roof tops, but we also see them take respite in more unusual locations. Shoppers at an ASDA supermarket in Hayle, Cornwall were left ‘flabbergasted’ when they saw a swarm of bees settle on a Honda vehicle in the car park. Many people find this sight pretty astonishing – it is quite the wonder of nature. Others find it quite frightening, and I can see how hundreds of insects with stings in their tails flying in unison seems pretty ‘horror film-esque.’ However, honey bee swarms are really quite harmless. I worry that this fear of swarms may lead to people harming bees when we desperately need to protect them. Here are the reasons why you shouldn’t be frightened of swarming bees, and what you should do if you see them.

Why do honey bees swarm?

Why on earth do bees swarm in the first place? Why would they leave the hive in the early summer when they’ve worked so hard to maintain it all year? In May, the queen bee will have often reached her peak rate of egg laying. A well-nourished queen may be laying anything from 1,500 to 6,000 eggs per day at this time of year. This rate of laying is limited by how much food worker bees provide for the queen, and the space the queen has to lay eggs. At the bottom of a hive is a brood box filled with frames where the queen lays her brood. When the space on the frames runs out, the bees will naturally swarm to create a new colony. Swarming is simply the bees’ method of reproducing! During a swarm, half of the bees will leave the hive with the original queen. The rest of the workers stay behind with a few sealed queen cells containing eggs that will hatch into a new queen. If more than one of these virgin queens hatch at the same time, they will sting each other until only one remains to become the new queen. It is a common misconception that a swarm is an angry clan of bees out on the attack. All we are seeing is the original queen and her workers looking for a new place to live!

Science behind the swarm…

You might be wondering how all individual bees within the hive know that it is time to swarm. Bees work as a single unit, often referred to as a ‘superorganism.’ Each individual plays a role in making the hive work as one, single organism: much like each cell contributes to the human body working as a single unit. In our bodies, hormones trigger bodily functions. In 1953, British entomologist Colin Butler discovered that a similar process takes place in the hive. Swarming is triggered by the release of a pheromone called ‘queen substance.’ This pheromone is produced by the queen and is passed throughout the hive when workers touch her and then each other. Butler found that the amount of ‘queen substance’ a queen produces reduces by half for each year of her life. He showed that this decrease in ‘queen substance’ reduces the queen’s ability to keep bees loyal to her. This reduction in ‘queen substance’ is now thought to be the primary trigger of swarming in a honeybee colony.

What do beekeepers do about swarms?

Beekeepers use different methods of swarm control to try and prevent their bees from swarming. The simplest method of swarm control is to increase the space available in the hive. This is done by adding more supers. A super is a box filled with frames where the bees normally store their honey. This gives the bees more space to move into, reducing congestion in the brood box.

Another form of swarm control is making sure the colony has a young queen. This ensures that enough ‘queen substance’ is produced to stop a swarm being triggered. Queens are often marked by beekeepers with a certain colour depending on what year they were born. It is good practise for a beekeeper to replace a queen in her third year to reduce the likelihood of swarming. Beekeepers can either buy a new queen or allow their bees to produce a virgin queen themselves using an artificial swarming method. There are three methods of artificial swarm control that allow the colony to produce a new queen. These methods essentially convince the colony that they have already swarmed, without them actually leaving the hive!

In the first method, the original queen and her brood are removed and left to one side. This means the workers are no longer in the presence of her ‘queen substance.’ A new queen and some brood are left on the original hive stand, so the worker bees fly to join her. This is typically used by commercial beekeepers as it means a colony can be re-queened while keeping the original foraging force, so the honey crop is not hindered in the process. The second method involves removing the queen from the original hive. The queen is put into a small nucleus hive with around 5,000 workers, leaving the rest of the colony to rear new queen cells while continuing to forage and bring in nectar. The third method sees beekeepers remove the original brood. This mimics a natural swarm more closely, as it simulates the situation where the queen leaves her colony with nurse bees to raise a new queen. The is the most common method used by beekeepers and is the basis for most methods of swarm control. Here, I have just scratched the surface in explaining these processes. You can read much more about swarm control online or in any good beekeeping book.

What should you do if you see a swarm?

It is easy to panic when you see a swarm of bees. Just please remember that swarms are actually the most docile bees you will ever come across. When they cluster in an area, the colony is resting while scout bees search for a place for them to live. They are tired and don’t have a hive to protect, meaning they are unlikely to sting you. Please remain calm and contact a beekeeper to come and safely collect the swarm. The British Beekeepers Association (BBKA) have a web-page that helps you locate beekeepers in your local area who are happy to collect a swarm.

In the past month, my beekeeping society have re-hived two swarms. One was delivered to us by another beekeeper in Maltby. The second we collected ourselves from a wall outside a house in Walkley, Sheffield. We went to the site and brushed the bees into a cardboard box, which we then taped up and drove to our hive. You can see a video of us re-hiving a swarm on our Facebook page. Here, we set up a new nucleus hive and placed a wooden board at a sloped angle up to the hive’s entrance. We put a sheet over this board and dropped the swarm onto it. The bees appeared confused at first, but soon began instinctively walking upwards. As they found the entrance to the hive, they realise it will make an excellent place to live. These first bees lift their lower abdomens to expose their Nasonov gland, which produces a pheromone that attracts the rest of the swarm to start walking into hive. If you look closely, this can be seen in our video! It is quite the sight to behold when you see all the bees marching into the new hive. Go check it out!