Temperatures are rising, the days are getting longer, and the trees are budding once again. Spring has finally sprung here in southern Ontario (better late than never). This is the time of year when a beekeeper’s mind turns to swarming. Just as I have noted the changes in the environment around me, so have the honey bees! Pollen of various colours is starting to pour into the hives, which is a telltale sign of Spring and expanding colony populations.
Many factors influence the population of a beehive, the season being chief among them. Populations start to shrink as summer bees die off throughout Autumn and the queen slows (and may stop) her laying. She responds to environmental cues such as warming temperatures. She starts slowly at first, but after pollen becomes available in the spring, brood production can increase dramatically with a healthy queen. The increasing population is in response to an increase in floral resources and to build up a strong field force for the Summer, but also in preparation for a common Spring phenomenon: swarming.
Swarming, What’s That?
Swarming occurs most often in the springtime, and is a natural part of the honey bee life cycle. When a colony decides to swarm, they will start to raise (usually several) new queens. They do this by feeding larvae from fertilized eggs a dedicated diet of royal jelly so she can develop her specialized sexual organs. The old queen will also eat less and start to slim down in preparation of the flight. When these new queens emerge, the old queen will leave with around half the population of the colony. There may be smaller “after-swarms” including virgin queens, but they will generally stay behind and battle the other new queens for supremacy of the now-queenless colony. The swarm will settle in an intermediate location (such as a tree branch, see Figure 1 below) for a few hours to a few days. Where there was one colony, there are now two! One in the home hive with a virgin queen ready to be mated, and one now out in the world with the old, mated queen looking for a new home.
Figure 1: A swarm resting on a tree branch.
Did You Know…
1) A swarm is a honey bee colony reproducing?
People love to use the word “swarming” to describe any large group of animals in one small area. But did you know, it represents a specific biological phenomenon in a honey bee hive?
Honey bees are eusocial insects whose colonies form superorganisms: a group of synergistically interacting organisms of the same species (other examples of superorganisms include ants, termites, and coral reefs). This means that individual honey bees cannot survive long on their own and require the support of their large family unit (the colony) in order to thrive.
To produce more individual honey bees, queen bees mate with drones (male honey bees) and lay eggs which develop into adults. Swarming is the reproduction of the superorganism: the entire colony! Since there is (usually) only one reproductive female in the honey bee colony- the queen- the need arises to raise new queens in anticipation of the swarm. When a queen leaves the hive with a portion of adult bees from her colony in a swarm, she is able to establish a new hive; where there was once one colony, there are now two!
2) Honey bee swarms are generally docile?
Although there are exceptions to every rule—especially in beekeeping—swarming honey bees are generally very docile. Honey bees typically use their stingers when threatened, or in defense of their hive which contains their queen, brood, and all of their stored food. However, swarming bees are (temporarily) homeless! They don’t have much to defend and are focused on finding a new nest site, so they have little interest in stinging.
Worker bees also gorge themselves on honey before swarming so they have maximum energy for the flight and to build comb in their new hive. Their swollen abdomens are harder to bend, making it more challenging to maneuver their stinger. I always liken this to trying to bend over to tie your shoes after eating Thanksgiving dinner!
However, this doesn’t mean you should throw caution to the wind. Honey bees and other stinging insects should always be treated with respect and prudence. Factors that may make swarms defensive include (but are not limited to): provocation, not finding a new nest site quickly, running out of food, and having Africanized genetics. A provoked bee at any time is capable of stinging you!
3) Honey bees are democratic?
Swarming honey bees are in search of a new home in which to make their hive. Honey bees are cavity nesters, meaning they are looking for specifically sized enclosed spaces with a small entrance (for example, the hollow of a tree). Scout bees will leave the swarm to try to source a location that fits the bill. If they find a good candidate, they will return to the swarm cluster to recruit fellow scouts to the site.
To communicate the location of the potential nest site, honey bees use the same dance used to share the location of prime forage sources with hive mates—the waggle dance (check out Video A below). As the scout bee dances her sisters note the angle and duration of the dance, and they are then able to find the potential nest site to evaluate. If it is found to be suitable the new scouts return, and the recruiting continues. Multiple scouts may each find their own site, and they return to recruit other bees to check it out. Those bees in turn recruit others, and more favourable sites attract more dancers to advertise its location. Once a majority of the dances are directing to the same location, the swarm takes off in a cloud and relocates to the new hive site.
Check out this waggle dance video: Swarming: Video A
Avoid the Swarm!
Swarming is a completely natural part of the honey bee life cycle, however there are both colony management and biosecurity reasons to manage against swarming. It is advantageous to both your own beekeeping operation and your neighbour’s to avoid allowing your honey bee colonies to swarm.
Why manage against?
- Productivity!
A swarming colony generally means that you have lost half of the population of that colony. This can mean reduced honey yield from that hive and, if the swarm occurs late in the season, reduced chance of overwintering success due to the loss of population. - Biosecurity!
If your honey bees swarm and establish as a feral colony, they will not be able to be treated for mites or diseases. If they survive the winter and swarm again next year, that cycle continues and can spread parasites and diseases throughout your local area. If your bees have a high mite or disease load and another beekeeper catches that swarm, it can spread those parasites or diseases into their beekeeping operation. This is a great reason why beekeepers who plan to catch and hive swarms should establish a “quarantine yard”. Such a yard allows swarms to establish in their new hives so they can be inspected (and perhaps treated) for disease prior to being introduced into one of your apiaries.
How to Avoid:
- First, you need to provide your colony with adequate space for its expanding population. This could mean adding additional brood chambers or honey supers to your hives.
- Maximizing ventilation can also help to deter a colony from swarming. As temperatures are increasing at this time of year, the growing colony requires more fresh air to maintain the internal temperature of the hive. Removing entrance reducers when the risk of robbing has diminished is a good way to provide the greatest ventilation to your colony.
- If you run double brood chamber colonies, you can also reverse their positions (putting the top box on the bottom and the lower box on top) to “trick” the bees into thinking they have more space. As the brood nest is generally maintained in a roughly spherical shape, this will break it up into an hourglass shape and encourage the queen to lay more in the “new empty space” (See: Figure 2).
- If you are expanding hive numbers in your apiary or need to make up winter losses, you may wish to split your colony. There are myriad ways to accomplish this (too many to get into here!), and each has their upsides and downsides depending on your management goals. All methods have the basic principles in common: separating some of the adult bees, brood, and food resources of the parent colony into a second hive. If you remove the mated queen with your split, you have simulated a swarm, and the colony may end up thinking they have already swarmed. If you make a queenless split, you can then either provide a mated queen, queen cell, or a frame with worker bee eggs so that the colony can rear their own queen. By reducing the population and replacing the brood and resource frames with empty drawn comb at the correct time, a swarm can usually be avoided.
Figure 2: Reversing brood chambers in a double hive can trick the bees into thinking they have more space and delay swarming.
In Conclusion…
There is no denying the beauty of watching a swarm come together. A honey bee colony is truly a superorganism, and swarming is akin to the wonder of birth. There are many reasons for managing against swarming (remember, honey bees are livestock), but when you catch it in the act you can see how miraculous it really is.
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