Why do bees swarm, and how do I prevent it?
Bees swarm to reproduce as a colony, usually in spring when the nest is crowded and the queen has nowhere left to lay. The first warning is queen cups along the frame bottoms with an egg or larva inside. Give space early, and once charged cells appear, split the colony — you cannot talk them out of it.
The full lesson
Swarming is a completely natural, reproductive method carried out by a bee colony to reproduce and continue its lineage. In spring, brood and honey amounts increase rapidly. Running out of space inside the hive is the biggest trigger for swarming.
As the hive gets crowded, the pheromone scent secreted by the queen bee to hold the colony together cannot reach all worker bees. When an aging or underperforming queen's power is no longer enough to rule, the bees raise a new leader and tend to swarm.
A sudden population boom on hot spring days makes ventilation difficult, raising hive stress and driving the bees to swarm. Once the colony decides to swarm, worker bees build peanut-shaped, vertical queen cells on the bottom edges of the combs.
Just before the new queens hatch, the old queen bee leaves the hive, taking about half of the current population with her. The swarm leaving the hive hangs in a cluster on a nearby tree branch or object, while waiting to find a permanent home.
Scout bees from the cluster disperse into the environment, searching for ideal permanent homes like hollow trees or empty hives. Beekeepers gently shake this cluster into a hive box, preventing the colony from escaping into nature and gaining a new hive.
This lesson is also in the app, along with the other twenty-nine.
Next lessons
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1:40 13What should I do for my hives in spring?
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1:40Lessons and forum answers describe beekeeping practice and peer experience, not veterinary guidance. Treatment thresholds, inspection timing and disease management vary by climate, subspecies and local regulation. Diseases that are notifiable where you live must be reported to your national bee inspectorate.