Swarm Cell
Lexikon
The swarm cell is a queen cell that a bee colony builds proactively when preparing for natural reproduction by swarming.
The swarm cell is a queen cell that a bee colony builds proactively when preparing for natural reproduction by swarming. Unlike the emergency queen cell, it is not converted from an existing cell but newly built by the worker bees as its own, vertically downward-pointing cup shape, usually at the lower edge or on the lateral margins of the combs. The queen then lays an egg herself into these prepared cups.
It is typical for a swarming colony to rear not just one but several swarm cells at the same time, often a whole row spread over several combs. The known beekeeper's rule applies to development time: three days as an egg, five days as an open larva, after which capping follows; overall the young queen hatches after about sixteen days.
In practice, finding capped swarm cells during the weekly swarm control is the most important warning sign, because from capping onward, around the eighth day after the egg is laid, the swarm can leave at any time. A common beginner's mistake is to confuse swarm cells with the smaller, still unlaid queen cups, thereby either intervening unnecessarily in a healthy colony or, conversely, missing an actual swarm departure.