Why Bees Swarm

When the first virgin queen is almost ready to emerge, and before the main nectar flow, the colony will Swarm during the warmer hours of the day. The old queen and about half of the bees will rush in mass out the entrance. After flying around in the air for several minutes, they will cluster on the limb of a tree or similar object. This cluster usually remains for an hour or so, depending on the time taken to find a new home by scouting bees.

When a location is found, the cluster breaks up and flies to it. On reaching the new location, combs are quickly constructed, brood rearing starts, and nectar and pollen are gathered. Swarming generally occurs in the Central, Southern, and Western States from March to June, although it can occur at almost any time from April to October.

After the Swarm departs, the remaining bees in the parent colony continue their field work of collecting nectar, pollen, propolis, and water. They also care for the eggs, larvae, and food, guard the entrance, and build combs. Emerging drones are nurtured so that there will be a male population for mating the virgin queen. When she emerges from her cell, she eats honey, grooms herself for a short time, and then proceeds to look for rival queens within the colony. Mortal combat eliminates all queens except one. When the survivor is about a week old, she flies out to mate with one or more drones in the air. The drones die after mating, but the mated queen returns to the nest as the new queen mother. Nurse bees care for her, whereas prior to mating she was ignored. Within 3 or 4 days the mated queen begins egg laying.

During hot summer days, the colony temperature must be held down to about 93° F. The bees do this by gathering water and spreading it on the interior of the nest, thereby causing it to evaporate within the cluster by its exposure to air circulation.

During the early summer, the colony reaches its peak population and concentrates on the collection of nectar and pollen and the storage of honey for the coming winter. After reproduction, all colony activity is geared toward winter survival. Summer is the time for storage of surplus food supplies. The daylight period is then longest, permitting maximum foraging, although rain or drought may reduce flight and the supply of nectar and pollen available in flowers. It is during the summer that stores are accumulated for winter. If enough honey is stored, then the beekeeper can remove a portion and still leave ample for colony survival.

Honeybees detect the need to Swarm and start a new colony for one or more of the following reasons:

• The colony is too congested in their current hive. There is not enough room for the queen to lay more eggs and/or for the worker bees to store more honey and pollen in the honeycomb.
• The queen has become weak with age, so she is not laying enough eggs or giving off enough pheromone scent to properly control the colony. This condition may also trigger superseding, which does not usually result in swarming. 
  
• The queen is missing.
• Prolonged periods of bad weather (rainfall, etc.) restrict the bees to the hive and cause congestion and lack of foraging activity.
• The queen is genetically defective, which can inactivate nurse bees, cause a higher genetic tendency to Swarm, lower queen pheromone production, or cause poor egg-laying activity or sporadic egg-laying, resulting in an uneven distribution of honeybee castes. This condition may also trigger supersedure, which does not usually result in swarming.
• Poor ventilation, resulting in higher-than-normal moisture levels or temperatures inside the hive
• Lack of food or water supply.
• Disease or pest infestation; these conditions may also trigger superseding, which does not usually result in swarming.