Figure 5.19 An emerged queen cell, indicating that the colony has recently swarmed, and that it is too late to take preventative measures.

      The colony swarms prior to the emergence of the queen cells. If the weather does not permit swarming, or if resources dry up, the colony will destroy the swarm cells without swarming.

Practical application: If the colony has recently swarmed, you will generally be able to see emerged cells, often with the round capping still attached (Figure 5.19). If, on the other hand, all the queen cells have been chewed out from the side, the colony may have “changed its mind.”

Practical application: A colony first issues a “prime swarm” containing a mated, successful, but typically aging queen. If the remaining colony is still too large for the cavity, one or more virgins may leave in “afterswarms.” Young queens will not tolerate a rival sister (Figure 5.20). In the case of either a swarm or an afterswarm, only one queen will be left remaining.

Swarming is coordinated by a few “experienced” workers (Rangel and Seeley 2008, 2010) rather than being controlled by the queen. The queen is pushed to exit the hive. Not all queens (which may not have flown for a year or more) are able to do so (Figure 5.21).

       Practical application: With time, the setae (“hairs”) on a queen's body get worn off, especially on the top of her thorax. This is one way to tell how old a queen is.

After emerging from the hive, a swarm temporarily bivouacs on a tree limb or other resting place while the scouts decide upon a permanent nest site. Beekeepers use this opportunity to “hive” a swarm by shaking it into an empty (not containing bees) hive (Figure 5.22).

       Practical application: A swarm may contain several queens, most being virgins. Workers may form protective walnut‐sized “balls” around them, that can be picked up and used to start new colonies.

      Once a swarm settles into a new cavity, the new colony is in a race against time, since the average longevity of a worker bee is about 35 days, and it takes around 20 days to complete a brood cycle. It is astounding how rapidly a swarm can build out a new hive and grow – provided that there is either a nectar flow on, or the colony is fed sugar syrup.

      Management to Minimize Swarming

Swarming is the natural reproductive process of the honey bee. It is challenging, but possible to manage colonies to minimize swarming. A colony swarms once it has grown to a certain size, or when it senses that it has grown too large for the cavity that it inhabits. The cues for those two factors are, respectively, the dilution of queen pheromone, and the lack of pheromones from young larvae.

Figure 5.20 A sharp‐eyed vet can really impress a beekeeper when they walk up to a hive, and with a glance at the ground pronounce that the colony has recently swarmed. The presence of a dead virgin queen in front of the hive, as in the photo above, is a sure sign of that occurrence.

Figure 5.21 An aged or damaged queen may not be able to fly far, and may land on the ground and not be able to return to the hive, in which case the swarm will return to the hive, only to leave again once a new queen emerges from a swarm cell. You may spot a flight‐impaired queen on the ground, sometimes surrounded by a few workers (note this aged queen's damaged wing).

Figure 5.22 A beekeeper about to shake a low‐hanging swarm into an empty box placed above a hive full of frames. A swarm will readily move into a box full of beeswax combs, and immediately begin foraging and establish a broodnest.

       Practical application: The short version is that the swarm impulse can be kept in check by:

       Providing drawn comb directly in contact with the broodnest so that the queen doesn't run out of cells in which she can lay eggs, or

       “Shaking bees” to decrease the population size, or

       Splitting the colony to reduce its size.

       More details can be found at (Oliver 2015).

       Practical application: Springtime swarm prevention can often be combined with requeening and varroa management.

      Usurpation Swarms

      I would be remiss not to mention that a swarm of honey bees may invade another colony and replace its queen with their own. Such behavior is well‐known for the Africanized Honey Bee (Schneider et al. 2004) but is also occasionally observed in European colonies (Mangum 2010; Oliver pers. obs.). This sort of aggressive usurpation allows a small swarm to take over the combs and valuable food stores of an established colony, thus giving the invading swarm a much better chance at their genetics surviving the winter. The invaded colony is often weak, queenless, or with a failing queen.

       Practical application: If a swarm lands next to the entrance of an established hive, an inspection may find a queen being balled on the bottom board, indicating that a hostile takeover has taken place.

      Emergency Queen Rearing

A queen may be unexpectedly lost without a supersedure cell in place. This may be due to sudden queen failure, disease, predation,

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