The Des Moines Backyard Beekeepers April 2019 meeting was about swarms. Doyle Kincy was the special speaker. Swarming is how a hive naturally reproduces. Half of the bees in the hive leave the hive with the old queen and find a new home. The other half raise a new queen.
2017 was an early spring in Iowa. A lot of beekeepers were caught off guard. 2018 was the opposite. It was a very cold winter, but it quickly warmed up.
Swarm prevention starts in spring with spring maintenance. We blogged about our Spring Hive Clean Up. A beekeeper should clean the bottom board, check how solid the foundation of the hive is, reverse the deeps, and equalize (give smaller hives brood or switch hives so that foragers return to the weaker hive). When reversing, two of the brood frames from the new bottom box should be put in the new top box so that the bees move up. When the first nectar flow begins, two supers with drawn comb should be put on top of every hive that has two deeps. This will prevent the bees from being overcrowded. Another way to relieve congestion is by putting upper entrances in every two supers.
What causes swarms? The three main triggers that cause swarming are congestion and overcrowding, backfilling of the brood boxes, and queen failure. Feeding may cause swarming. Congestion and overcrowding is when the hive is too full of bees or there are not enough entrances for the bees. The bees swarm so that they have more space. Backfilling of the brood boxes is when the bees fill in former brood cells with nectar. This is often a result of the bees not having enough drawn empty combs. The queen can cause swarming if her pheromones are not being distributed throughout the hive. Feeding may cause swarms because it may cause any of the above factors.
Beekeepers will use swarm traps to catch swarms. This is not stealing (as we often get asked) because swarms will leave hives no matter what and there is absolutely no way of telling whose bees swarmed. Two or three frames of comb should be put in a swarm trap. Propolis and beeswax should be rubbed all over the trap. A few drops of lemongrass oil should be put on cotton balls. The cotton balls should then be places in a ziplock bag and put on the bottom of the box. All these things attract honey bees to the trap. Traps should be taken down at the end of June as other creatures may try to move in.
If bees are bringing pollen into a trap a swarm has moved in. A beekeeper should wait a few weeks before moving the trap into a hive. Ideally, the swarm should be moved three miles away from where it was found, but if it cannot be moved that far, a shim can be placed slightly in front of the entrance. Swarms should be treated with a small dose of oxalic acid after they are moved into a deep.
Swarms are really cool and we are hoping to catch one this year.