Beekeeper Pat Hults wrote to us to suggest an article about the temperament of honey bee colonies, why they can change over the season, and what you can do to "improve the mood" of a colony with a nasty disposition. If you want to suggest a future newsletter story, send a suggestion to newsletter@betterbee.com.
Defensiveness in honey bee colonies
Some circ*mstances can change previously pleasant honey bees’ temperaments, including nectar dearth, robbing, loss of the queen, or the weather. Most of the time, a mean hive is caused by simple genetics: A worker bee’s genes determine her instinct for defensiveness* and govern how likely she is to fly up at a beekeeper or sting when she detects a threat or smells alarm pheromone.
*It's important to remember that the meanest honey bees in the world are still being "defensive," not "aggressive." The bees are merely defending their homes — some with much more gusto than others — but bees will never roam the neighborhood, plotting attacks against picnics or pool parties. A highly defensive colony may ENGAGE with a potential threat more intensely, may GUARD a wider radius around their home, and may PURSUE a threat as it retreats to make sure it won’t come back. Some of those behaviors may look like “aggression,” but they are ultimately just different forms of “defensiveness.”
Why do bees become defensive?
Sometimes the story with a “mean hive” or “aggressive bees” is that they “were suddenly defensive after they’d been nice all spring.” There are three common explanations for this.
Population
First, it’s important to remember that a new package, nuc, or small overwintered colony in the springtime has very few total bees, and therefore very few total guards. Small colonies tend to be calmer and easier to work with than larger ones, and even if they do get riled up there aren’t as many guard bees that will take flight. Even a colony carrying problematic genes for increased defensiveness will be more pleasant in the spring than they will be later in the summer after their population has grown. For that reason, if you’re trying to diagnose a touchy colony you can’t rule out queen (and stored sperm) genetics just because the colony was pleasant when they were smaller. Beginning beekeepers with just one or two hives may have a hard time judging if a colony has gotten “meaner” as they grew, but with experience (and multiple hives) it becomes easy to pick out unpleasantly defensive bees in comparison to neighboring hives, no matter the size.
Climate, weather, and timing
The second reason for a hive to "become unpleasant" concerns beekeeper scheduling. If you inspect your bees on a sunny day, you’ll be interacting with all of the nurse bees, nectar-processing bees, and guard bees, but most of the foragers will be out foraging. The hive will have fewer bees inside, so there are fewer chances for you to smoosh someone.
If you inspect your bees late in the day, on a cool and cloudy day, or on a rainy day, you’ll be interacting with every single bee in a colony because the foragers will be at home. When foragers can’t go out and forage, some will serve as extra hive defenders. So inspecting at the wrong time of day or in bad weather means you’ll be manipulating crowded frames full of experienced flyers who are on the lookout for trouble. It’s no surprise that some beekeepers accuse their bees of having a bad temperament after a rainy-day inspection.
Hive stress levels
Various stressors can cause a colony to become more defensive, and it’s important to rule these out before you requeen a “mean colony.” Otherwise, you may kill a perfectly lovely queen, and your bees will be just as unpleasant as they were before. Defensive behaviors can increase in stressed hives, and remain — sometimes for weeks — after the source of stress has been removed.
How genetics affect bee temperament
If you’ve examined the hive and see no obvious sources of stress to the colony, you may be dealing with a genetic temperament concern. The genetics of a defensive hive aren't entirely the "fault" of the queen — half of the genes inside every worker came from their father. Since young queens mate with multiple drones, the worker daughters they produce will be half-sisters by a few different fathers. If every bee in your colony has a bad disposition, we might guess that their behavior problem is linked to the queen’s own genes. If only some of the bees are fiery, perhaps it’s just one of the fathers that contributed those genes for unpleasant behavior.
How to fix bee colony temperament issues
How do you deal with an aggressive beehive — or, more accurately, what should you do if you have a feisty colony that would rather sting you than be inspected? Consider these options for calming a hot hive.
Remove or reduce stressors that cause defensiveness
Examine the hive and the apiary to look for sources of stress, which can change nice bees to downright nasty ones. Common stressors include:
Honey Robbing: A recently published study by Grume et al. at the University of Kentucky¹ showed that honey bees engaged in honey robbing behavior are more defensive than bees uninvolved in robbing. Robbing typically happens during a nectar dearth, like we experience in midsummer and autumn, and our hives are much more sensitive to disturbance during late autumn feeding than they are during a May nectar flow. Therefore, while your bees are robbing and defending from robbers you’ll likely see more defensiveness than usual.
Pests and Predators: Being attacked by pests or predators can also make a colony more defensive than they used to be. Small enemies like honey-stealing yellow jackets can easily upset a colony, while larger enemies can have greater impact. If a colony is attacked by a bear but survives the ordeal, they’ll sometimes become very aggressive for days, weeks, or even months after the attack. Skunks will return to the same apiary night after night to scratch at the entrance, stomp on the bees that emerge, and lick up their nutritious bodily fluids. If you find trampled grass in front of your "mean hive" with a pile of smashed bee bodies near the entrance, you likely have a skunk problem on your hands. Shore up your protections against bee pests and predators: Elevated hive stands deter skunks, electric fences protect against bears, and strong colonies with reduced entrances can keep yellow jackets and robber bees out.
Requeening a defensive colony
If there’s no outside explanation for the hive’s poor temperament, consider dequeening the colony. Remember how genetic defensiveness works when you’re deciding whether to buy a brand new queen or have your bees raise a new queen on their own — and potentially wind up with the same bad genes in the next generation of bees! You can allow the colony to raise a new emergency queen, but since you can’t simply ask the queen not to fertilize any more eggs with the sperm stored from Mean Drone #7, you may wind up with the same genes leading to defensive behaviors. Usually, the best option is to remove the source of the “bad” genes: The queen. Buy a replacement queen to completely break the genetic lineage of the ill-tempered colony.
Requeening a colony with a bad temperament forces a genetic reset on the whole population. A month or more after requeening, once the daughters of the original queen die and are replaced by the daughters of the new queen, you will hopefully see an improvement in the temperament of the whole colony. Of course, if the new queen inherited genes for defensiveness from her own parents, or mated with drones carrying genes for defensiveness, you could wind up with a colony that’s just as peppery as ever.
While bees may seem aggressive, their behavior is rooted in defensiveness and a desire to protect their home and resources. After you sort out the cause of the behavior, these tips can help you reset your bees’ behavior. Explore our Beekeeping Guide for more expert advice.
