PHOTO: Kenneth Cole Schneider/Flickr

Many equate the act of swarming to aggression, but in truth, if you were to encounter a swarm of honeybees, you’d be facing off with the gentlest nature of Apis melifera. Without a home to defend or young to care for, the 10,000 (or so) bees and the single queen that typically comprise a swarm are as carefree as bees get—for a little, anyway.

So how does that swarm cluster end up draped up high on tree limb, and what are they doing there? Let’s start at the beginning.

Preparing To Split

In the early spring, when flowers begin to bloom, and nectar starts to flow, the hive’s queen ramps up her laying. Soon, a demure winter cluster of a few thousand bees becomes a hive of 50,000 or 60,000 strong, busting at the seams and dripping from the entrance. As the hive’s capacity reaches its limit and the colony knows the structure simply can’t hold anymore, the bees instinctively know it’s time to swarm. A swarm is the honeybee’s way of propagation, after all.

To begin swarming preparations, nurse bees get to work on creating a new queen, because the swarm will take the resident queen with them. Through this process, a few select eggs are chosen as potential queens—continually fed royal jelly throughout their larvae-hood—and queen cells (sometimes called swarm cells) are created around them. There, they grow. The swarm is long gone once the queens hatch, but when they do, the first one to emerge will kill the other potential queens in their cells and take the honeycomb throne, so to speak. She then sets off on her mating flight, returns full of fertilized eggs, and leads the next chapter of that colony. But, I digress!

Swarm Time

Once the process of swarming is underway, the worker bees will prepare to leave by filling up with as much honey as their tiny bodies can carry. Along with their mated queen, who will spearhead their future colony, the entire swarm sets off. To a watching bystander, the process of swarming looks terrifying—akin to an insect version of The Birds.

Buzzing and rapidly flying honeybees fill the sky, turning it dark. The air around them literally buzzes. Eventually, the wayward bees find a spot to settle and rest. Forming a ball, or cluster, with their queen in the center, they find a place to wait and rest. Usually, the swarm cluster lands only several feet from the mother colony. And that’s when things get interesting.

With the queen’s pheromones keeping the majority of the bees within the cluster, a few “scout bees” will set off in search of a safe new location to set up their colony. The bees search anywhere and through anything that may fit the bill: old buildings, hollow trees, barns or other existing human structures, even a vacant grill. The scout bees now do an amazing feat: While out scouting, they actually take measurements of potential new home sites and return with that information to the cluster. Through a series of dances (much like the waggle dance that honeybees use to share information about foraging sites), the scouts convey information about the potential new home to the cluster, and encourage other scouts to get take a look.

Home, Sweet Home

Original scouts and new scouts then congregate in and around the chosen home sites. Some studies suggest that as the bees gather, a consensus is formed on the home site with the most scout bees in attendance. The decision is then made for the site with the most “votes,” and the scout bees return to the waiting cluster to alert the rest of the bees to the decision.

The entire process from the departure of the mother hive, to unanimous group decision of new home site may go on for a few hours to a few days, though a typical wait is about 24 hours. Then they’re off yet again, buzzing and darting in the sky, now with set destination: their new home.

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