By Scott Solomon, Rice University
In the wild, honeybees have to find a suitable place to live, usually a small cave or a hollow space in a tree. Each year, as the colony grows, the bees must find a new, slightly larger site to build a new home. The way they locate these sites, and agree on which site is best, involves a remarkable example of complex communication.
Complex Communication
The first person to notice the complex aspect of honeybee communication was Martin Lindauer. One afternoon in 1949, Lindauer noticed a swarm of bees. Some of the bees were performing waggle dances, but these bees were outside of the hive, which happens when the queen and a group of workers are in search of a new home. Looking more carefully, he noticed that some of the bees looked dirty.
Lindauer collected some samples of the dirt and examined them under a microscope. He noticed that the dirt from these dancing bees looked like dust from bricks and soot from chimneys. He suspected that the bees he saw dancing had been inspecting new nest sites. He would later find out that his guess was correct.
By marking individual bees with dots of colored paint, deciphering the location information contained in the waggle dance they were performing, and chasing after the swarm as it flew towards the site the colony had selected, Lindauer discovered that the bees were indeed dancing to report the location of potential new homes. But with lots of real estate options to choose from, how does a colony of bees determine which one is best?
By offering swarming honeybees artificial nests that differ in specific ways, and then observing which options they choose, Cornell University biologist Thomas Seeley has figured out what properties the bees find most important in a home.
This article comes directly from content in the video series Why Insects Matter: Earth’s Most Essential Species. Watch it now, on Wondrium.
An Ideal Honeybee Nest
The first key thing the bees look for is related to volume. Honeybees prefer a home that is large enough to accommodate all the bees and their stored honey, but not so big that they can’t keep it warm in winter. The optimal size is about one and a half cubic feet. If the hive already has a honeycomb from a previous colony of bees, that makes it even more desirable.
The next important thing is the entrance size. Honeybees need an entrance to the hive that is small enough to be easily defended if an enemy attempts to enter and also to keep the heat inside in winter, but large enough to make it easy for the bees to come and go. The ideal size is an entrance between 2 and 12 square inches in area.
The net key aspect is the direction of the entrance. Honeybees living in the northern hemisphere prefer south-facing entrances, which face the Sun more directly and help them stay warm in the winter.
Finally, the height of the entrance matters a lot as well. To defend it from enemies, like bears, honeybees prefer a hive with an entrance about 15 feet off the ground. They also prefer if the entrance is near the bottom of the cavity.
Who Calls the Shots in the Bee World?
Seeley’s work makes it clear that bees have preferences, but how does a colony that consists of ten thousand individuals make a decision about which home to choose? Contrary to the way that bees are often depicted in books and movies, the queen does not actually play any role in this process. The queen’s role is purely reproductive. A queen is an egg-laying machine: a queen bee can lay more than 1,500 eggs in a single day!
It’s worker bees that make the decision about what new home to choose. Certain workers, called scouts, visit different possible home sites and evaluate them using the criteria that bees care most about—entrance size, location, and volume. The scouts then return to the swarm and perform a waggle dance to indicate the location of the potential new home.
Because there are numerous scout bees—typically a few hundred—many of them are likely to have found different potential new homes. That means there are multiple different waggle dances being performed at the same time, representing different options for the colony to choose from.
Finalizing the New Home
The other scout bees observe the dances by feeling the vibrations with their antennae—it’s dark inside the hive so they can’t watch with their compound eyes. The better a potential nest site is, the more vigorously the scout will dance. Specifically, scout bees advertising particularly good nest sites will dance faster and for a longer time.
But the bees don’t just accept the opinions of the scouts. After watching a scout advertise a potential home with its waggle dance, the other scouts then go to the site to assess it for themselves. If they agree that the site meets all the necessary criteria, they return to the colony and join the first scout in dancing to advertise its location.
In this way, each scout bee has the opportunity to evaluate each of the potential sites, and those that are better suited eventually end up having more bees advocating for them with their dances.
Eventually, a consensus is reached in which all the scout bees are dancing for the same site. In this way, a decision is reached and the colony soon flies off all together and get settled in the new home they have chosen.
Common Questions about How Honeybees Choose Their Nests
There are some properties that the bees find most important in a home, such as volume, entrance size, entrance direction, and entrance height.
As it’s dark inside the hive, the bees can’t watch with their compound eyes. They observe the dances of the scouts by feeling the vibrations with their antennae. The better a potential nest site is, the more vigorously the scout will dance.
When searching for a new home, the worker bees called scouts visit different possible home sites and evaluate them using the criteria that bees care most about—entrance size, location, and volume. The scouts then return to the swarm and perform a waggle dance to indicate the location of the potential new home.
