bee biology

How honey bees build perfect & practical six-sided wax cells

Hexagonal comb cells have fascinated mankind from the beginning.

Many elaborate theories explain the six-sided shape of honeycomb, but the real answer may arise from soap bubbles.

For as long as mankind has pursued honey bees, he has been fascinated by the shape of comb cells. Since the beginning, many types of intelligence have been ascribed to honey bees that might account for their extraordinary ability to build perfect hexagons. If you ever tried to draw a regular hexagon, one with equal sides and equal angles, you know how difficult it can be.

The science of soap bubbles

But the most plausible theory is that honey bees do not actually build hexagons. Instead, they build wax cylinders that conform to the shape of their bodies. They take the secreted wax flakes, soften them with their mandibles, and assemble them in a tube around themselves. For worker cells, they build a size that just fits. Small bees build small cells and larger bees build larger cells.

The flattened areas result where two cells touch each other. The most obvious example can be seen in soap bubbles. Wherever two bubbles touch, a flat wall is formed between them. Imagine building row after row of tightly packed cylinders. If you warmed them up so the walls flowed like liquid, they would develop flat sides wherever they touched, just like soap bubbles.

Heat changes circular cells to hexagonal

Researchers now believe that as the cells are constructed they are warmed by the bees’ bodies which causes the common sides to flow together and form a flat wall. Because they are closely packed, the rows form a series of hexagons that we recognize as a honeycomb.

In their paper, “Honeybee combs: how the circular cells transform into rounded hexagons” (2013), B. L. Karihaloo, K. Zhang, and J. Wang report that the transition from round sides to flat can happen in just seconds, depending on the temperature of the wax.

Other cell shapes are common in a colony

Some of the most compelling evidence for the soap-bubble theory can be found not in the perfectly-shaped cells but in the imperfect ones. For example, wherever the cells are not tightly packed, such as at the intersection of worker cells and drone cells, you can find many other shapes. Four- or five-sided cells are not uncommon in this area. Some look quite random, stretched in odd ways in order to meet another cell.

Also telling are the shapes of supersedure cells and swarm cells. Since queen cells are built separately and do not touch other cells, they remain cylindrical. Even queen cells that are started on hexagonal foundation soon depart from the embossed shape and become cylindrical.

Many social insects build hexagonal cells

In nature, honey bees are not the only insect to build hexagonal nests. Some of their kin, including various wasps, also build hexagonal cells—proof that the hex shape is not exclusively a honey bee thing. As shown below, social wasps’ combs look very similar to honeycombs.

Rusty
Honey Bee Suite

soap-bubbles stuck together
Where soap bubbles stick together, the intersection is flat. Pixabay photo.
Circular layers of comb filled with brood
Many of the social wasps also build hexagonal cells, such as these aerial yellowjackets. © Rusty Burlew.

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24 Comments

  • Rusty,

    You explain the mechanism by which honey bee cells become hexagons. When mud drys, it produces a matrix of hexagons too. The mud has little structure for this to happen, and it is not a surprise that nature chooses a crack pattern where the broken fragments of soil fit, but why is it the hexagon as opposed to a random crack pattern or a bunch of triangles?

  • I’m not sure I believe their explanation. I’ve seen lots of half-formed hexagons, only a millimeter or less deep, just an outline, really, on the inner cover or sides of the hive. It seems to me they start out with a hexagon pattern. I always assumed it was due to the shape of their wax glands. I did not realize this was not understood well.

    But maybe I just saw what I wanted to see. Nice blog post! Packages coming soon!

    • Tim,

      I think you make an excellent point. I’m going to have to look at those start-up patterns more carefully, but I think I’ve noticed the hex there are well. The plot thickens. Wax scales, though, are just sort of irregular ovals without much shape at all.

    • Ever think when the bee was created he was programmed to do it, the most effective use of space for storage? Thank Jehovah for the bee

      • And hurricanes, and floods, and plagues, and mass starvation, and congenital diseases…thank Jehovah!

        • If it weren’t for bad things we couldn’t have good things cause you wouldn’t have anything to compare the good to.

  • I, seriously, learn something new almost every time you publish a new article! Thanks for the transfer of knowledge.

  • The melted wax theory sounds plausible enough. But are wasp building paper nests in hexagonal shapes in both horizontal positions susceptible to similar influences?

    • Mike,

      I don’t know. I assume that the wood fibers take on a liquid-like form when they are combined with wasp saliva, so it’s possible the material flows. It’s a good question.

  • Thanks for the fascinating article. So, what’s the current thinking on how bees and wasps **know** how to make hexagons? Is it something they simply learn from one another, or is it inherent knowledge ????

  • I’m not buying it. I was listening to a podcast earlier this year where they were talking about some research into cell shapes. I believe it was Jamie Ellis’s podcast – Two Bees in a Podcast (but I could be wrong about that) – from probably sometime in February. I remember them talking about when there is a larger drone-sized cell next door to a smaller worker cell. They noted that there will always be a 5-sided cell with a corresponding 7-sided cell. If this was an accident of expansion, I don’t think it would be that uniform.

  • I like to watch paper wasps build nests in my barn. They don’t build circles in the horizontal position with wood pulp and form hexagonal cells using the gravity bubble theory. Last I checked gravity doesn’t work that way. I highly doubt it applies to honey bees even in the vertical position. I sometimes get hexagon burr comb in the horizontal position under slatted racks. Try flipping a piece of foundation on its side. Bees still build hexagons just not in the pattern we would expect.

  • Hi Rusty, have you seen the YouTube video called “Hexagons are the Bestagons?” Its worth the time, and fun. Bees are amazing.

  • Rusty,

    Making a round shape, then turning it into a hexagon is not an efficient use of wax, which is an extremely valuable resource and not easy for them to make.

    “The comb construction commences when individuals with well-developed wax scales disconnect themselves from their sisters, climb upward through the hanging braids of bees, and deposit their wax on the cavity’s ceiling or walls. To remove a wax scale from one of the wax-gland pockets on the underside of her abdomen, a bee presses a hind led firmly against the ventral surface of her abdomen and then slides it rearward until one or more of the larger spines in the leg’s pollen comb skewers a scale and dislodges it from it’s wax-gland pocket. Next, the hind leg bearing the scale is drawn towards the head, where the wax scale can be grasped by the forelegs and chewed by the mandibles. The scale is chewed to mix it with a mandibular gland secretion that makes it more plastic, then it is deposited on the surface where the comb building is getting started or is already underway. Initially, these wax deposits produce just small piles of wax, but eventually the piles merge into a ridge of wax several millimeters (ca. 0.25 inch) long. At this point, the sculpting of cells begins. First, a cavity the width of a worker cell is excavated in one side of the wax ridge, and the excess wax is deposited along the sides of the hole. This work is repeated on the other side of the ridge of wax, but here two cells are dug, such that the center of the first cell on one side is between the two cells on the other side. Next, the raised edges of these cells are sculpted into thin lines to form the bases of each cell’s six walls, with the adjoining walls laid out at an angle of 120 degrees. This gives each cell a hexagonal cross section from the start. As additional bits of wax are deposited, the bases of additional cells begin to take shape at the appropriate distances from the preexisting cells, and the walls of the first cells are raised by adding rough particles of wax to the top of each wall and then shaving each one down on both sides to form a thin, smooth, plane of wax in the middle (fig 5.10, middle). The cutaway wax is then piled up, together with some fresh wax, on the top of the wall, and the process is repeated. So, bit by bit, a wonderfully thin wall of wax grows steadily outward, and always crowned by a broad opening.

    Throughout this process of comb construction there runs a theme of economy in the use of the energetically expensive beeswax. The most conspicuous expression of this frugality is the cell shape in the combs of honey bees: a right hexagonal prism capped on the inner end by a trihedral pyramid…A comb of circular cells also requires wax to fill the spaces between the cell walls (fig. 5.10, left), so the volume of wax required to build a hexagonal-cell comb with a given number of cells is, all things considered, less than half that required to build a circular-cell comb with the same number of cells.

    Several other features of the comb construction process, besides the hexagonal cell design, also contribute to the economy in wax use by honey bee colonies. One is the skill of worker bees in shaving down the wax partitions between cells, which leaves the walls of the cells only 0.073 millimeter (0.003 inch) thick.”

    -The Lives of Bees. Thomas D. Seeley 2019