Bees at Work: The Wonders of Wax
Beeswax comb is a marvel of nature, showcasing intricate construction and variation depending on the hive environment. Understanding how honey bees build comb, the unique properties of beeswax, and the geometry behind the famous hexagonal cells offers insight into the efficiency and intelligence of honey bee colonies. However, not all comb cells are perfectly hexagonal—some deviate in size and shape, prompting curiosity about the flexibility and purpose of the structural choices made by bees.
How does comb vary between different hive environments?
Wild combs are built downward in trees, rocky outcrops, or other cavities. Each sheet of comb resembles a stalactite with an attachment point at its top surface. As the bees determine the spacing and layout of their hive, the comb's shape and size are often irregular and follow the contours of the space. Brood cells are typically located on combs at the center of the hive, surrounded by pollen combs, with honey combs forming the outer layers. Similarly, brood will be in the center of each individual piece of comb and will usually be surround by nectar and pollen on the outskirts. This arrangement protects the brood from the elements, while also making sure there is plenty of food located throughout the hive.
In Langstroth hives, such as those used at Buddha Bee, the two lower boxes contain the broods nest and we use a queen excluder to prevent the queen from moving into the top honey storage boxes. This helps manage the hive’s population and preserves space for precious honey. Our removeable frames feature wax-coated plastic foundations in the middle, providing bees with a internal base layer for constructing comb on both sides. These foundations encourage bees to construct uniform, hexagonal cells, which makes hive management, honey extraction, and inspections more efficient. However, it does slightly limit the bees' natural freedom in their comb building process.
The images below show our wax-coated plastic foundation (left) and a typical comb-filled frame (right). The frame on the right is from the broods’ nest, and shows a beautiful "brood rainbow" in the center, surrounded by a golden ring of pollen and shiny nectar on the edges.
Natural beekeeping often uses top-bar hives (photo below on left), empty wooden frames (photo below in middle), or thin wax foundations with wire supports (photo below on right). These methods mimic wild hive behavior more closely, but they can result in irregular sizes, shapes, and spacings of comb cells. With these frame styles, bees are given more flexibility in comb building, however, it can be more difficult to manage colonies and extract honey without the comb flying off the frames.
How do bees construct comb?
Comb construction results from the inspiring, collective behavior of thousands of worker bees. Comb consists of hollow, thin-walled, hexagonal cells (well, for the most part as you will see later!). These combs are made from wax secreted by eight wax-producing glands called “Wax Scales,” located on the underside of bee abdomens. Young worker bees consume honey in order to trigger their Wax Scales to secrete small, flat, clear flecks of wax. The bees gather, chew, and add saliva to shape the scales into their desired comb structures. Bees gradually add these scales one at a time to create the comb rather than assembling pre-made pieces. The environment within the hive, including temperature and humidity, plays a crucial role in the wax consistency and the comb's construction.
Energy needed for comb production: A hive takes between two weeks and two months to produce enough honey comb for winter honey storage (this is excluding brood/other cells). The speed of comb building depends on colony size and typically occurs during the spring nectar flow, when bees expand their storage capacity. Worker bees produce about eight wax scales per day, and it takes 450,000 scales to make 1 lb. of beeswax. To produce 1 lb. of wax, bees must consume 6-8 lb. of honey, which requires collecting over 40 lb. of nectar from 12-16 million flowers.
As discussed in more detail below, worker bees have a seemingly innate ability to build nearly perfect comb structures with cells that are (for the most part) consistently uniform in size, shape, and tilt. This precision suggests they must contain some ability to measure and plan before beginning construction. Honey bees use “festooning,” where they cluster and hang in chains, to measure distances and ensure proper alignment of their comb. During festooning, bees coordinate their scaffolding all while working in complete darkness and relying on touch or chemical pheromones for communication.
As beekeepers, we often observe festooning when we pull frames apart in our Langstroth hives. While the bees pictured here aren't using festooning to measure their scaffolding, this behavior resembles how they measure and space their comb during construction.
What are the properties of beeswax?
Beeswax is composed of natural fats and oils produced by bees, which they obtain from consuming honey and pollen. The fatty substances give the wax strength and stability, while the oils keep it flexible and malleable. Wax is hydrophobic, meaning it repels and does not absorb water. This property is crucial, as it prevents excess moisture build-up when it rains.
Although these properties are essential for the structure of honeycomb, there is a downside. While wax repels water, it tends to attract various other substances. As bees walk over the comb, their feet carry dirt and other materials from their foraging activities. Wax readily holds onto things like dirt, pathogens, pesticides, herbicides, and environmental particles. Over time, this accumulation of debris transforms the wax from its original clean white/tan color (photo on left) to a darker, dirtier brown (photo on right).
As beekeepers, we value the time and effort bees invest in constructing comb and strive to reuse frames with drawn comb. However, comb can become too old for reuse. Bees signal this by filling many cells on a frame with wax, indicating that they are covering something undesirable. They may also simply ignore or avoid using frames they consider unclean.
At Buddha Bee, we have implemented a few strategies to address this issue. One effective method is freezing frames, which kills pests, pathogens, and fungi that may inhabit the comb. During swarm season, we also make splits, which involves removing five deep frames from a hive and replacing them with new ones. This process ensures that each spring, our hives receive a significant clean-out of frames that are too old for continued use.
Why do comb cells have a hexagonal shape?
Honey bees are known for constructing beautiful, hexagonal comb cells in their hives, which serve as storage space for brood, nectar, honey, pollen, and bee bread. The exact process is still debated, but historically, Marcus Terentius Varro and Charles Darwin offered theories as to how honey bees achieve the revered hexagonal shape. Varro believed bees had geometric skills, linking their six legs to the hexagonal shape, though this idea is now seen as a bit far-fetched. Darwin suggested hive success depended on minimizing energy and resources spent on wax production and that six-sided cells achieved this goal, which is definitely a more reasonable theory.
Recent research has shifted from attributing the hexagonal shape to bees' geometry skills and maximum efficiency, focusing instead on physical forces and the mechanical actions of the bees. Cell construction begins with spherical shapes as the base layer. Once cells reach their full diameter, the bees will start forming the walls by depositing wax flakes around the rim. As the rims grow taller to form the sides of the cells, the hexagonal shape emerges due to pressure exerted by adjacent cells. Most often, each cell is surrounded by six other cells, which creates “triple junctions” of three, 120° angles. This is possible because the wax has a "visco-elastic" quality, meaning it behaves like a semi-solid within these triple junctions. The bees heat the wax within these triple junctions to approximately 113°F, making it pliable and malleable. This temperature creates tensile stress in the cell walls, causing them to stretch and fuse into hexagonal shapes with slightly rounded corners.
The image on the left shows how the base of cells start out circular, before the bees begin building up the side walls. Notice how there is excess space in between the spheres! The image on the right shows the shape of the cells after two days of building. Once the side walls are added, the cells begin to take on the hexagonal shape and there no longer is any space left between the cells.
A clarifying example: The image below on the left shows a close-packed tube of plastic straws. Notice how there are little gaps in between the circles! The image on the right shows how the straws transformed into hexagons after heating them up. This is a result of minimizing the surface energy, which required that the curved walls fuse together and increase the contact area by becoming planar rather than spherical.
Why are some comb cells not hexagonal?
Bees work collectively to mold and shape wax, aiming for perfect hexagons, but errors in measurement or construction can lead to irregular shapes. When a cell isn’t surrounded by exactly six others, the number of neighboring cells determines its shape. For example, if a cell has five neighboring cells then it will become a five-sided cell. These variations reflect the bees' adaptability and problem-solving abilities, showing that their comb-building involves more than just instinct.
Bees start comb construction in multiple places on a frame (or in wild/natural hives on whatever surface they occupy) and later merge these sections. This merging can result in size and alignment adjustments, producing irregular shapes like four-, five-, or even seven-sided cells. These irregular cells often form clusters of 5-7-5 or 7-5-7. Interestingly, patterns like 7-7-7 or 5-5-5 don’t usually occur.
This is a photo of comb that has had each cell shape color coded, hexagons are orange. Notice the occurrence of irregular cells along the four merge lines (colored in with pink, yellow, purple, or green depending on the number of sides). Irregular cells also occur along the outer edges of the comb as well.
Besides merging, the difference in size between worker and drone brood cells also contributes to irregularities in cell shape. Worker cells are typically 11 mm deep with a diameter of 5.4 mm, while drone cells are 13 mm deep with a diameter of 6.2-6.6 mm. Intermediate-sized cells often form in the transitional space between worker and drone cells. Cells too large for drones may be used for food storage, while those too small for worker brood are often filled with wax.
The last factor for irregular cell occurrence is cell tilt, which is crucial for comb structure. Rather than being perfectly flat (180° in the plane of the vertical comb), cells tilt slightly upward at around 12°. This prevents honey and nectar from spilling and helps contain larvae. When two comb sections merge, variations in cell tilt can lead to irregular cells at the merge line. For example, if one comb tilts at 9° and another at 13°, the cells at the merge line may tilt at 11° to make up the difference.
This image is from a natural beekeeping frame. The top and bottom photos are of the same frame, with only a few days in between when the photos were taken. This is a great example of what merging comb looks like, the occurrence of irregular cell sizes, and the difference in size between worker and drone cells.
Sources:
https://www.nature.com/articles/srep28341
https://www.pnas.org/doi/full/10.1073/pnas.2103605118
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3730681/
https://orca.cardiff.ac.uk/id/eprint/14030/1/Pattern_transformations_in_periodic_cellular_solids_under_external_stimuli.pdf