In 1780, Swiss naturalist Francois Huber revolutionized beehive design by introducing movable combs. Huber designed his hives as an aid to studying the history of the bee, rather than beekeeping. His hive would go on to inspire the Langstroth design that is a staple in beekeeping best practices.
But what takes place in those hives and how are honeycombs constructed? Honeybees construct hives by chewing wax until it softens, then bonding large amounts of wax into the cells of a honeycomb.
When worker bees carry nectar within their pollen pouch, it mixes with a specialized enzyme. After a worker bee is able to transfer the nectar to another worker bee, the liquid from the nectar evaporates and becomes honey.
Comb construction requires the effort of many worker bees. The glands of worker bees convert the sugar contents of honey into wax, which produces tiny flakes of wax. Workers chew these pieces of wax until they become soft and moldable, and then add the chewed wax to the honeycomb construction. Until the comb is in place, there is no way to grow the colony.
According to a TED Talk by Zack Patterson and Andy Peterson, “bees must consume eight ounces of honey for every ounce of wax they produce.” Thousands of hexagonal cells make the best use of the space available. Mathematically, this structure has been proven optimal to maximize storage space and stability while minimizing building material.
The hexagonal cells serve as storage vessels for:
- honey for winter storage,
- rearing bee brood,
- storing pollen,
- as well as a place to raise young bees.
Research shows that the comb of honeybees is usually built downward, attached to the underside of a supporting structure such as a tree branch, a rocky outcrop or the upper surface of a cavity such as a hollow tree. Most of these natural surfaces are not smooth or flat.
In dealing with these challenges, bees are seen as architects. While one might assume that once the foundation is laid, bees could then switch to simple rules, building repetitive hexagons where the size is aligned with the worker’s body dimensions; however, the Proceedings of the National Academy of Sciences of the United States of America notes that bees must adapt the cell structures to merge those of differing size, orientation, and offset.
Uncommon Comb Shapes
An enormous diversity of cell shapes was found: Pentagons and heptagons were the most commonly observed non-hexagonal shapes, but there were also four-, eight-, and nine-sided cells.
The most common non-hexagonal cells (pentagons and heptagons) were often found in pairs or triplets, where a cell with a surplus face was found adjacent to another with fewer. It appears that bees, even when prevented from building a perfect specimen, will deviate from that ideal by as little as possible.
The article Imperfect comb construction reveals the architectural abilities of honeybees found that workers preemptively change their building behavior in constrained geometries to make space for larger hexagonal cells.
Researchers Vince Gallo and Lars Chittka suggest that “Cells that are of an incorrect size or not hexagonal will seldom be used to raise brood but will be utilized for food storage and so are not wasted.”
Stigmergy and Behavioral Patterns
A Brief History of Stigmergy is rooted in the study of social insects. Stigmergy is understood within insect societies where individuals work as if they were alone while their collective activities appear to be coordinated.
To better understand how multiple, “independent” building actions can be coordinated through a stigmergic behavioral algorithm, it is instructive to look at nest construction in solitary species. Once many individuals have joined to form a group, they must be able to maintain its cohesion long enough to benefit from cooperative effects.
So why the different shapes for the honeycomb structure? Gallo and Chittka think that one possibility is a combination of stigmergy combined with a highly rich behavioral repertoire. The structure of hexagonal cells is useful for bees, especially during the winter to store honey.