Bees know how to build honeycombs in their hives by accident, that’s the biological answer to the question.
The dazzling geometric perfection of the honeycomb, with its perfectly flat surfaces made of straight rows of elegant hexagons, compact, yet capacious enough inside to support a population of 80,000, is the product of blind instinct, the artistry of an intricate genetic program.
Every action the bees perform in building their metropolis, such as poking the cell walls in a honeycomb with their mandibles (jaws) as they form them to make sure the thickness is right, is dictated by instructions in the genes of their body cells.
The instructions were “written” by a series of rare genetic accidents occurring over millions of generations; certain accidents were preserved and passed along to the next generation because they helped the animal survive and reproduce.
Each cell of the bee’s body contains a complete set of genes, the “blueprint” in cell language for making an entire bee. The bee gets its genes from its parents, as it is conceived.
If something happens to change the molecular structure of those donated genes, either before or shortly after conception, the instructions change, and the creature will develop or behave differently; such genetic accidents or mutations happen at random every so often. Most mutations are so catastrophic that the animal doesn’t even hatch.
A few, however, are beneficial, giving the organism a new quality that helps it survive. When it reproduces, it passes on the “good” mutation in its genes to its offspring.
A series of genes for testing the thickness of cell walls would make worker bees much more efficient, since they would not waste wax making walls too thick, or lose hatching young when a section of thin wall collapsed.
Greater efficiency in construction would let the “mutant” bees move on to other work, producing more young, while non-mutants were repairing broken walls or making extra wax to replace what was squandered on thick walled cells. Because of their greater efficiency, the generations of wall testers would soon outproduce all others so dramatically that they would snatch up all the good food and nesting sites. After thousands or millions of generations, only wall testers would remain. A beehive is a select combination of the most successful genetic accidents in the history of bees.
But how do they build the hives so exactly once they have their genetic instructions? For example, how do the bees build the comb flat, along a single plane? The tools a worker bee uses are her own body (workers are sexually undeveloped females), raw materials from the environment, and the unseen forces of the planet Earth itself.
Experiments have shown that bees can all somehow sense the earth’s magnetic field and innately know how to make a structure turned at a certain angle to it. Thus they can all agree on which way the comb should face, with no foreman bee to tell them.
Bees can line up the hexagonal cell openings in perfect horizontal and vertical rows because every bee carries her own plumb line wherever she goes: her head. The head is attached to the neck by two pivot points, which are surrounded by bristle-like sensory hairs.
When the heavy head is pulled in any given direction by the force of gravity, the hairs on that side of the bee’s neck are tickled, so she always knows which way is “down,” and can get her bearings accordingly. Each cell is a hexagonal prism, a tube with six sides, because this is the best possible shape to hold a given volume of anything while using as little building material as possible. Furthermore, the cells are tilted back at a grade of 13 degrees, to keep the honey from running out.
No one knows for certain how the bees manage to construct six perfect 120 degree angles in each cell, but it seems that they measure distances and angles with the span between their two front legs, as they spread the wax with their mandibles.
Since all the workers in the hive are the same size, it is easy to see why the results are uniform. Beeswax itself is a fatty secretion from glands lining the underside of the creature’s abdomen; it comes out in flakes, which the bee passes forward to her mandibles with her hind legs. Then she chews it awhile, mixing it with her saliva until it is the right temperature and consistency. She spreads the wax to a uniform thickness of .003 inch, scraping and adding until the layer is perfect; she tests it by butting it with her mandibles with the antennae resting on its surface, the way the layer vibrates in response to her pokes tells her how thick it is.
Bees start building a section of comb at the top, from two or three different spots. A crowd of bees huddles together at each spot like a football team before the hike, keeping the wax warm with their bodies as they shape it together.
They make the cells three or four at a time, proceeding from common walls. They “spell” each other so that each bee works at the exhausting process for about 30 seconds at a stretch before being relieved by a substitute. Each huddle of bees spreads out as work progresses, and the sections of the comb are joined, they fit together so perfectly that it’s impossible to tell they were begun separately. The cells are not literally all the same size, but come in three carefully delineated varieties: the smallest are for hatching new workers and storing pollen and honey; the next largest are for rearing drones (males); and the largest are for raising new queens.
Bees’ reputation for efficiency is well founded: aside from being well organized, they conserve resources by recycling their building materials.
When a contingent leaves a hive to found a new one (called “swarming”), they pack supplies of wax taken from abandoned cells in the mother hive into their special leg baskets to use in building their new honeycomb.