The familiar hexagon pattern of honeycombs, thought to be made by bees by design, may actually just be a side effect of physical forces.
Engineer Bhushan Karihaloo at the University of Cardiff, UK, and his co-workers say that bees simply make cells that are circular in cross section and are packed together like a layer of bubbles. According to their research, which appears in the Journal of the Royal Society Interface1, the wax, softened by the heat of the bees’ bodies, then gets pulled into hexagonal cells by surface tension at the junctions where three walls meet.
This is only the latest argument in a debate that scientists have been having for centuries.
A regular geometric array of identical cells with simple polygonal cross sections can take only one of three forms: triangular, square or hexagonal. Of these, hexagons divide up the space using the smallest wall area, and thus, for a honeycomb, the least wax.
This economy was noted in the fourth century ad by the mathematician Pappus of Alexandria, who contended that the bees had “a certain geometrical forethought”. But in the seventeenth century, the Danish mathematician Erasmus Bartholin suggested that the insects need no such forethought. He said that hexagons would result automatically from the pressure of each bee trying to make its cell as large as possible, much as the pressure of bubbles packed in a single layer creates a hexagonal foam. [Nature]