Unraveling the Mechanisms of the Apis mellifera Honeycomb Construction by 4D X‐ray Microscopy

Abstract

Honeycomb is one of nature's best engineered structures. Even though it has inspired several modern engineering structures, an understanding of the process by which the hexagonal cells are formed in 3D space is lacking. Previous studies on the structure of the honeycomb are based on either 2D microscopy or by direct visual observations. As a result, several critical features of its microstructure and the precise mechanisms of its growth are not well understood. Using 4D X‐ray microscopy, this study shows how individual and groups of honeycomb cells are formed. Cells grow additively from a corrugated central spine in a dynamic manner. The previously undocumented, corrugated spine contributes significantly to the comb's robust mechanical properties in all three dimensions. As cells grow, honey bees create a “coping,” which this study shows to be the location where new wax material is deposited behind where compaction and densification take place. This is exemplified by pores in the wax observed at the coping and alternating rear junctions between the comb cells that arise from the additive building technique and the highly efficient cell packing methodology, respectively. Additional mechanisms for growth and formation are discussed and described.

Honey bees perform fine-scale detailing that continuously reduces comb area after nest expansion

“…4, b-e). Therefore, the leading edge is likely important not just for the initial growth phase (Franklin et al 2022), but also when colonies undergo additional nest expansion. Whether and how the leading edge may signal comb expansion to workers is unknown, but it is an intriguing area for future work.…”

“…The nest of the Western honey bee, Apis mellifera , is made up of multiple parallel combs, and each comb is made of thousands of hexagonal cells (Seeley and Morse 1976; Smith et al 2021, 2023). Workers start construction with a spine of wax which they mold into cells (Huber 1814; von Frisch 1974; Pratt 2000; Franklin et al 2022). As workers construct cell walls from the wax base, they maintain a border of unshaped wax along the outer edge of the comb (Franklin et al, 2022).…”

“…Workers start construction with a spine of wax which they mold into cells (Huber 1814; von Frisch 1974; Pratt 2000; Franklin et al 2022). As workers construct cell walls from the wax base, they maintain a border of unshaped wax along the outer edge of the comb (Franklin et al, 2022). This “leading edge” is visible in combs that are actively being built, and serves as a growth front where workers can deposit wax and shape it into new hexagonal cells (Casteel 1912; Franklin et al 2022; Gallo et al 2023).…”

Advanced Composites Inspired by Biological Structures and Functions in Nature: Architecture Design, Strengthening Mechanisms, and Mechanical‐Functional Responses

“…Typically, the honeycomb consists of equal-sized cells, each surrounded by other cells and separated by wax walls. [219][220][221] Excitingly, the honeycomb architecture has and parameters of honeycomb core sandwich. d) Two typical failure modes of sandwich panels with honeycomb core after impact tests.…”

A computational building block approach towards multiscale architected materials analysis and design with application to hierarchical metal metamaterials

“…Many hierarchical material architectures are found in biological materials [1][2][3][4][5], such as in bone [2], wood [6], sea sponges and diatoms [7][8][9][10][11], or honeycomb structures [12][13][14] (figure 1(a)). Conventionally, hierarchical materials are often analyzed using multiscale methods such as finite element modeling, particle simulations such as coarse-grained mesoscale modeling or atomistic simulations, but more recently machine learning has been proposed as a means to analyze and design hierarchical composites and architected materials [15][16][17][18][19].…”