Browsing > By speaker > Lopez Jimenez Francisco

We explore how bees collectively adapt their environment to build their honeycomb structure in the presence of various types of geometric frustrations preventing the use of a regular hexagonal lattice. In order to create well controlled and repeatable experiments, we 3D-print starter frames with imprinted foundations, imposing a variety of constraints. These range from misalignment between regular hexagonal regions, to imposing hexagonal lattices of different size from that naturally used by the bees. The resulting constructed combs show clear evidence of reoccurring, self-organized patterns built by the bees in response to specific geometric frustrations in the starter frames.

In the case of misalignment, we observe grain boundaries similar to those observed in other 2D crystal systems, such as graphene or colloidal crystals. We also show that the patterns can be replicated using a simulated annealing process, in which the minimized potential is a variation of the Lennard-Jones potential that only takes into account first-neighbor interactions according to a Delaunay triangulation.

We have also explored the case in which the 3D-printed panels have a regular hexagonal lattice, but with size different from the natural worker cells. Our findings suggest three distinct construction modes when faced with foundations of varying cell sizes. For smaller cell sizes, bees occasionally merge adjacent cells to compensate for the reduced space. However, for larger cell sizes, the hive uses adaptive strategies like tilting for cells up to twice the reference size, and layering for cells that are three times larger than the reference cell. We use X-ray microscopy to characterize these complex three-dimensional structures.

Inspired by our results, we leverage simulated annealing as a design tool, in which the cellular solid is defined as the Voronoi/Delaunay tessellation of the particles used in the minimization process. We explore potentials that, while not directly based in physics, have use in a design process, particularly for problems in which a cellular solid conforms to irregular geometries. We also explore the effect of isolated topological defects (e.g., a disclination) on the mechanical properties of an otherwise topologically regular lattice.