Crystallography of Honey Bee Comb Construction

University Of Colorado At Boulder, Boulder CO

Investigators

Abstract

The honeybee comb is a masterpiece of distributed architecture. This wax-made storage structure, which is essential to the survival of the colony, is constructed in a near-optimal manner that minimizes the wax-to-storage space ratio, due to the high energy cost associated with wax production. Honeybees construct the comb with remarkable precision, regardless of irregular boundaries or unevenness of the surface on which they work. Yet the mechanisms by which honeybees adapt their construction to the constraints of the environment (e.g., a pre-existing cavity in a tree) are poorly understood. The goal of this project is to shed light on the process of comb construction by framing it as a pattern formation process, which allows us to leverage the similarities between comb structure and the structure of non-living materials such as crystals and graphene. This project bridges tools from multiple disciplines, bringing insights from animal behavior and crystallography. The outcome of this research is a novel framework for modeling the collective behavior of honeybees as well as quantitatively describing the geometry and topology of the honeybee lattices. This project will not only help us understand the collective behavior of bees, but will also help leverage that understanding to create bio-inspired system designs in the fields of swarm robotics, collective construction, and lightweight cellular structures. This research project will address three specific questions: (1) Are the irregularities in the honeycomb structure the result of global planning that accounts for distant frustration sources (e.g., solid boundaries of a tree cavity) or a local reaction to the immediate surroundings of a given cell? (2) Can the honeycomb pattern be explained as the result of an energy minimization process, and if so, are the solutions comparable to patterns consistently found in a diverse range of self-organized crystallographic systems under geometric frustration (e.g., colloidal crystals or graphene)? (3) To what extent is the optimality of the solution to the geometric problem of comb construction modulated by large-scale changes in the environment, such as engineered boundaries, various given cell sizes, or curvature? The investigators in this project will use 3D-printing to construct precisely controlled and quantified honeycomb foundations, which can be used to introduce systematic and repeatable sources of geometric frustration in the experiments. The final comb structures will be imaged and analyzed (computer vision techniques, x-ray microscopy) to precisely characterize the geometry of individual cells and the topology of the global lattice. This rich information set will be used to develop and validate data-driven agent-based models to explore possible underlying mechanisms of collective comb construction. The approach followed in this project goes beyond the traditional view of collective behavior as stigmergy -- wherein organisms respond to local cues with little or no long-range effects -- to explore the influence of long-range interactions that are physically mediated. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.