Dynamical Numerical Model of the Molluscan Radula in its Interaction with the Substrate and Food Particles

Abstract

The radula, a chitinous membrane with teeth, is the molluscan autapomorphy for food gathering and processing. Even though this structure is studied for decades, the interplay between the structure and the particular food or/and the substrate remains mostly enigmatic. Here, we provide a numerical model approach to understand the relationship between structure, feeding efficiency, and partial work performed by the system. This first simple dynamic numerical radular model interacts with the food particles and the uneven substrate. This protocol can be applied to any system in the future, as the parameters (interaction between structures, adhesion, size of food particles, attachment angle of teeth to membrane, etc.) can be easily altered. This will shed light on the biomechanical adaptations of this feeding structure (e.g., wear and failure prevention) to the specific environment.

Large‐Scale Numerical Simulation of the Solid Lubricant Behavior in the Leg Joints of Insects

“…We aimed to model the removal process of the contaminant particles with the aid of the lubricant particles. It is supposed that in the frames of the model such a semisolid [ 13–17 ] lubricant between the joint surfaces serves a number of the following demands. It has to: free enough move between inner and outer surfaces of the joint; spontaneously form mesoscopic clots, which can appear and disappear in the course of motion; dynamically support outer surface, which under external pressure (weight of the animal and other forces caused by its motion) otherwise tends to “fall down” to the inner surface without such a support; protect both joint surfaces from scratches by means of enveloping and isolating rigid foreign (contaminant) particles; bind and promote transport of thus enveloped particles as a “garbage” outside the joint system. …”

“…We aimed to model the removal process of the contaminant particles with the aid of the lubricant particles. It is supposed that in the frames of the model such a semisolid [13][14][15][16][17] lubricant between the joint surfaces serves a number of the following demands. It has to:…”

“…Recently we already used this approach to simulate the lubricant in relatively simple model, where the lubricant is confined between planar rigid surfaces which are periodically moving in 3D space. [13][14][15][16][17] The model which will be studied here has some common features with the original one: it includes an external pressure acting on at least one of the surfaces ("upper" surface) and shear force caused by mutual relative motion of the surfaces. For planar surfaces, such model construction represents a rather typical, often studied, tribological situation.…”

“…Such properties of materials were recently simulated in a number of our previous works. [13][14][15][16][17] Formally, the model describes a system of N "interacting particles" represented by the vector radius r i , the momentum p i , and the interaction potential U(|r i − r j |) corresponding to the following Hamiltonian:…”

“…On the mesoscopic scale of the problem, these "particles" correspond to some abstract mathematical objects which simulate dynamic behavior of the system and often named as "movable automata." [13][14][15][16][17] In the planar friction system, one of the surfaces is usually moving in the horizontal direction. In the beetle Zophobas morio, the joint counterpart surfaces have complex shape and between them lubricant particles are confined.…”