Abrasive Wear in The Leg Joints of Insects

Abstract

The presence of wear of the joint cuticle of the beetle legs is demonstrated experimentally and is represented by abrasive wear. Presence of the abrasive wear in the natural‐habiting beetles of various families is also established. Abrasive wear comprises of both two‐body and three‐body wear as a result of the action of particles that have entered the joint. The presence of the sliding wear in the absence of abrasive particles is not found. The wear effects are represented by microcuttings, indentations, cracking, delamination, brittle fracturing, and destruction of the surface layer (epicuticle). The correlation of quantitative indicators of wear between the types of experimental substrates (paper, wood, sand) and the length of exposure of beetles on a particular substrate turned out to be very weak. It is hypothesized that the lubricating material in the leg joints of beetles may provide an anti‐wear function by binding particles and facilitating their removal thereby reducing surface damage by sharp asperities, and protecting the damaged surface to prevent further wear.

Comparative analysis of the ultrastructure and adhesive secretion pathways of different smooth attachment pads of the stick insect Medauroidea extradentata (Phasmatodea)

“…The superficial layer of the connective pad is patterned in a hemispherical shape at the predominantly peripheral position towards the centre. This position suggests that such structures act as an adhesion- and friction-reducing system (anti-adhesive structures, Figure 7B ) [ 86 ]. The hemispherical pattern reduces the contact area between the cuticle and the substrate, thus decreasing contact forces.…”

“…They might also reduce the risk of trapping contaminants in the inter-tarsomeric membranous region. The removal of particulate contaminants is very important as they are known to cause abrasive wear in the open insect joints [ 86 ]. Anti-adhesive surface structures in the periphery of the active working areas of the attachment pads could establish zones facilitating detachment.…”

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

“…As it has been previously shown for the darkling beetle Zophobas morio , the entry of foreign particles with high hardness into an open joint can lead to considerable abrasive wear. [ 11 ] The important role of the lubricant as part of the auto‐cleaning mechanism in cleaning the joint cavity was demonstrated using the example of the beetle Pachnoda marginata , which specializes in digging. [ 12 ] At the same time, the mechanism for cleaning joints in non‐specialized species, such as Zophobas morio , still remains unclear and there are only indirect indications of the role of lubricant in this process.…”

“…[ 12 ] At the same time, the mechanism for cleaning joints in non‐specialized species, such as Zophobas morio , still remains unclear and there are only indirect indications of the role of lubricant in this process. [ 11 ]…”

“…The modeling is based on the data on the lubricant from the darkling beetle Zophobas morio , [ 7,8 ] and on the experimental data showing the role of lubricant in removing foreign contaminant particles from the joint cavity. [ 11,12 ]…”