In the course of evolution, insects have developed a variety of strategies to reduce surface contamination and thus to avoid inhibition of physiological functions. For example, ants regularly clean their antennae with a sophisticated cleaning structure located on their forelegs. During a cleaning movement, the ant’s antenna is clamped into a two-piece cleaning device and then pulled through unidirectionally. In a second step, the ant cleans these structures with its mouthparts in order to allow reuse. The antenna cleaner in ants is equipped with tiny hairs, which form comb or brush-like arrays, and vary in shape, size or spacing. Having different hair configurations on one cleaning structure enables the insects to pick up surface contaminants of different sizes with a single cleaning stroke.
This colourised Scanning Electron Microscopy (SEM) image shows a 10 μm polystyrene particle (ten times smaller than the diameter of a human hair) covered with smaller particles, attached to a cleaning hair after its removal from a Camponotus rufifemur ant’s antenna. So far, nothing is known about the forces acting between the cleaning hairs and the dirt particles, and this is the first time that a SEM image shows adhesion between a single cleaning hair and a contaminant. Understanding the underlying principles of the cleaning mechanisms of insects might enable us to develop artificial devices for surface cleaning of sensitive systems on a micro- or nano-scale.
Alexander Hackmann is a 3rd year PhD student in the Department of Zoology.