How insects stay clean

Abstract

This thesis considers a physical perspective to an insect's maintenance of a clean body surface. Flying insects are faced with a barrage of particles in their environment, including dust, pollen, pollutants, and parasitic mites, the last of which are responsible for the modern decline of honey bees, of critical importance to agriculture around the world. In this combined experimental, theoretical, and numerical study, we elucidate the mechanisms by which insects stay clean. These mechanisms all rely on the insect’s coverage by a dense array of hairs. We show that these bristles divert incoming flow, reducing deposition of particles, especially onto the eyes. We replicate this mechanism with microfabricated pillar arrays, demonstrating the feasibility by which they may be incorporated into self-cleaning sensors. During grooming, the bristles on the limbs interact with those on the body and particle removal is achieved through combing and catapulting, driving particles at over 1000 gravities. We show that the three million hairs covering the body of a honey bee are crucial for the efficient removal of accumulated pollen.