Magnetically Induced Flickering Change in the Light-Reflecting Cuticulae of the Common Bluebottle Butterfly Graphium Sarpedon

Abstract

In this paper, we investigated the magnetic and optical properties of particles isolated from the cuticulae of the common bluebottle butterfly Graphium sarpedon . When subjected to ultrasonic treatment, the cuticulae in the scale cells disintegrate and fine particles of about 100 nm are generated. These particles behave as bioreflectors, which cause dynamic light reflection changes (flickering). When the particles are exposed to magnetic fields of up to 5 T, the light reflection intensity is inhibited. The motions of the particles were recorded with a microscope. The flickering of the particles disappears when they are exposed to a magnetic field, whereas the particles flicker with a frequency of several hertz in the absence of a magnetic field. Fiber optic measurements suggest that this constrained light reflection occurs when the particles magnetically rotate and the most reflective side of a particle is extremely dislocated. In addition, we determined the maximum reflection side of the particles by orienting them under a magnetic field of 5 T. Scanning electron microscopy indicates that the particles are disk-shaped and the disks floating in water orient and change their maximum reflection side when exposed to a magnetic field.