A Device for visualizing the Pattern of Plane Polarized Light from Blue Sky

Abstract

THE entomologist studying insect behaviour faces the problem of determining how the environment appears to insects, through their sense organs. The many differences in the sensory apparatus of man and insects represent one reason why it is difficult for us to appreciate fully the insect environment. For example, our own insensitivity to the plane of polarization of light has long kept us from recognizing an aspect of sky light which is of significance in the behaviour of many insects and other arthropods. Although it has long been known that daylight from most areas of blue sky is partly plane polarized, in a pattern which bears a definite relationship to the Sun's position, only within the past decade has it become established that arthropod eyes are sensitive to changes in the polarization of light. It has been found, also, that a variety of these animals refer to the plane of polarization of light from blue sky in their orientation reactions¹.