Polarization vision: A discovery story

Abstract

During the last half a century, polarization vision has become a flourishing field of multidisciplinary research in neuroethology and sensory ecology spanning the full methodological range from membrane biophysics and photoreceptor optics to behavioural analyses in the laboratory as well as in the field. It comprises a multitude of behavioural tasks accomplished by various groups of animals in both terrestrial and aquatic environments. The fact that this richness of behaviours mediated by naturally occurring polarized light has come to the fore only rather recently is certainly due to our own inability to perceive these polarized light phenomena without the aid of special optical devices. While in the present book the chapters are arranged according to animal taxa, so that questions are posed and arguments are presented within the branching pattern of the phylogenetic tree, this introductory chapter retraces the time arrow of discovery. For example, immediately after Karl von Frisch had demonstrated that bees can perceive the polarization of skylight, the 1950s were dominated by the search for the polarization analyser in arthropod eyes. The 1970s and early 1980s became high noon for the behavioural experimental analysis of the bee’s and ant’s skylight compass, followed in the 1990s by the advent of forceful neurobiological investigations of the polarization vision network residing in the insect (especially locust) brain. At about the same time polarized reflections from water surfaces were recognized as cues used by flying aquatic insects on dispersal. In the late 1980s vertebrates, mainly fish and birds, appeared on the polarization vision scene as well. Since the turn of the millennium long-standing studies of various aspects of underwater polarization vision have received an enormous boost, especially by including small-field, close-range polarization signalling, and now advance at an ever increasing pace. Most recently, with new technologies at hand, the interest in the basic mechanisms of polarization sensitivity comes full circle when now a closer and more sophisticated look can be taken at the molecular mechanisms of how dichroism is generated within the photoreceptor membrane.