The subject of this volume is two-fold. First, it gathers typical polarization patterns occurring in nature. Second, it surveys the polarization-sensitive ani mals, the physiological mechanisms and biological functions of polarization sensitivity as weIl as the polarization-guided behaviour in animals. The monograph is prepared for biologists, physicists and meteorologists, espe cially for experts of atmospheric optics and animal vision, who wish to under stand and reveal the message hidden in polarization patterns of the optical environment not directly accessible to the human visual system, but measur able by polarimetry and perceived by many animals. Our volume is an attempt to build a bridge between these two physical and biological flelds. In Part I we introduce the reader to the elements of imaging polarimetry. This technique can be efflciently used, e. g. in atmospheric optics, remote sens ing and biology. In Part 11 we deal with typical polarization patterns of the natural optical environment. Sunrise/sunset, clear skies, cloudy skies, moonshine and total solar eclipses all mean quite different illumination conditions, wh ich also affect the spatial distribution and strength of celestial polarization. We pre sent the polarization patterns of the sky and its unpolarized (neutral) points under sunlit, moonlit, clear, cloudy and eclipsed conditions as a function of solar elevation. The polarization pattern of a rainbow is also shown. That part of the spectrum is derived in which perception of skylight polarization is optimal under partly cloudy skies.

This book covers advances made since the 2004 Springer volume “Polarized Light in Animal Vision” edited by Horvath and Varju, but also provides reviews and synopses of some areas. Part I examines polarization sensitivity across many animal taxa including vertebrates and invertebrates and details both terrestrial and aquatic life. Part II is devoted to the description of polarized light in nature and explores how the physics of light must be taken into account when understanding how polarized light is detected by the visual system. This includes underwater polarization due to scattering; polarization patterns reflected from freshwater bodies; polarization characteristics of forest canopies; normal and anomalous polarization patterns of the skies; skylight polarization transmitted through Snell’s window and both linearly and circularly polarized signals produced by terrestrial and aquatic animals. This Part also examines polarized “light pollution” induced by anthropogenic factors such as reflection off asphalt surfaces, glass panes, car bodies, and other man-made structures that are now known to form ecological traps for polarotactic insects. Part III surveys some of the practical applications of polarization vision including polarization-based traps for biting insects, ground-based polarimetric cloud detectors and an historical examination of the navigational abilities of Viking seafarers using the sky polarization compass. The deterrent qualities of ungulate pelage to polarization-sensitive biting insects is also examined in this section.

A comprehensive treatment of visual ecology Visual ecology is the study of how animals use visual systems to meet their ecological needs, how these systems have evolved, and how they are specialized for particular visual tasks. Visual Ecology provides the first up-to-date synthesis of the field to appear in more than three decades. Featuring some 225 illustrations, including more than 140 in color, spread throughout the text, this comprehensive and accessible book begins by discussing the basic properties of light and the optical environment. It then looks at how photoreceptors intercept light and convert it to usable biological signals, how the pigments and cells of vision vary among animals, and how the properties of these components affect a given receptor's sensitivity to light. The book goes on to examine how eyes and photoreceptors become specialized for an array of visual tasks, such as navigation, evading prey, mate choice, and communication. A timely and much-needed resource for students and researchers alike, Visual Ecology also includes a glossary and a wealth of examples drawn from the full diversity of visual systems. The most up-to-date overview of visual ecology available Features some 225 illustrations, including more than 140 in color, spread throughout the text Guides readers from the basic physics of light to the role of visual systems in animal behavior Includes a glossary and a wealth of real-world examples

This new edition presents a state-of-the-art exploration of polarized light and polarization vision. Part I of the book examines polarization sensitivity across many animal taxa, including invertebrates and vertebrates, and it details both terrestrial and aquatic life. Part II is devoted to the description of environmental polarization with implications to animal and human polarization vision. This includes underwater polarization, polarization signals, sky-polarimetric Viking navigation and astronomical polarization. This part also examines polarized light pollution induced by anthropogenic factors, such as reflection off asphalt surfaces, glass panes, car bodies, and other man-made structures that are now known to form ecological traps for polarotactic insects. The new edition features a number of novelties, including chapters on trilobites, springtails, bats, seals, imaging polarimetry, and astronomical polarization.

The above consideration indicates that at present many of the experi mental facts on PS in animals can be quantitatively explained within the limits of the "universal" photoreceptor membrane concept. Of course, existence of preferential orientation of the absorbing dipoles in the tubuli of the rhabdomeres can not be totally rejected. We hope that the concept of the "universal" photoreceptor membrane may serve as the useful instrument when dealing with newly discovered properties of visual cells so that true mechanisms of electrical and optical coupling will be searched for instead of assumptions being made on additional properties of the photoreceptor membrane in every new animal under study. 5. Absorption Spectrum of the Universal Photoreceptor Membrane and Spectral Sensitivity of the Photoreceptor 5. 1 Preliminary Notes It seems nearly self-evident that the absorption spectrum of the pho toreceptor membrane coincides exactly with that of the visual pigment it contains. Hence, the membrane must exhibit three bands of absorp tion - the principal band with its peak within the limits of visible spectrum (or a-peak); the secondary band between 340 and 380 nm (S peak); and the third, protein band, in the ultraviolet (UV) at 280 nm (COLLINS et al. , 1952). The main peak of absorption is located within the range 433-575 nm for retinol-based pigments and between 438 and 620 nm for 3-dehydroretinol-based pigments, the position of Amax de pending on many ecological factors.