Ultraviolet vision in a bat.
Most mammals, with the exception of primates, have dichromatic vision and correspondingly limited colour perception. Ultraviolet vision was discovered in mammals only a decade ago, and in the few rodents and marsupials where it has been found, ultraviolet light is detected by an independent photoreceptor. Bats orient primarily by echolocation, but they also use vision. Here we show that a phyllostomid flower bat, Glossophaga soricina, is colour-blind but sensitive to ultraviolet light down to a wavelength of 310 nm. Behavioural experiments revealed a spectral-sensitivity function with maxima at 510 nm (green) and above 365 nm (ultraviolet). A test for colour vision was negative. Chromatic adaptation had the same threshold-elevating effects on ultraviolet and visible test lights, indicating that the same photoreceptor is responsible for both response peaks (ultraviolet and green). Thus, excitation of the beta-band of the visual pigment is the most likely cause of ultraviolet sensitivity. This is a mechanism for ultraviolet vision that has not previously been demonstrated in intact mammalian visual systems.
Winter
York
Y
Department of Biology, University of Munich, Luisenstrasse 14, 80333 Munich, Germany and Max-Planck Research Centre for Ornithology, 82305 Seewiesen, Germany. winter@zi.biologie.uni-muenchen.de
López
Jorge
J
Von Helversen
Otto
O
D000222:Adaptation, Physiological; D000818:Animals; D002685:Chiroptera / Q000502:physiology*; D003118:Color Perception / Q000502:physiology*; D003216:Conditioning, Operant; D005260:Female; D035264:Flowers; D008297:Male; D020419:Photoreceptor Cells, Vertebrate / Q000502:physiology; D012680:Sensitivity and Specificity; D014466:Ultraviolet Rays