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Author (up) Orbach, D.N.; Fenton, B.
Title Vision impairs the abilities of bats to avoid colliding with stationary obstacles Type Journal Article
Year 2010 Publication PloS one Abbreviated Journal PLoS One
Volume 5 Issue 11 Pages e13912
Keywords Analysis of Variance; Animals; Chiroptera/*physiology; Cyclonic Storms; Echolocation/*physiology; Female; Flight, Animal/*physiology; Light; Male; Space Perception/physiology/radiation effects; Vision, Ocular/*physiology/radiation effects; Vocalization, Animal/physiology
Abstract BACKGROUND: Free-flying insectivorous bats occasionally collide with stationary objects they should easily detect by echolocation and avoid. Collisions often occur with lighted objects, suggesting ambient light may deleteriously affect obstacle avoidance capabilities. We tested the hypothesis that free-flying bats may orient by vision when they collide with some obstacles. We additionally tested whether acoustic distractions, such as “distress calls” of other bats, contributed to probabilities of collision. METHODOLOGY/PRINCIPAL FINDINGS: To investigate the role of visual cues in the collisions of free-flying little brown bats (Myotis lucifugus) with stationary objects, we set up obstacles in an area of high bat traffic during swarming. We used combinations of light intensities and visually dissimilar obstacles to verify that bats orient by vision. In early August, bats collided more often in the light than the dark, and probabilities of collision varied with the visibility of obstacles. However, the probabilities of collisions altered in mid to late August, coincident with the start of behavioural, hormonal, and physiological changes occurring during swarming and mating. Distress calls did not distract bats and increase the incidence of collisions. CONCLUSIONS/SIGNIFICANCE: Our findings indicate that visual cues are more important for free-flying bats than previously recognized, suggesting integration of multi-sensory modalities during orientation. Furthermore, our study highlights differences between responses of captive and wild bats, indicating a need for more field experiments.
Address Department of Biology, University of Western Ontario, London, Ontario, Canada. dnorbach@gmail.com
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-6203 ISBN Medium
Area Expedition Conference
Notes PMID:21085481; PMCID:PMC2976695 Approved no
Call Number IDA @ john @ Serial 96
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Author (up) Warrant, E.
Title Vision in the dimmest habitats on earth Type Journal Article
Year 2004 Publication Journal of Comparative Physiology. A, Neuroethology, Sensory, Neural, and Behavioral Physiology Abbreviated Journal J Comp Physiol A Neuroethol Sens Neural Behav Physiol
Volume 190 Issue 10 Pages 765-789
Keywords Animals; Circadian Rhythm/physiology; *Darkness; Eye/anatomy & histology; Fishes/physiology; Invertebrates; Oceans and Seas; Ocular Physiological Phenomena; Orientation/physiology; Space Perception/physiology; Vision, Ocular/*physiology
Abstract A very large proportion of the world's animal species are active in dim light, either under the cover of night or in the depths of the sea. The worlds they see can be dim and extended, with light reaching the eyes from all directions at once, or they can be composed of bright point sources, like the multitudes of stars seen in a clear night sky or the rare sparks of bioluminescence that are visible in the deep sea. The eye designs of nocturnal and deep-sea animals have evolved in response to these two very different types of habitats, being optimised for maximum sensitivity to extended scenes, or to point sources, or to both. After describing the many visual adaptations that have evolved across the animal kingdom for maximising sensitivity to extended and point-source scenes, I then use case studies from the recent literature to show how these adaptations have endowed nocturnal animals with excellent vision. Nocturnal animals can see colour and negotiate dimly illuminated obstacles during flight. They can also navigate using learned terrestrial landmarks, the constellations of stars or the dim pattern of polarised light formed around the moon. The conclusion from these studies is clear: nocturnal habitats are just as rich in visual details as diurnal habitats are, and nocturnal animals have evolved visual systems capable of exploiting them. The same is certainly true of deep-sea animals, as future research will no doubt reveal.
Address Vision Group, Department of Cell and Organism Biology, University of Lund, Helgonavagen 3, 22362 Lund, Sweden. Eric.Warrant@cob.lu.se
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0340-7594 ISBN Medium
Area Expedition Conference
Notes PMID:15375626 Approved no
Call Number IDA @ john @ Serial 33
Permanent link to this record