Run and hide: visual performance in a brittle star
| Autor: | Lauren Sumner-Rooney, John D. Kirwan, Carsten Lüter, Esther Ullrich-Lüter |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
0106 biological sciences
Spatial vision Ophiomastix genetic structures Physiology Computer science Vision Aquatic Science Stimulus (physiology) 010603 evolutionary biology 01 natural sciences 03 medical and health sciences Looming Brittle star Orientation Shadow Animals Extraocular vision Computer vision Molecular Biology Ecology Evolution Behavior and Systematics Orientation Spatial Vision Ocular 030304 developmental biology 0303 health sciences biology business.industry Orientation (computer vision) biology.organism_classification eye diseases Stars Ophiuroids Insect Science Animal Science and Zoology Artificial intelligence business Echinodermata Research Article Echinoderms |
| Zdroj: | The Journal of Experimental Biology article-version (VoR) Version of Record |
| ISSN: | 1477-9145 |
| Popis: | Spatial vision was recently reported in a brittle star, Ophiomastix wendtii, which lacks discrete eyes, but little is known about its visual ecology. Our aim was to better characterize the vision and visual ecology of this unusual visual system. We tested animal orientation relative to vertical bar stimuli at a range of angular widths and contrasts, to identify limits of angular and contrast detection. We also presented dynamic shadow stimuli, either looming towards or passing the animal overhead, to test for potential defensive responses. Finally, we presented animals lacking a single arm with a vertical bar stimulus known to elicit a response in intact animals. We found that O. wendtii orients to large (≥50 deg), high-contrast vertical bar stimuli, consistent with a shelter-seeking role and with photoreceptor acceptance angles estimated from morphology. We calculate poor optical sensitivity for individual photoreceptors, and predict dramatic oversampling for photoreceptor arrays. We also report responses to dark stimuli moving against a bright background – this is the first report of responses to moving stimuli in brittle stars and suggests additional defensive uses for vision in echinoderms. Finally, we found that animals missing a single arm orient less well to static stimuli, which requires further investigation. Summary: Brittle star responses to static visual stimuli of varying size and contrast show that visually guided habitat selection requires large, high-contrast stimuli. Responses to the appearance of overhead shadows reveal additional uses for photoreception in defensive behaviours. |
| Databáze: | OpenAIRE |
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