Behavioural relevance of polarization sensitivity as a target detection mechanism in cephalopods and fishes

Abstract

Aquatic habitats are rich in polarized patterns that could provide valuable information about the environment to an animal with a visual system sensitive to polarization of light. Both cephalopods and fishes have been shown to behaviourally respond to polarized light cues, suggesting that polarization sensitivity (PS) may play a role in improving target detection and/or navigation/orientation. However, while there is general agreement concerning the presence of PS in cephalopods and some fish species, its functional significance remains uncertain. Testing the role of PS in predator or prey detection seems an excellent paradigm with which to study the contribution of PS to the sensory assets of both groups, because such behaviours are critical to survival. We developed a novel experimental set-up to deliver computer-generated, controllable, polarized stimuli to freeswimming cephalopods and fishes with which we tested the behavioural relevance of PS using stimuli that evoke innate responses (such as an escape response from a looming stimulus and a pursuing behaviour of a small prey-like stimulus). We report consistent responses of cephalopods to looming stimuli presented in polarization and luminance contrast; however, none of the fishes tested responded to either the looming or the prey-like stimuli when presented in polarization contrast.

Null point of discrimination in crustacean polarisation vision

“…This is widely accepted as a problem for two-channel polarisation vision, yet, with the exception of some associative learning experiments with cephalopods (Moody and Parriss, 1961;, this has not been investigated in detail at the behavioural level. To this end, we used a modified LCD monitor (Glantz and Schroeter, 2006;Pignatelli et al, 2011;How et al, 2012; to present polarised looming stimuli to the two-channel polarisation vision system of the fiddler crab Uca heteropleura (Smith 1870) and to the dynamic, multi-channelled polarisation vision system of the stomatopod Haptosquilla trispinosa (Dana 1852). These looming stimuli differed in the degree of polarisation, while the overall light intensity remained constant.…”

News from the field

“…Stay tuned…-J.B.I. Talbot, C. M., & Marshall, J. N. (2011 The classic face-vase figure appears in almost every elementary psychology textbook as an example of figureground assignment, which involves perceiving some regions as closer, foreground surfaces and objects. The face-vase figure is interesting because it is bi-stable, allowing observers to perceive either the lateral faces or the central vase as the 'figure,' but preventing both the faces and the vase from being figures simultaneously.…”

No response to linear polarization cues in operant conditioning experiments with zebra finches

“…S1). This is a drawback of using LCD-screens, which do not transmit light in the UV unless UV light is added to the screen behind the polarizing filter (Pignatelli et al, 2011). In many insects, UV light is necessary for sky polarization orientation (e.g.…”

“…Note that not all birds were included at all levels. vertebrates, UV light is important for polarization vision in several species of fish (Mussi et al, 2005;Pignatelli et al, 2011). In species such as goldfish (Carassius auratus) and rainbow trout (Oncorhynchus mykiss) there appears to exist an opponent mechanism between a UV-sensitive and a long-wavelengthsensitive channel most sensitive to vertically and horizontally polarized light, respectively (Hawryshyn and McFarland, 1987;Ramsden et al, 2008).…”

“…1). This allowed for controlled rotation of the direction of polarization without changing intensity or spectral composition (Glantz and Schroeter, 2006;Pignatelli et al, 2011;Hanke et al, 2013;Temple et al, 2012). Initially, the birds were trained to associate food rewards with visible stimuli to produce a generalized behavioural response to any stimulus shown on the screens.…”