Behavioural evidence for polarisation vision in stomatopods reveals a potential channel for communication.
Polarisation sensitivity (PS) - the ability to detect the orientation of polarised light - occurs in a wide variety of invertebrates [1] [2] and vertebrates [3] [4] [5], many of which are marine species [1]. Of these, the crustacea are particularly well documented in terms of their structural [6] and neural [7] [8] adaptations for PS. The few behavioural studies conducted on crustaceans demonstrate orientation to, or local navigation with, polarised sky patterns [9]. Aside from this, the function of PS in crustaceans, and indeed in most animals, remains obscure. Where PS can be shown to allow perception of polarised light as a 'special sensory quality' [1], separate from intensity or colour, it has been termed polarisation vision (PV). Here, within the remarkable visual system of the stomatopod crustaceans (mantis shrimps) [10], we provide the first demonstration of PV in the crustacea and the first convincing evidence for learning the orientation of polarised light in any animal. Using new polarimetric [11] and photographic methods to examine stomatopods, we found striking patterns of polarisation on their antennae and telson, suggesting that one function of PV in stomatopods may be communication [12]. PV may also be used for tasks such as navigation [5] [9] [13], location of reflective water surfaces [14] and contrast enhancement [1] [15] [16] [17] [18]. It is possible that the stomatopod PV system also contributes to some of these functions.
VTHRC, The University of Queensland, Brisbane, 4072, Australia. j.marshall@vthrc.uq.edu.au
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J
Marshall
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Cronin
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Shashar
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Land
D000818:Animals; D001522:Behavior, Animal; D015350:Contrast Sensitivity / Q000502:physiology*; D033364:Decapoda / Q000502:physiology*; D008027:Light; D017956:Photoreceptor Cells, Invertebrate / Q000502:physiology; D014785:Vision, Ocular / Q000502:physiology*