Filtering and polychromatic vision in mantis shrimps: themes in visible and ultraviolet vision

Abstract

Stomatopod crustaceans have the most complex and diverse assortment of retinal photoreceptors of any animals, with 16 functional classes. The receptor classes are subdivided into sets responsible for ultraviolet vision, spatial vision, colour vision and polarization vision. Many of these receptor classes are spectrally tuned by filtering pigments located in photoreceptors or overlying optical elements. At visible wavelengths, carotenoproteins or similar substances are packed into vesicles used either as serial, intrarhabdomal filters or lateral filters. A single retina may contain a diversity of these filtering pigments paired with specific photoreceptors, and the pigments used vary between and within species both taxonomically and ecologically. Ultraviolet-filtering pigments in the crystalline cones serve to tune ultraviolet vision in these animals as well, and some ultraviolet receptors themselves act as birefringent filters to enable circular polarization vision. Stomatopods have reached an evolutionary extreme in their use of filter mechanisms to tune photoreception to habitat and behaviour, allowing them to extend the spectral range of their vision both deeper into the ultraviolet and further into the red.

Biological Sunscreens Tune Polychromatic Ultraviolet Vision in Mantis Shrimp

“…Coupled with the narrow shapes of some of the sensitivity spectra ( Figure 1C), this suggested that several UV-specific optical filters are present somewhere in the MB. Colored optical filters that alter the spectral sensitivity of a photoreceptor by selectively transmitting only certain wavelength ranges of light are common in animal eyes [15], and sets of multiple colored filters within a single eye have been described in various vertebrates [16][17][18], butterflies [19][20][21], and stomatopods [22][23][24]. In visual systems, however, UV filters are primarily involved in photoprotection of the retina or in suppression of the UV-absorbing b band of visual pigments [15].…”

Landmark navigation in a mantis shrimp

“…Do mantis shrimp learn to recognize landmarks encountered during foraging routes, exhibiting “trapline foraging”? Further, mantis shrimp are famed for possessing complex color vision, linear polarization vision in two spectral channels, and circular polarization vision [19]. Besides spatial vision alone, do stomatopods use these visual channels to identify landmarks?…”

Aggressive communication in aquatic environments

“…Most fish species, cephalopods and many crustaceans show highly derived photoreceptors, allowing them to see various colours, including the UV range (Cronin, ; Douglas & Djamgoz, ; Marshall & Oberwinkler, ). While modern teleosts possess four spectral classes of cones (Bowmaker, ), some mantis shrimp have up to 20 functional colour receptors allowing them to perceive wavelengths of light ranging from deep ultraviolet to far‐red (Cronin, Bok, Marshall, & Caldwell, ) as well as polarized light (Thoen, How, Chiou, & Marshall, ). Still, the usefulness of visual cues in communication strongly depends on the environment (Endler, ).…”

“…Male Lysiosquillina glabriuscula, for example, threaten their opponents by raising the head and thorax, spreading the striking appendages and other maxillipeds, and laterally extending the prominent, oval antennal scales. Such displays are accentuated by colour patterns emitted both in the visual and UV spectrum (Cronin et al, ; Franklin, Marshall, & Lewis, ). Fluorescent coloration contributes to signal brightness and visibility of yellow spots, particularly at greater depths.…”