Editing Mantis shrimp (section)

====Suggested advantages of visual system====
[[File:Pseudosquilla.JPG|thumb|left|upright|Close-up of the trinocular vision of ''[[Pseudosquilla ciliata]]'']]
What advantage sensitivity to polarisation confers is unclear; however, polarisation vision is used by other animals for sexual signaling and secret communication that avoids the attention of predators.<ref>{{cite journal |last1=How |first1=M. J. |last2=Porter |first2=M. L. |last3=Radford |first3=A. N. |last4=Feller |first4=K. D. |last5=Temple |first5=S. E. |last6=Caldwell |first6=R. L. |last7=Marshall |first7=N. J. |last8=Cronin |first8=T. W. |last9=Roberts |first9=N. W. |title=Out of the blue: the evolution of horizontally polarized signals in Haptosquilla (Crustacea, Stomatopoda, Protosquillidae) |journal=Journal of Experimental Biology |date=7 August 2014 |volume=217 |issue=19 |pages=3425–3431 |doi=10.1242/jeb.107581 |pmid=25104760 |doi-access=free|hdl=11603/13393 |hdl-access=free }}</ref> This mechanism could provide an evolutionary advantage; it only requires small changes to the cell in the eye and could easily lead to [[natural selection]].<ref>{{cite press release |title=Mantis shrimps could show us the way to a better DVD |publisher=University of Bristol |date=25 October 2009 |url=http://www.bristol.ac.uk/news/2009/6591.html |access-date=May 13, 2020 |archive-date=31 October 2020 |archive-url=https://web.archive.org/web/20201031051957/http://www.bristol.ac.uk/news/2009/6591.html |url-status=live }}</ref>

The eyes of mantis shrimp may enable them to recognise different types of coral, prey species (which are often transparent or semitransparent), or predators, such as [[barracuda]], which have shimmering scales. Alternatively, the manner in which they hunt (very rapid movements of the claws) may require very accurate ranging information, which would require accurate depth perception. The capacity to see UV light may enable observation of otherwise hard-to-detect prey on coral reefs.<ref name= "Science 6UV"/>

During mating rituals, mantis shrimp actively [[fluoresce]], and the wavelength of this fluorescence matches the wavelengths detected by their eye pigments.<ref>{{cite journal |author1=C. H. Mazel |author2=T. W. Cronin |author3=R. L. Caldwell |author4=N. J. Marshall |year=2004 |title=Fluorescent enhancement of signaling in a mantis shrimp |journal=[[Science (journal)|Science]] |volume=303 |issue=5654 |page=51 |doi=10.1126/science.1089803 |pmid=14615546 |s2cid=35009047}}</ref> Females are only fertile during certain phases of the [[Tide|tidal cycle]]; the ability to perceive the [[lunar phase|phase of the moon]] may, therefore, help prevent wasted mating efforts. It may also give these shrimps information about the size of the tide, which is important to species living in shallow water near the shore.{{Citation needed|date=December 2024}}

Researchers suspect that the broader variety of photoreceptors in the eyes of mantis shrimp allows visual information to be preprocessed by the eyes instead of the brain, which would otherwise have to be larger to deal with the complex task of [[opponent process]] colour perception used by other species, thus requiring more time and energy. While the eyes themselves are complex and not yet fully understood, the principle of the system appears to be simple.<ref>{{cite journal |last1=Morrison |first1=Jessica |title=Mantis shrimp's super colour vision debunked |journal=Nature |date=23 January 2014 |doi=10.1038/nature.2014.14578 |s2cid=191386729}}</ref> It has a similar set of sensitivities to the human visual system, but works in the opposite manner. In the human brain, the inferior temporal cortex has a huge number of colour-specific neurons, which process visual impulses from the eyes to extract colour information. The mantis shrimp instead uses the different types of photoreceptors in its eyes to perform the same function as the human brain neurons, resulting in a hardwired and more efficient system for an animal that requires rapid colour identification. Humans have fewer types of photoreceptors, but more colour-tuned neurons, while mantis shrimp appear to have fewer colour neurons and more classes of photoreceptors.<ref>{{cite web |last1=Macknik |first1=Stephen L. |title=Parallels between Shrimp and Human Color Vision |url=https://blogs.scientificamerican.com/illusion-chasers/parallels-between-shrimp-and-human-color-vision/ |website=Scientific American Blog Network |date=March 20, 2014 |access-date=May 13, 2020 |archive-date=May 25, 2020 |archive-url=https://web.archive.org/web/20200525140407/https://blogs.scientificamerican.com/illusion-chasers/parallels-between-shrimp-and-human-color-vision/ |url-status=live }}</ref>

However, a study from 2022 failed to find unequivocal evidence for a solely "barcode"-like visual system as described above. Stomatopods of the species ''Haptosquilla trispinosa'' were able to distinguish high and low-saturation colors from grey, contravening Thoen and colleagues.<ref name=":5" /><ref name="Science" /> It may be that some combination of [[color opponency]] and photoreceptor activation comparison/barcode analysis is present.<ref name=":5" />

The shrimps use a form of reflector of polarised light not seen in nature or human technology before. It allows the manipulation of light across the structure rather than through its depth, the typical way polarisers work. This allows the structure to be both small and microscopically thin, and still be able to produce big, bright, colourful polarised signals.<ref>[http://www.bristol.ac.uk/news/2016/february/mantis-shrimp.html New type of optical material discovered in the secret language of the mantis shrimp] {{Webarchive|url=https://web.archive.org/web/20160307200843/http://bristol.ac.uk/news/2016/february/mantis-shrimp.html |date=2016-03-07 }}. Bristol University (17 February 2016)</ref>