Shrimps' Amazing Eyes

Attention: open in a new window. PDFPrintE-mail

Shrimps' amazing eyes revealed, as described in articles in EurekAlert, UQ News Online and ScienceNOW, 20 March 2008. A group of researchers led by Justin Marshall of the University of Queensland and the Queensland Brain Institute have been studying the eyes of mantis shrimps - large reef dwelling crustaceans, also known as stomatopods. They found the crustaceans have the ability to distinguish between right and left circular polarised light (CPL) - spiralling beams of light that can twist to the right or left. Some animals are known to be able to distinguish between different planes of linear polarised light, but Mantis shrimp eyes have a special filter orientated at 45 degrees to their photoreceptor (light sensitive) cells. The filter converts the circular polarised light into linear polarised light, which the photoreceptors can detect.

To confirm that the mantis shrimps could detect the two different forms of light the researchers gave the animals food in association with either right or left CPL. They then tested them by presenting two feeding tubes, one reflecting left CPL and the other reflecting right CPL. The shrimps went to the tube that reflected the light that had been associated with their food.

The exact function of the ability is not known. Justin Marshall commented: "It's complicated physics, but that makes it all the more amazing that some animals would use it for something." The best clue so far is that males, but not females, have patches on their carapace that reflect circularly polarised light, so it may be part of the shrimps' sexual signalling.

Marshall also commented: "It's quite amazing to think how much circular polarisation technology we have, and that 400 million years ago nature got there first with a mantis shrimp's eyes." He went on to say: "Us humans only have three colour channels. These little guys have 12, and can see both linear and circular polarised light - it is remarkable."

Circular polarised light is used in human technology in photography and image detection systems. The UQ article comments that the mantis shrimp is "an amazing animal to study as it has a very small brain but one of the world's most complex visual systems." EurekAlert record this comment from the research team: "Whatever the use of CPL signals and CPL vision to stomatopods, comparing design features of their CPL reflectors and sensors to those of man-made systems will be interesting. Humans use CPL filters and imaging in everyday photography, medical photography, and object-detection systems in turbid environments. The reefs and waters that many stomatopods inhabit are often turbid, and it is perhaps no surprise that, perhaps as long as 400 million years ago (when stomatopod crustaceans first appeared), nature got there first."

EurekAlert, University of Queensland

Editorial Comment: The fact that CPL can be seen in turbid water does not explain how the mantis shrimp eyes were made to see it. It required intelligent observation of the properties of light by human scientists to discover, and creative design to make use of it in human technology. In a scientific world that defines itself as limited to naturalistic explanation only, it may be unacceptable, even though it is far more logical to believe that a creative Designer made the mantis shrimp's eyes and a reflective carapace. It is regarded as more intelligent to believe that unintelligent evolutionary accidents gave rise to it. When your world view of naturalism prevents you from discovering truth because it limits you to arguing about whether something is philosophically science or religion, rather than what is true or false - it's time for Emperor Science to wake up to his Naked stupidity. The scientists who are amazed at the technology built into this crustacean's eye will one day have to give an account of why they failed to honour the One who made it, rather than credit the shrimp or "nature" with making themselves. (Ref. design, optics, arthropods)

Evidence News 23 April 2008

q_and_a2
crc_youtube
outdoor_museum_panel
free_audio2