|Photograph by Dr. Roy Caldwell
Shining Through: Lysiosquillina glabriuscula fluoresces
Another amazing piece in the puzzle of stomatopod vision fell into place last year when Charles Mazel of NightSea discovered a fluorescing mantis shrimp. Although other animals have been found to fluoresce, this phenomenon has never been directly linked to its use as a a way of communicating in the dark depths of the ocean, where the extraordinary visual system of mantis shrimps (the most complex in the world) might at first glance seem to be quite useless.
In a recent paper published with Dr. Roy Caldwell, Dr. Thomas Cronin, and Dr. Justin Marshall, the group explored the use of fluorescence by mantis shrimps in communication. In an interview with UC Berkeley News, Dr. Caldwell explained:
"If you look at this animal in shallow water or in bright white light, you pick out this set of yellow-green spots it uses in species recognition, and probably in mating as well - it's a typical signal that says, 'Here I am, I'm a Lysiosquillina glabriuscula,'" said marine biologist Roy Caldwell, professor of integrative biology at the University of California, Berkeley. "But this animal also occurs at 40 meters, where there's no yellow light for that pigment to reflect, so that species-specific signal should be gone. But when you go down to 40 meters and you look at it, the yellow spot is still there."
"The stomatopod (or mantis shrimp) apparently is using a yellow-green fluorescence to maintain visual constancy of a species-specific signal,"
In order to get the fantastic photograph of the fluorescing stomatopod, Dr. Roy Caldwell flashed a blue light and viewed the scene through a yellow filter that removed the blue light but let through the fluorescing colors - red, green and yellow. He noted: "The pigments are taking in the blue light that is present at that depth and turning it into yellow to maintain the signal."
They hit the jackpot when they then found that the color emitted by the fluorescing skin pigments overlaps exactly with the sensitivity range of one of the receptor sets in the stomatopod's eye, thus indirectly bolstering the hypothesis that the mantis shrimps are using their fluorescent signals as a way to communicate with one another.
To read more about this, click here.
To read the paper submitted to Science and view a video of a fluorescing mantis shrimp catching a fish, click here.
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