Although its not yet clear exactly what the mantis shrimps newfound visual ability is good for in nature, Marshall said its likely all about sex.
Stomatopods are known to use highly specialized color and linear polarization signals for complex social interactions, he noted. And by using circular-polarization imaging, his team has identified three species of stomatopods (within the genus Odontodactus) where CPL is reflected from the cuticles of males but not females. Those sex-specific reflective areas are on parts of the body that stomatopods frequently use for behavioral displays.
The precise role that these signals, visible to a CPL visual system, play in stomatopod sexual signaling is not yet known, but we speculate that these CPL reflections could act as a secret communication channel, the researchers concluded. Linear polarization signals, used by marine invertebrates, are visible to animals like cephalopods that prey on stomatopods and are therefore open to exploitation. Also, other genera of stomatopods that we have examined have variable CPL sensitivity, and may be unable to view the sexual displays of Odontodactylus species, making this a private channel of communication, unavailable to both predators and potential stomatopod competitors.
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, they added. 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), nat
|Contact: Cathleen Genova|