this Odontodactylus oratoria demonstrates
how a mantis shrimp can thoroughly clean its
own body—no mantis shrimp is dependent
on the services of a cleaner shrimp.
ed body- and claw-shaking of little Periclimenes holthuisi
shrimps behind the glass of the sales tanks of various
aquarium dealers, constantly offering me their cleaning services during time-consuming macro-photography
sessions. Were a fish to approach a mantis shrimp burrow where Periclimenes species were resident, it seems
very likely that they would likewise offer the visitor their
cleaning services, and in so doing lure fishes to their
doom. And the stomatopod “pays” the shrimps for their
involuntary service as bait by providing them with food
residues and behaving with exceptional tolerance, allowing them to literally dance around its face unscathed.
This is all my guesswork at this point, and we can hope
that science will provide clearer answers to this unusual
case of apparent commensalism. (See Interview with Dr.
Roy Caldwell, page 26, for another interpretation.)
bottom (both): r. caldwell
Clubs and spears
As already mentioned, mantis shrimps employ two very
distinct methods of capturing prey, both of which involve similar movement of the “arms” but with quite
different results.
In the first group of mantis shrimps,
known as “spearers”, the second pair of
thoracopods are modified into lance-shaped implements. They can shoot these
sharp, barbed, harpoonlike appendages
forwards to impale the prey and simultaneously hold it fast—ideal for the capture
of fishes, as well as other crustaceans and
moving prey items.
The other group, the “hackers” or
“smashers” have the corresponding pair
of thoracic appendages modified into club-like implements which they can shoot forwards at record speed
to strike a solid structure—perfect for dealing with hard-shelled targets, such as snails, clams, and other crustaceans. This implement not only allows them to overpower prey, but is also useful for cave modification in solid
stony structures—many of the clearly audible dactylus
blows that take place within the rockwork have nothing to do with capturing prey or self-defense, but relate
solely to “home improvements,” in particular enlarging
the passageway. Analogous to the pistol shrimps of the
family Alpheidae, these mantis shrimps are also able to
chip off small pieces from the calciferous rock of the reef
to glue into the matrix of their tunnel linings.
The primary purpose of these appendages is, however,
to crack the defenses of a living creature, be it potential
prey or an assailant. In 2004, UC Berkeley biologist Sheila
Patek working with Dr. Roy Caldwell set out to measure
the speed and power of a Peacock Mantis Shrimp’s strike
and made an amazing discovery. Working with a BBC
camera crew working with a new, high-speed, low-light,
5,000 frames/second camera system, Patek showed that
