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THE STROPPY JOB!
Good name. Indeed, these various larval stages
of a variety of Mantis Shrimps and Mantis Lobsters from tropical
and subtropical seas, are stroppy. Stroppy by appearance and stroppy
by nature, soon into their larval development they become endowed
with their most distinct feature, namely a pair of viciously effective
raptorial limbs, similar but different to those of the flying
mantid insects of tropical rainforests.
"Raptorial" is a term used to describe limbs
that engage their prey by gripping between forearm and upper arm
or between wrist and forearm. The marine versions of stomatopods
- the Mantis Shrimps - modify the inner side of the terminal part
of their second pair of subchelate mouthparts to become a series
of very sharp, slightly recurved teeth, the final one of which
is nothing short of sabre-like. These teeth, at rest, come to
lie in a groove of the next most proximal section of the limb
which acts as both a sheath and an "anvil" or "chopping-block"
against which the teeth smash the victim in a power strike that
is measured in hundredths of a second.
Mantis Shrimps, from their burrows in the sandy
lagoon floor, or amongst coral rubble, can strike, hold and capture
fast, over swimming fish. The larger stomatopods may be fourteen
inches in length, banded in brilliant yellow and black bars and
capable of inflicting extremely painful and serious injury to
a human hand. Some related "Knocker Shrimps" that strike outwards
rather than inwards can smash their way out of strong glazed aquarium
tanks!
The larval stages pass from "erichthus" to "antizoea"
to lysierichthus" and finally to "alima" forms. The earlier stages
are not dissimilar to other crustacean larvae such as decapod
crabs. The later stages are beautiful, glassy transparent, 5 cm
long planktonic versions of the adults. In the plankton community
they must be the "lions of the Serengeti".
Another claim to fame for the stomatopods is their
eyesight and eye development. Adults and larvae have stalked eyes.
In the adults, the dumbbell-shaped compound eyes on each stalk
imply a degree of 3-D vision from each eye. Justin Marshall at
the University of Queensland has carefully researched Mantis eyes
and has shown that they contain an unparalleled diversity of visual
pigments and spectral receptors. The waisted area of the dumbbell
is shown to be very receptive to polarised light and the receptivity
of individual species varies in accordance with the depth at which
they live and the wavelengths there encountered.
All in all - some of a cool dude!
This article was written
by Peter Parks
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