- The Uropygi
- (Thelyphonida) (Whip Scorpions)
Introduction
Whip Scorpions look like their cousins the Scorpions, except
that they have a long slender tail, it is this 'caudal appendage'
which gives the group its name. They are mostly tropical in distribution
with the largest species being found in the genus Mastigoproctus
which is only found in America, other genera are Hypoctonus in
Malaya, Typopeltus in Chochichina and Japan, and Thelyphonus
in various parts of the Indo-pacific region. In captivity they
tend to be very aggressive to one another and it is only possible
to keep them in individual cages. When disturbed they will often
discharge a gas from their back end that is said to smell of
Acetic Acid (vinegar) in some species and Chlorine in others.
This production, usage and smelling of acetic acid has resulted
in their being called 'Vinergarones' in southern USA and the
West Indies. In Taiwan Thelyphonus skimkewitchii is known as
'Mengpon-menn' or the 'Stinking Scorpion'.
- Whip Scorpions are much larger than the similar
looking Palpigradi, ranging in size from 25 to 70mm in length,
Unlike the more common arachnids Whip Scorpions have no poison
glands and their chelicerae are not chelate (i.e. they do not
work like pincers as they do in many other arachnids) and kill
their prey by crushing them. They are also unusual in that they
use their long thin front legs as feelers, in much the same way
that insects use their antennae, for this reason their front
legs are referred to as 'antennaeform'. They have four pairs
of rather weak simple eyes. Their abdomen has 12 segments, the
last three of which are small and form a small plate called a
'pygidium', from which the tail or 'caudal appendage' extends.
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- Feeding / Ecology
Whip Scorpions are purely nocturnal hunters feeding mostly on
insects such as cockroaches and grasshoppers, though they also
eat worms and slugs. The prey is siezed between the two pedipalps
and crushed between special teeth on the inside of the trochanters
(the second segment of the leg) of the front legs. The large
American Mastigoproctus giganteus carries its prey back to its
burrow to eat and has been known to feed on small frogs and toads.
They will readily drink water, at least in captivity. They spend
the daylight hours in holes under rocks and stones which they
dig using their large pedipalps.
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- Mating
Mating involves a brief courtship which begins with the male
holding the females antennaeform forelegs in his pedipalps with
their tips in his chelicerae and walking backwards until the
female raises her abdomen. It then progresses to his stroking
her genital segment with his antennaeform forelegs and the top
of her abdomen with his chelae. Finally the male produces a spermatophore
which he holds against the females genital apperture for several
hours.
- The pregnant female digs a special burrow
with a larger area at the end, when the eggs are laid they are
inside a special membrane that prevents them from drying out.
The female remains in the end of her burrow guarding the eggs.
When the eggs hatch the young are white and look nothing like
their mother, they climb onto her back and attach themselves
there with special suckers. After a while they moult and the
creature which now emerges looks like a miniature Whip Scorpion.
They soon leave their mother, who, now exhausted having spent
so long without food, dies. The young are slow growing and go
through three moults in about three years before they reach maturity.
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- gordon@earthlife.net
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Bringing Insects to the World http://www.earthlife.net/insects/
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