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Picture of flourescence of Androctonus australis under ultra violet light, courtesy of Pascal Riewe
Another one by Alexandros Pagidas
Other Interesting Facts about scorpions
Observing scorpions by itself is interesting. However, the scorpion still holds a surprise or two when one probe further.
Flourescence:
Picture of flourescence of Androctonus australis under
ultra violet light, courtesy of Pascal Riewe
Another one by Alexandros Pagidas
In most public exhibits of scorpions, flouresence of scorpions is featured
strongly.
Longwave ultraviolet light when shine upon the scorpion is absorbed and
reflected as greenish visible light. Other than scorpions, some sowbugs,
millipedes, centipedes, solfugids and even beetles are shown to exhibit
flourescence.
Under the sun, the greenish tinge of the scorpion can be observed.
The exact substance causing the flourescence is
not yet known but is probably a complex of mucosaccharides and proteins.
The flourescence is emitted from the surface epicuticle (aka hyaline layer
in Dr Scott A. Stockwell page) which is part of the integument which includes
epicuticle, mesocuticle and endocuticle; the terms has not been standardised
yet. Such flourescence is observed even in most of the fossils of euryterids
(ancient scorpions). Even in specimens dried and mounted or preserved,
flourescence is observed. In fact, flourescence in alcohol preserved specimens
leads to the discovery of florescence in scorpions(1956). This shows that
the flourescence arises from a stable substance which does not need nutrition
to substain.
It is observed that newly molted scorpions shows little or no flourescence.
Also intersegmental cuticle even in mature cuticle shows no flourescence.
It is postulated that the flourescence may be due to secretion of the scorpion
or a by product of the tanning process.
My personal opinion is that since even troglobitic (cave dwelling) scorpions
not exposed to sun shows flourescence, the first hypothesis is more likely.
This and the fact that baby scorpions in the first instar shows less flourescence,
swings the argument in favour of the possibilty of secretion.
The ecological advantage of having flourescence is not known and apparently
UV light shows little to no effect on the behaviour of scorpions. Koehler
in his studies hypothesise that the flourescence may help in the scorpion's
UV senstivity. This may prove advantageous to their nocturnal living.
Their flourescence when discovered has been been used extensively in their
collection and studies. Much advances in their knowledge and discovery
of new species arises from this peculiar property. However, I personally
disfavour it unless it is for research purpose otherwise the natural population
can quickly deplete. Most scorpions with their very long gestation period
(even if compared to mammals) has relatively low recovery rate.
Scorpions in the Sea:
To many people, scorpions on the land is distressing thought.
Few knows that scorpions can also be found in the sea or more correctly,
the beach. Most of the following information is extracted from 'Biology
of Scorpions' by Polis. At least 10 species of scorpions (Polis) can be
found on the beach. Above the high tide line on some beaches, it is found
to have abundant scorpion life mainly of the Centruroides spp. Scorpions
like Vaejovis littoralis can be found among the Sargassum
algae while Opistopthalmus litoralis lives un scrapes and under
driftwood along Skeleton Coast of Africa. Most of these scorpions are small
and pose no threat to human except perhaps for some Centruroides sp.
Astronomers/ navigators:
Glittering stars of the sky. Is there by chance a Scorpius
out there?
Most scorpions shows some sort of homing ability. A few scorpions despite
their poor vision has been demonstrated to orient by the lights of the
stars and moon (astromenotaxis). Scorpions have some of the most light
sensitive vision amongst animals.
Other scorpions may navigate by wind direction. Though not mentioned in
books I've read, I think that they may also be able to detect chemical
markers secreted by themselves or others (akin to ants). There is also
possibilty that they can navigate by the quality of substrate but that
again is my hypothesis
Prolonged Pregnancy:
Despite their short lifespan compared to human and other many other
mammals (refer to what is scorpion: age),
the female scorpion carries the 'babies' for a very long time. According
to many studies summed up by Polis, the average gestation period (from
mating to giving birth)for Buthids is 5.4 months while that for non-Buthids
is 11.4 months. For Opisthacanthus spp, it can be as long as 18
months. If their lifespan works out to be 5 years and takes 3 years to
mature, then female Opisthacanthus spp. would be pregnant more than
half their mature lifespan. When compared to human's average lifespan of
60-70 years and gestation of 9 months, it is very long indeed.
The female Hadogenes spp. is found to have a parturition period
(labour) of 240 hours (William 1971)!! Mothers of our species (man) would
surely recoil in horror at the thought of such long labour. However, partutition
period of others is generally much less. (an hour to a few days).
Many more interesting discoveries awaits us in the study of scorpions. With the advent of DNA (deoxyribonucleic acid) and genetic studies, the understanding of scorpions may leap frog to a higher level. The list above is selected on personal bias and represents a small fraction of what is interesting about scorpions <even to myself ;-)>
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Copyright
All pictures and information are copyright © Chua Kian Wee, 1997
The information in the page are painstakingly compiled by me. Please do
not use the information for purpose other than personal reference without
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