The 
Diary
The
Diary
BACKGROUND:
On 12th June 1998, my Asian Forest Scorpion, Heterometrus spinifer, successfully give birth to its offspring. Prior to the parturition (giving birth), it became highly aggressive and feed a lot. Its opisthosoma (abdomen) also swell to extreme size and seems on the verge of bursting.
Since this specimen is acquired in early September 97 with a male (happily departed Nov 97) which has been contributed to science (dead and preserved as research material), I think mating may have occured during captivity as the gestation period is just about right and the female was apparently not gravid. The average for Heterometrus longimanus is 12 months (Schultze 1927) while that of sister genus Emperor scorpion Pandinus imperator is about 7 months (Larrouyl et al. 1973). There is a lot of variation among individuals and this is related to environmental conditions like suitability of substrate, humidity, temperature, availability of food, water, size of enclosure, sense of security. The conditions I provide, in my opinion, has been ideal and thus may have accelerated the development.
Pictures was taken of them at each stage and will be online around mid July. Till then, it is all words.
Heterometrus method
of embryo development is katoikogenic which in simplified terms means 'no
yolk'. As such, the developing embryo derives all its nutrition from the
adult scorpion and much of the digestive system development occurs early.
They develop in the diverticula from the female ovariuterus and do not
possess embryonic membrane when born. Katoikogenic development occurs in
Scorpinidae, Ishnuridae and Diplocentridae which incidentally consist of
some of the largest scorpions in the world.
On the other hand, apoikogenic scorpion embryo develop in the oocytes in
the ovarian follicle. They possess a prominent yolk and draws nutrition
from it. However diffusion of material from the maternal system to the
yolk exist and thus nutrition is indirectly derived from the mother. Apoikogenic
scorpion larave is enclosed in embryonic membrane when first born. This
form of development occurs in Vaejovidae, Iuridae, Chactidae, Buthidae,
Bothriuridae and Superstitionidae.
Now on to whatever I witness:
June 8th 1998:
The female scorpion look way too fat at the opisthosoma with some patchy
discolouration for too long. Based on the birth month for Heterometrus
(July) as recorded by Schultze in 1927 and the fact that many of my friends
got newly born Heterometrus, I know my scorpion is pregnant and delivering
soon. She exhibit weird behaviour. She (10.2cm in length) actively searched
and killed all 7 adult crickets I gave with such energy that I would have
suspect it is starving if not for its size and that she has been fed 4
days ago. However, she only ate 2 of them and the rest are killed and just
piled up to rot. She also did something I least expect. I put my hand just
outside my tank and she struggled out of the tank to give me a pinch without
provocation. After giving a good painful pinch, she struggled back into
the tank...... Seemingly, her senses and aggressiveness is greatly enhanced.
I have planned ahead and added fertilised 5 adult crickets to lay eggs
in the soil within the tank so that their hatching (2 weeks) coincide with
the second moult (1 week from birth) of the scorpions (which by then they
can feed upon).
June 12th 1998 (2000hr):
I came back from study and as usual fully expecting my scorpion to give
birth. However, expectations aside, I was happily surprised when I really
see white 'maggot' like larva on the mama scorpion's back. They are arrange
in random direction and some of them pile on top of each other as the mama
scorpion's back area is way too small. She seems to be still delivering
babies from her underside and I can see her gently cuddling the newly born
with her first 2 pairs of legs while the back legs stood stilted. The young
larva crowd her underside as well and appears quite active when disturbed.
I observed for an hour before deciding to spare the irritable mum from
further disruption
June 13th 1998:
I emailed all the local enthusiast I know to ask for congratulatory note.
<(^o*)> Also purchase a film to take those fascinating pictures of
larva on the mama scorpion's back. There's not much change except that
mama scorpion has relax a little (until it detect me). The young ones also
seems a little less active. To keep up the humidity, I wet the soil and
sprinkle some water on the scorpions. This infuriates the mama scorpion
which hisses and goes into defensive stance. She chases round the tank
after the phamtom enemies which are vibration from the waterdrops.....
June 15th 1998:
Some of the scorpionlings has developed a tinge of brown on its opisthosoma.
Nothing significant has changed and the mama scorpion remain very protective
June 17th 1998
Gosh!! Crickets! Apparently I mistimed the breeding of crickets as over
a 100 hatch just after 9 days. The mama scorpion got extremely irritated
by the pinheads and surprisingly manage to kill some even though her pedipalp
got gaps bigger than the pinheads....... Most of the rest are just shoved
away.
June 19th 1998
Brownish streak along the median line of the abdomen of some scorpion larva
is apparent. I hold in abated breathe for the young ones to undergo first
ecdysis (moult).
June 20th 1998
Yippee, the larva has molted. The 1st instar still clutter the back and
underside of the mama scorpion. They now look fully like white miniature
version of the adult. The setae (hair) not apparent prior to this molt
is now very obvious.
June 21st 1998
Nothing much change but the 2nd instar scorpions got quite active.One or
two at times strayed from the mama scorpion. I saw 2 of them have pinheads
in their chelicera. Yay they have started feeding.
June 22nd 1998
I removed the log and realised that about half of the baby scorpions which
has strayed from the mum. They have started crawling about. I also witness
cannibalism as pedipalp of one unfortunate baby is in the chelicera of
another. I counted about 20+ scorpionlings.
June 24th 1998
One of the scorpionlings seems to be slightly crushed under the log and
has sadly passed away. Almost all are now roaming about. I decided not
to use the log and now they hide under the mum. However, I see that they
don't feel secure being exposed. I give 3 of my scorpionlings away. Those
3 are very fat from feeding on 15 pinheads between them in the previous
night. That night I realised I actually have about 36 of them including
ones cannibalised, crushed and given away. A very big brood to say the
least. The molts of the larva remain stuck to the back of the mama scorpion.
June 25th 1998
I separated 6 of the scorpionlings from the original tank to experiment
keeping them without their mum. I also gathered large leaves as a safer
refuge for the scorpionlings. They appear satisfied with the new hideouts.
I attempted to feed the mama scorpion crickets and it did something which
surprise me. It plucks off the hind legs of the first cricket and then
went for the neck. Just when I thought it will feed, the scorpionlings
swarmed all over the cricket and her and attempted to feed. On her part,
I can see she's just using the chelicera and pedipalp to crush the cricket
to prevent its struggle and allow the hemolymph to flow out. In about 30minutes
the first cricket is dried. Its hindlegs are contended among the scorpionlings
which alas the vistor cannot penetrate the thick cuticle..... I fed the
second and third and the mama scorpions was surprisingly swift. She is
also able to sift out the cricket among the scorpionlings and not crush
any of them though a few went between her pedipalp to feed on the remnants.
All of them are fed dry by the scorpionlings. The fourth cricket went and
suffered the same fate. The fifth cricket capture was more dramatic as
a few scorpionlings cling on between her pedipalp. She almost pince a few
of them but release at the last minute. She also shook off one persistent
scorpionlings between her pedipalp. By the fifth adult cricket, most of
the scorpionlings are well fed and has dispersed. The mama scorpion did
not feed at all..... I tried to feed those in the tank using mediumsize
crickets without success. Later I crushed the cricket to kill it like the
mama scorpion but the scorpionlings in the separate tank remain apprehensive.
I realised that 2nd instar at least for Heterometrus spinifer should
be kept with the mother.
June 26th 1998
The cricket which was left in the separate tank got only a section of the
head left. The rest is consumed. Again, I misted their tank slightly to
prevent dehydration. The mother scorpion got more comfortable with water
misting but is still extremely aggressive to other vibrations. One scorpionling
remain on her back and I can see among them that 2 of them is underdeveloped.
The rest has developed a brownish tinge most prominent on the median line
of the body. That 2 remain white and inactive. They also does not feed
as well.
June 27th 1998.
I gave another cricket to the mama scorpion. She killed it and as usual
left it between her chelicera. However, only 3-4 scorpionlings came and
attempted to feed. Their mesosoma is very distended still from previous
feeding. I removed the dead half fed cricket with some difficulties and
give it to the ones in separate tank. Again those in separate care seems
more apprehensive and secretive. They also appear less rapid in development.
When I put in the second adult cricket with the mama scorpion, she killed
in and sensing no scorpionlings coming, she brandished it like a gift and
go round the tank 'luring' them out. At last, 3-4 scorpionlings tries to
feed on it and she remain unsatisfied and try to show to more. She still
appear very thin and does not feed. Talk about maternal instincts and sacrifice.
At the same time, I attempted to breed another batch of pinheads as the
previous pinheads population (about 150)has all been eaten
June 28th 1998
The half consumed cricket in the separate tank is gone with only a leg
to show. Another cricket into the mama scorpion tank is killed with enthusiam
by the mum but again there's lukewarm response from the scorpionlings.
In the process, she accdentally pince on a bloated scorpionlings a little.
The scorpionlings appear alright except for a very slight indentation on
the posterior mesosoma. I watch it and its activity remains normal.
June 29th 1998
The scorpionlings crushed lies dead on the soil. Apparently, they are very
fragile at this stage and the bloated abdomen may have reduced the accomodation
for slight crushing <sigh> Other than that, the scorpionlings are
mostly much bigger and more brown now. The growth in the separate tank
remain a little stunned though they seems to be doing fine. I didn't count
their number and assume there's no cannibalism as the dead one has lies
there without being touched for sometime by then.
July 1st 1998
The first time I observed the scorpions using their stings to stun their
prey. They have also begin to make burrows
July 4th 1998
The scorpionlings make extensive burrows at the corners of the tank. Many
are hide within.
July 7th 1998
I decide to dig them out as it is difficult to monitor whether the scorpionlings
are feeding well. I also transferred the scorpionlings to another container
with less deep substrate. This will facilitate monitoring and counting.
However in the process of digging the 20+ scorpionlings all in one burrow,
I severed accidentally one of the scorpionlings 3rd and 4th right legs
despite using extra care. It was a sad moment but unfortunately it survived.
July 15th 1998
I feed my scorpionlings a regular diet of 4 killed adult crickets per week.
They are real gluttons and nothing is left of the crickets after one night.
The scorpionlings all appear very bloated and has turned darker in appearance.
July 20th 1998
One of the scorpionlings molted again. I saw the exuvia and keep track
of them. It appear very pale and much larger than the rest.
July 30th 1998
About half of the scorpionlings has molted. The older ones are very dark
and the pedipalp is almost black. They really look like miniature adult
now.
August 11th 1998
The gluttons started to eat sub adult crickets half their length. They
manage to make the kill themselves and their sting seems to work well against
the crickets. There is no casualty thus far and I'm really glad.
August 22nd 1998
All but 4 scorpionlings has molted. They are all quite big and fight for
crickets by shoving with their metasoma. There also appear to have threat
display using waving of the metasoma and some pedipalp pincing and shoving.
The scorpionling with the severed legs molt at last. It was stunned probably
by the need to regenerate the legs. Unfortunately, as David Gaban said,
the regeneration is minimal and only stumps is seen where there were legs.
:(
August 23rd 1998
Another typical day but I decide to update my pages.
Copyright of Chua Kian Wee 1998