Rearing the giant huntsman spider Sparassus walckenaeri

Introduction
Sparassus walckenaeri is the only Sparassid to occur in the eastern Mediterranean countries but it is abundant further south and east including Africa, Central Asia and throughout the Middle East. The large retreat (sometimes as large as a man's palm) is a common sight under stones and fallen branches and consists of two white papery sheets forming a flattened envelope with two concealed openings which the spider usually slips out of rapidly. These spiders are extremely fast moving (a problem when trying to collect) and build no webs for prey capture, instead, actively foraging for their large variety of food (large specimens are known to take small vertebrates such as geckos) in close proximity to their retreat. Individuals may show aggression when approached, even raising the legs offensively before beating a hasty retreat. Fortunately, however, none of these large spiders is known to be dangerous to man.

Collecting
An egg sac was brought back from holiday in southern Turkey after I was fortunate enough to stumble over the impressive sight of a large mature female sitting on the wall of my hotel. As is always the case, she was sitting in an awkward position just below the one storey eves and was just out of arms reach. Eventually (with the aid of a convenient patio chair), the female was caught and placed in a container for further observation. She settled quickly in captivity accepting food almost immediately. Two days later she was discovered sitting beneath a large egg sac and the following day she was released and the egg sac brought home.

Description
S. walckenaeri is a large spider. Size varies between individuals and therefore this cannot be used accurately as a form of identification. Typically females are more robust than the slender long legged males. An average female can reach a mature leg span of 11 cm with the male being slightly smaller. Colour: Legs; light tan / cream with several dark brown annulations. Abdomen; yellowish with scattered light brown irregular patches and a median line surrounded by dark bands which converge posteriorly. Carapace; cream / tan with dark brown spots arranged around the sides and a dark median band surrounding the fovea. Sternum; light tan / cream. Occasional individuals have little pattern, the abdomen and carapace having a distinct smooth, shiny appearance.

Housing
Spiderlings can be housed together for some weeks after emerging from the egg sac provided enough room is allowed. Hiding places are essential at this stage using pieces of twisted paper towel. When separated, tall containers are preferred (Huntsman spiders rarely visit the ground) and when housed in their permanent container, it can be furnished with a covering of dry vermiculite or peat with a firmly fixed branch or slice of cork bark. Containers should be well ventilated and if possible, stood upside down to prevent escapes as these spiders tend to run upward when disturbed.

Food and water requirements
S. walckenaeri will take a wide variety of prey and this often consists of prey of a considerable size in comparison to themselves. A large female will have no fear when tackling adult crickets, large locusts and the like, eagerly leaping on the insect and wrestling it to the ground. Even young specimens will accept large blow flies and waxworms. Huntsman spiders almost always emerge after dark to exercise their 'sit and wait' tactics, adopting the typical Sparassus stance known as the laterigrade position (all the legs appear to point forward, always poised for the imminent rush forward). Actual feeding is a simple affair. Prey can either be simply dropped in the container and the spider will eventually catch it (they are very sensitive to movement around them, leaping on crickets from inches away). Captive specimens can be calm enough to be fed outside their container by placing the prey item close by (after the spider has settled) and they will quite happily remain still as they feed--quite unusual behaviour for an araneomorph. Food size should vary in accordance with the size of the spider; micro crickets and fruit flies for spiderlings (which are quite large in this species). In their early stages, S. walckenaeri spiderlings should be offered water at least once a week on a piece of damp paper towel but as they grow, this should be reduced until when adult, no water is required. As these spiders come from mainly arid environments (Turkey during the summer months can be very dry) excess water in the micro-environment of captivity can be fatal. Sign that the atmosphere in the container are too moisture are a change of the tip of the abdomen from the usual cream to a pink or red appearance and the apparent loss of the use of the spinnerets. Specimens showing this discolouration should be moved to drier conditions and if caught early enough, most individuals survive. In adults, water may be refused even after many months of dry conditions as enough moisture is gained from feeding. This procedure, however does not apply to all species of huntsman in captivity and the country of origin should act as a guide to relative humidity levels.

Ecdysis
S. walckenaeri mature with approximately 10 - 11 moults. Pre moult behaviour consists of lack of appetite coupled with the building of a moulting 'tent'. The spider seals itself inside the envelope of silk (usually attached to the top of the container) and there it remains until it moults, sometime for several weeks. S. walckenaeri moults hanging upside down inside this tent (the web varies in size depending on the available room but more often it is only large enough for the spider to turn around in). This web should be confused with the retreats that the spider regularly builds described earlier - the silk is more dense and sometimes the spider is invisible inside. S. walckenaeri is unusual in that when they moult the old skins splits first above the pedicel and not along the line above the chelicerae which is usually the case with other spiders. During moulting is the only time when extra humidity is required. The substrate should be well wetted during this period as many specimens die from becoming caught in the cast skin. After emerging from their moulting envelope, the spider should be re-housed in a clean, dry container. Food should be offered as early as possible as vital moisture is required at this time.

Sex determination
When young, there is no sexual dimorphism in huntsman spiders and sex determination is only successful after the males penultimate moult. At this time the males palps become instinctively enlarged and bulbous and it is then that immature males should be removed to a cooler position to retard their growth to coincide with the maturation of the females. Mature males are much more slender than their mates but what they lack in bulk, they certainly make up in leg span. A mature female is determined by the unusual epigynum which is formed into two large, heavily incised triangular plates, acquired following her final moult.

Breeding
Actual mating is both unusual and very simple. When both male and female have had time to feed after maturing, a pairing can be easily achieved by placing the male in the females container. The following is an extract from my personal observations while mating this species:-
The male was introduced at 8.30 pm. He entered and wandered until coming into contact with the female and she retreated from him. He followed and on the second touch, the female remained motionless as he moved onto her and proceeded to bite her, sinking his fangs into the soft tissue between her carapace and coxa. Surprisingly the female allowed this and he remained with his fangs embedded in her for a short time. She soon became limp and the male began to work his legs under her and move around so that he was above her facing in the opposite direction (the female was on the side of the container facing upward while he was on top, facing downward). Curling his legs under her, the male proceeded to pull her upward and away from the side so that he could get into position. The female was now well and truly 'drugged' from the males venom (?) and although managing to retain her grip on the container side, she remained motionless apart from a slight chewing of her chelicerae. The male (now with just two rear legs holding onto the side and all other legs under the female) moved his front half to the right side of her and using his front legs, he twisted the females abdomen towards him. He then moved his left palp between her rear leg and abdomen and tried to insert his left embolus into her epigynum. Having failed to do this, he altered his position and tried from the other side (her right, his left palp) but again, he failed. This procedure continued for over an hour. Every time the female moved he would strengthen his grip on her but if she struggled, a slight bite was given in the same carapace/coxa area. They eventually fell from the container wall and after resuming his position, he successfully inserted his left palpal hook and the embolus was inflated and sperm injected. On inflation, his body went limp and pulsed for a few seconds and all of the prominent bristles on both the male and female moved up and down. He withdrew approximately 30 seconds later. 10 minutes later the female became active again and moved away from him. He followed slightly but she gave him an aggressive slap and she moved further away. He wandered slightly and was finally removed after nearly 2 hours. It was quite unusual to see the male actually bite the female. He must only inject enough venom (?) to subdue her, enabling him to mate in relative safety. The males problems with palp insertion were probably due to the female being rather plump as a result of feeding. Had she been slimmer (which is probably the case in their natural environment), he may have been more successful.

Egg sac construction and incubation
Several weeks (dependent on temperature) after mating the female eventually prepares to build her egg sac. Again, a large silken tent-like structure is built usually at the top of the container, in which the female seals herself. The eggs are laid and attached to the top of the structure and she hangs below them, guarding them with the tips of her legs surrounding the egg mass. During incubation the female does not leave the security of the egg tent and does not feed. Approximately 5 months later (again dependent on temperature) the eggs hatch and at this point the female leaves the nest and plays no further part in their development. The spiderlings moult and finally disperse. Females can lay up to 3 egg sacs from one mating, each time the size and quantity of eggs becoming smaller.

Longevity
In their natural environment, S. walckenaeri go through a dormant winter period and mature in their second year but in captivity specimens can continue straight through their growth cycle and mature in around 1 year. Mature specimens can be expected to live from 18 months to 2 years.

Acknowledgements
I am indebted to Paul Hillyard for his help with identification of this species.

References
G. Levy "The family of huntsman spiders in Israel with annotations on species of the Middle East (Araneae: Sparassidae)." J. Zool. Lond. (1989) 217, 127 - 176.


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