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Monday, December 13, 2010

Night of the spiders

DELICATE WEB: This horizontal web could be photographed thanks to a fine mist of cornstarch.

Cheong Ah Kwan

STRETCHED across the lower branches of a tree was the convoluted three- dimensional ‘circus tent’; a magnificent piece of web architecture.
Constructed by a tent- spider, the elaborate web is a deadly trap to insects.
Guide lines and safety lines have been woven into the web to protect the builder, lest it becomes a victim of its own device.
There are also signal lines built into the design to facilitate the monitoring of the massive web.
The ensnared prey in its struggle to escape causes vibrations to be transmitted through the signal lines, thereby unwittingly hastening an untimely death.
The sun had just set and we were gathered outside the Rainforest Cafe waiting for Joseph Koh, affectionately known as the Spiderman, to guide us on a spider hunting night walk along the Red and Blue Trail at the Permai Rainforest Resort.
A couple of days earlier, the expert on Southeast Asian spiders had presented the Malaysian Nature Society Kuching Branch with a very interesting talk on the defence strategies of spiders.
The audience was so captivated by the arachnids and their webs that most of those who attended the talk turned up for the three- hour night walk on a weekday.
Koh was pleased that we had found a tent web. Not all spiders construct webs.
For those that do, web architecture is species specific.
Hence, there are various types of webs ranging from a minimalist single strand ‘clothesline’ to the convoluted three- dimensional ‘circus tent’.
The net-casting spider (Deinopidae family) spins an unusual web that it suspends between its front legs to catch prey. It gives the impression that it is holding the net, casting it over potential prey such as ants, beetles, crickets and other 
spiders. One of the aims of the 
walk was to catch the Nephila spider or golden orb web spider in action 
The Nephila constructs impressive webs that come complete with early warning systems on the outer edges to alert the arachnid of incoming prey or guard against spider hunting predators.
Just a few metres from the cafe, we stumbled upon a beautiful horizontal web that was perfectly displayed for photography.
I was doubtful my humble instant camera could pick up the fine silk threads in the dim light when Koh produced a cunning solution to aid photography; a fine mist of cornstarch dusted over the delicate structure. 
“It helps to enhance the web,” he said with a twinkle in his eye as we clicked away with our cameras. 
Spiders that hunt at night have excellent night vision adapted for nocturnal predation. As we walked along the trail, we saw a great number of them hiding under leaves and on trees.
Koh taught us the ‘eye shine’ technique to spot spiders in the dark. 
We would not have been able to see any spiders at all if we held our torches normally.
The torch has to be held 
at eye level. The eyes of the spider reflect light well to produce ‘eye shine’.
In the dark velvet night, the spiders were exposed looking very much like glittering jewels.
Koh wanted to show us just the bigger spiders as they are more spectacular to the layman.
We managed to identify several spider species such as the carnivorous huntsman spider, lichen spider, and a Ctenus species just by staying on the trail.
Spiders not identified in the field were collected for further study. Collecting the spiders requires technique as these creatures possess exceptional agility and speed to jump away to safety.
It was well past 11pm by the time we left the resort. Although we did not see the golden orb
web spider spinning its trap, we were not disappointed as we had a few treats that evening.
There were two green snakes by the side of the trail in the trees above us, a gecko on a tree trunk, a tiny frog whose length approximated one centimetre, a centipede, stick insects and a couple of trilobite larvae.
The trilobite larvae were an entomological enigma for a century in the scientific world until the puzzle was solved by a Swede entomologist in the 1920s in the rainforests of Sarawak.

BIG STAR: A carnivorous huntsman spider was among spiders spotted on the trail.

We also had an unexpected encounter; that of a spider eating another of its kind. Needless to say, both the victor and the vanquished were no match for the Spiderman, who caught them with his dollar scoop net from Tesco.

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