Docent Informations
What does "docent" mean?
We are a young group. The pioneers started the group in April 1997. Since then, we have grown modestly to 93 docents. The Night Safari Volunteer Rangers were brought under the Docent Programme in March 1999.
The docents are self-run by a committee of docents which co-ordinates inputs from all docents and liaises with the zoo management to put into motion the group's activities.
A docent newsletter is issued every two months so docents can keep up with the latest in zoo happenings and docent activities. Sprinkled with inspiring stories and amusing anecdotes, the Docent Deliberations is always a great read! We also constantly undertake research projects to expand and update our knowledge as well as explore new areas of interest.
Singapore Zoological Gardens Docents
GOLDEN ORB WEB SPIDER (Nephila spp)

Webs of steel: The Golden Orb Web Spider is not the largest spider, but makes the largest and strongest web. It gets its name from the golden colour of its silk. The web can run from the top of a tree 6m high and up to 2m wide. Unlike other spider webs, the Golden Orb Web Spider's web is not dismantled often and can last several years.

 

Designed to catch large flying insects, the web is slightly angled. It is not a perfect wheel and is usually off-centre. To make its web, the spider releases a thin thread into the wind. When it catches on something, the spider walks along it trailing a stronger non-sticky thread. It repeats the process in the centre of the line to form a strong Y-frame. Around this, it spins the rest of the web out of sticky capture silk.

 

VITAL STATISTICS

 

Size: females are 20cm across from toe to toe, with a body about 3-5cm; males are only one-tenth as big, at 5-6mm.
Metamorphosis: Incomplete, no pupal stage. Hatchlings look like miniature adultes. Females mature in 8-10 months.

Distribution: Tropical areas from Africa, India, China, Japan across Southeast Asia to Northern Australia and the South Pacific islands.
Habitat: Rainforest, secondary vegetation and mangroves.

Classification: Belongs to the family Araneidae which build orb-webs. Members of 2 other families also build orb webs (Tetragnathidae and Uloboridae) but these have hairy legs.
More about spiders ...
Spiders in general
Ingenious uses of silk

Tarantulas

 

The silk is so strong that it can trap small birds, which the spider doesn't eat. These trapped creatures often destroy the web by thrashing around. To avoid such damage, the spider often leaves a line of insect husks on its web (like the safety strip across glass doors!); or builds smaller barrier webs around the main web.
Sweet nothings: The male is many times smaller than the female, some are 1,000 smaller! There are suggestions that it is not a case of the males being dwarves, but the females being giants! The male is so tiny that he can live on the female's web, stealing her food, without her even noticing him. She may not even notice that he has crept up and inseminated her! Nevertheless, just to be sure, he usually does the deed when she is feeding. In some, mating can take up to 15 hours! The female lives only slightly longer than the male.

 

Spiderlings: The female spins a sac for her eggs, digs a pit and buries the egg sac under debris and soil. Spiderlings hatch with their eggyolks still attached and don't have fully developed mouthparts, venom glands, digestive tracts or spinning organs. They may stay together at this stage. When they are fully developed, they have to disperse or they will cannibalise each other. Free-loading on the web: Golden Orb-web Spiders in Queensland (Nephila plumipes) often have small silvery coloured spiders (Argyrodes) living in their webs which get most of their food by stealing the Orb-web Spider's food. To steal the food, they may attach a thread to the food item, then cut it free from the web and swing away with the stolen item "Tarzan-style". They can steal prey items that 30 times heavier than themselves.

 

Role of the Golden Orb Web spider: Like other predators, the spiders control the population of prey. The Golden Orb Web Spider's venom is generally harmless to humans and they rarely bite even if we blunder into and destroy their webs. The bite is just a scratch. They are clumsy on the ground.

 

In fact, in modern times, Orb-web Spider silk is set to become a major product. The silk is almost as strong as Kevlar, the strongest man-made material which is drawn from concentrated sulphuric acid. In contrast, spider silk is drawn from water. If we could manufacture spider silk, it would have a million uses from parachutes, bulletproof vests, lightweight clothing, seatbelts, light but strong ropes, as sutures in operations, artificial tendons and ligaments. Studies are now being done to have genetically engineered plants produce fluid polymers which can be processed into silk! Spiders are not used to produce silk fabric because Silkworm Moth caterpillars produce twice as much silk and are easier to manage (for example, they don't each other up!!)


Further informations in german can be found here!

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