| Photo Information |
Copyright: Peter Thomas (FunkyMunky)
![Silver Star Critiquer/Silver Note Writer [C: 42 W: 0 N: 32]](http://i1.treknature.com/misc/s-n-s.gif) (134) |
| Genre: Animals |
| Medium: Color |
| Date Taken: 2009-03-02 |
| Categories: Insects |
| Camera: Canon EOS 400D |
| Photo Version: Original Version |
| Date Submitted: 2009-03-05 3:19 |
| Viewed: 3395 |
| Points: 2 |
|
| [Note Guidelines] Photographer's Note |
On a recent visit to Kruger National Park we were fascinated by all the beautiful golden spider webs alongside the road and also at the lodge where we were staying. I got quite close while taking photos and I remember wondering if they were poisonous or how far they could jump!
Golden Orb Web Spider
Nephila maculata
Giant Wood Spider
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.
Female: 20cm across from toe to toe, with a body about 3-5cm; males are only one-tenth as big, at 5-6mm.
World distribution: Tropical areas from Africa, India, China, Japan across Southeast Asia to Northern Australia and the South Pacific islands.
Classification: Family Araneidae which build orb-webs. Nephila maculata is the largest of its genus.
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.
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.
Breeding: 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, often 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.
The female buries her eggs in the ground. First she digs a shallow hole with her strong mandibles and legs, which is then lined with woolly silk. She lays her eggs on this silk, covers it with another woolly layer then covers the whole assembly with camouflaging debris and soil. Laying can take 4 hours. 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.
Role in the habitat: Like other predators, the spiders control the population of prey. They are in turn preyed upon by other creatures such as birds. In New Guinea, some tribes consider them a tasty treat. 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.
Uses by humans: Tribal people have long used the webs of these spiders. In the South Pacific, the web silk is used to make fishing lures, traps and nets. In the Solomon Islands, the spider web is collected by winding it around sticks to make large sticky balls which are suspended just above the water. Needle fish are lured to jump out and get entangled in the ball. In Southeast Asia, people make a net by scooping up the web between a stick bent into a loop. Spider webs have been used as bandage to stop blood flow and used to make bird snares.
In modern times, the Golden Orb Web Spider's 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, bullet-proof 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 eat each other up!!).
From: http://www.naturia.per.sg/buloh/inverts/nephila.htm |
Miss_Piggy has marked this note useful
Only registered TrekNature members may rate photo notes. |
|
![Gold Star Critiquer/Gold Note Writer [C: 1400 W: 4 N: 2294]](http://i1.treknature.com/misc/g-n-g.gif)
(7411)