| 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. 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. 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!!). |
