Golden orb-weaver spiders, known scientifically within the Nephila and Trichonephila genera, are also called giant wood spiders. They are known for their impressive size and the spectacular, golden-hued webs they construct. Recently, scientific classification shifted many species into the Trichonephila genus, but they are still collectively known as golden orb-weavers.
Identifying a Golden Orb-Weaver
A striking feature of the golden orb-weaver is sexual dimorphism, the dramatic size difference between sexes. Females are four to ten times larger than males, with a body length up to 2 inches (5.1 cm) and a leg span that can reach 20 cm across. In contrast, males are tiny, often measuring less than a quarter of an inch (around 5-6 mm) in body length.
The female’s appearance is distinct and colorful. Her body is elongated with a silvery-white cephalothorax (the fused head and thorax), and the abdomen is a shade of yellow or olive-brown, sometimes with yellow stripes or spots. One of their most recognizable characteristics is the presence of dense, hairy tufts or brushes on their long legs. These are particularly noticeable on juvenile females and tend to disappear as the spider matures.
The Signature Golden Web
The golden orb-weaver’s most known creation is its massive and durable web. These structures are often several feet in diameter, with anchor lines that can span over six meters. The web is asymmetrical, with the hub located closer to the top. This design creates a larger capture area in the lower portion, where most insects are intercepted.
The silk produced by these spiders has a golden yellow tint, derived from carotenoids and other pigments like xanthurenic acid. The golden hue serves a dual purpose. In direct sunlight, it can attract prey like bees, while in shaded areas, it provides camouflage by blending with surrounding foliage.
Beyond its color, the silk is known for its exceptional strength. The silk’s tensile strength is higher than a steel fiber of the same thickness. This strength allows the webs to withstand large insects like cicadas and locusts. The webs are so strong they have been known to ensnare small birds and bats.
Habitat and Behavior
Golden orb-weavers are found in warmer regions of the world, with a wide distribution across Asia, Australia, Africa, and the Americas. They thrive in tropical and subtropical climates, preferring moist habitats with dense vegetation to support their large webs. They build their webs in forests, gardens, and areas near surface water to intercept the flight paths of insects.
These spiders are diurnal and are permanent residents of their webs, performing constant maintenance. When a section of the web is damaged or loses its stickiness, the spider will consume that portion and re-weave it. Their diet consists mainly of flying insects. They use vibrations in the silk to locate their catch before immobilizing it by wrapping it tightly.
Other, much smaller spiders known as kleptoparasites are often present in the web. These tiny opportunists, from the Argyrodes genus, live within the orb-web and steal small prey from the host. The golden orb-weaver may tolerate these thieves, which can number in the dozens on a single web.
Venom and Bite Significance
While their large size can be intimidating, golden orb-weavers are not dangerous to humans. They are venomous, but their venom is specialized for subduing insects and is not medically significant to people. These spiders are reluctant to bite and will try to flee if disturbed.
A bite only occurs if the spider is provoked or pressed against the skin. In the rare event of a bite, symptoms are mild and localized. The effects are compared to a bee sting, resulting in temporary pain, redness, and swelling. The mechanical puncture from their fangs may cause initial discomfort, but the venom’s effects are short-lived.