Orb weaver spiders, members of the Araneidae family, are a common and widespread group of arachnids found globally, except in the Arctic and Antarctic regions. They are known for constructing intricate, circular, wheel-shaped webs, which gives them their “orb” name. These spiders are important predators in many ecosystems.
Key Features and Web Construction
Orb weaver spiders exhibit a wide range of appearances, size, and color. They generally have eight similar eyes, hairy or spiny legs, and often possess a relatively large, sometimes round or lobed abdomen that can display unique patterns or colors. Many nocturnal species are typically brown or gray, while some diurnal orb weavers showcase vibrant yellow, orange, or black markings.
The most defining characteristic of orb weavers is their impressive circular web, designed to efficiently capture flying insects. These webs begin with the spider releasing a silk thread into the air, allowing the wind to carry it until it attaches to a surface, forming a bridge line. After securing this initial line, the spider drops another thread from the center to create a “Y” shape, establishing the core framework. From this central point, non-sticky radial spokes are extended outward, resembling the spokes of a wheel.
The spider then lays down a temporary spiral of non-sticky silk to support itself while constructing the final, sticky capture spiral. This sticky silk, coated with glue-like droplets, is laid from the outside of the web inward, designed to ensnare prey.
Where They Live and What They Eat
Orb weaver spiders are highly adaptable and can be found in a variety of outdoor environments. Their preferred habitats include gardens, fields, forests, and areas around human structures like fences, walls, and bushes. They strategically choose locations with abundant prey and suitable anchor points for their large webs, which can measure up to three feet in diameter.
As carnivores, orb weavers primarily feed on insects caught in their sticky webs. Their diet commonly includes small flying insects such as flies, moths, beetles, wasps, bees, and mosquitoes. When prey hits the web, the spider detects the vibrations, quickly moves to immobilize it with a bite of venom, and then wraps it in silk for later consumption.
Are Orb Weavers Dangerous?
Despite their sometimes large size and impressive webs, orb weaver spiders are generally not considered dangerous to humans. They are non-aggressive and tend to avoid people, preferring to flee or drop from their web if disturbed. Bites from orb weavers are rare and typically occur only if the spider feels directly threatened or is accidentally handled.
The venom of orb weaver spiders is designed to paralyze insects and is not medically significant to humans. An orb weaver bite is often compared to a mild bee sting, resulting in localized symptoms such as slight pain, redness, and minor swelling at the bite site. Numbness, itching, or a small raised bump may also occur. These symptoms are usually temporary and resolve on their own without the need for medical intervention.
Allergic reactions are exceptionally uncommon, but as with any bite, medical attention should be sought if symptoms worsen or cause concern. Orb weavers are beneficial predators that help control insect populations, making them a welcome presence in many ecosystems.