Garden spiders are essential contributors to the balance of garden ecosystems, primarily known for their pest control capabilities. These spiders consume a wide variety of insects, including many common garden pests. Understanding their diet and habits can help gardeners appreciate their role and create environments that attract these beneficial creatures.
Garden Spiders as Pest Control Allies
Spiders are among the most effective natural pest controllers in gardens. Their diet consists mainly of common garden insects such as aphids, caterpillars, beetles, mosquitoes, and flies. Without spiders and other beneficial predators, these pests could thrive unchecked, causing significant damage to plants and crops.
Diverse Diets of Different Spider Types
Different species of spiders have different hunting strategies and prey preferences. Orb-weaver spiders, for instance, construct large, circular webs between plants to capture flying insects like flies, moths, and mosquitoes. Other spiders, such as wolf spiders and jumping spiders, are active hunters, patrolling the garden floor and pouncing on insects hidden in leaves and mulch.
Understanding the Yellow Garden Spider (Argiope aurantia)
The yellow garden spider, scientifically known as Argiope aurantia, is a common species found throughout the contiguous United States, Hawaii, southern Canada, Mexico, and Central America. This spider, also known as the black and yellow garden spider, golden garden spider, writing spider, zigzag spider, zipper spider, black and yellow argiope, corn spider, Steeler spider, or McKinley spider, is easily identifiable by its distinctive yellow and black markings on the abdomen and a mostly white cephalothorax. Its scientific Latin name translates to "gilded silver-face," reflecting its striking appearance.
Habitat and Web Construction
Yellow garden spiders prefer open, sunny fields where they can stay concealed and protected from the wind. They build distinctive circular webs, up to 2 feet (60 cm) in diameter, characterized by a dense zigzag of silk known as a stabilimentum in the center.
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Purpose of the Stabilimentum
The purpose of the stabilimentum is debated. Some theories suggest it serves as camouflage for the spider, attracts insect prey, or warns birds of the web's presence.
Web Construction Process
To construct the web, the spider stretches several radial lines among four or five anchor points, which can be more than three feet apart. These lines meet at a central point, and the spider then creates a frame with additional radial lines. The center is filled with a spiral of silk, leaving a small gap between the spiral rings, starting from the innermost ring and moving outward. The spider bends the radial lines slightly together while applying the silk spiral to ensure the web is taut.
Differences Between Male and Female Webs
Female yellow garden spiders build significantly larger webs than the small zigzag webs constructed by males, which are often found nearby.
Hunting Behavior
The spider occupies the center of the web, usually facing straight down, waiting for prey to become ensnared. If disturbed, it may drop from the web and hide on the ground.
Diet of the Yellow Garden Spider
Yellow garden spiders help control insect pests by feeding on insects that get caught in their webs. They rely on vibrations to detect trapped prey and use venom to immobilize the insect before wrapping it in silk. Their diet includes flying insects like mosquitoes, flies, and moths, as well as larger bugs such as grasshoppers and beetles.
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The Banded Garden Spider
The female banded garden spider is similar to its close relative, the black-and-yellow garden spider. However, the banded garden spider is slightly smaller overall, with a pointier hind end. Also, the abdomen is patterned with many thin silver and yellow transverse lines and thicker black, spotty lines. The cephalothorax (head) is small and covered with silvery hairs. This spider eats a variety of insects, including grasshoppers, cicadas, and katydids. Once an insect is caught in the sticky strands of the web, the spider often shakes the web to make the insect more fully ensnared. Then, the spider further subdues her prey by injecting it with venom and wrapping it securely in sheets of silk.
Garden Spider's Hunting Techniques
As members of the orb weaver family, garden spiders spin intricate orb webs with a visible X-shaped zig-zag pattern to trap prey. This pattern is believed to help birds avoid flying into the web. The garden spider waits for flying insects, grasshoppers, and beetles to get tangled in the web. Once trapped, it bites its prey, injecting venom to paralyze it, and then wraps the prey in silk for later consumption.
Benefits of Garden Spiders
Garden spiders are beneficial to have around yards and gardens because they eat annoying pests like mosquitoes, gnats, and flies. This makes them welcome guests for many gardeners and people who spend time outdoors.
Life Cycle and Behavior
Female garden spiders can create up to four egg cases, each containing over 1,000 eggs that hatch in late fall or early spring. As winter approaches, the females die. These spiders are most noticeable in the fall, when they grow larger after feeding on insects throughout the summer. In the fall, they mate and lay eggs before dying.
Reproduction
Yellow garden spiders breed twice a year. Males roam in search of females, building small webs near or within the female's web. They court the females by plucking strands on her web and often have a safety drop line ready in case the female attacks. The male uses the palpal bulbs on his pedipalps to transfer sperm to the female.
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Egg Laying
The female lays her eggs at night on a sheet of silky material, covers them with another layer of silk, and then adds a protective brownish silk. She uses her legs to form the sheet into a ball with an upturned neck. Egg sacs range from 5/8" to 1" in diameter and are suspended near the web or placed several feet away. Each spider produces one to four sacs, each containing over a thousand eggs. Females produce clutches containing approximately 978 eggs.
Spiderlings
In the spring, the young spiders exit the sac. They are tiny and resemble dust gathered inside the silk mesh.
Creating a Spider-Friendly Garden
Creating a garden environment that welcomes spiders can enhance natural pest control. To attract spiders, avoid using broad-spectrum insecticides, which harm beneficial creatures like spiders as well as pests.
Preferred Habitats
The yellow garden spider prefers sunny, undisturbed spaces with tall grass, flowering plants, and shrubs, providing the structure needed to build webs and stay hidden from predators. These spiders rely on both cover and open space to trap prey and are often found stretched between plants or anchored near fences.
Garden Spider Bites
Argiope spiders are not aggressive and will only bite if grabbed. Their venom contains polyamine toxins with therapeutic potential. A bite from Argiope aurantia is comparable to a bee sting, causing redness and swelling, but is not considered an issue for healthy adults.
First Aid for Spider Bites
If bitten by a garden spider, wash the area with soap and warm water. Spider bites can cause pain, redness, and itchiness. An over-the-counter antihistamine can help relieve symptoms. Avoid scratching the bite to prevent infection.
When to Seek Medical Care
Seek immediate care if you suspect an allergic reaction or experience trouble breathing, difficulty swallowing, expanding redness and swelling, red streaks around the wound, or severe pain or abdominal cramping.
Dispelling Myths About Garden Spiders
Many people fear garden spiders, but most of these fears are unfounded. Garden spiders are generally harmless to humans and are more interested in catching pests than bothering gardeners. The idea of humans being caught in spider webs and devoured is a common movie trope but has no basis in reality.