American Nursery Web Spider
Pisaurina mira
Pisauridae (Nursery Web Spiders), Order Araneae
Physical Description
A medium-to-large spider with an elongated, slender body. The cephalothorax and abdomen are roughly similar in width, with the abdomen tapering toward the rear. They have a fine, velvety texture due to dense, short hairs.
Size Estimate
Body length typically 10-19mm for females; leg span can reach 50-75mm (2-3 inches). This specimen appears to be an adult female based on body proportions.
Coloration & Markings
Variable but typically tan to reddish-brown. It features a prominent, dark brown longitudinal median stripe running from the front of the head to the tip of the abdomen, often bordered by thin white or cream-colored lines. The edges of the stripe may be straight or wavy.
Web Type
They do not use webs for hunting but construct a 'nursery tent' out of silk and folded leaves to harbor their young after the egg sac begins to hatch.
Eye Arrangement
Eight eyes arranged in two rows. The posterior row is slightly recurved (curving backward), and the eyes are relatively equal in size, providing excellent vision for hunting.
Leg Characteristics
Long, tapered legs with prominent spines. In a resting position, they often hold the first two pairs of legs together, pointing forward, which aids in camouflage against twigs or leaves.
Venom & Safety Information
Venom Information
Possesses a protein-based venom used to immobilize insect prey. It is not considered toxic to humans.
Medical Significance
Harmless to humans. Bites are rare and usually only occur if the spider is pinched or if a female is defending her egg sac. Symptoms are typically limited to mild local pain and swelling similar to a bee sting.
Safety Recommendations
No special precautions needed. To relocate, gently nudge into a container. They are beneficial for gardens and should be left alone to hunt pests.
Habitat & Behavior
Habitat & Range
Common across Eastern North America, from Ontario to Florida and west to the Rockies. Found in tall grass, shrubs, gardens, and forest edges.
Behavior & Temperament
Active wandering hunters that do not use a web to catch prey. Diurnal and nocturnal. Generally shy and will retreat if disturbed, but females are highly protective of their nursery tents.
Diet & Prey
Generalist predators feeding on various insects, including flies, moths, and beetles. They use an ambush strategy, pouncing on prey and delivering a quick bite.
Seasonal Activity
Most active from late spring through late summer. Adult females are most visible in July and August when guarding nurseries.
Description
An elegant and distinct inhabitant of North American gardens, the American Nursery Web Spider is a master of camouflage. Often seen resting on large leaves like the hydrangea pictured, it blends perfectly with dried foliage or stems. It is a beneficial predator that provides excellent natural pest control.
Key Features
Bold dark central stripe on a tan body; long legs held in pairs; carrying of the egg sac with mouthparts; construction of leaf-integrated nursery tents.
Similar Species
Often confused with Wolf Spiders (Lycosidae), but Wolf Spiders carry egg sacs on their spinnerets (rear). Also similar to Grass Spiders (Agelenidae), which have much longer, visible spinnerets and build funnel webs.
Life Cycle
Mating occurs in early summer. The female carries her large, globular egg sac under her chin, held by her chelicerae and pedipalps. Just before the spiderlings emerge, she builds a nursery web and guards it until the young disperse.
Ecological Importance
Significant apex invertebrate predator in garden ecosystems, helping to keep populations of leaf-eating insects in check.
Conservation Status
Not evaluated by IUCN, but considered stable and common throughout its range.
Interesting Facts
Mating involves a unique 'gift-giving' behavior where the male may offer the female a silk-wrapped fly to avoid being eaten, or he may wrap the female's legs in silk (veils) to temporarily restrain her during the process.
Photography Tips
Focus on the cephalothorax to capture the eye arrangement and the borders of the central stripe. Side profiles are excellent for showing how they carry the egg sac (if present).
Identified: 2026-07-09T23:10:14.969335