Nursery Web Spider, American Nursery Web Spider
Pisaurina mira
Pisauridae (Nursery Web Spiders), Order Araneae. They are known for their unique maternal care behavior.
Physical Description
A robust, elegantly proportioned spider with a long, tapering abdomen. The body is covered in fine, velvety hairs. Females are significantly larger than males, with a swollen abdomen particularly visible in this specimen, suggesting she may be carrying eggs.
Size Estimate
Body length is typically 12-19mm for females; leg span can reach 50-75mm (2-3 inches). This specimen appears to be a fully grown adult female.
Coloration & Markings
Extremely variable ranging from tan to reddish-brown. This individual displays a classic wide, dark brown median stripe running from the head to the end of the abdomen, bordered by lighter tan edges. The sides of the abdomen are a lighter grayish-brown.
Web Type
They do not use webs to catch prey. However, females build a 'nursery web'—a protective silk tent among leaves—to house their egg sac just before the spiderlings hatch.
Eye Arrangement
Eight eyes arranged in two rows. The bottom row is slightly curved (recurved), and the eyes are fairly uniform in size, providing excellent vision for active hunting.
Leg Characteristics
Long, spindly, and powerful legs suited for running. They often rest with the first two pairs of legs held close together and stretched forward, creating a distinctive 'X' or four-legged appearance.
Venom & Safety Information
Venom Information
Possesses a mild venom used to immobilize insect prey. It is not considered toxic to humans and lacks any necrotic or neurotoxic components of medical concern.
Medical Significance
Harmless. A bite might cause localized redness or minor swelling similar to a bee sting, but this is rare as they are not aggressive toward humans. No medical treatment is usually required.
Safety Recommendations
No special precautions needed. If found in the home, they can be easily moved outside using a cup and a piece of paper. They are more beneficial in the garden where they can hunt pests.
Habitat & Behavior
Habitat & Range
Common throughout Eastern North America, from Ontario down to Florida and west to the Great Plains. They prefer tall grass, shrubs, and the edges of wooded areas where they can blend into foliage.
Behavior & Temperament
Active diurnal hunters that roam foliage rather than waiting in a web. They are generally shy and will flee if disturbed, but females can be protective when guarding a nursery web.
Diet & Prey
Generalist predators feeding on various insects, including flies, moths, and other smaller spiders. They use their speed and strong legs to overpower prey rather than silk.
Seasonal Activity
Most active from late spring through mid-summer. Egg sacs are commonly seen in early summer, and nursery webs are most frequent in July and August.
Description
A graceful and fascinating hunter often found in gardens and brush. It is easily recognized by its long legs and the dark 'racing stripe' down its back. Its name comes from the specialized silk tent it constructs to protect its young.
Key Features
Wide longitudinal dorsal stripe, tapering abdomen, specific resting posture with forward legs paired together, and the absence of a capture web.
Similar Species
Often confused with Wolf Spiders (Lycosidae), but Wolf Spiders carry egg sacs attached to their spinnerets at the rear. Also similar to Fishing Spiders (Dolomedes), which are usually larger and found near water.
Life Cycle
Females carry their large, spherical egg sacs in their chelicerae (mouthparts). Before hatching, the mother builds a silk nursery and stays nearby to guard the spiderlings until their first molt.
Ecological Importance
Significant natural pest control in gardens and meadows, helping to manage populations of agricultural pests and biting flies.
Conservation Status
Not evaluated by IUCN, but considered common and stable throughout its range with no immediate threats.
Interesting Facts
The female P. mira is known to be less likely to eat the male after mating compared to some other spiders, though males often use silk to tie her legs down during the process to ensure their safety.
Photography Tips
Capturing the spider from a top-down angle is best for identifying the dorsal stripe. Use a macro lens if possible to show the velvety texture and eye arrangement.
Identified: 2026-05-28T21:26:02.053662