American Nursery Web Spider
Pisaurina mira
Pisauridae (Nursery Web Spiders), Order Araneae. Key family characteristics include similar eye sizes arranged in two curved rows, robust bodies, long spiny legs, and the female's unique habit of carrying her egg sac in her jaws before constructing a specialized nursery tent.
Physical Description
The body is elongated and somewhat flattened, featuring a long, tapering abdomen and a distinct cephalothorax with pale central bands. The spider has a slightly hairy texture and elongated proportions built for rapid movement across vegetation and vertical surfaces.
Size Estimate
Body length ranges from 12 to 18 millimeters for females, with a leg span extending up to 50 to 75 millimeters.
Coloration & Markings
Predominantly brown or grayish-brown, featuring a prominent, pale median stripe running down the length of the carapace and abdomen, often bordered by darker brown bands or wavy margins.
Web Type
These spiders do not use webs to capture prey. Instead, females construct a silken nursery web (tent) by folding leaves together when they are ready to lay eggs and protect their young.
Eye Arrangement
Equipped with eight eyes of roughly equal size, arranged in two distinct, slightly curved or recurved rows across the face.
Leg Characteristics
Long, robust legs featuring prominent dark spines and subtle banding. They are typically held outstretched in a characteristic spread-eagled posture when resting on surfaces.
Venom & Safety Information
Venom Information
Contains mild, non-neurotoxic venom used primarily to immobilize small invertebrate prey. It is not dangerous to humans.
Medical Significance
Not medically significant. Bites are extremely rare, usually only occurring if the spider is directly trapped or squeezed against skin, resulting in mild localized pain similar to a mild bee sting.
Safety Recommendations
No special safety measures required. If found indoors, it can be gently guided into a container and relocated outside to the nearest garden or shrubbery.
Habitat & Behavior
Habitat & Range
Found throughout eastern and central North America. They prefer tall grasses, low shrubs, woodland edges, and gardens, and are frequently encountered on the exterior walls of buildings near vegetation.
Behavior & Temperament
Active nocturnal or crepuscular hunters that rely on stealth, vibration detection, and rapid bursts of speed to catch prey. They are generally docile and will attempt to flee rather than bite when disturbed.
Diet & Prey
Carnivorous predators feeding on a wide variety of insects including flies, beetles, grasshoppers, and moths, captured by actively chasing and pouncing on them.
Seasonal Activity
Most active from late spring through autumn, with mating typically occurring in early summer and the nursery webs appearing mid-to-late summer.
Description
The American Nursery Web Spider is a remarkable hunter recognized by its elongated body, pale central stripe, and long spiny legs. Rather than building a traditional web to trap food, it roams freely through foliage. Its fascinating maternal care involves carrying the egg sac and building a silken nursery tent for the emerging spiderlings.
Key Features
Elongated body shape, prominent pale central stripe running down the carapace and abdomen, long spiny legs, and lack of an orb or sheet web for hunting.
Similar Species
Often confused with Wolf Spiders (Lycosidae) and Grass Spiders (Agelenidae). Unlike wolf spiders, nursery web spiders have eyes of roughly equal size. Unlike grass spiders, they do not build funnel webs.
Life Cycle
Females carry their round egg sacs in their chelicerae until just before hatching, at which point they spin a silken nursery tent, place the sac inside, and stand guard until the spiderlings disperse after their first molt.
Ecological Importance
Serves as an effective natural pest control agent by keeping insect populations in check, while also functioning as an important food source for birds, amphibians, and small mammals.
Conservation Status
Secure and widespread throughout its natural geographic range, with stable populations and no special conservation status.
Interesting Facts
Females can appear intimidating due to their size, but they exhibit complex maternal care by carrying their egg sacs in their jaws and constructing sophisticated leaf-tent nurseries.
Photography Tips
Photograph from a dorsal angle to clearly capture the distinct pale stripe and markings on the carapace and abdomen. Use a macro lens in natural indirect light for best clarity.
Identified: 2026-09-02T01:47:16.795954