American Nursery Web Spider
Pisaurina mira
Pisauridae (Nursery Web Spiders), Order Araneae. Key family characteristics include the ability to walk on water surfaces and carrying egg sacs with their chelicerae rather than attaching them to a web.
Physical Description
Elongated body with a tapering, cigar-shaped abdomen. The cephalothorax is slightly wider than it is long, and the legs are long and robust, radiating outwards in a characteristic sprawling stance.
Size Estimate
Body length ranges from 12 to 20 millimeters for females, with males being slightly smaller. Leg span can reach up to 50 to 75 millimeters.
Coloration & Markings
Typically brown, tan, or grayish with highly distinctive dark brown or black longitudinal stripes running along the length of the carapace and abdomen, bordered by lighter cream or white bands.
Web Type
Nursery web spiders do not use webs to capture prey. Instead, females construct a specialized silken nursery tent in tall grass, bushes, or leaves just before their eggs hatch.
Eye Arrangement
Eight eyes arranged in two curved rows, all roughly equal in size, unlike the enlarged anterior median eyes of wolf spiders.
Leg Characteristics
Long, powerful legs featuring subtle dark banding and prominent spines. When resting on vertical surfaces, they often hold their front two pairs of legs held close together.
Venom & Safety Information
Venom Information
Contains mild neurotoxic venom used primarily to subdue insect prey. It is not considered dangerous to humans.
Medical Significance
Not medically significant. A bite may cause minor, localized pain and swelling similar to a mosquito bite, but they rarely bite humans.
Safety Recommendations
No special precautions needed. If found indoors, they can be safely gently relocated outside using a cup and a piece of card.
Habitat & Behavior
Habitat & Range
Found across eastern and central North America, typically inhabiting tall grasslands, shrublands, woodland edges, and frequently encountered on the exterior walls of buildings or in gardens.
Behavior & Temperament
Active hunters that rely on excellent eyesight and touch to detect prey. They are non-aggressive toward humans, preferring to flee or drop to the ground when disturbed.
Diet & Prey
Generalist predators feeding on a wide variety of insects, including grasshoppers, flies, beetles, and occasionally small aquatic prey.
Seasonal Activity
Most active during the warm spring and summer months, with mating occurring in early summer and nursery webs appearing mid-to-late summer.
Description
The American Nursery Web Spider is a striking, slender hunter known for its bold longitudinal stripes and fascinating maternal care behaviors. Often found patrolling garden foliage or the sides of homes, this agile arachnid plays an important role in controlling insect populations.
Key Features
Distinctive dark longitudinal stripes running the entire length of the body, cigar-shaped abdomen, and the habit of carrying egg sacs in the jaws.
Similar Species
Wolf spiders (Family Lycosidae), which can be distinguished by their prominent eye arrangement (larger anterior median eyes) and the fact that wolf spiders carry egg sacs attached to their spinnerets.
Life Cycle
Females carry their spherical egg sacs in their jaws until just before hatching, at which point they build a silken nursery web, guard it fiercely, and mate during the late spring or summer months.
Ecological Importance
Acts as an effective natural pest control agent by consuming large numbers of herbivorous and nuisance insects within gardens and natural habitats.
Conservation Status
Secure and widespread throughout its native geographic range with stable populations.
Interesting Facts
Male nursery web spiders often present potential mates with a silk-wrapped nuptial gift, such as a captured insect, to distract the female and reduce their risk of becoming cannibalized.
Photography Tips
Shoot from a parallel or slightly elevated angle to capture the distinct longitudinal stripes clearly. Use natural, diffused lighting and maintain a safe distance to avoid startling the spider.
Identified: 2026-09-25T18:07:41.912189