Pisaurina

Members of Pisaurina can be distinguished from wolf spiders (Lycosidae) by their eye arrangement—Pisaurina has all eyes essentially the same size, whereas wolf spiders have two enlarged posterior median eyes. They are also more likely to be found in vertical habitats (foliage, shrubs) rather than on the ground. Pisaurina dubia is distinguished by a central tuft of hair projecting from between the eyes like a tiny horn. Immature Pisaurina spend winter as sub-adults, making spring specimens smaller than typical mature nursery web spiders. Mature females of P. mira measure 12.5–16.5 mm in body length with a leg span of 35–45 mm; males are slightly smaller at 10.5–15 mm. Most mature individuals show a broad, dark longitudinal stripe on a light brown, beige, or grayish background, though some adults and immatures lack this stripe. The spider often rests with the first two pairs of legs held tightly together.

Pisaurina species inhabit vegetated areas including meadows, tall grass, bushes, shrubs, and forest understory. They are found along forest edges, among grapevines, and on weeds in open fields. Pisaurina dubia has been documented in diverse microhabitats: lawn grass, woodland litter and understory, barns on hay bales, exterior walls of homes (occasionally indoors), pitcher plants, Spanish moss (a bromeliad), sugarcane fields, and low vegetation in southeastern U.S. wetlands. Nursery webs are constructed amid foliage at least a few inches above ground.

The genus occurs in Canada (Ontario, Quebec), the United States, and Cuba. Pisaurina mira ranges from southern Ontario and Quebec to Florida, west to Minnesota, Nebraska, Kansas, Oklahoma, and the Rio Grande Valley of Texas. Pisaurina dubia occurs across the southern two-thirds of the eastern U.S. from New Jersey to Florida, west to eastern Nebraska, Kansas, Oklahoma, and Texas. Pisaurina brevipes and P. mira occur in both the USA and Canada; P. undulata is found in the USA and Cuba.

Pisaurina mira reaches maturity in spring, making adults conspicuous during this period. Mating occurs in mid-summer. Young overwinter as sub-adults in protected locations such as cracks, crevices, beneath loose bark, or under stones, becoming mature the following spring.

Females produce white spherical egg sacs carried in their jaws. Prior to spiderling emergence, the female constructs a nursery web—tangled silk enveloping a small section of foliage—where she suspends the egg sac. She guards both the sac and emerging spiderlings until they undergo one molt and disperse. In P. mira, offspring reach a sub-adult stage by autumn and overwinter, maturing the following spring.

Pisaurina are hunting spiders that do not build prey-capture webs, though they may produce minimal scaffolding at ambush sites. They sit motionless on foliage to ambush prey and may hunt actively, including visiting outdoor lights to capture attracted insects. They respond quickly to motion, either attacking prey or fleeing from threats. During mating, male P. mira employ a silken veil to bind the female's first and second pairs of legs while both are suspended from draglines; this wrapping behavior prevents postcopulatory sexual cannibalism. Females of P. mira that consume their mates produce heavier and longer-lived offspring than those that do not, indicating fitness benefits from sexual cannibalism when it occurs.

Pisaurina spiders function as generalist predators of insects and other arthropods. They are considered beneficial in agricultural and garden settings due to their predation on pest insects.

Pisaurina mira is among the most frequently submitted spiders for identification in some regions due to its large size and abundance in populated areas. Despite their intimidating appearance, nursery web spiders are not dangerously venomous to humans or pets. They occasionally enter homes or are found on building exteriors. Their predation on insects provides natural pest control in yards, gardens, farms, and orchards.

• Tibellus (Philodromidae)Slender crab spiders in this genus resemble small Pisaurina specimens, particularly sub-adult P. dubia in spring; both are lanky with striped patterns and found in similar habitats, though Tibellus are true crab spiders with different eye arrangement and leg posture.
• Wolf spiders (Lycosidae)Similar large size and ground-dwelling appearance, but wolf spiders have two enlarged posterior median eyes and are typically found on the ground rather than in vertical vegetation; Pisaurina has uniform eye size and prefers elevated perches.

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Bug Eric: A Nursery Web Spider, Pisaurina dubia
• Bug Eric: Spider Sunday: Nursery Web Spider
• Female nursery web spiders (Pisaurina mira) benefit from consuming their mate