Identify a Nursery Web Spider

The nursery web spider (Pisaurina mira) is called so because the female makes a silken nursery web for its young. These common spiders are large and hairy and are often confused with the Identify-a-Wolf-Spider. Their coloration is quite varied compared to most spiders, making them harder to identify than many other species.[1] Still, with a little knowledge and practice, you can identify a nursery web spider.

Steps

Observing the Physical Features

  1. Look for large spiders. The nursery web spider is one of the largest true spiders.[2] They are so big that they are sometimes mistakenly thought to be close relatives of the tarantula.[3]
    • The nursery web spider's body is typically about a quarter of an inch to an inch in size, but it may spread its legs out to as far as three inches.[4]
  2. Take note of coloration. Although there are several different variations in coloring, nursery web spiders generally have a base color that is tan, gray, beige, or buff, with darker brown stripes or other markings.[1]
    • Close inspection of the legs of these spiders will reveal small black spines sticking out.
  3. Examine the spider's eyes. Nursery web spiders have eight eyes. They appear in two horizontal rows. The bottom row is nearly straight, while the top row curves upward forming a "u" shape.[1]
    • The eyes of the upper row are somewhat larger than the lower one.
    • Examining the eyes, if you can get close enough to do so, is a good way to differentiate between the nursery web spider and the wolf spider, which have a different arrangement of eyes. Specifically, wolf spiders have three rows of eyes.[5]
  4. Look at the shape of the spider's body. The nursery web spider has a slender body.[6] Its abdomen is widest in the middle and tapers toward the rear.[1]
    • Male nursery web spiders are typically very slender. An egg-bearing female, however, may have a very large abdomen.

Watching Habits and Behaviors

  1. Watch for an egg sac. Possibly the easiest way to identify a female nursery web spider is to watch for any spiders that are carrying an egg sac. A nursery web spider will carry her eggs in her fangs until they are nearly ready to hatch.[7]
    • The egg sac looks like a tiny white golf ball. It typically contains a few hundred eggs.[4]
    • The spider will carry the egg sac underneath her body.[8]
  2. Look for a nursery web. When it is almost time for the eggs to hatch, the female spider will spin a protective nursery web. This tangled web is usually spun in high weeds or low shrubs, with the egg sac itself suspended inside a leaf.[7]
    • After spinning the nursery web, the mother spider will stand guard over it until the eggs have hatched.[4]
    • The nursery web spider will shelter the young spiders until they are ready to fend for themselves.
  3. Watch hunting behavior. Nursery web spiders, unlike many other species, do not spin webs for hunting purposes. Instead, these spiders hide in wait for prey (typically insects) and then spring out quickly to catch it.[6]
    • Instead of entangling insects in a web, the nursery web spider simply overpowers and subdues its prey.[1]
    • These spiders hunt both by day and by night.
  4. Observe posture. A nursery web spider, while at rest, will often adopt an "X" shaped posture, holding its front and hind pairs of legs together.[1]

Knowing the Nursery Spider's Range and Habitat

  1. Learn the nursery web spider's range. Nursery web spiders are quite common across much of North America. They are most commonly found in the eastern part of the US and southeastern Canada.[1]
    • People disagree about how far west these spiders can be found. Some say they have been found all the way out in the states of the West Coast.[7] Others disagree. It is safe to say, however, that they are less common in western states and provinces.
  2. Look for them in their normal habitats. You can look for nursery web spiders in a variety of different types of habitats. They are often found near water.[4] They are known to inhabit the following areas:
    • Woodlands
    • Farms and gardens
    • Grasslands and heaths
    • Old fields
    • Rocky areas along the edge of streams and other water
  3. Watch for them in the right season. Nursery web spiders mature in late spring and reproduce in the summer.[1] They are most often seen between the beginning of May and the end of July.[6]
    • Juvenile spiders will hide under loose bark or rocks in the fall and will remain there for protection during the winter. They will emerge in the spring mature.
    • Like most spiders, the lifecycle of this spider is about year.

Tips

  • Nursery web spiders are closely related to both wolf spiders and fishing spiders. Fishing spiders are very similar, but hunt aquatic prey and are found almost exclusively near water.[3] Learning to tell the difference between these three varieties of spider will make nursery web spiders easier to identify.

Warnings

  • Nursery web spiders are not aggressive to humans, but the female guards her egg sac ferociously, so interfering or tampering with it could result in a bite.
  • A nursery web spider bite is likely to be large and painful due to the size of this spider. However, it is not considered dangerous.[3]

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Sources and Citations

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