Wolf Spiders

( Family Lycosidae )

Characteristics

SIZE: Wolf spiders come in many sizes, with most having a body size ranging from one-quarter of an inch to more than 1 ½ inches in length. The largest species may have a leg measuring up to three inches or more, leading many homeowners to mistake them for tarantulas.

COLOR: Most wolf spiders are brown, although some may appear black.

BEHAVIOR: Wolf spiders are active hunters that search for prey during the day or night, depending on the species. These common spiders may live in significant numbers around homes and other buildings, especially those structures that have lush landscaping. Wolf spiders enter underneath doors or through cracks in the exterior walls. Wolf spiders are unique in that they carry their egg sacs from the tip of their abdomens attached to the spinnerets. The young spiderlings also ride on the mother’s back for a few days after hatching. Bites involving wolf spiders are rare and are not dangerous.

Habitats

Outdoors, wolf spiders occupy a wide variety of habitats, usually at ground level. They will be common in heavy ground covers, such as ivy or monkey grass, and can be found beneath stones and other items, as well as within cracks between landscape timbers. They do not breed in homes, and usually only one to a few will be seen inside.

Tips for Control

The best approach for controlling wolf spiders is through placement of sticky traps to capture the few spiders that may have entered. Maintaining sticky traps behind furniture, to either side of exterior doors and in the garage is an excellent way to intercept most spiders as they enter. Steps that should be taken to prevent new spiders from entering include:

  • Removing or limiting heavy, ground-covering vegetation near the building.

  • Sealing cracks and holes in the building's exterior.

  • Installing tight-fitting screens on all attic and foundation vents.

  • Sealing holes around pipes indoors to prevent spiders from entering the living spaces by following plumbing lines in basements and crawl spaces.

Where wolf spider invasions are persistent, a professional should be consulted to conduct a thorough inspection and recommend possible treatments.

Ask the Entomologist: Stephanie L. Richards, PhD, Medical Entomologist - Wolf Spiders: Friend or Foe?

Facts about Wolf Spiders

Wolf spiders, depending on species, are usually a dark brown color and are typically around one inch long. They do not build webs and are predators of other insects, hence they can be considered beneficial.

They are found in woodland leaf litter, under rocks in the garden, in agricultural fields, and other habitats. Occasionally, they may be found indoors, either accidentally or if insects are present that may provide suitable prey for the wolf spiders to hunt. They usually are not aggressive toward humans. However, if a person is bitten by a wolf spider, swelling and irritation at the bite site may occur. Consultation with a medical professional may be required, especially if the victim is unsure if the bite was due to a wolf spider or other spider species that may be more dangerous.

In mid-summer (timing depends on region), female wolf spiders may be observed carrying egg sacs (for 20-40 days) or hatched spiderlings (baby spiders) on their backs. While egg care is common in all spiders, carrying eggs and young around is unusual in invertebrates, such as spiders, and some scientists are studying chemical cues that may be associated with this behavior (Ruhland et al. 2017).

Tigrosa helluo (also called Hogna helluo) and Pardosa milvina are common species of wolf spiders in the United States. Tigrosa helluo sits and waits for prey to approach before attacking, while P. milvina hunts by actively seeking out prey.

Pardosa milvina is much larger than T. helluo and, along with being a predator of insects, it is also a predator of T. helluo (Persons et al. 2001).

Why are they called “wolf” spiders?

Scientists previously thought that wolf spiders hunted for prey in groups, like wolves, hence wolf spiders are classified in Family Lycosidae (in Greek, Lycos means wolf).

Spiders Have Personalities

Did you know that wolf spiders (even within the same species) have different personalities? A study was carried out on P. milvina in which miniature ecosystems were set up containing different mixtures of pests/prey and predators (Royaute and Pruitt 2015). The study showed that a mixture of spider personalities (both inactive and active predators) performed at least as well (and in some cases, performed better) at reducing pest/prey populations as having a spider population composed of only active predators. However, pea aphids showed lower abundance, no matter what spider personalities were present (Royaute and Pruitt 2015).

Clearly, predator/prey dynamics depend on a variety of factors and this should be studied further as this information could be useful to programs interested in implementing biological control in different environments.

References

Persons MH, Walker SE, Rypstra AL, Marshall SD (2001). Wolf spider predator avoidance tactics and survival in the presence of diet-associated predator cues (Araneae: Lycosidae). Animal Behaviour 61: 43-51.

Royaute RL, Pruitt JN (2015) Varying predator personalities generates contrasting prey communities in an agrosystem. Ecology 96: 2902-2911.

Ruhland F, Schulz S, Trabalon M (2017) Variations of cocoon external lipids during wolf spiderlings’ development. Journal of Comparative Physiology 13: doi: 10.1007/s00359-017-1194-4.

RELATED ARTICLES