The spider family Lycosidae (wolf spiders) includes 2396 described species according to Platnick (2013), ranking it among the most species-rich of the 112 spider families recognized by Platnick (only seven spider families include more than 2000 described species). Nearly 250 lycosid species are known from North America north of Mexico (Dondale 2005). Lycosids are among the most common and widespread spiders, ranging from the Arctic to the subtropics. They are found in an extremely wide variety of habitats, including the coastal intertidal zone.
The unusual lycosid eye arrangement makes lycosids generally easy to recognize as such. Typically, there is a row of four small anterior eyes; two large and forward-facing posterior median eyes (PME); and well behind the PME, a pair of large posterior lateral eyes (PLE), which usually face to the side or even backwards. Wolf spiders have excellent vision and because of the arrangement of their eight eyes, they are able to see in all directions. Courtship in lycosids often includes a strong visual component (e.g., waving legs or palps).
Nearly half of the lycosid species found in North America north of Mexico are in the genera Pardosa (which have nearly perpendicular spines on their hind legs) or Pirata (these small spiders usually have a dark tuning fork-shaped mark on the cephalothorax).
Many lycosids are nocturnal or crepuscular (active at dawn or dusk), but others hunt during the day. Most lycosids do not build a capture web (in North America, only Sosippus species build webs) but they do use a dragline, which is laid down as they wander and provides an indirect mode of communication between individuals. Female lycosids exhibit unusual parental care. After constructing an egg sac, the female attaches it to her spinnerets and carries it with her as she hunts (in contrast, females of most species in the closely related family Pisauridae carry their round egg sac under the body, grasping it with their chelicerae and pedipalps). When the young emerge from the egg sac, they clamber onto her body (mainly on the abdomen, but sometimes spilling onto her cephalothorax). The young ride about on their mother for some days as they grow, then disperse.
Wolf spiders are mainly sit-and-wait predators, pouncing on prey that passes too close. Many wolf spiders build burrows, ranging from temporary shallow holes just a few centimeters deep to silk-lined tubes extending well into the ground. The burrows of some species may be marked by turrets of silk and debris or a silk sheet door similar to those of trapdoor spiders.
Dondale (2005) includes key references that provide an excellent entry into the literature on lycosid courtship and mating behavior, life histories, hunting behavior, and taxonomy.
(Dondale 2005 and references therein; Bradley 2013)
Wolf spiders are members of the family Lycosidae (from Ancient Greek λύκος (lúkos) 'wolf'). They are robust and agile hunters with excellent eyesight. They live mostly in solitude, hunt alone, and usually do not spin webs. Some are opportunistic hunters, pouncing upon prey as they find it or chasing it over short distances; others wait for passing prey in or near the mouth of a burrow.
Wolf spiders resemble nursery web spiders (family Pisauridae), but wolf spiders carry their egg sacs by attaching them to their spinnerets, while the Pisauridae carry their egg sacs with their chelicerae and pedipalps. Two of the wolf spider's eight eyes are large and prominent; this distinguishes them from nursery web spiders, whose eyes are all of roughly equal size. This can also help distinguish them from the similar-looking grass spiders.
The many genera of wolf spiders range in body size (legs not included) from less than 10 to 35 mm (0.4 to 1.38 in).[1][2] They have eight eyes arranged in three rows. The bottom row consists of four small eyes, the middle row has two very large eyes (which distinguishes them from the Pisauridae), and the top row has two medium-sized eyes. Unlike most other arachnids, which are generally blind or have poor vision, wolf spiders have excellent eyesight.
The tapetum lucidum is a retroreflective tissue found in eyes. This reflective tissue is only found in the four[3] largest eyes ("secondary eyes") of the wolf spider. Flashing a beam of light over the spider produces eyeshine; this eyeshine can be seen when the lighting source is roughly coaxial with the viewer or sensor.[4] The light from the light source (e.g., a flashlight or sunlight) has been reflected from the spider's eyes directly back toward its source, producing a "glow" that is easily noticed. Wolf spiders possess the third-best eyesight of all spider groups, bettered by jumping spiders of the family Salticidae (which can distinguish colors) and the huntsman spiders.
Wolf spiders are unique in the way that they carry their eggs. The egg sac, a round, silken globe, is attached to the spinnerets at the end of the abdomen, allowing the spider to carry her unhatched young with her. The abdomen must be held in a raised position to keep the egg case from dragging on the ground. Despite this handicap, they are still capable of hunting. Another aspect unique to wolf spiders is their method of care of young. Immediately after the spiderlings emerge from their protective silken case, they clamber up their mother's legs and crowd onto the dorsal side of her abdomen. The mother carries the spiderlings for several weeks before they are large enough to disperse and fend for themselves.
Because they depend on camouflage for protection, they do not have the flashy appearance of some other kinds of spiders. In general, their coloration is appropriate to their favorite habitat.
Hogna is the genus with the largest of the wolf spiders. Among the Hogna species in the U.S., the nearly solid dark brown H. carolinensis (Carolina wolf spider) is the largest, with a body that can be more than 2.5 cm (1 in) long. It is sometimes confused with H. helluo, which is somewhat smaller and different in coloration. The underside of H. carolinensis is solid black, but the underside of H. helluo is variegated and has reds, oranges, and yellows with shades of black.
Some members of the Lycosidae, such as H. carolinensis, make deep, tubular burrows in which they lurk much of the time. Others, such as H. helluo, seek shelter under rocks and other shelters as nature may provide. As with spiders in general, males of almost any species can sometimes be found inside homes and buildings as they wander in search for females during the autumn.
Wolf spiders play an important role in natural population control of insects and are often considered "beneficial bugs" due to their predation of pest species within farms and gardens.[5]
Wolf spiders inject venom if continually provoked. Symptoms of their bites include swelling, mild pain, and itching. In the past, necrotic bites have been attributed to some South American[6] and Australian[7] species, but further investigation has indicated that those problems that did occur were probably actually due to bites by members of other genera[6] or not inducing those effects.[7]
As of June 2022, the World Spider Catalog accepts these genera:[8]
Wolf spiders likely originated after the K–Pg extinction event sometime in the late Paleocene, with most main subfamilies likely originating during the Eocene and Early Oligocene between 41 and 32 million years ago.[9]
Wolf spiders are found in a wide range of habitats both coastal and inland. These include shrublands, woodland, wet coastal forest, alpine meadows, suburban gardens, and homes. Spiderlings disperse aerially; consequently, wolf spiders have wide distributions. Although some species have very specific microhabitat needs (such as stream-side gravel beds or montane herb-fields), most are wanderers without permanent homes. Some build burrows which can be left open or have a trap door (depending on species). Arid-zone species construct turrets or plug their holes with leaves and pebbles during the rainy season to protect themselves from flood waters. Often, they are found in man-made locations such as sheds and other outdoor equipment.
Many species of wolf spiders possess very complex courtship behaviors and secondary sexual characteristics, such as tufts of bristles on their legs or special colorations, which are most often found on the males of the species. These sexual characteristics vary by species and are most often found as modifications of the first pair of legs.[10] First-leg modifications are often divided into elongated bristles on the legs, increased swelling of leg segments, or the full elongation of the first pair of legs compared to the other three pairs. Some mating behaviors are common between wolf spider genera, and many more that are species-specific. In the most commonly studied genus of wolf spiders, Schizocosa, researchers found that all males engage in a seismic component of their courtship display, either stridulation, or drumming their fore legs on the ground, but some also dependent on visual cues in their courtship display, as well as the seismic signaling, such as waving the front two legs in the air in front of the female, concluding that some Schizocosa species rely on multimodal courtship behaviors.[11]
The Lycosidae comprise mainly wandering spiders, and as such, population density and male-to-female sex ratio puts selective pressures on wolf spiders when finding mates. Female wolf spiders that have already mated are more likely to eat the next male that tries to mate with them than those that have not mated yet. Males that have already mated have a higher probability of successfully mating again, but females that have already mated have a lower probability of mating again.[12]
South Carolina designated the Carolina wolf spider (Hogna carolinensis) as the official state spider in 2000 due to the efforts of Skyler B. Hutto, a third-grade student at Sheridan Elementary School in Orangeburg.[13]
At the time, South Carolina was the only U.S. state that recognized a state spider.[14] In 2015, efforts began to name an official state spider for neighboring North Carolina.[15]
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Hogna radiata wolf spider, adult female.
Wolf spider with 3-inch spread
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Female with egg sac
Female with juveniles
Burrowing wolf spider
{{cite web}}: CS1 maint: url-status (link) Wolf spiders are members of the family Lycosidae (from Ancient Greek λύκος (lúkos) 'wolf'). They are robust and agile hunters with excellent eyesight. They live mostly in solitude, hunt alone, and usually do not spin webs. Some are opportunistic hunters, pouncing upon prey as they find it or chasing it over short distances; others wait for passing prey in or near the mouth of a burrow.
Wolf spiders resemble nursery web spiders (family Pisauridae), but wolf spiders carry their egg sacs by attaching them to their spinnerets, while the Pisauridae carry their egg sacs with their chelicerae and pedipalps. Two of the wolf spider's eight eyes are large and prominent; this distinguishes them from nursery web spiders, whose eyes are all of roughly equal size. This can also help distinguish them from the similar-looking grass spiders.
