drumming sword wolf spider

Drumming sword wolf spiders are medium-sized wolf spiders. They occur in the United States and southern Canada east of the Great Plains, and there is a separated (disjunct) population in Colorado. They are found in oak, beech, and maple forests and in other woodlands. They are nocturnal, hiding under leaf litter during the day and hunting at night.

Females are 7⁄16″ to 9⁄16″ (11 to 14 mm) in length. Males are smaller, ⅜″ to ½″ (10 to 12 mm) in length. The legspan is 1″ to 1⅜″ (25 to 35 mm). The body is light brown, grayish brown, reddish brown, or yellowish brown (pale) with dark brown (dark) and black markings.

The front part of the body (cephalothorax) is longer than wide. The upper side (carapace) of the cephalothorax is high, and there is a long, distinct, longitudinal groove in the middle. The lateral margins are smoothly convex, and the rear margin is concave. There is a broad pale stripe in the middle bordered by a broad dark stripe on each side. The dark stripes are crossed by radiating black lines.

The face is pale. The eye region is dark. There are eight eyes in two rows of four each. The front (anterior) row has four small eyes and is straight or slightly curved forward. The rear (posterior) row has two very large posterior median eyes (PME) and two large posterior lateral eyes (PLE). The PLE are set behind the PME, and some authors describe this arrangement as three rows of eyes. The rear row is about equal in width to the middle row. The PME are closer to the PLE than to each other. The PME and PLE have a layer of reflective tissue internally. This allows the spider to see in relative darkness. It also causes their eyes to shine when hit by the beam of a flashlight. The basal segments of the jaws (chelicerae) are large and powerful. They are dark at the base, becoming paler in the middle, and almost black at the tip. The front and rear margins each have three teeth.

The abdomen is egg-shaped and is covered with short hairs. It is pale at the base with a pair of black patches on each side at the base. There are four small but distinct pale spots toward the front and a few scattered small dark spots.

The legs are short, stout, spiny, and sparsely hairy. They are pale at the base, becoming dark at the tip. The fourth segment (femur) of each leg has dark bands on the upper and lateral surfaces.

On the male, the chelicerae are pale at the base. Dark markings on the front half of the abdomen form a continuation of the dark stripes on the carapace. The rear of the abdomen does not have the distinct chevrons shared by other members of this genus. The femurs do not have dark bands.

Female Body Length: 7⁄16″ to 9⁄16″ (11 to 14 mm)

Male Body Length: ⅜″ to ½″ (10 to 12 mm)

Legspan: 1″ to 1⅜″ (25 to 35 mm)

Oak, beech, and maple forests and other woodlands

The common name of this spider is a reference to male courtship behavior, which usually takes place in the spring. The courtship involves rapid movements of the finger-like sensory mouthparts (palps) and abdomen to produce vibrations and sounds. Upon encountering a female, the male begins drumming his palps alternately against the substrate, creating a distinct purring or humming sound. The palps are raised slightly during this process, and the abdomen is held at an angle, causing its tip to strike the substrate as it twitches vertically. These vibrations are likely perceived by the female and may excite her, similar to the effect of web vibrations in web-building spiders.

The sound is produced not solely by drumming but also involves a sound-producing (stridulatory) organ located on the palps. This organ consists of a file on the fifth segment (tibia) and a scraper at the base of the palpal cymbium, with stiff hairs (macrosetae) at the palpal tarsus tip aiding in anchoring the palpus to the substrate. This mechanism facilitates rapid oscillations at the joint, generating the sound.

The drumming sounds can be heard from a distance of 10 feet or more, and the behavior includes additional movements such as leg quivering and stroking the female's legs or abdomen during courtship.

Sources

24, 29, 30, 82, 83.

Brady, A. R. (1987). Nearctic species of the new wolf spider genus Gladicosa (Araneae: Lycosidae). Psyche, Cambridge 93(3-4, 1986): 285-319.

Genus
This species was formerly placed in the genus Lycosa. That genus formerly contained more than 50 North American species along with many European, Asian, and South American species. All New World species have recently been moved to new genera. The genus Gladicosa was established based on features of the male genitalia and on dorsal color patern.

Spider's Creepy Mating 'Purr' Recorded by Researchers
LiveScience

Greg Watson
4/30/2025

Location: Whitewater State Park

I noticed that you don’t have a picture of a Drumming Sword Wolf Spider, Gladicosa gulosa, in your list. I took the picture on the Dakota Trail in Whitewater State Park this past Wednesday.