By Justin Scarborough
Geographic Range
Rabidosa rabida is very common and widely distributed. It is often recorded as a wandering spider. It is typically found in east to central Texas and Oklahoma, northward to Nebraska. It has frequently been traced as far east as Maine and as far south as Florida. (Jackman, 1997)
Habitat
Rabidosa rabida ismost often found in wooded areas, cotton fields, and buildings. These spiders usually reside among litter, rubbish, in holes, under rocks, and on low foliage in these areas. Some individuals have been found around ponds or in deep burrows with a turret of debris. (Jackman, 1997; Milne and Milne, 1980; Parker, 1982)
These animals are found in the following types of habitat:
temperate
; terrestrial
.
Terrestrial Biomes:
forest
.
Other:
urban
; suburban
; agricultural
.
Physical Description
A typical rabid wolf spider has a dark gray cephalothorax with two light longitudinal stripes extending across the top and a narrow light line on each lateral margin of the thorax. The abdomen has a dark median band, notched on each side in front of the middle of the abdomen, with several pairs of light spots on the rear part of the abdomen. The first pair of legs is often black or dark brown, and the other legs are brown. Females average 16 to 21 mm long, Males are typically much smaller than females, measuring an average of 13 mm in length. (Comstock and Gertsch, 1965; Milne and Milne, 1980)
Some key physical features:
ectothermic
; bilateral symmetry
.
Sexual dimorphism:
female larger.
Development
Female R. rabida drag their egg mass around, having spun a silken cocoon around the egg mass and attached it to spinnerets. The cocoon darkens from shiny white to dirty brown before the eggs hatch.
Spiderlings ride on their mother's back until they are ready for dispersal. Egg sacs are from 7 to 10 mm in diameter and contain from 168 to 365 eggs. (Jackman, 1997; Milne and Milne, 1980)
Reproduction
Breeding occurs from late summer to early fall.
Female R. rabida release a dragline. Males stumble across the line, which leads them to the female. Once courting is over, the male spins a ball of silk and then releases sperm onto the ball. The female attaches the ball and drags it along with her until she is fertilized. (Rovner, 1991)
Reproduction in R. rabida is one of the most commonly debated and studied areas of the animal's behavior. Rabid wolf spiders efficiently detect movements. When males and females are in courtship mode, they use a series of displays to interact and breed. R. rabida perform a series inter-bout turns in which one spider turns in a given direction based upon the direction in which the other spider turned previously. Pheromones also play a role in these intricate courting rituals. Scientists have shown that the intensity of the pheromone is directly related to the turning in males, specifically the degree and time of turning.
Female R. rabida drag their egg mass around, having spun a silken cocoon around the egg mass and attached it to spinnerets. The cocoon darkens from shiny white to dirty brown before the eggs hatch.
Spiderlings ride on their mother's back until they are ready for dispersal. Egg sacs are from 7 to 10 mm in diameter and contain from 168 to 365 eggs. (Jackman, 1997; Milne and Milne, 1980; Rovner, 1991)
Key reproductive features:
seasonal breeding
; sexual
; oviparous
; delayed fertilization
.
The spiderlings hatch and remain on the mother's back until they are ready for dispersal. (Jackman, 1997)
Parental investment:
precocial
; pre-fertilization (provisioning, protecting: female); pre-hatching/birth (provisioning: female, protecting: female); pre-weaning/fledging; pre-independence (protecting: female).
Lifespan/Longevity
Most rabid wolf spiders live up to around two years, six months of which is sometimes spent on the mother's back. The larger, more fit R. rabida can live beyond two years in stable environments. (Comstock and Gertsch, 1965)
Behavior
Because rabid wolf spiders are among the most common spiders in the United States, they have adapted to many types of environments. These spiders are very aggressive towards humans, spiders,other animals and insects. Because of their wandering habits, these spiders are subject to a plethora of interactions between the same and other species. Although harmless to humans, its bite is often feared. (Milne and Milne, 1980)
Communication and Perception
Rabid wolf spiders communicate in many different ways. One way is through the release of pheromones. Both males and females lay out a dragline and deposit a chemical attractor on the line. Male wolf spiders intersect these lines and use their palps to follow the line for mating. Another type of communication is web vibrations. This type of communication, known as the substratum-coupled vibration system, is used mainly by males to attract females, but is also used for males to communicate with one another. Essentially, a male "plucks" the web fibers to play a "song". (Comstock and Gertsch, 1965; Milne and Milne, 1980; Rovner, 1991; Unknown, 1999)
Other communication keywords:
pheromones
; vibrations
.
Perception channels:
visual
; tactile
; acoustic
; vibrations
; chemical
.
Food Habits
Rabid wolf spiders usually prefer to eat small insects and other invertebrates. They have been known to eat crickets, locusts, ants, grasshoppers and even other spiders. R. rabida is very strong and is not usually intimidated by larger organisms. These spiders are "sit-and-wait" predators. In order to more easily detect visual and vibratory cues from prey, R. rabida must remain motionless. These spiders do not eat solid material, so once they overtake the insect, they usually suck out liquids and nutrients of their prey. (Jackman, 1997; Parker, 1982; Rovner, 1989)
Primary Diet:
carnivore
(insectivore
).
Animal Foods:
insects; terrestrial non-insect arthropods.
Predation
- Other Wolf Spiders
- Dogs
- Cats
- Snakes
While Rabidosa rabida is nomadic and moves frequently, it does so in a manner that is inconspicious to larger predators. By staying low in the brush, under litter or ground cover, the spider can move efficiently and most often remains undetected. Wolf spiders get their name from they way they stalk their prey slowly and from a distance, which has been associated with wolves and other wild dogs. (Parker, 1982; Rovner, 1989)
Ecosystem Roles
Rabidosa rabida has a limited role in th ecosystem. Its main job as a predator is to control the booming insect population. However, as an occasional prey species, it may contribute to feeding other organisms also.
Economic Importance for Humans: Negative
Rabidosa rabida has little adverse affect on humans outside of being pests. These spiders are not poisonous but have been know to bite unsuspecting victims.
Ways that these animals might be a problem for humans:
household pest.
Economic Importance for Humans: Positive
Although it is of little direct benefit to humans, R. rabida is very common among semi-urban and rural areas and is very active in its predation of insects. This can be a big benefit where pests are a problem.
Ways that people benefit from these animals:
controls pest population.
Conservation Status
IUCN Red List: [link]:
Not Evaluated.
US Federal List: [link]:
No special status.
CITES: [link]:
No special status.
State of Michigan List: [link]:
No special status.
Rabid wolf spiders are not currently endangered or at any prevelant risk of becoming threatened.
For More Information
Find Rabidosa rabida information at
Contributors
Justin Scarborough (author), Southwestern University.
Stephanie Fabritius (editor), Southwestern University.
Nancy Shefferly (editor), Animal Diversity Web Staff.

