Rabidosa rabida

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.

• Biogeographic Regions
• nearctic nearctic
  • native native

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.

• Habitat Regions
• temperate temperate
• terrestrial terrestrial

• Terrestrial Biomes
• forest forest

• Other Habitat Features
• urban urban
• suburban suburban
• agricultural 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.

• Other Physical Features
• ectothermic ectothermic
• bilateral symmetry 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.

Reproduction

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.

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.

• Key Reproductive Features
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• oviparous oviparous
• delayed fertilization delayed fertilization

The spiderlings hatch and remain on the mother's back until they are ready for dispersal.

• Parental Investment
• precocial 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.

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.

• Key Behaviors
• terricolous
• motile motile
• nomadic nomadic

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".

• Communication Channels
• tactile tactile
• acoustic acoustic
• chemical chemical

• Other Communication Modes
• pheromones pheromones
• vibrations vibrations

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• vibrations vibrations
• chemical 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.

• Primary Diet
• carnivore carnivore
  • insectivore insectivore

• Animal Foods
• insects
• terrestrial non-insect arthropods

Predation

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.

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: 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.

• Positive Impacts
• controls pest population

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.

• Negative Impacts
• household pest

Conservation Status

Rabid wolf spiders are not currently endangered or at any prevelant risk of becoming threatened.

Additional Links

Encyclopedia of Life

Contributors

Nancy Shefferly (editor), Animal Diversity Web.

Justin Scarborough (author), Southwestern University, Stephanie Fabritius (editor), Southwestern University.

References

Comstock, J., W. Gertsch. 1965. The Spider Book . Ithaca, New York: Comstock Publishing Company, Inc..

Jackman, J. 1997. A Field Guide to Common Texas Insects . Houston: Gulf Publishing Company.

Milne, L., M. Milne. 1980. The Audubon Society Field Guide to North American Insects and Spiders . New York: Chanticleer Press, Inc..

Parker, S. 1982. Synopsis and Classification of Living Organisms Volume 2 . McGraw-Hill Book Company.

Rovner, J. 1991. Turning behavior during pheromone-stimulated courtship in wolf spiders. Animal Behaviour , 42: 1015-1016.

Rovner, J. 1989. Wolf Spiders lack mirror-image responsiveness seen in jumping spiders. Animal Behaviour , 38: 526-533.

Unknown, 1999. "Introduction to Ethology" (On-line). Accessed Oct. 3, 2001 at http://cas.bellarmine.edu/tietjen/Ethology/introduction_to_ethology.htm .