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Bronze Jumper

Eris militaris male

Eris militaris male

(Eris militaris)

This spider is found throughout most of the continental United States and Canada. Only a handful of Salticids have such an extensive geographical range (two of those species, Phidippus audax and Salticus scenicus, are also included in this publication).

Description
The males have a dark cephalothorax with white bands along the sides. The chelicerae are relatively long and extend forward from the front. The abdomen is lighter in color than the cephalothorax and it too has white bands that run laterally. Females have a lighter cephalothorax than the males and a slightly darker abdomen, but they do not have the lateral white bands. The abdomen has a short white band near the cephalothorax and a series of elongated dorsal white spots. Females are 6 to 8 millimeters long, while males are 4.7 to 6.7 millimeters.

Life History/Behavior
Eris militaris is a jumping spider that can be seen around many homes and in fields and woods, though it is often overlooked due to its small size and bronze-brown color. Found in both rural and suburban locations, it is most often seen in the fall crawling on the exterior or interior of buildings. Bronze jumpers will sometimes aggregate in the fall to overwinter under the bark of dead trees.

Medical Importance
As with other jumping spiders, this species is not medically important. (Note: The author has personal experience in this regard. While attempting to get the spider to look at the camera by using his index finger to get the spider’s attention, the male pounced upon the fingertip, bit it, and hopped off. The pain was immediate and surprisingly distracting. After only 15 seconds the pain was gone and no other symptoms developed.)

Authored by: Steve Jacobs, Sr. Extension Associate
February 2015

References
Baerg, W. J. 1936. The Black Widow. Ark. Agr. Expt. Sta. Bul. 325. 34 pp.

Baerg, W. J. 1959. The Black Widow and Five Other Venomous Spiders in the United States. Ark. Agr. Expt. Sta. Bul. 608. 43 pp.

Bradley, R. A. 2013. Common Spiders of North America. University of California Press. 271 pp.

Breene, R. G., et al. 2003. Common Names of Arachnids. 5th ed. The American Arachnological Society Committee on Common Names of Arachnids. 42 pp.

Gertsch, W. J., and F. Ennik. 1983. “The spider genus Loxosceles in North America, Central America, and the West Indies (Araneae, Loxoscelidae).” Bul Amer Mus. Nat. Hist. 175: 24–360.

Herms, W. B., and M. T. James. 1961. Medical Entomology. 5th ed. The MacMillan Company, New York. 616 pp.

Howell, W. M., and R. L. Jenkins. 2004. Spiders of the Eastern United States: A Photographic Guide. Pearson Education. 363 pp.

Isbister, G. K., and M. R. Gray. 2003. “Effects of envenoming by combfooted spiders of the genera Steatoda and Achaearanea (Family Theridiidae: Araneae) in Australia.” J. Toxicol. Clin. Toxicol. 41: 809–819.

Kaston, B. J. 1948. “Spiders of Connecticut.” Conn. State Geol. Nat. Hist. Survey. Bull. 70. 874 pp.

Kaston, B. J. 1972. How to Know the Spiders. 3rd ed. Wm. C. Brown Company, Dubuque, Iowa. 272 pp.

Levi, H. W. 1959. “The Spider Genus Latrodectus (Araneae, Theridiidae).” Trans. Amer. Microscopical Soc. 78(1): 7–43.

Long, D., R. Snetsinger, and K. F. Helm. 1995. “Localized Pruritic Rash Due to Recurrent Spider Bites.” J. Geriatr. Dermatol. 3(6): 186–190.

McKeown, N., R. S. Vetter, and R. G. Hendrickson. 2014. “Verified spider bites in Oregon (USA) with the intent to assess hobo spider venom toxicity.” Toxicon 84: 51–55.

Ubick, D., P. Paquin, P. E. Cushing, and V. Roth, eds. 2005. Spiders of North America: An Identification Manual. American Arachnological Society. 377 pp.

Vetter, R. S., and P. Kirk Visscher. 1998. “Bites and Stings of Medically Important Venomous Arthropods.” International. J. Derm. 37: 481–496.

Vetter, R. S., et al. 2006. “Verified Bites By Yellow Sac Spiders (Genus Cheiracanthium) in the United States and Australia: Where Is the Necrosis?” Amer. J. Trop. Med. Hyg. 74(6): 1,043–1,048.

Vetter, R. S., and G.K. Isbister. 2008. “Medical aspects of spider bites.” Annu. Rev. Entomol. 53: 409–429.

 

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