The+Black+Widow

=The Black Widow Spider and its Relatives=

__Taxonomy:__
Kingdom: Animalia Phylum: Arthropoda Class: Arachnida Order: Araneae Family: Theridiidae Genus: Latrodectus

__Habitat:__
(Szalay, Jessie 2013), (Busse, et. al., 2013)
 * Black widows are found all over the world in temperate regions.
 * While they can be found all over the United States, the majority are found in the southern and western United States
 * They prefer dark damp habitats such as, garages, sheds, or any outdoor structures
 * Although usually found outside, they can move inside to escape colder weather and will often be found in closets and attics
 * Black widows are cobweb weavers



__Biology:__
(Hannum and Miller)
 * Description**
 * The typical image of a Black Widow spider is of the adult female, which is known for its glassy jet black appearance with a red marking (often hourglass shaped) on a large abdomen. (However, there can be significant variability in appearance between species of widow spiders)
 * The females have a leg span usually between 1-1.5 inches while the males will have an average leg span of only a quarter inch
 * Juvenile widows are grayish to black in color and usually contain white striping coloration on the abdomen, often with orange to yellow spotting
 * Males can be completely black but often retain some juvenile coloration. They will usually have some red markings on their abdomen but will lack the hourglass shape of the females

**Life Cycle** (Hannum and Miller), (Szalay, Jessie 2013)
 * Beginning in late spring females can lay between four and nine egg sacs within a single summer
 * Each egg sac usually contains between 200 and 400 eggs
 * The female will rarely leave the web, protecting her egg sac and ensuring a consistent environment for the eggs
 * Juvenile spiders will emerge after two to four weeks and disperse via ballooning on passing air currents
 * Juveniles will reach sexual maturity in as little as three to four months, sexually mature by early spring
 * The cycle repeats by late spring
 * Single generation per year


 * The Bite**
 * The bite of a black widow, while still dangerous, is not usually fatal. Young children, elderly, or weekend persons are most at risk
 * The bite of a black widow releases the neurotoxin known as alpha-latrotoxin which induces neurotransmitter release by destabilizing cell membranes and nerve terminal degranulation (Rauber 1983).
 * Following a bite, the toxin can cause severe pain, abdominal rigidity, swelling, difficulty breathing, nausea, among other symptoms (Peterson 2006).
 * The most effective treatment for a widow bite is administration of an antivenin
 * Successful antivenin properties have been found in other spiders. For example the Red-back spiders of Austrailia contain antivenin that counteracts the effects of widow bites. Mice administerd with the Red-back antivenin were resistant to envenomation by widow bites (Graudins et al. 2001).


 * Name**
 * The Black "Widow" retrieved its name because it was believed that as part of a mating ritual, the female would devour and kill the male spider after mating, "widowing" the female.
 * This is a misconception. This is because early behavioral studies kept both spiders in a closed container and the female would at some point mistake the male for prey and eat him. In nature it is very rare for the female to eat the male as long as the male leaves the web after mating (Hannum and Miller).

Created by Castro. S

Related and Useful links
https://www.osha.gov/OshDoc/data_Hurricane_Facts/black_widow_spider.pdf http://www.nlm.nih.gov/medlineplus/ency/article/002858.htm http://animaldiversity.ummz.umich.edu/accounts/Latrodectus_mactans/ http://bugguide.net/node/view/1999 http://www.medicinenet.com/spider_bites_black_widow_and_brown_recluse/article.htm

References:
Busse, Paul, Julia H. Cothron, and Norbert Hamm. "Description." // SpiderRoom.info //. MSIC, n.d. Web. 11 Nov. 2013. .

Graudins, Andis, Matthew Padula, Kevin Broady, and Graham M. Nicholson. 2001. “Red-Back Spider (Latrodectus Hasselti) Antivenom Prevents the Toxicity of Widow Spider Venoms.” //Annals of Emergency Medicine// 37 (2) (February): 154–160. doi:10.1067/mem.2001.113033.

Hannum, Charles, and Dini M. Miller. “Widow Spiders.” //Virginia Cooperative Extension//: 444–422. http://pubs.ext.vt.edu/444/444-422/444-422_pdf.pdf

Peterson, Michael E. 2006. “Black Widow Spider Envenomation.” //Clinical Techniques in Small Animal Practice// 21 (4) (November): 187–190. doi:10.1053/j.ctsap.2006.10.003.

Rauber, Albert. 1983. “Black Widow Spider Bites.” //Clinical Toxicology// 21 (4-5) (January): 473–485. doi:10.3109/15563658308990435.

Szalay, Jessie. 2013. “Black Widows: Facts & Information.” //LiveScience.com//. September 24. http://www.livescience.com/39919-black-widow-spiders.html.

Images:
Figure 1 "Skip Menu." //Widow Spiders//. N.p., n.d. Web. Accessed 11 Nov. 2013. from: .

Figure 2 Washington, National Geographic Society, 2013. “Black Widow Spiders, Black Widow Spider Pictures, Black Widow Spider Facts.” //National Geographic//. Accessed November 11, 2013. from .

Figure 3

Hannum, Charles, and Dini M. Miller. “Widow Spiders.” // Virginia Cooperative Extension // : 444–422. Accessed Nov. 11, 2013. from: < http://pubs.ext.vt.edu/444/444-422/444-422_pdf.pdf>