Recluse spider

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Recluse spiders
Brown recluse spider
Brown recluse spider
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Arachnida
Order: Araneae
Family: Sicariidae
Genus: Loxosceles
Heineken & Lowe, 1832
Diversity
100 species
Species

see article

The recluse spiders (genus Loxosceles), also known as fiddle-back or violin spiders, are a venomous genus of spiders known for their necrotic bite. They are members of the family Sicariidae, having formerly been placed in their own family, "Loxoscelidae".

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[edit] Habitat and appearance

Loxosceles is distributed nearly worldwide in warmer areas, and are often known as violin spiders or fiddlebacks. All have six eyes arranged in three groups of two (dyads) and are usually brownish with a darker brown characteristic violin marking on the cephalothorax. Most Loxosceles can live for one and a half to two years. Members of both genera can live for very long times without food or water.

The recluse spider family includes about 13 species in the United States, the brown recluse spider (Loxosceles reclusa) being the best known of these. It is found in a large area of the Midwest, west to Colorado and the New Mexico state line and east to Northern Georgia. Sporadic records from other locations only represent incidental introductions, not established populations.

Other notable members of this genus include the Chilean recluse (L. laeta) and the Mediterranean recluse (Loxosceles rufescens).

[edit] Venom components and effects

Loxosceles spiders, like their cousins in Sicarius, have potent tissue-destroying venoms containing the dermonecrotic agent, sphingomyelinase D, which is otherwise found only in a few pathogenic bacteria. This venom is highly necrotic in effect, capable of causing lesions (open sores) as large as a US quarter. The wounds take a long time to heal and may require skin grafts. If these open wounds become infected there are often serious consequences. Rarely, the venom is carried by the blood stream to internal organs causing systemic effects.

The Chilean recluse (Loxosceles laeta) supposedly has a more potent venom, which results in systemic involvement more often. This spider was accidentally introduced to the Los Angeles area (Alhambra, Sierra Madre, and Monterey Park). This spider, however, seems to be confined to a very limited area, even though it has lived there for over 30 years. Other members of the genus that have been tested have venoms similar to the brown recluse and all members of this genus are best avoided. However, the brown recluse and its relatives are not very aggressive and huge populations have been found in houses where the human inhabitants remained unbitten after years of cohabitation.[1]

A possible problem with diagnosing a recluse spider bite is that the bite of these spiders is probably both underreported in some areas and over reported generally.[2] Unfortunately several diseases can mimic the lesions of a recluse spider bite, including Lyme disease, various fungal and bacterial infections and the first sore of syphilis([1]). Therefore it is extremely important to associate the spider directly with the bite, if at all possible, and consider alternative diagnoses if no spider was seen.

Generally, recluse spiders are usually found in the center of a sort of space web of fungal-like silk, which often contains the remains of their recent meals. For the Arizona recluse (Loxosceles arizonica) the most abundant food item seems to be night-active ants like carpenter ants. The brown recluse is known to feed on whatever small prey is available, and this is probably true of all sicariids.

[edit] Species

  • Loxosceles accepta Chamberlin, 1920 — Peru
  • Loxosceles adelaida Gertsch, 1967 — Brazil
  • Loxosceles alamosa Gertsch & Ennik, 1983 — Mexico
  • Loxosceles alicea Gertsch, 1967 — Peru
  • Loxosceles amazonica Gertsch, 1967 — Brazil
  • Loxosceles anomala (Mello-Leitão, 1917) — Brazil
  • Loxosceles apachea Gertsch & Ennik, 1983 — USA, Mexico
  • Loxosceles aphrasta Wang, 1994 — China
  • Loxosceles aranea Gertsch, 1973 — Mexico
  • Loxosceles arizonica Gertsch & Mulaik, 1940 — USA
  • Loxosceles aurea Gertsch, 1973 — Mexico
  • Loxosceles baja Gertsch & Ennik, 1983 — Mexico
  • Loxosceles barbara Gertsch & Ennik, 1983 — Mexico
  • Loxosceles belli Gertsch, 1973 — Mexico
  • Loxosceles bettyae Gertsch, 1967 — Peru
  • Loxosceles blancasi Gertsch, 1967 — Peru
  • Loxosceles blanda Gertsch & Ennik, 1983 — USA
  • Loxosceles boneti Gertsch, 1958 — Mexico, El Salvador
  • Loxosceles candela Gertsch & Ennik, 1983 — Mexico
  • Loxosceles caribbaea Gertsch, 1958 — Greater Antilles
  • Loxosceles carmena Gertsch & Ennik, 1983 — Mexico
  • Loxosceles chinateca Gertsch & Ennik, 1983 — Mexico
  • Loxosceles colima Gertsch, 1958 — Mexico
  • Loxosceles conococha Gertsch, 1967 — Peru
  • Loxosceles coquimbo Gertsch, 1967 — Chile
  • Loxosceles coyote Gertsch & Ennik, 1983 — Mexico
  • Loxosceles cubana Gertsch, 1958 — Cuba, Bahama Islands
  • Loxosceles deserta Gertsch, 1973 — USA, Mexico
  • Loxosceles devia Gertsch & Mulaik, 1940 — USA, Mexico
  • Loxosceles fontainei Millot, 1941 — Guinea
  • Loxosceles foutadjalloni Millot, 1941 — Guinea
  • Loxosceles francisca Gertsch & Ennik, 1983 — Mexico
  • Loxosceles frizzelli Gertsch, 1967 — Peru
  • Loxosceles gaucho Gertsch, 1967 — Brazil, Tunisia
  • Loxosceles gloria Gertsch, 1967 — Ecuador, Peru
  • Loxosceles guatemala Gertsch, 1973 — Guatemala
  • Loxosceles harrietae Gertsch, 1967 — Peru
  • Loxosceles herreri Gertsch, 1967 — Peru
  • Loxosceles hirsuta Mello-Leitão, 1931 — Brazil, Paraguay, Argentina
  • Loxosceles huasteca Gertsch & Ennik, 1983 — Mexico
  • Loxosceles immodesta (Mello-Leitão, 1917) — Brazil
  • Loxosceles inca Gertsch, 1967 — Peru
  • Loxosceles insula Gertsch & Ennik, 1983 — Mexico
  • Loxosceles intermedia Mello-Leitão, 1934 — Brazil, Argentina
  • Loxosceles jaca Gertsch & Ennik, 1983 — Mexico
  • Loxosceles jamaica Gertsch & Ennik, 1983 — Jamaica
  • Loxosceles jarmila Gertsch & Ennik, 1983 — Jamaica
  • Loxosceles julia Gertsch, 1967 — Peru
  • Loxosceles kaiba Gertsch & Ennik, 1983 — USA
  • Loxosceles lacroixi Millot, 1941 — Ivory Coast
  • Loxosceles lacta Wang, 1994 — China
  • Loxosceles laeta (Nicolet, 1849) — America, introduced to Finland and Australia
  • Loxosceles lawrencei Caporiacco, 1955 — Venezuela, Trinidad, Curaçao
  • Loxosceles lutea Keyserling, 1877 — Colombia, Ecuador
  • Loxosceles luteola Gertsch, 1973 — Mexico
  • Loxosceles manuela Gertsch & Ennik, 1983 — Mexico
  • Loxosceles martha Gertsch & Ennik, 1983 — USA
  • Loxosceles meruensis Tullgren, 1910 — Tanzania
  • Loxosceles misteca Gertsch, 1958 — Mexico
  • Loxosceles mulege Gertsch & Ennik, 1983 — Mexico
  • Loxosceles nahuana Gertsch, 1958 — Mexico
  • Loxosceles neuvillei Simon, 1909 — Somalia, East Africa
  • Loxosceles olmea Gertsch, 1967 — Peru
  • Loxosceles pallidecolorata (Strand, 1906) — Ethiopia
  • Loxosceles palma Gertsch & Ennik, 1983 — USA, Mexico
  • Loxosceles panama Gertsch, 1958 — Panama
  • Loxosceles parrami Newlands, 1981 — South Africa
  • Loxosceles piura Gertsch, 1967 — Peru
  • Loxosceles pucara Gertsch, 1967 — Peru
  • Loxosceles puortoi Martins, Knysak & Bertani, 2002 — Brazil
  • Loxosceles reclusa Gertsch & Mulaik, 1940 — North America
  • Loxosceles rica Gertsch & Ennik, 1983 — Costa Rica
  • Loxosceles rosana Gertsch, 1967 — Peru
  • Loxosceles rothi Gertsch & Ennik, 1983 — Mexico
  • Loxosceles rufescens (Dufour, 1820) — Cosmopolitan
  • Loxosceles rufipes (Lucas, 1834) — Guatemala, Panama, Colombia
  • Loxosceles russelli Gertsch & Ennik, 1983 — USA
  • Loxosceles sabina Gertsch & Ennik, 1983 — USA
  • Loxosceles seri Gertsch & Ennik, 1983 — Mexico
  • Loxosceles similis Moenkhaus, 1898 — Brazil
  • Loxosceles smithi Simon, 1897 — Ethiopia
  • Loxosceles sonora Gertsch & Ennik, 1983 — Mexico
  • Loxosceles spadicea Simon, 1907 — Peru, Bolivia, Argentina
  • Loxosceles speluncarum Simon, 1893 — South Africa
  • Loxosceles spinulosa Purcell, 1904 — Southern Africa
  • Loxosceles surca Gertsch, 1967 — Peru
  • Loxosceles taeniopalpis Simon, 1907 — Ecuador
  • Loxosceles taino Gertsch & Ennik, 1983 — Bahama Islands, Jamaica, Hispaniola
  • Loxosceles tehuana Gertsch, 1958 — Mexico
  • Loxosceles tenango Gertsch, 1973 — Mexico
  • Loxosceles teresa Gertsch & Ennik, 1983 — Mexico
  • Loxosceles tlacolula Gertsch & Ennik, 1983 — Mexico
  • Loxosceles valdosa Gertsch, 1973 — Mexico
  • Loxosceles valida Lawrence, 1964 — South Africa
  • Loxosceles variegata Simon, 1897 — Paraguay
  • Loxosceles virgo Gertsch & Ennik, 1983 — Virgin Islands
  • Loxosceles vonwredei Newlands, 1980 — Namibia
  • Loxosceles weyrauchi Gertsch, 1967 — Peru
  • Loxosceles yucatana Chamberlin & Ivie, 1938 — Mexico, Belize, Guatemala
  • Loxosceles zapoteca Gertsch, 1958 — Mexico

[edit] See also

[edit] Footnotes

  1. ^ Vetter R, Barger D (2002). "An infestation of 2,055 brown recluse spiders (Araneae: Sicariidae) and no envenomations in a Kansas home: implications for bite diagnoses in nonendemic areas". J Med Entomol 39 (6): 948-51. 
  2. ^ Vetter R, Bush S (2002). "The diagnosis of brown recluse spider bite is overused for dermonecrotic wounds of uncertain etiology". Ann Emerg Med 39 (5): 544-6. doi:10.1067/mem.2002.123594. 

[edit] External links