The brown widow spider, Latrodectus geometricus
The Situation: The brown widow spider, Latrodectus geometricus, became established in Southern California in early on 2000 and has become well entrench as separate of the local spider fauna in urban Los Angeles and San Diego. The brown widow spider is continuing its expansion in Southern California and could possibly move north into Central California .
The brown widow is suspected to have evolved in Africa although it was first described from South America, which adds confusion as to where it might have originated. The Brown Widow Spider is a cosmopolitan tropical and subtropical spider having established populations in Hawaii, Florida, some Caribbean Islands, parts of Australia, South Africa, Japan, and Cyprus. In North America, the Brown Widow Spider was restricted for many decades to the Florida peninsula. however, around the class 2000, it started showing up in other Gulf Coast states. Brown widows are now known from Texas to Georgia and South Carolina. As specimens were found in new locations in the southeast United States, this species was simultaneously being collected with greater frequency in southerly California. The foremost specimens were collected in Torrance in 2003. After that, the spider was found with greater frequency in Los Angeles, Orange and San Diego counties .
Description of the Brown Widow: Unlike its starkly black-and-red biased relative, the black widow, the coloration of a brown widow consists of a mottling of tan and brown with black dialect marking. In fledged females, there is normally a abaxial longitudinal abdominal stripe and three diagonal stripes on each flank. At the crown of each diagonal chevron, there is a black mark, which is quite conspicuous and square-ish. The Brown Widow Spider does have an hourglass but it is typically an orange tad preferably than the graphic red of a black widow. The brown widow looks like to immatures of the western black widow spider, the latter of which has smaller black spots on the top of the diagonal abdominal stripes and more olive grey background coloration. Being able to discern brown widows from green black widows is consequently unmanageable and requires some experience. however, a more diagnostic sport of a brown widow is its egg theca. Most spider egg pouch that are free ( i.e., are not attached to flat surfaces ) look like a lemon dangle sugarcoat or a little cotton ball with indistinct edges. The egg sac of a embrown widow has multiple silk spicules projecting out from the surface. The egg pouch has been described as looking like a large pollen grain or a World War II harbor mine designed to blow up ships. The egg sac of the Brown Widow Spider is so classifiable that it is promptly recognizable .
Reproduction: Brown widows are prolific breeders in that they can produce many egg theca in a life, frequently respective in agile succession. They lay about 120-150 eggs per sac and can make 20 egg theca over a life. In comparison, the larger western total darkness widow spiders lay about 300 eggs per pouch but make 10 or so egg pouch before they die.
Reading: Center for Invasive Species Research
Habitat Preferences: The brown widow builds its vane in privy, protect sites around homes and in woody vegetation with branches. Some typical sites selected by embrown widows for web build up are empty containers such as buckets and greenhouse pots, mail boxes, submission room corners, under eaves, storage closets and garages, recessed hand grips of plastic garbage cans, undercarriages of motor vehicles that are stationary for long periods, and the undersides of outdoor furniture and work iron railings. They choose places that are more debunk than sites chosen by black widows and hence, appear to be at higher risk for interactions with humans deoxyadenosine monophosphate for as bites are concerned.
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Spider Bites: The bite of a brown widow spider is minor in comparison to that of a black widow. Although one frequently cited cogitation demonstrates that, drop per drop, brown widow spider malice is adenine toxic as early widow species, venom perniciousness is merely one aspect when considering a spider ‘s morsel likely. An african survey with 15 affirm bites demonstrated that the brown widow spider bite victims showed none of the classic symptoms of latrodectism, a response induced by neurotoxins in the malice of spiders in the genus Latrodectus ( for example, embrown widows, black widows [ L. mactans ], australian redbacks [ L. hasselti ], european black widow [ L. tredecimguttatus ], and New Zealand ‘s katipo spider [ L. katipo ] ). The reason for the weaker effect of brown university widow bites on humans is possibly because the brown widow does not have or can not inject as much venom as its larger relatives. The two major symptoms of a embrown widow bite were that the pungency hurt when it was inflicted and it left a red target. These two symptoms are not much different from the bite of normal family spiders. however, there is one late reputation of a control brown widow bite manifest in more austere symptoms that required hospitalization of the pungency victim.
Brown widows appear to be occupying the same recess as black widows therefore consequently, there may be a lurch in the species constitution. Considering that the embrown widow is less dangerous and may be supplanting the native western black widow from habitats, it is conceivable that the risk of serious injury from overall spider pungency may decrease in southern California as the brown widow spreads .
Control of Brown Widows: There is no specific information regarding the operate of brown widows by insecticides. Most stream advice is what is used for controlling spiders in general. therefore, most commercially available insecticides should work on brown widows. Take wish to spray up into holes and crevices. Reducing clutter around the sign of the zodiac and in the garage should eliminate nest sites for them. besides, one should store garage items in slide fastener blockage formative bags where there might be interactions with spiders. These items include rarely wear garments such as garden clothes and gloves, amateur items like sports equipment ( i.e., baseball gloves, roller skates ) and other items where spiders can crawl up into holes where fingers can be inserted .