Spider Bites: The bite of a brown widow spider is minor in comparison to that of a black widow. They choose places that are more exposed than sites chosen by black widows and hence, appear to be at higher risk for interactions with humans as for as bites are concerned. Some typical sites selected by brown widows for web building are empty containers such as buckets and nursery pots, mail boxes, entry way 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 wrought iron railings. Habitat Preferences: The brown widow builds its web in secluded, protected sites around homes and in woody vegetation with branches. In comparison, the larger western black widow spiders lay about 300 eggs per sac but make 10 or so egg sacs before they die. They lay about 120-150 eggs per sac and can make 20 egg sacs over a lifetime. Reproduction: Brown widows are prolific breeders in that they can produce many egg sacs in a lifetime, often several in quick sequence. The egg sac of the Brown Widow Spider is so distinctive that it is readily recognizable. The egg sac 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 a brown widow has multiple silk spicules projecting out from the surface. Most spider egg sacs that are free (i.e., are not attached to flat surfaces) look like a lemon drop candy or a little cotton ball with indistinct edges. However, a more diagnostic feature of a brown widow is its egg sac. Being able to discern brown widows from immature black widows is therefore difficult and requires some experience. The brown widow looks similar 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. The Brown Widow Spider does have an hourglass but it is typically an orange shade rather than the vivid red of a black widow. At the top of each diagonal stripe, there is a black mark, which is rather conspicuous and square-ish. In mature females, there is usually a dorsal longitudinal abdominal stripe and three diagonal stripes on each flank. After that, the spider was found with greater frequency in Los Angeles, Orange and San Diego counties.ĭescription of the Brown Widow: Unlike its starkly black-and-red colored relative, the black widow, the coloration of a brown widow consists of a mottling of tan and brown with black accent marking. The first specimens were collected in Torrance in 2003. As specimens were found in new locations in the southeastern United States, this species was simultaneously being collected with greater frequency in southern California. Brown widows are now known from Texas to Georgia and South Carolina. However, around the year 2000, it started showing up in other Gulf Coast states. In North America, the Brown Widow Spider was restricted for many decades to the Florida peninsula. 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. 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 continuing its expansion in Southern California and could possibly move northward into Central California. The Situation: The brown widow spider, Latrodectus geometricus,became established in Southern California in early 2000 and has become well entrenched as part of the local spider fauna in urban Los Angeles and San Diego.
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