| Brown widow spider | |
|---|---|
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Arachnida |
| Order: | Araneae |
| Suborder: | Araneomorphae |
| Family: | Theridiidae |
| Genus: | Latrodectus |
| Species: | L. geometricus |
| Binomial name | |
| Latrodectus geometricus Koch, 1841 |
|
The spider Latrodectus geometricus, commonly known as the brown widow, grey widow, or geometric button spider, is one of the widow spiders in the genus Latrodectus. As such, it is a "cousin" to the more famous Latrodectus mactans. The brown widow is found in parts of the southeastern, southern and southwestern United States (including Florida, Alabama, California, Kansas, Oklahoma, Nevada, Louisiana, Mississippi, Georgia, South Carolina, North Carolina, Tennessee, Ohio, Michigan, Arizona, New Mexico and Texas); outside of the U.S. there are reports in parts of Australia, Afghanistan, Japan[1], South Africa and Cyprus. The origin of this species is uncertain, as specimens were independently discovered in both Africa and the Americas. They are usually found around buildings in tropical areas.
L. geometricus is generally lighter in color than the black widow species—the color can range from tan to dark brown to black, with shades of grey also possible. Like the black widow species in the United States, L. geometricus has a prominent "hourglass" marking on the underside of the abdomen; the brown widow's hourglass, however, is usually a vivid orange or a yellowish color. Unlike the black widow, L. geometricus has a black-and-white "geometric" pattern on the dorsal side of its abdomen. Although the Latin name comes from this pattern, a spider's coloring can and does darken over time and the pattern may become obscured. Brown widows are often preyed on by mud daubers and sometimes by digger wasps.
Brown widows can be located by finding their eggsacks, which are easily identifiable. They resemble a sandspur, having pointed projections all over, and they are sometimes described as "spiky" in appearance. Eggs hatch in approximately 20 days.[2]
Like all Latrodectus species, L. geometricus has a neurotoxic venom that, drop by drop, is as toxic as the black widow's. Dr. G.B. Edwards, a University of Florida arachnologist, claims brown widow venom is twice as potent as black widow venom, but is usually confined to the bite area and surrounding tissue, as opposed to the black widow's. A UC Riverside professor stated toxicity isn't the only factor. After viewing spider bites, he claimed the majority of spider bites were similar to those of other house spiders, possibly because they cannot deliver the same amount of venom as the black widow. Other sources say the brown widow is less venomous than L. mactans. Regardless, very few people who have been bitten describe the experience as painful. Unless a person is allergic or has a pre-existing medical condition, no concern is needed in the garden, home, or shed.
Similar widows include the L. rhodesiensis, a brown-colored relative of L. geometricus which is native to Zimbabwe; both species are collectively known as brown button spiders throughout southern Africa.