Female Brown Widow, Latrodectus geometricus
Photo ©Sean McCann used with permission
 

Latrodectus geometricus is commonly known as the brown widow, grey widow, brown button spider, or geometric button spider. The brown widow is found in parts of the northeastern and southern United States (including Florida, Alabama, California, Louisiana, Mississippi, Georgia, Tennessee, and Texas); as well as in parts of Australia and South Africa.

L. geometricus is generally lighter in color than the black widow species; the color can range from tan to dark brown to black. Like the black widow, L. geometricus has a prominent "hourglass" marking on the underside of the abdomen. However, the brown widow's hourglass is usually an orange or a yellowish color.

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.

Like all Latrodectus species, L. geometricus has a medically significant neurotoxic venom. Dr. G.B. Edwards, a University of Florida arachnologist claims that brown widow venom is twice as potent as the black widow venom, but is usually confined to the bite area and surrounding tissue, as opposed to the Black Widow. Other sources say that the brown widow is less venomous than L mactans. Regardless, people who have been bitten typically describe the experience as very painful and extreme care should be taken when working or playing in the areas they inhabit.

A sexually mature male spins a "sperm web", deposits semen on it, and charges his palpi with the sperm. The male then inserts his palpus into the female's spermathecal openings. The female deposits her eggs in a globular silken container in which they remain camouflaged and guarded. A female black widow spider can produce four to nine egg sacs in one summer, each containing about 100-400 eggs. Usually, eggs incubate for twenty to thirty days. Rarely, do more than one hundred survive through this process. On average, thirty will survive through the first molting, due to cannibalism, lack of food, or lack of proper shelter. It takes two to four months for black widow spiders to mature enough to breed, however full maturation typically takes six to nine months. The females can live for up to five years, while a male's lifespan is much shorter. Contrary to popular belief, the female only rarely eats the male after mating, and L. mactans is the only black widow species for which this form of sexual cannibalism has been observed in the wild.