The brown widow spider, Latrodectus geometricus, has become increasingly common in various regions, raising public concern. This spider, a relative of the more infamous black widow, is often encountered in urban and suburban environments. Understanding its specific characteristics and the effects of its bite is important for accurate risk assessment.
Identifying Brown Widows
Brown widow spiders exhibit a range of colors, from light tan to dark brown, and sometimes even nearly black, often with a mottled or spotted pattern. A key identifying feature is the hourglass marking on the underside of their abdomen, which is typically orange or yellowish, rather than the vivid red seen in black widows. Female brown widows are relatively small, with a body length of about 12-16 mm, while males are roughly half that size.
The most distinctive characteristic for identifying a brown widow is its egg sac. Unlike the smooth, pear-shaped egg sacs of black widows, brown widow egg sacs are spherical and have numerous small, spiky projections, often described as resembling a sandspur or a thistle.
Understanding Brown Widow Venom
Brown widow spiders possess neurotoxic venom. However, the effects of a brown widow bite are generally considered less severe than those of a black widow. While the venom itself can be potent, brown widows typically inject a much smaller amount during a bite, leading to milder symptoms. This reduced envenomation often results in localized pain at the bite site, redness, and swelling, which may be accompanied by mild muscle cramps, nausea, or headache.
Bites are usually self-limiting, with symptoms resolving within a few hours to a couple of days. Severe systemic reactions are rare, and fatalities are exceedingly uncommon. Though the venom contains neurotoxins, the low quantity injected means that the classic severe symptoms associated with black widow bites, such as widespread muscle pain, intense cramping, and abdominal rigidity, are typically absent or significantly less pronounced.
Distinguishing from Other Spiders
Black widows are typically shiny black with a bright red hourglass marking on their underside, while brown widows display varying shades of brown and an orange or yellowish hourglass. Immature black widows can sometimes be tan with white stripes, making them visually similar to brown widows, but the distinctive spiky egg sac of the brown widow remains a reliable differentiator.
Behavioral differences also exist; brown widows are generally more timid and less aggressive than black widows. They often play dead or drop from their webs as a defense mechanism rather than biting. Black widows, particularly females protecting their egg sacs, can exhibit more aggressive behavior. While both spiders build tangled, irregular webs, brown widows tend to construct theirs in more exposed locations around human dwellings, such as under outdoor furniture or in containers, compared to the more secluded spots favored by black widows.
Responding to a Bite
If bitten, clean the bite area with soap and water. Applying a cold compress or ice pack to the site can help reduce pain and swelling. Elevating the affected limb may also help minimize swelling. Over-the-counter pain relievers, such as acetaminophen or ibuprofen, can manage discomfort, and antihistamines may alleviate itching.
Medical attention is not usually necessary for brown widow bites, as symptoms are typically mild and resolve on their own. However, it is advisable to seek medical care if symptoms worsen, if the bite victim is a child, elderly, or has an underlying health condition, or if there is a concern about an allergic reaction. To reduce the likelihood of bites, consider wearing gloves when gardening or working in areas where spiders might hide, and shake out shoes or clothing left outdoors before use.