Many people encounter dark-colored spiders and wonder about their identity and potential threat. While “black spider” is not a single species, this term encompasses numerous types. Understanding common black spiders can help in identifying them and assessing potential risks.
Common Black Spiders to Know
The Southern Black Widow (Latrodectus mactans) is a well-known black spider, recognized by its glossy black body and a distinct red or orange hourglass marking on the underside of its abdomen. Females measure 13-16 mm, while males are smaller and may have red spots or streaks. Northern Black Widows (Latrodectus variolus) are similar but often display a broken hourglass pattern, appearing as two separate red triangles. Both species construct irregular, tangled webs, usually at ground level in sheltered, dark locations like woodpiles or basements.
Another frequently encountered dark spider is the False Widow (Steatoda grossa), which can be mistaken for a black widow due to its glossy, dark brown to black appearance and rounded abdomen. These spiders range from 6-10 mm and may have lighter markings, but they lack the prominent red hourglass. False widows also build tangled, criss-cross webs in sheltered spots, including indoors.
The Bold Jumper (Phidippus audax) is a robust, fuzzy black spider ranging from 8-15 mm, noted for its large, forward-facing eyes and a distinctive iridescent orange, red, or white spot on its abdomen. Its chelicerae can also display an iridescent green or blue sheen. Unlike web-building spiders, bold jumpers are active hunters that stalk prey and do not construct webs for capture, though they may create silk retreats for resting or egg cases.
The Black House Spider (Badumna insignis) is a velvety black to dark brown spider with a robust body, measuring 10-18 mm for females. Its abdomen can appear charcoal grey with white markings. These spiders create messy, lacy, funnel-shaped webs, often around window frames, earning them the alternative name “window spiders.”
How to Identify Black Spiders
Identifying black spiders involves observing several key physical characteristics and behaviors. Look for distinguishing features like body shape, texture (glossy, fuzzy, velvety), and specific markings. For example, the red hourglass on a female black widow’s underside is a primary identifier, while bold jumpers often display a single iridescent spot.
Also, consider web characteristics or hunting behavior. Tangled, irregular webs suggest a widow or false widow, whereas a funnel-shaped web is typical of a black house spider. Spiders like the bold jumper, which do not build webs for hunting, are known for their quick, jerky movements and jumping ability.
Are Black Spiders Dangerous
Most black spiders are not dangerous to humans; bites are rare and occur only when threatened or disturbed. The primary concern is the female black widow, whose neurotoxic venom affects the nervous system.
A black widow bite can cause immediate sharp pain, followed by severe muscle pain, cramping, nausea, sweating, headache, and difficulty breathing. While rarely fatal for healthy adults, bites can be more serious for young children, older individuals, or those with compromised immune systems, requiring medical attention.
Other common black spiders (false widows, bold jumpers, black house spiders) possess venom, but their bites are not medically significant. Bites from these spiders might result in localized pain, redness, or swelling, similar to a bee sting. To minimize bites, it is advisable to avoid direct contact, wear gloves when working in areas where spiders might hide, and clear clutter in and around the home.