The bold jumper spider (Phidippus audax) is a common arachnid found across North America. This article explores concerns about their bites and provides information on identifying them and understanding their behavior.
Are Bold Jumpers Venomous?
Bold jumper spiders are venomous. The distinction between “poisonous” and “venomous” is important: poisonous substances cause harm when ingested, while venom is injected, typically through a bite. Bold jumpers produce venom, which they primarily use to subdue insect prey like caterpillars, flies, and other small arthropods. Their venom works rapidly to immobilize their quarry, allowing the spider to feed.
However, their venom is not considered medically significant to humans, meaning its effects are generally minimal. Bites are rare and usually occur only if the spider feels threatened, cornered, or accidentally pressed against skin. They are more inclined to escape or display a defensive posture by raising their front legs rather than biting.
What Happens After a Bold Jumper Bite?
If a bold jumper spider does bite, the reaction is typically mild and localized. The sensation is often compared to a bee sting or a mosquito bite, causing a small welt, localized pain, and some itching or stinging at the site. Redness and slight swelling may also develop, usually resolving within one to two days. In many instances, a bite might even be asymptomatic, meaning no symptoms are felt.
For managing a bold jumper bite, basic first aid is usually sufficient. Clean the bite area thoroughly with mild soap and water to reduce the risk of infection. Apply a cold compress to alleviate swelling and discomfort. Over-the-counter pain relievers (e.g., ibuprofen, acetaminophen) can manage pain, and antihistamines may help with itching. Seek medical attention only if symptoms worsen, signs of infection appear, or an allergic reaction develops, though such reactions are uncommon.
Recognizing Bold Jumpers and Their Habits
Bold jumper spiders have several distinct physical characteristics. Adults have a black, fuzzy body, 6 to 15 mm long, with females slightly larger. A prominent feature is often a large white, orange, or reddish triangular spot on their abdomen, sometimes accompanied by two smaller spots. Their most striking characteristic is their large, iridescent chelicerae, appearing metallic green, blue, or pinkish-purple. They have eight eyes, including a large, forward-facing pair that provides excellent vision.
These spiders are active hunters during the day, relying on their keen eyesight to stalk and pounce on prey. Unlike many other spiders, bold jumpers do not build webs to catch food; instead, they use silk as a safety line when jumping. Their jumping ability allows them to cover distances up to 40 times their body length for hunting or escaping predators. Bold jumpers are not aggressive towards humans and typically flee when approached, often found in gardens, on fences, or inside homes.