Crab spiders, known for their distinctive appearance and hunting strategies, are often a source of curiosity and sometimes concern. While these arachnids possess venom, a common misconception is that they are “poisonous” to humans. Crab spiders are not considered medically significant or dangerous to people. Their venom and behavior are adapted for subduing small insect prey, not for causing harm to larger mammals.
Understanding Crab Spider Venom
Their venom is a complex mixture of compounds specifically designed to immobilize and digest insect prey, such as bees and flies. This venom is highly effective against the spider’s typical diet, quickly subduing insects.
The chemical composition of their venom is largely benign for mammals. Crab spider venom is not formulated to affect human physiological systems in a harmful way. While a crab spider’s bite can be lethal to an insect, it typically produces only minor, temporary effects in people.
What to Expect from a Bite
Should a crab spider bite a human, which is rare and occurs only in self-defense, symptoms are typically mild and localized. A bite often feels comparable to a mild bee sting. Common reactions include slight pain, redness, or itching at the bite site.
These minor symptoms usually subside within a few hours. Severe reactions, such as an allergic response, are rare but possible, like any insect bite. In most cases, basic first aid, such as cleaning the wound with soap and water and applying a cold compress, is sufficient. Medical attention is generally unnecessary unless symptoms persist, worsen, or an allergic reaction is suspected.
Identifying Crab Spiders
Crab spiders derive their name from their crab-like appearance and movement. They possess two prominent front pairs of legs that are longer and stronger than their others, often held outstretched like a crab’s claws. Many species can also move sideways or backward, further contributing to their crab-like demeanor.
These spiders are ambush predators and do not construct webs for hunting. Instead, they wait on flowers, foliage, or tree bark, often camouflaging themselves by changing color to match their surroundings, appearing in shades of white, yellow, green, or brown. Their flattened bodies and ability to blend in make them effective at surprising insects.