Hawaii is home to a diverse array of spiders, leading to questions about which ones might pose a threat. Understanding the species present can help alleviate common fears. Most spiders encountered in the Hawaiian Islands are not harmful to humans. This article clarifies the reality of spiders in Hawaii, highlighting species that warrant caution and those that are harmless.
Dangerous Spiders Found in Hawaii
While the brown recluse spider (Loxosceles reclusa) is not established in Hawaii, the closely related Mediterranean recluse spider (Loxosceles rufescens), also known as the brown violin spider, is present. This spider is light to dark brown with a distinct violin-shaped marking on its back, measuring about 7 to 7.5 millimeters. It prefers secluded, undisturbed locations such as basements, closets, and storage areas, often found in damp environments. Bites can cause localized tissue damage, leading to open sores, swelling, and necrosis, though they are generally not life-threatening.
Two widow spider species are found in Hawaii: the Southern black widow (Latrodectus mactans) and the brown widow (Latrodectus geometricus). The Southern black widow has a glossy black body and a red hourglass marking on its underside. Its venom contains neurotoxins that can affect the nervous system, causing muscle pain and cramping. Brown widow spiders are tan to light brown with an orange or yellow hourglass marking on their abdomen. While their venom is potent, brown widows typically inject less, resulting in milder bites compared to the black widow. Both species build irregular webs in undisturbed outdoor areas like woodpiles, sheds, and under patio furniture; bites usually occur when the spiders feel threatened.
Common Harmless Spiders
The cane spider (Heteropoda venatoria), also known as the huntsman spider, is one of Hawaii’s largest spiders, with a leg span up to 4 to 6 inches. It has a flat, hairy body and ranges from brown to grayish-brown. These incredibly fast hunters do not spin webs for prey. Despite their size, cane spiders are timid, and bites are rare, occurring only in self-defense. If a bite occurs, it typically results in minor, localized pain similar to a bee sting, and they are beneficial for controlling household pests like cockroaches.
Hawaiian garden spiders (Argiope appensa) are common, known for constructing large, intricate orb-shaped webs with a distinctive zig-zag pattern in the center. These spiders have a silver carapace and a yellow and black banded abdomen. While they possess venom, it is not harmful to humans. Bites are infrequent, usually only happening if the spider is provoked or handled, resulting in mild, localized symptoms like pain, swelling, and redness that resolve without serious medical intervention.
“Daddy long-legs” commonly refers to two different arachnids in Hawaii. Cellar spiders (Pholcidae) are true spiders with long, thin legs and small bodies, often found in dark, undisturbed corners of homes. Although they have venom, their small fangs mean bites are generally harmless to humans, typically causing only a brief, mild stinging sensation. Harvestmen, another arachnid called “daddy long-legs,” are not true spiders and do not produce venom, posing no threat.
Responding to a Spider Bite
If you suspect a spider bite, immediate first aid can help manage symptoms. Gently wash the affected area with mild soap and water. Apply a cold compress or an ice pack wrapped in cloth to the bite site to reduce swelling and discomfort. Elevating the bitten limb, if possible, also minimizes swelling. Over-the-counter pain relievers can alleviate pain, and antihistamines may help with itching.
Seek professional medical attention if certain symptoms develop. Medical consultation is advised for severe pain, significant swelling, muscle cramping, or stiffness spreading from the bite area. Other concerning symptoms include blister formation or deep blue/purple discoloration around the bite, as well as systemic reactions like fever, nausea, vomiting, headache, or difficulty breathing. If the bite area shows signs of infection (increasing redness, warmth, or pus), or if you are unsure about the spider, prompt medical evaluation is recommended.