Hawaii, a popular destination known for its natural beauty, often prompts questions about its wildlife, particularly venomous spiders. While the islands are home to numerous spider species, only a small number are considered medically significant to humans. Understanding which spiders pose a risk and how to react to potential encounters can help visitors and residents enjoy the islands with greater peace of mind.
Venomous Spiders Present in Hawaii
Two species of widow spiders are recognized as medically significant in Hawaii: the brown widow spider (Latrodectus geometricus) and the black widow spider (Latrodectus mactans). The brown widow is more commonly found across the islands. This spider is typically mottled tan and brown with black accents and an orange hourglass marking on its underside. Brown widows also produce spiky or spiny egg sacs.
The black widow spider is generally less common in Hawaii. Female black widows are glossy black with a prominent red hourglass shape on their underside. Both brown and black widows prefer secluded, protected areas such as woodpiles, under outdoor furniture, in garages, and around homes. The brown recluse spider, a concern elsewhere, is not established in Hawaii; however, a related species, the brown violin spider (Loxosceles rufescens), can be found on some islands.
Recognizing and Responding to Bites
Widow spider bite symptoms vary, but generally begin with pain at the bite site, often described as a pinprick. This initial sensation is followed by dull muscle pain spreading from the bite area, intensifying over several hours. Systemic effects include muscle cramps and spasms, particularly in the abdomen, chest, or back, along with nausea, vomiting, sweating, headache, and elevated blood pressure. While brown widow venom is potent, these spiders typically inject less venom, leading to milder, more localized reactions than black widow bites.
If a spider bite is suspected, clean the wound thoroughly with mild soap and water. Applying a cool compress or ice pack to the affected area can reduce pain and swelling. Elevating the bitten limb, if possible, may minimize swelling. Over-the-counter pain relievers or antihistamines can manage discomfort and itching.
Seek prompt medical attention if the bite is from a known widow spider or if the species is uncertain. Seek professional care immediately if severe symptoms develop, such as intense pain, abdominal cramping, a spreading wound, or difficulty breathing or swallowing. If the spider can be safely captured, bring it to the medical facility to assist in diagnosis and treatment.
Minimizing Encounters and Understanding Risk
To reduce spider encounters, especially venomous ones, take several practical measures around homes and during outdoor activities. Sealing cracks and openings, installing window screens, and removing spider webs can deter them from entering living spaces. Keeping outdoor areas clear of clutter like woodpiles, rocks, and debris minimizes spider hiding spots.
When disturbing spider habitats, such as gardening, moving firewood, or cleaning storage areas, wear protective clothing like gloves, long-sleeved shirts, and long pants. Inspect and shake out shoes and clothing before putting them on to prevent accidental bites. While venomous spiders are present in Hawaii, bites are uncommon, and fatalities are rare, especially with timely medical care. Most spider bites occur as a defensive reaction when a spider is disturbed or trapped.