Spiders Commonly Found in Utah
Utah's diverse geography provides habitats for a variety of spider species. While the majority of spiders in Utah are harmless, some species can inflict painful bites and should be avoided. Knowing how to identify local spiders can help homeowners take precautions and coexist safely with these remarkable creatures.
Web-Building Spiders
Many spiders construct webs to capture prey. Web designs vary among species and showcase unique architectural skills. Common web-builders in Utah include:
Garden Spiders
Garden spiders (genus Araneus) weave distinctive orb-shaped webs with spokes radiating from a central hub. The cross spider (Araneus diadematus) is one of the most commonly seen. They build large, impressive webs in vegetation around homes.
Long-Jawed Orb Weavers
Closely related to garden spiders, long-jawed orb weavers get their name from extended mouthparts. Common species in Utah are the black and yellow argiope (Argiope aurantia) and banded garden spider (Argiope trifasciata). Their webs often contain prominent zig-zag patterns.
Funnel Weavers
Funnel weavers construct sheets or funnel-shaped webs and wait for prey in the small end. Common Utah species include the grass spider (Agelenopsis sp.) with its long spinnerets and the hobo spider (Eratigena agrestis), which can inflict painful bites.
Wandering Spiders
Many spiders hunt and forage without building webs. These wandering spiders play important roles controlling pest populations in Utah.
Wolf Spiders
Large, hairy wolf spiders actively hunt instead of waiting in webs. Common Utah species include the Carolina wolf spider (Hogna carolinensis) and the plains wolf spider (Lycosa species). Their venom is not considered medically significant.
Jumping Spiders
Jumping spiders have excellent eyesight and pounce on prey. The daring jumping spider (Phidippus audax) is commonly seen around homes. Jumping spiders have mild venom and are not aggressive towards humans.
Crab Spiders
Crab spiders do not spin webs but ambush prey. Whitebanded crab spiders (Misumenoides formosipes) frequent flowers waiting to capture pollinators. Goldenrod crab spiders (Misumena vatia) can change color to blend in.
Sac Spiders
Sac spiders wander at night and hide in silken tubes or sacs during the day. The woodlouse hunter (Dysdera crocata) hunts woodlice at night. Yellow sac spiders (Cheiracanthium) may bite defensively but are generally not dangerous.
Dangerous Spider Species in Utah
A few spider species found in Utah pose more significant risks to humans and pets if they bite. These include:
Black Widow Spiders
The infamous female black widow has a distinctive red or orange hourglass marking on her underside. Venom from a black widow bite can cause muscle spasms, pain, and nausea. Seek medical attention if bitten.
Brown Recluse Spiders
Brown recluse spiders have violin-shaped markings on their heads and may wander indoors. Their venom can break down skin and tissue around a bite wound. Seek immediate medical care if bitten.
Hobo Spiders
Some research suggests the hobo spider's venom may cause necrosis and require hospitalization, though findings are conflicting. Apply first aid and monitor any bites from these fast-moving funnel weavers closely.
Identifying Common Utah Spiders
Learning to recognize spider species helps assess potential risks and appreciate their diversity. Here are some identification tips for common Utah spiders:
Orb Weavers
Orb weavers like garden spiders have rounded abdomens and build intricate, circular webs. Look for signature web shapes, patterns, and behaviors:
- Garden spiders make near-perfect circular webs with zig-zag designs.
- Long-jawed orb weavers build vertical webs and hang head down.
- Males are much smaller than females and live at web edges.
Funnel Weavers
Funnel weavers have more elongated bodies and spinnerets at the end of their abdomens. Webs form sheets or funnels close to the ground:
- Grass spiders build flat, maze-like webs in vegetation.
- Aggressive hobo spiders do not spin webs and wander into homes.
- Males have bulbous pedipalps (mouthparts) for reproduction.
Wandering Spiders
Wandering spiders do not build webs and actively hunt instead. Look for eye patterns, methods of ambush, and behaviors:
- Jumping spiders have large front eyes and pounce on insects.
- Crab spiders hide in flowers and can change color.
- Wolf spiders carry egg sacs attached to their spinnerets.
Dangerous Spiders
Black widows, recluses, and hobo spiders have distinctive markings and behaviors to note:
- Black widows have red hourglass shape on their undersides.
- Brown recluses have violin-shaped markings on their heads.
- Hobo spiders aggressively charge when threatened.
Spider Bite Symptoms and Treatment
Most spider bites only cause mild pain, itching, or redness. However, some Utah spiders can inflict painful, medically significant bites. Know how to recognize and respond to dangerous spider bites in the state.
Black Widow Spider Bites
Black widows have potent neurotoxic venom. Bite symptoms include:
- Intense pain spreading from bite area
- Rigid abdominal muscles or muscle spasms
- Nausea, profuse sweating, headache
- Elevated blood pressure and breathing rate
If bitten by a black widow, clean the wound and apply ice packs. Seek medical evaluation for possible antivenom treatment.
Brown Recluse Spider Bites
Brown recluse venom can destroy surrounding skin and tissue. Bite signs include:
- Sharp burning pain developing over several hours
- Blistering, ulceration, dark scab formation
- Systemic symptoms like fever, rash, nausea (less common)
See a doctor immediately if bitten by a brown recluse. Rapid treatment can reduce damage from venom toxins.
Hobo Spider Bites
Though controversial, some research links hobo spider bites to dermonecrosis. Watch for:
- Instant burning pain, possibly spreading from bite site
- Itching, tingling, numbness of skin
- Blistering, ulceration at bite area hours later
Clean hobo spider bites and monitor for spreading pain, rash, or blisters. Seek medical care promptly if symptoms worsen.
Preventing Spider Bites in Utah
While most spiders pose little danger, minimize risks from venomous species with these tips:
- Remove piles of debris and wood around the home.
- Keep basements, sheds, and garages clutter-free.
- Seal cracks and openings in the foundation.
- Install good lighting and motion-activated lights outdoors.
- Shake out shoes, clothing, and linens before use.
- Use insecticides sparingly and only when necessary.
Teach children not to touch spiders and to alert adults if they spot one. Seek treatment quickly if you suspect a venomous bite.
Understanding local spiders helps homeowners take sensible precautions while still appreciating the vital roles of these fascinating creatures in Utah's ecology.
FAQs
What is the most common spider in Utah?
Some of the most common spiders spotted around Utah homes and gardens include orb-weavers like garden spiders and long-jawed orb weavers. Jumping spiders, crab spiders, wolf spiders, and funnel weavers like grass spiders are also widespread.
How dangerous are wolf spiders in Utah?
Wolf spiders are very common in Utah but not considered dangerous to humans. Their venom is not toxic to people. They may bite if threatened or handled but will otherwise retreat. Wolf spider bites cause mild pain and swelling.
Where are brown recluse spiders found in Utah?
Brown recluse spiders inhabit darker, undisturbed spots like attics, basements, and sheds. They are most common in southern Utah but may range statewide. Carefully inspect or shake out items from storage areas before touching them.
What should I do if bitten by a black widow?
Black widow bites can be very painful and dangerous. Seek emergency medical care if bitten. Clean the wound, apply ice packs, and capture the spider safely for identification. Antivenom can be given to treat black widow envenomation.
How can I spider-proof my home?
To discourage spiders from entering your home, seal cracks and gaps, install good lighting and motion lights outdoors, clear clutter from basements and sheds, and shake out or inspect items from storage before moving them inside. Be vigilant in warmer months when spiders are most active.
Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional before starting any new treatment regimen.
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