A Guide to Identifying Venomous and Harmless Brown Spiders Found in Iowa

What To Know About Brown Spiders Found in Iowa

Iowa is home to a variety of spiders, some of which have the potential to inflict bites that can be medically significant. One spider group that generates particular concern are brown spiders. Learning to identify and safely avoid Iowa's brown spiders can help reduce bite risks.

Brown Recluse Spiders in Iowa

The most notorious brown spider in Iowa is the brown recluse spider. Despite their name, brown recluse spiders are not exclusive to reclusive areas. They have been found throughout Iowa in homes, garages, barns, and other man-made structures.

Brown recluse spiders are usually light to medium brown in color with a darker violin-shaped marking on the cephalothorax (fused head and thorax). They have six equal-sized eyes arranged in three pairs, with a leg span around the size of a quarter.

Brown Recluse Bite Symptoms

While reclusive by nature, brown recluse spiders may bite if threatened or pressed against the skin. Their venom contains a tissue-destroying enzyme called sphingomyelinase D.

Most brown recluse bites produce mild symptoms like itching, redness, and slight swelling. In some cases bites can cause more intense local effects:

• Severe pain, swelling, and redness
• Blistering of the skin
• Ulceration and necrosis of tissue
• Sloughing off skin and exposed underlying tissue
• Scarring where damaged tissue regenerates

Healing typically takes 6-8 weeks but scars may remain. Seek medical care if bite reactions seem severe or persist beyond 48 hours.

Northern Brown Spider Facts

Another brown spider found in Iowa is the northern brown spider. They appear medium to dark brown and grow up to around 9mm in body length. Their legs have faint gray or brown banding.

Northern brown spiders construct irregular web retreats in dark corners of buildings. The webbing is a crisscross mesh with no obvious pattern. Northern brown spiders prey mainly on other spiders.

Bites from northern brown spiders are uncommon. When they do occur, symptoms tend to remain mild with some localized itching and pain. Northern brown spider bites are not medically significant.

Identifying Other Harmless Brown Spiders in Iowa

Not all brown spiders in Iowa are potentially dangerous. Some harmless spiders that may reside in Iowa homes and property include:

Cellar Spiders

Cellar spiders have very long, thin legs and small bodies under 9mm in length. Their coloring ranges from pale yellowish to brown. A dark stripe may run down the top of their abdomen.

Cellar spiders build loose irregular webs in dim corners of basements and cellars. The messy webs help trap insects for the spider to eat. Cellar spider bites pose no real hazard to humans.

Pirate Spiders

Pirate spiders are characterized by a cephalothorax that is wider than it is long, and 8 eyes arranged in two rows. Their bodies grow up to around 1/5 inch long with brown and gray mottled patterns.

Pirate spiders do not spin webs to catch prey. They hunt by ambushing passing insects on surfaces like leaves and tree trunks. Pirate spider bites are not toxic to humans.

Wolf Spiders

Wolf spiders have robust bodies measuring up to 1 inch long covered in brown and grey camouflaging hair. They have 8 black eyes arranged in 3 rows. Some wolf spiders construct burrows while others actively hunt prey.

Though wolf spiders appear intimidating, their bites cause only mild stinging comparable to a bee sting. They are not medically significant to humans in most cases.

Avoiding Brown Spider Encounters in Iowa Homes

To reduce the chances of meeting brown spiders around your Iowa property, you can:

• Clear clutter like stacks of materials or cardboard where spiders may hide
• Regularly vacuum and dust to remove spiders, webs, and egg sacs
• Seal cracks in floors, walls, windows to block spider entry points
• Inspect items like firewood, plants, boxes before bringing them indoors
• Keep beds pulled away from walls and tuck in sheets to prevent nighttime encounters
• Install insect screens on windows and doors to deter spiders

Safely Controlling Brown Spiders

If you spot a potentially dangerous brown spider, use caution and avoid direct contact:

• Vacuum the spider if possible then dispose of the bag outside immediately
• Apply insecticides labeled for spiders into cracks and corners
• Use glue boards or sticky traps to capture wandering spiders
• Seal boxes and bags containing items removed from infested areas for 2 weeks to contain spiders

Consider professional pest control if brown spider sightings are frequent in the home. Treatment focuses on exclusion methods and insecticide webs around likely harborage sites.

What to Do After a Potential Brown Spider Bite

Should you suspect a brown spider bite, take these immediate steps:

• Wash the bite area with soap and water to prevent infection
• Apply a cool compress to relieve swelling and pain
• Elevate the bite location if possible to slow venom spread
• Take an over-the-counter pain medication if needed for discomfort
• Monitor for signs of severe reaction and contact a doctor promptly if they develop

Bring the spider specimen with you for identification if possible. Prompt medical care can mitigate problems if a toxic spider is confirmed as the biter.

The Takeaway

Brown spiders like the brown recluse found in Iowa can inflict bites with the potential for severe reactions. But other harmless brown spiders also reside in the state. Learning to properly identify and safely avoid Iowa's brown spiders reduces the risks posed by venomous species.

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.