Brown recluse or look-alike? A spider ID guide for DFW

The surest way to tell a brown recluse from a look-alike is its eyes: recluses have six eyes arranged in three pairs, while most spiders have eight. A true recluse also has uniformly colored legs and abdomen with no stripes, bands or spots. The violin mark on its back is much less reliable, because many harmless spiders have markings that look like one.

Are brown recluses found in Dallas-Fort Worth?

Yes. Texas A&M AgriLife Extension says brown recluse spiders can be found inside and outside throughout Texas. They are active outdoors from spring through fall and can stay active year-round in climate-controlled buildings.

Texas actually has several recluse species. AgriLife's Field Guide to Common Texas Insects lists the brown recluse (Loxosceles reclusa), the Texas recluse (L. devia) of Central and South Texas, the Big Bend recluse (L. blanda) of West Texas, and others in scattered locations. Telling these species apart takes a specialist and a microscope, but they share the same basic field marks. For homeowners, the practical question is simpler: is this a recluse or not?

Know the suspect: what does a brown recluse look like?

Use these field marks together. No single one is enough by itself, except that a spider with eight eyes is not a recluse.

1. Six eyes in three pairs. The University of California, Riverside spider ID guide describes one pair in front and a pair on either side, arranged in a semicircle. The CDC's venomous spider page notes that most spiders have eight eyes. A magnifying glass or a zoomed phone photo helps.
2. Uniform color on the abdomen. UCR describes a uniformly colored abdomen that ranges from cream to dark brown, covered in fine hairs, with no pattern.
3. Uniform color on the legs. No stripes and no bands. UCR also notes the legs have only fine hairs, not spines.
4. Modest size. AgriLife describes an adult as about the size of a quarter to a half-dollar, legs and all, and a light tan to dark, grayish brown color that is uniform. UCR puts the body at about ⅜ inch.
5. The violin, with caution. A recluse has a dark violin shape on the front body section (cephalothorax), with the neck of the violin pointing back toward the abdomen.

Recluses also make small retreat webs behind objects, not webs out in the open, according to UCR.

The illustrations on this site are drawings, not identification photographs. Compare any spider you find with the field marks above and with our brown recluse profile.

Why isn't the violin mark enough?

Because people see violins everywhere. UCR's guide warns that non-arachnologists "creatively misinterpret many markings on spiders as 'violins.'" An arachnologist writing for the Burke Museum goes further and calls the fiddle mark "worthless" for identification, noting that six eyes in three pairs are shared by fewer than 1% of spiders, so checking the eyes rules out most mistakes.

Even AgriLife's entomologist notes the violin mark is sometimes faint and can resemble markings on other, non-venomous spiders, while the eye pattern is "pretty distinctive."

Which spiders get mistaken for brown recluses?

UCR's guide walks through spiders that are often sent in as recluses. Here is how to rule them out:

• Spitting spiders (Scytodes). These have a similar six-eyed pattern, which makes them the trickiest. But they have no violin, and they have more than one color on the legs and abdomen. AgriLife notes that only one other spider group in Texas shares the recluse eye pattern, and that group is not venomous.
• Cellar spiders. Some have a mark that looks like a violin, but they have eight eyes and more than one pigment on the abdomen.
• Kukulcania spiders. They can darken near the eyes, but they have eight eyes clumped together and dark spines on the legs.
• Funnel weavers. Multiple colors or patterns on the legs or abdomen.
• Orbweavers. Multiple colors on the legs or abdomen, plus large, obvious webs that a recluse would never build.
• Huntsman spiders. Multiple pigments on the legs or abdomen.

The pattern is the same each time. Stripes, bands, spots, spines or eight eyes all mean "not a recluse."

What about black widows?

Black widows are the other spider of medical concern in North Texas, and they look nothing like a recluse. The CDC describes them as shiny black with a pattern of red coloring on the underside of the abdomen, the familiar hourglass. They build webs between objects and are often found in undisturbed places like woodpiles and fence lines. See the black widow profile for more.

Was it really a recluse bite?

Often, no. UCR states that "many conditions are misdiagnosed as recluse bites when their cause is something else like infection, bad reaction to medication, diabetic ulcers, Lyme disease, or other underlying medical conditions." The same guide notes that many of the graphic wounds labeled as recluse bites online can be other conditions, such as necrotizing bacterial infections.

AgriLife's entomologist makes a similar point, citing antibiotic-resistant staph infections that look similar to spider bites, and adds that there has never been a confirmed death attributed to the brown recluse spider.

That does not mean real bites are harmless. AgriLife's brown recluse fact sheet says bites can be serious, sometimes leading to secondary infections, skin ulcers, pain and, rarely, life-threatening complications. It also says brown recluses often live in homes without incident.

The takeaway: do not diagnose a wound from a photo, and do not assume a spider caused a sore you never saw it make. Let a medical professional evaluate it.

What should you do after a suspected spider bite?

This is general guidance, not a diagnosis. The CDC's first aid steps for a venomous spider bite are:

1. Stay calm.
2. Wash the bite with soap and water.
3. Apply a cloth dampened with cold water or filled with ice to reduce swelling.
4. Raise the bitten limb if you can.
5. Do not try to remove venom.
6. Get medical attention.

AgriLife notes that most recluse bites behave like an ordinary wound that should be cleaned, dressed and watched, and that a serious reaction or a wound that is not healing properly needs medical attention. If symptoms are severe or you are worried, do not wait. Call Poison Control at 1-800-222-1222 for advice on any bite or sting.

How do you avoid surprise encounters?

Recluses are shy, which is how they got the name. AgriLife describes bites as typically accidents, and the CDC notes a brown recluse cannot bite without pressure against the skin. These AgriLife prevention tips reduce the odds:

• Wear gloves. Use leather gloves when working outside, cleaning out sheds or moving stored items.
• Shake things out. Shake out seasonal clothes, linens and shoes before using them.
• Use the dryer. AgriLife suggests running seasonal clothes in the dryer on high heat for about 45 minutes.
• Cut the clutter. AgriLife's fact sheet points to cluttered closets, garages, crawl spaces and attics as favored hiding spots, and recommends removing clutter and taping storage boxes shut.
• Seal entry points. Seal doors and windows.
• Monitor. Sticky traps placed along walls passively capture recluses and show where they are active.

If you consider an insecticide, AgriLife's fact sheet notes recluses are difficult to kill with most insecticides. The label is the law: the EPA notes it is a violation of federal law to use a product in a manner inconsistent with its labeling. For a walkthrough of what a label tells you, see how to read a pesticide label.

When to get help

Get medical care for any serious reaction to a bite, symptoms such as fever or chills, or a wound that is not healing properly. For a household where recluses keep turning up, AgriLife's fact sheet says a professional pest control company is the best solution to an infestation. In Texas, the Structural Pest Control Service of the Texas Department of Agriculture licenses applicators who treat in and around structures, so look for a licensed pest professional.

This field guide is educational and does not offer treatment bookings.