Do Sowbug Killer Spider Bite? Exploring the Facts and Myths

Sowbug killer spiders, also known as Dysdera crocata, are a species of spiders known for preying on small, land-based crustaceans called sowbugs and pillbugs. These spiders can be easily identified by their reddish-brown coloration and their elongated, cylindrical bodies.

Although sowbug killer spiders possess large, strong fangs used for hunting, their bites are not typically harmful to humans. Generally, they only bite when they feel threatened or cornered.

As they are predators of sowbugs and pillbugs, these spiders indirectly serve as a natural pest control method in gardens and landscapes. However, they may have some drawbacks, such as their potential to spread indoors and create webs in undisturbed areas.

Sowbug Killer Spider Overview

Identification and Physical Features

The Sowbug Killer, also known as the Woodlouse Hunter (Dysdera crocata), is from the Araneae order within the Animalia kingdom, belonging to the Arthropoda phylum, Arachnida class, and Dysderidae family. These spiders are known for their distinctive features:

  • Six eyes
  • Long legs
  • Coloration: brown, tan, red, purple, orange, or yellow

Habitat and Distribution

Dysdera crocata spiders can be found in various environments, including:

  • Under rocks
  • Among leaf litter
  • In gardens
  • Inside garages

These spiders thrive in moist, dark spaces and are primarily found in North America and Europe.

Feeding Habits and Prey

Sowbug Killer Spiders are experts in preying on specific creatures such as:

  • Pillbugs
  • Mites

They utilize their long legs to catch and immobilize their prey effectively.

Bites and Symptoms

Causes of Bites

Sowbug killer spiders, like most spiders, usually bite humans only when they feel threatened or accidentally disturbed.

Some examples of situations leading to bites:

  • Unknowingly putting on a piece of clothing with a spider inside
  • Accidentally touching or stepping on a spider

Signs and Symptoms of Bites

A sowbug killer spider bite can cause various symptoms. Some common ones are:

  • Itching
  • Pain
  • Swelling
  • Redness

In some cases, bites from more venomous spiders like the brown recluse or the black widow can lead to more severe symptoms, such as:

  • Muscle pain or cramping
  • Headache
  • Increased sweating
  • Difficulty breathing

Severity and Potential Complications

The severity of a spider bite depends upon the type of spider and the individual’s reaction to the venom. In general, sowbug killer spider bites are not considered dangerous and typically cause only mild discomfort.

However, complications can arise in case of bites from venomous spiders such as brown recluse or black widow spiders. These can include:

  • Allergic reactions
  • Skin ulcers
  • Scarring
  • In severe cases, death (very rare)

Dangerous Spider Comparisons

Here’s a comparison table of some dangerous spiders:

Spider Venom Symptoms Severity Remarks
Brown Recluse Necrotizing venom Pain, redness, blisters, necrosis Moderate to severe Can cause severe skin damage
Black Widow Neurotoxic venom Severe muscle pain, cramps, abdominal pain, tremors Moderate to severe Antivenom available
Sowbug killer spider Mild venom Itching, pain, swelling, redness Mild Not considered dangerous

Overall, sowbug killer spiders are not as dangerous as the venomous brown recluse or black widow spiders, and their bites usually cause minor symptoms.

Treatment and Medical Care

First Aid for Bites

If you’re bitten by a sowbug killer spider, follow these first aid steps:

  • Wash the area well with soap and water.
  • Apply an ice pack or wet compress to reduce swelling.
  • Take over-the-counter pain medicine for pain relief.
  • Consider using antihistamines for severe swelling. source

When to Seek Medical Care

You should seek medical care if you experience:

  • Fever or chills
  • Nausea or vomiting
  • Severe pain or worsening pain
  • Signs of infection (e.g., increased redness, warmth, pus)
  • Black widow spider bite symptoms (e.g., muscle cramps, abdominal pain, difficulty breathing) source

Medical Treatment Options

Doctors may prescribe the following treatments, depending on diagnosis and symptoms:

  • Antibiotics to treat or prevent skin infections
  • Pain relievers for moderate to severe pain
  • Antihistamines to reduce itching and swelling
  • Antibiotic ointment for skin sores and blisters source

Pros and Cons of Medical Treatments

Treatment Pros Cons
Antibiotics Effective against infections Potential side effects, antibiotic resistance
Pain Relievers Reduces pain Side effects, potential for addiction
Antihistamines Reduces itching and swelling Side effects, potential for drowsiness
Antibiotic Ointment Helps prevent infections Requires regular application

Remember to always consult a healthcare professional for proper diagnosis and treatment of spider bites.

Prevention and Safety Measures

Minimizing Sowbug Killer Spider Encounters

Sowbug killer spiders, also known as woodlouse spiders, are typically found in damp areas like basements, gardens, and woodpiles. To minimize encounters with these spiders:

  • Keep woodpiles away from the house
  • Remove dead leaves and debris from the yard
  • Seal gaps and cracks in walls and foundations

By creating a clean and dry environment, you will be less likely to encounter these spiders.

Protective Gear and Precautions

When working in areas where dangerous spiders may be present, such as in gardens or basements, it is important to wear protective gear:

  • Gloves
  • Long-sleeved shirts
  • Long pants

Additionally, be cautious when reaching into dark or hidden spaces where spiders may be hiding. Using a tool like a stick to probe areas before reaching in can help prevent bites.

Home and Garden Maintenance

Keeping your home and garden well-maintained is essential in preventing sowbug killer spiders and other dangerous spiders from nesting. Some tips for maintenance include:

  • Regularly cleaning basements and other damp areas
  • Trimming overgrown vegetation and removing leaf litter
  • Removing potential hiding places like woodpiles and rocks

By following these guidelines, you can help reduce your risk of encountering sowbug killer spiders or other dangerous spiders.

Comparative table between Sowbug Killer Spider and other dangerous spider (e.g., Redback Spider):

Feature Sowbug Killer Spider Redback Spider (Australia)
Prevalence Basements, gardens Australia, around the home
Distinct Body Feature Large red fangs Red hourglass shape on the abdomen
Type of Bites Painful but harmless Painful, can cause cramping
Home and Garden Maintenance Importance High High

By understanding the differences between various dangerous spiders, you can better assess the risk in your environment and take appropriate safety measures.

Reader Emails

Over the years, our website, has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Sow Bug Killer


Red Spider with Large Brown Shiny Abdomen
January 13, 2010
Found in the garage this morning next to a box that had been in storage for a long time and had been taken out.
It seems “shy” – it prefers to stay motionless with its legs drawn tightly to the body. I wasn’t even sure it was a spider at first since the abdomen resembles some kind of seed.
To take the photo and get it to extend its legs I had to shake the container a bit.
Malibu, CA

Sow Bug Killer
Sow Bug Killer

Your spider is Dysdera crocata, and BugGuide calls it by three different common names that refer to variations on the common name of its prey.  The names on BugGuide are Woodlouse Hunter, Sow Bug Hunter and Pill Bug Hunter, though Charles Hogue, in his wonderful book Insects of the Los Angeles Basin, refers to it by the even more accurate name Sow Bug Killer.  The Biosecurity of New Zealand website calls this species a Slater Spider because Slater is a common name for the prey in New Zealand and Australia.  According to that site:  “Slater spiders originate in Europe but are now common throughout much of the world. They may be found throughout New Zealand and are common in suburban gardens.

Letter 2 – Battle of the Woodlouse Hunters


Subject: Red Woodlouse Hunters, unfortunate carnage
Location: Maumee, Ohio
October 15, 2012 3:13 am
I was rearing one red woodlouse hunter, a side project from the usual friendly caterpillars, when I found a larger one roaming around in the dark hours of the night. I decided to attempt to rear them together… an obvious rookie mistake as the two mighty spiders began to square off for what looks like a fight to the death… I wish I would’ve done my research before introducing these two impressive spiders, a hard lesson learned.
Signature: Jake

Battle of the Woodlouse Hunters

Hi Jake,
Especially among predators, competition within a species for survival is often greater that inter-species competition.  Your letter did not indicate if the smaller captive was the victim.  Woodlouse Hunters or Sowbug Killers are actually quite amazing spiders.  They are an introduced species native to Europe.  For the record, we only tag postings as Unnecessary Carnage when a person kills a beneficial or harmless species out of fear, ignorance, cruelty or disgust.

Letter 3 – Slater Spider in New Zealand


Subject:  What kind of spider?
Geographic location of the bug:  Auckland, New Zealand
Date: 10/24/2021
Time: 03:57 PM EDT
Your letter to the bugman:  Hi, appreciate if you could please identify this. Thank you, Mahesh
How you want your letter signed:  Sincerely

Slater Spider

Dear Mahesh,
This is a Sow Bug Hunter,
Dysdera crocata.  According to BugGuide, a North American insect identification site:  “Introduced to North America and widely distributed in the Nearctic. Originally from the Mediterranean area.”  According to The Spruce:  “this spider is very common throughout the U.S., primarily in the East from New England down to Georgia, then west to California. Outside the U.S., it is common in Australia, northern Europe, and England. Although it lives outside to hunt its prey, it may come indoors in the fall for shelter.”  We suspect it may have been introduced to New Zealand from Australia.  According to the Museum of New Zealand, it is called a Slater Spider and “While this spider is capable of capturing other prey, it has earned its common name because of accounts documenting its feeding on the common slater (also known as the common woodlouse), Porcellio scaber. It doesn’t build a web to capture its prey. Rather, it seizes its victim in its very large chelicerae.”  The site also indicates:  “With its large fangs, this species is capable of delivering a sharp bite. Symptoms include local swelling and pain. However, bites are rare, and only a handful of bites by this species have been recorded from New Zealand even though these spiders are very common.”

Letter 4 – Sowbug Hunter


Subject: bug in my pool
Location: Jessup PA
June 2, 2017 4:56 am
Can you id this creature?
Signature: Bob Goodwin

Sowbug Hunter

Dear Bob,
This Spider,
Dysdera crocata, is commonly called a Sowbug Hunter.  According to BugGuide:  “Primary prey is isopods; hence the large chelicerae and fangs” and “Bites by the woodlouse spider, Dysdera crocata, are virtually innocuous. The main symptom is minor pain, typically lasting less than 1 hr, probably due mostly to the mechanical puncture of the skin.”

Letter 5 – Sow Bug Killer


We believe we have a Sow Bug Killer
My sons were exploring under paving stones in our yard and ran across this guy. We immediately jumped on your site to help us identify our newest member. Based on searching your photos, we believe that it is a Sow Bug Killer. Can you confirm?

Hi Melinda,
Yes, this is a Sow Bug Killer, Dysdera crocota.


  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

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  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

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8 thoughts on “Do Sowbug Killer Spider Bite? Exploring the Facts and Myths”

  1. As of this morning both are still alive but have separated now! Woodlouse hunters are possibly immune to the venom of other woodlouse hunters? I have seen other woodlouse spiders in the past kill adult wolf spiders with single bites in less than 20 seconds.

  2. naturally like your website but you have to test the spelling on quite a few of your posts. A number of them are rife with spelling problems and I in finding it very troublesome to inform the reality on the other hand I’ll certainly come back again.

    • We do not correct the spelling nor grammatical errors in the letters we post from our readership, however we do strive for accuracy with our responses, but we are not perfect. We do not have an editor to check our accuracy prior to posting.

  3. Haven’t tried the Clark zapper yet, right now it’s just an idea.

    I was looking at the conventional bug zapper in Home Depot, and noticed it has about 3/8″ spaces between the bars, this won’t work unless I can find a way to make it small enough so a mite can’t slip through it, or devise something that will fry them if they land, or fall, on it?

  4. Haven’t tried the Clark zapper yet, right now it’s just an idea.

    I was looking at the conventional bug zapper in Home Depot, and noticed it has about 3/8″ spaces between the bars, this won’t work unless I can find a way to make it small enough so a mite can’t slip through it, or devise something that will fry them if they land, or fall, on it?


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