Woodlouse Spider: Identification, Behavior, and Control

Woodlouse spiders may not be as well-known as other arachnids, but their unique features and role in the ecosystem make them fascinating creatures. Known for their distinctive reddish bodies and large fangs, these spiders are specialized predators that primarily hunt woodlice. Despite their fearsome appearance, woodlouse spiders pose little threat to humans. In this blog, we’ll explore everything you need to know about woodlouse spiders from how to identify them to their behavior, habitat, and even how to control their presence in your home or garden.

Woodlouse Spider Identification

How do you identify a woodlouse spider?

Woodlouse spiders (scientific name: Dysdera crocata) are easily recognizable due to their unique physical features. These arachnids typically have a reddish-brown body and large, curved fangs, which help them pierce the tough exoskeletons of woodlice. Here’s a breakdown of their key identifying traits:

• Size: These spiders usually range from 4 to 10 mm in body length.
• Color: Reddish cephalothorax with a yellowish or grey abdomen.
• Eyes: Unlike many spiders that have eight eyes, woodlouse spiders have six, arranged in three pairs.
• Fangs: Their most notable feature, the large chelicerae (fangs), allows them to prey on woodlice with ease.

Are woodlouse spiders often mistaken for other spiders?

Yes, due to their color, woodlouse spiders are sometimes mistaken for other species like the redback spider. However, their six eyes and large fangs make them distinctive. They are unlikely to be confused with orb weavers or house spiders, which have different body shapes and behaviors.

Woodlouse Spider Habitat

Where are woodlouse spiders commonly found?

Woodlouse spiders thrive in dark, damp environments where woodlice— their main prey—are plentiful. Here are some common habitats:

• Under Rocks and Logs: Woodlouse spiders are frequently found in garden settings, hiding under stones, mulch, and debris.
• Leaf Litter: Woodlands and gardens with decaying plant material provide an excellent hiding place for these spiders.
• Basements & Damp Corners: In residential areas, woodlouse spiders might seek refuge in basements, cellars, or even bathrooms, especially where there is moisture.

Do woodlouse spiders prefer specific climates?

Yes, woodlouse spiders prefer temperate climates with higher humidity levels, which makes moist gardens and wooded areas ideal for their survival. They are found in many parts of Europe and North America, particularly in areas where woodlice populations are abundant.

Woodlouse Spider Diet

What is the diet of a woodlouse spider?

As their name suggests, woodlouse spiders primarily feed on woodlice, also known as pill bugs or sowbugs. These crustaceans are commonly found in damp environments and are easy prey for woodlouse spiders due to their soft underbellies, which the spider can easily pierce with its powerful fangs.

How do woodlouse spiders hunt?

Unlike web-building spiders, woodlouse spiders are ambush predators. They lie in wait for their prey and use their large fangs to inject venom that paralyzes woodlice. Once the woodlouse is immobilized, the spider consumes it, liquefying the internal tissues to make them easier to digest.

“Research published in the Journal of Arachnology explains that woodlouse spiders are specialized predators of woodlice, using their large fangs to pierce the tough exoskeleton of their prey.” (Journal of Arachnology, 2021)

Woodlouse Spider Behavior

What are the behavior patterns of woodlouse spiders?

Woodlouse spiders are solitary and nocturnal creatures, preferring to hunt at night when woodlice are most active. During the day, they remain hidden under rocks, logs, or other debris, making them hard to spot. They do not spin webs to capture prey like other spiders. Instead, they are ambush predators, lying in wait for their prey to come within striking distance.

Are woodlouse spiders aggressive?

Woodlouse spiders are not aggressive towards humans and generally avoid confrontation. They will only bite if they feel threatened or provoked, such as when being handled. Their bites are rare and typically result in mild symptoms for humans, such as localized pain or redness, similar to a bee sting.

Woodlouse Spider Bite

Can a woodlouse spider bite humans?

Yes, woodlouse spiders are capable of biting humans, but such incidents are rare. They generally only bite when provoked or threatened, such as when accidentally handled. While their large fangs are capable of piercing human skin, they are not considered dangerous to humans.

What are the symptoms of a woodlouse spider bite?

A woodlouse spider bite is typically no more severe than a mild bee sting. The most common symptoms include:

• Localized Pain: Mild to moderate pain around the bite area.
• Redness: The area around the bite may become red and inflamed.
• Itching: Some individuals may experience slight itching as the bite heals.

In rare cases, a bite may cause swelling or discomfort that lasts a few hours. However, the venom of the woodlouse spider is primarily effective against its prey (woodlice) and does not pose any serious health risks to humans.

What should you do if bitten?

If you’re bitten by a woodlouse spider, follow these simple steps:

1. Clean the Area: Gently wash the bite with soap and water to reduce the risk of infection.
2. Apply Ice: Use a cold compress to reduce swelling and alleviate pain.
3. Monitor for Symptoms: If symptoms worsen or an allergic reaction occurs, seek medical advice.

Most bites heal on their own without the need for medical attention. If you experience any unusual symptoms or an allergic reaction, consult a healthcare provider.

Woodlouse Spider Reproduction

How do woodlouse spiders reproduce?

The reproduction process of woodlouse spiders is typical of most arachnids. During mating season, males seek out females, using pheromones to locate them. Males transfer sperm to the female using their pedipalps, which are specially adapted for reproduction.

After mating, the female lays eggs in a silken egg sac, typically hidden in a safe location such as under rocks or logs. She may guard the egg sac until the spiderlings hatch. Once hatched, the spiderlings disperse to find their own territory.

What is the lifespan of a woodlouse spider?

Woodlouse spiders have a relatively short lifespan, generally living one to two years. Their life cycle consists of several stages: egg, spiderling, juvenile, and adult. The time it takes to mature depends on environmental factors, including temperature and availability of prey.

How to Get Rid of Woodlouse Spiders

How can you control woodlouse spiders in your home or garden?

Though they are harmless to humans, woodlouse spiders can become unwelcome visitors in homes, particularly in dark, damp areas such as basements, crawl spaces, and bathrooms. Fortunately, there are several effective methods to prevent and remove them:

1. Encouraging Natural Predators

Birds, larger spiders, and certain insects like centipedes and beetles are natural predators of woodlouse spiders. Encouraging these predators in your garden can help keep the population of woodlouse spiders under control. Birds can be attracted by installing birdhouses or using feeders that provide a food source. Ground-dwelling insects may be more prevalent if your garden has a healthy ecosystem with diverse plant life.

2. Seal Cracks and Gaps

Preventing woodlouse spiders from entering your home starts with sealing up potential entry points. Inspect your home’s foundation, walls, and windows for any cracks or gaps where spiders could sneak in. Use caulk or weather stripping to close off any openings, paying special attention to areas around doors and windows. Ensure that window screens are intact and fit properly.

3. Remove Dampness

Woodlouse spiders are attracted to moisture, so reducing dampness in your home is key to discouraging them. In basements, bathrooms, and other damp areas, consider using a dehumidifier to maintain dry air. Fix leaky pipes, improve ventilation, and ensure that crawl spaces are well-aerated. Keeping your home dry will not only prevent woodlouse spiders but also reduce the presence of their prey, like woodlice and other insects that thrive in damp conditions.

4. Remove Clutter and Debris

In gardens and yards, woodlouse spiders hide under stones, mulch, leaves, and logs. Regularly clearing away debris, especially near your home’s foundation, can help reduce their hiding spots. Keeping gardens and yards tidy minimizes the likelihood of woodlice and spiders establishing a habitat close to your house.

5. Use natural Deterrents

Essential oils such as peppermint oil, tea tree oil, and eucalyptus oil are known to repel spiders. You can create a homemade spider repellent spray by mixing a few drops of these oils with water and spraying it in areas where spiders are likely to hide. Natural deterrents can be a safer option for homes with pets or children.

6. Insecticides and Chemical Treatments

If the infestation is severe, using insecticides specifically designed for spiders can be effective. Sprays containing pyrethroids are often used for spider control, but it is essential to apply them carefully to avoid harming beneficial insects or pets. These treatments can be applied around the exterior of your home, in basements, or in other spider-prone areas.

7. Professional Pest Control Services

For persistent or larger infestations, it’s best to consult a professional pest control service. Pest control professionals have access to stronger chemical treatments and can provide a comprehensive solution tailored to your specific needs. They will assess the extent of the infestation and recommend safe and effective ways to manage it.

8. Regular Maintenance

Consistent maintenance is key to preventing a re-infestation. Regularly check for cracks, leaks, and clutter around your home, and ensure proper ventilation in areas prone to dampness. Routine cleaning and organizing will go a long way in keeping woodlouse spiders and other pests at bay.

9. Minimize Outdoor Lighting

Woodlouse spiders, like many other arachnids, are drawn to areas where insects congregate. Outdoor lighting, especially bright lights near doors and windows, attracts a variety of insects, which in turn can attract spiders that feed on them. Minimizing outdoor lighting or using insect-repelling light bulbs can reduce the number of insects around your home and, consequently, limit the presence of woodlouse spiders. Consider motion-activated lights to reduce the amount of constant lighting around your home.

10. Regular Yard Maintenance

Keeping your yard well-maintained is another effective way to reduce woodlouse spider populations. Regularly mow your lawn, trim back overgrown bushes, and remove leaf litter, wood piles, and other debris. This reduces the habitat for both woodlice and woodlouse spiders. Creating distance between your home and potential hiding spots outside makes it less likely that the spiders will move indoors. You can also mulch with inorganic materials like gravel instead of organic mulch, which tends to attract woodlice and other pests.

Woodlouse Spider Myths

Myth: Woodlouse spiders are deadly to humans.

Despite their intimidating appearance, woodlouse spiders are not dangerous. Their venom is only potent against woodlice and typically causes minor symptoms like mild pain and redness in humans.

Myth: Woodlouse spiders infest homes in large numbers.

Woodlouse spiders are solitary creatures. They rarely enter homes in large numbers and do not form infestations like some other pests. Their presence is usually limited to a few individuals.

Myth: Woodlouse spiders build webs to catch prey.

Woodlouse spiders do not rely on webs to hunt. Instead, they are ground predators that actively seek out woodlice, using their large fangs to capture prey.

Woodlouse Spider vs. Brown Recluse Spider

Body Color:
The Woodlouse Spider has a distinct reddish-brown color, making it stand out, while the Brown Recluse Spider is typically light to dark brown, which can make it harder to notice in many environments.

Size:
The Brown Recluse Spider is generally larger, growing up to 20 mm, whereas the Woodlouse Spider is smaller, measuring between 4-10 mm.

Venom:
The Brown Recluse Spider is highly venomous and can cause serious medical issues, including tissue damage. In contrast, the Woodlouse Spider’s venom is mild, mostly affecting its prey, and rarely causes more than minor irritation to humans.

Bite Symptoms:
A bite from a Brown Recluse Spider can lead to severe pain and significant tissue damage, sometimes requiring medical treatment. The Woodlouse Spider’s bite, however, causes only localized pain and redness, with no serious effects.

Habitat:
Woodlouse Spiders prefer damp environments, such as gardens, basements, or under rocks. The Brown Recluse Spider, on the other hand, is commonly found in dark, undisturbed indoor spaces like basements or closets.

Prey:
The Woodlouse Spider primarily feeds on woodlice (pill bugs), while the Brown Recluse Spider hunts a variety of small insects.

Web Type:
The Brown Recluse Spider builds irregular webs, which it uses as a retreat. The Woodlouse Spider does not rely on webs to catch prey but instead hunts its prey actively on the ground.

Danger to Humans:
The Brown Recluse Spider is significantly more dangerous to humans due to its potent venom, which can lead to serious health issues. The Woodlouse Spider is not considered dangerous to humans, and its bite causes only minor symptoms.

This bar graph illustrates a comparison between the Woodlouse Spider and the Brown Recluse Spider across different features. The green bars represent the Woodlouse Spider, while the orange bars represent the Brown Recluse Spider.

Conclusion

Woodlouse spiders are unique and fascinating creatures that play an important role in controlling woodlice populations. Though they may appear intimidating due to their large fangs and reddish color, they are generally harmless to humans and prefer to avoid interaction. Understanding their behavior, habitat, and role in the ecosystem can help dispel common myths and reduce unnecessary fear.

If you encounter woodlouse spiders in your home, there are effective ways to manage them, from reducing moisture and sealing entry points to encouraging natural predators in your garden. Ultimately, woodlouse spiders are more beneficial than harmful, and their presence can even be a sign of a healthy, balanced ecosystem.

FAQs

1. Are woodlouse spiders beneficial?

Yes, they help control woodlice populations, which can be pests.

2. Do woodlouse spiders infest homes?

No, they rarely enter homes and do not form large infestations.

3. Where are woodlouse spiders found?

They are commonly found under rocks, logs, and in damp environments.

4. Do woodlouse spiders eat pill bugs?

Yes, woodlouse spiders primarily prey on pill bugs and woodlice.

5. Are woodlouse spiders dangerous to humans?

No, woodlouse spiders are not dangerous to humans. Their bites are rare and typically cause only mild symptoms.