Health Care

Black House Spider: Facts, Bites, and Prevention Tips

Written by Dr. James Andrews

What Is a Black House Spider?

The Black House Spider (Badumna insignis) is a common web-building spider known for living around homes, sheds, and tree trunks. It has a dark, velvety body and builds messy, funnel-shaped webs, usually in quiet and undisturbed areas.

This spider is native to Australia, but can also be found in New Zealand and occasionally in other regions. Despite its scary appearance, the Black House Spider is not aggressive and is generally harmless to humans.

These spiders are considered beneficial because they help control pests like flies, mosquitoes, and moths. Their shy and reclusive nature makes them more of a hidden houseguest than a threat.

How to Identify a Black House Spider

how to identify a black house spider

Identifying a Black House Spider is quite easy once you know what to look for. Here are the key features:

Color and Texture

  • Dark brown to black body
  • Covered with dense, velvety hair
  • Legs are typically dark and short

Size

  • Females: Around 18 mm (larger and more robust)
  • Males: Smaller, around 9 mm

Their legs may appear thick compared to other house spiders

Web Structure

  • Builds messy, sheet-like webs with a funnel retreat (where the spider hides)
  • Webs are often found in corners of windows, sheds, walls, fences, or tree trunks

Preferred Hiding Spots

  • Inside cracks, crevices, window frames
  • In garages, outdoor toilets, and garden walls
  • Often in dry and sheltered locations

Pro Tip:

Unlike some other house spiders, Black House Spiders don’t roam around much. They stay in or near their web and rarely wander inside your home.

Where Are Black House Spiders Commonly Found?

where are black house spiders commonly found

Black House Spiders prefer dry, sheltered spaces where they can safely build their webs and catch prey. They are often found in both natural environments and human-made structures.

Geographic Locations

  • Native to Australia
  • Also found in New Zealand
  • Occasionally seen in other countries via imported goods or shipping containers

Typical Indoor Locations

  • Window frames and sills
  • Ceiling corners
  • Behind furniture or wall cracks
  • Inside garages or sheds
  • Around doorways and vents

Typical Outdoor Locations

  • Tree bark and crevices
  • Wooden fences and posts
  • Garden furniture and tool sheds
  • Under eaves and roof edges
  • Brick walls and rock piles

Are Black House Spiders Dangerous to Humans?

The Black House Spider may look intimidating, but it is not considered dangerous to humans. While it is a venomous spider, its venom is mild and not life-threatening.

What Happens If You’re Bitten?

A bite from a Black House Spider can cause:

  • Mild to moderate pain at the bite site
  • Redness and swelling
  • In rare cases: headache, nausea, or sweating

When to See a Doctor

You should seek medical attention if:

  • You are allergic to insect or spider bites
  • Symptoms worsen or last longer than a day
  • You experience dizziness, fever, or intense swelling

Good to Know:

  • Black House Spiders are shy and prefer to hide rather than bite
  • Bites usually occur only when the spider feels trapped or threatened

Black House Spider Bite: Symptoms and Treatment

A Black House Spider bite is usually not serious, but it can be painful and uncomfortable for a short time. Most bites happen when the spider is accidentally disturbed—like during cleaning or gardening.

Common Symptoms

If bitten, you may experience:

  • Sharp, local pain at the bite site
  • Redness and swelling
  • Itching or a burning sensation
  • Headache or nausea (in rare cases)
  • Mild sweating or fatigue (very rare)

These symptoms usually last a few hours to a couple of days and go away on their own.

First Aid and Treatment Tips

If you suspect a bite from a Black House Spider, follow these steps:

  • Stay calm – the bite is not deadly
  • Clean the area with soap and warm water
  • Apply a cold pack to reduce swelling and pain
  • Take over-the-counter pain relief like paracetamol or ibuprofen
  • Apply an antihistamine cream if the bite is itchy

When to Seek Medical Help

Call your doctor or visit a clinic if:

  • Pain or swelling gets worse
  • The bite looks infected (pus, increased redness, warmth)
  • You feel dizzy, weak, or nauseous
  • You’re allergic to spider bites

Black House Spider Web: What Makes It Unique?

The Black House Spider’s web is one of its most recognizable features. Unlike the perfect circular webs spun by orb-weavers, this spider creates a messy, tangled web with a distinct funnel-shaped retreat.

Web Structure

  • Irregular, sheet-like web with a funnel-shaped hole
  • The spider hides inside the funnel and waits for prey
  • The web is dense and sticky, perfect for trapping insects

Where They Build Their Webs

Black House Spiders love quiet, sheltered spots, such as:

  • Window corners
  • Cracks in walls
  • Under eaves and ledges
  • Between fence posts or tree bark
  • Inside sheds and garages

Once they choose a spot, they rarely move and may reinforce the same web for years.

How the Web Works

  • Insects like flies, moths, and mosquitoes get trapped in the sticky outer threads
  • Vibrations from the struggling prey alert the spider, who quickly rushes out of the funnel to attack
  • The spider drags the prey back into the funnel to eat in safety

Web Maintenance

  • Black House Spiders regularly repair and thicken their webs
  • They may build several funnel retreats within one large web, especially in high-insect areas.

What Do Black House Spiders Eat?

Black House Spiders are carnivorous predators that feed mainly on insects and other small arthropods. They don’t hunt actively—instead, they rely on their sticky webs to trap prey.

Common Prey Includes:

  • Flies
  • Mosquitoes
  • Moths
  • Beetles
  • Ants
  • Cockroaches

Occasionally, other smaller spiders

How They Hunt

  • The spider stays hidden in its funnel-shaped retreat
  • When an insect gets stuck in the web, it senses the vibrations
  • It quickly dashes out, bites the prey, and injects venom
  • Then it drags the catch back into the funnel to feed

Feeding Habits

  • Black House Spiders can survive for weeks without food
  • They typically eat every few days if insects are available
  • After feeding, they may leave dried-out remains near the web

Why They’re Actually Helpful

These spiders help control household pests, making them natural pest controllers. Their presence can reduce the number of flies and mosquitoes in and around your home.

Black House Spider Life Cycle and Reproduction

The Black House Spider follows a simple but fascinating life cycle, from tiny eggs to fully grown adults. Their reproduction is typical of many spider species, but they are known for being loyal to one web location throughout their life.

Egg Stage

  • The female spins a white, papery egg sac inside her web
  • Each sac can contain up to 40 eggs
  • She may lay several sacs throughout the year
  • Eggs hatch in about 2 to 3 weeks, depending on the temperature

Spiderlings

  • Once hatched, baby spiders (called spiderlings) stay in the mother’s web for a short time
  • They soon disperse by crawling away or using silk threads to float on air (a behavior called ballooning)
  • Most spiderlings don’t survive to adulthood due to predators or lack of shelter

Growth and Molting

  • Black House Spiders go through several molts as they grow
  • They shed their exoskeleton to become larger
  • This process continues until they reach maturity, which can take several months

Mating and Adult Life

  • Males mature faster than females
  • A mature male will leave his web to search for a female
  • After mating, the male usually dies shortly after
  • Females can live for up to 2 years or more, while males have a shorter lifespan

Fun Fact:

Females often stay in the same web their entire life, simply repairing and expanding it as needed.

Signs of a Black House Spider Infestation

While Black House Spiders are generally shy and not aggressive, a large number of them in your home can be unsettling. Knowing the signs of an infestation helps you take action early.

Multiple Webs in Quiet Areas

  • Their webs are messy and funnel-shaped
  • You may find them in corners, window frames, ceilings, or outdoor walls
  • Webs may look thick, greyish, and dusty if they’ve been there a long time

Increased Insect Activity

  • More spiders often mean more insects for them to feed on
  • If you notice lots of flies, moths, or mosquitoes, spiders may follow

Frequent Spider Sightings

  • Seeing one or two spiders isn’t unusual, but multiple sightings in different rooms can indicate a breeding population
  • You may spot them near their webs or rushing out from hiding when disturbed

Presence of Egg Sacs

  • Look for small, round, white sacs in or near their webs
  • These sacs may be tucked into corners or web retreats and can hold dozens of eggs

Droppings or Debris

  • Spiders leave behind insect remains and droppings, which appear as tiny black or brown spots on walls or surfaces near webs

Outdoor Clusters

  • Check fences, eaves, and brick walls outside—if you find clusters of webs, it’s a sign that Black House Spiders are establishing themselves nearby

Quick Tip:

A few spiders aren’t usually a problem—but a sudden increase in webs or spider activity may mean it’s time to take preventive steps.

How to Get Rid of Black House Spiders Naturally

If you’re dealing with Black House Spiders in or around your home, you don’t always need harsh chemicals. There are several natural and safe methods to remove or prevent them.

Regular Cleaning

  • Vacuum webs and egg sacs from walls, corners, and ceilings
  • Clean behind furniture, shelves, and window sills
  • Sweep out garages, sheds, and basements regularly

Tip: Remove the entire web, not just the spider, to prevent return.

Use Essential Oils

Spiders dislike certain scents. Mix with water and spray in spider-prone areas:

  • Peppermint oil
  • Tea tree oil
  • Lavender oil
  • Citrus or lemon oil

Spray around windows, doors, vents, and cracks weekly.

Seal Cracks and Gaps

  • Block entry points with caulk or sealant
  • Close gaps around windows, pipes, doors, and air vents
  • Install door sweeps and weatherstripping

Turn Off Outdoor Lights

  • Lights attract insects, which attract spiders
  • Keep outdoor lights off at night, or switch to yellow “bug lights”

Plant Spider-Repelling Herbs

Grow natural repellents near windows and doors:

  • Mint
  • Basil
  • Lemon balm
  • Eucalyptus

Declutter Your Home

  • Spiders love hiding in piles of boxes, clothes, or papers
  • Keep storage areas neat and avoid stacking things directly on the floor

Install Screens

  • Use fine mesh screens on windows and vents
  • Repair any holes or tears to keep spiders out

Preventing Black House Spiders in Your Home

While Black House Spiders are helpful in controlling insects, most people prefer to keep them outside the home. The good news is that with a few simple habits, you can prevent them from settling indoors.

Seal All Entry Points

  • Use silicone caulk to seal cracks in walls, windows, and door frames
  • Install door sweeps and repair any torn window screens
  • Cover vents and chimney openings with mesh screens

Keep Your Home Clean

  • Regularly vacuum floors, corners, ceilings, and behind furniture
  • Dust window sills, baseboards, and ceiling corners where webs may form
  • Clear cobwebs as soon as you spot them

Declutter Indoor & Outdoor Spaces

  • Store boxes, shoes, and clothes off the floor
  • Avoid piling up unused items in closets, garages, and sheds
  • Tidy up outdoor areas like woodpiles, garden tools, and leaf piles

Reduce Outdoor Lighting

  • Bright lights attract flying insects—which attract spiders
  • Use motion-sensor or yellow-toned lights to reduce attraction
  • Turn off porch or garden lights when not needed

Use Natural Repellents

  • Spray peppermint oil + water around doors, windows, and wall corners
  • Place eucalyptus or citrus peels near entry points
  • Use vinegar spray as a deterrent in crevices

Manage Your Garden

  • Trim back trees and bushes from touching your walls and windows
  • Avoid placing potted plants too close to the house
  • Remove garden debris and keep your yard clean

Clean Outdoor Structures

  • Regularly clean sheds, patio furniture, and storage areas
  • Knock down webs on fences, eaves, and exterior walls

When to Call Pest Control for Black House Spiders

While Black House Spiders are usually harmless and can be managed naturally, there are times when professional pest control is the best solution. Knowing when to call the experts can save you time, stress, and even health risks.

You See a Large Number of Spiders

  • Finding multiple spiders across different rooms is a sign of infestation
  • This likely means they are breeding and have built multiple hidden webs

Webs Keep Reappearing

  • If you clean webs and they quickly return, spiders may be deeply settled in your home
  • Professional treatment ensures webs and nests are fully eliminated
  • You or a Family Member Has Allergies or Phobias
  • If anyone in your home is highly allergic or fearful of spiders, it’s best to let professionals handle the situation safely

You Suspect a Bite and Have Symptoms

  • Although Black House Spider bites are mild, a suspected bite that causes pain, swelling, or allergic reactions should be taken seriously

Pest control can prevent future incidents by removing spiders completely

  • You’ve Tried Everything, But They Keep Coming Back
  • If natural methods and DIY efforts fail, a pest control service can use safe and targeted treatments to eliminate the source
  • They’ll also seal entry points and provide prevention tips

You Want Peace of Mind

  • Even if the infestation isn’t large, a professional inspection ensures your home is spider-free and well-protected in the future

What to Expect from Pest Control

  • Full home inspection (inside and outside)
  • Safe, pet- and child-friendly sprays or treatments
  • Advice on sealing up entry points and preventing future infestations

Interesting Facts About the Black House Spider

The Black House Spider may seem like just another creepy-crawly, but it’s actually a fascinating creature with some surprising traits. Here are some interesting facts you might not know:

They Rarely Leave Their Web

  • Unlike some spiders that wander in search of food, Black House Spiders are homebodies. They stay hidden in their funnel-shaped web and wait for prey to come to them.

They’re Loyal to One Spot

  • Once a Black House Spider builds its web in a cozy spot, it will often live there for life, reinforcing and repairing the same web over and over.

Their Webs Are Super Sticky

  • Their webs aren’t pretty—but they are extremely strong and sticky, making them great at catching all kinds of insects like flies, mosquitoes, and moths.

They Look Scarier Than They Are

  • With their dark color and hairy legs, they can look intimidating. But in reality, they are shy and non-aggressive, only biting when threatened.

Native to Australia

  • Black House Spiders are originally from Australia, but they’ve also spread to New Zealand and sometimes even appear in other countries due to international shipping.

Females Live Longer

  • Female spiders can live for up to 2 years or more, while males usually die shortly after mating.

They’re Prey Too

  • Black House Spiders are not at the top of the food chain. They are often hunted by birds, wasps, lizards, and larger spiders.

They Help Control Pests

  • These spiders eat annoying insects, making them natural pest controllers around your home and garden.

Black House Spider vs. Other Common House Spiders

Not all house spiders are the same—and the Black House Spider has some distinct traits that set it apart. Here’s a side-by-side comparison with other spiders you’re likely to find at home:

Appearance

Spider TypeColorSizeBody Texture
Black House SpiderDark brown to blackFemale: ~18 mm, Male: ~9 mmVelvety, hairy body
Daddy Long LegsLight brown/greyVery small body, long thin legsSmooth
Common House SpiderLight to medium brown4–10 mmGlossy, round abdomen
Huntsman SpiderBrown/grey with patternsUp to 15 cm leg spanFlat and wide

Web Structure

Spider TypeWeb TypeLocation Preference
Black House SpiderMessy, funnel-shaped webCracks, windows, corners
Daddy Long LegsLoose, tangled webCeilings, corners
Common House SpiderClassic orb or tangleBehind furniture, basements
Huntsman SpiderNo web (active hunter)Behind curtains, under objects

Aggression & Bites

Spider TypeAggressivenessBite RiskDanger Level
Black House SpiderShyWill bite if provokedMild to moderate pain
Daddy Long LegsHarmlessCannot bite humansNone
Common House SpiderPassiveRare and mildNone to low
Huntsman SpiderTimid but fastPainful bite possibleModerate

Pest Control Value

  • Black House Spiders are very effective at catching flies, mosquitoes, and moths.
  • Daddy Long Legs also eat insects, including other spiders.
  • Common House Spiders help control small indoor bugs.
  • Huntsman Spiders are great at reducing cockroach and insect populations.

Summary:

TraitBlack House SpiderDaddy Long LegsCommon House SpiderHuntsman Spider
Most Sticky Webyesnonono
Most Visibly Intimidatingyesnonono
Best Pest Controlleryesyesyesyes
Most Likely to BiteOccasionallyNeverRarelySometimes

Frequently Asked Questions About Black House Spiders

Are Black House Spiders dangerous to humans?

Black House Spiders are venomous, but their bite is usually not dangerous to healthy people. It may cause mild pain, redness, or swelling but rarely needs medical treatment.

What happens if a Black House Spider bites you?

You might feel a sharp sting or mild pain, with some swelling or redness. The symptoms usually go away in a few hours. If they don’t, see a doctor.

Where do Black House Spiders live?

They like quiet, dry places like corners of windows, cracks in walls, sheds, garages, and tree bark. They stay in the same web for a
long time.

How big are Black House Spiders?

Females are around 18 mm long, and males are about 9 mm. Their legs are short and sturdy compared to other spiders.

How do I get rid of Black House Spiders naturally?

You can use peppermint oil spray, vinegar, or keep your home clean and clutter-free. Also, seal any cracks and remove their webs often.

What do Black House Spiders eat?

They eat flies, mosquitoes, moths, and other small insects. They help control household pests naturally.

Can Black House Spiders live indoors?

Yes, they often live in corners, behind furniture, or window frames indoors—especially in quiet or undisturbed areas.

How long do Black House Spiders live?

Females can live for up to 2 years or more. Males usually die shortly after mating.

Do they attack people or pets?

No. They are shy and avoid contact. They only bite if they feel trapped or threatened.

Should I call pest control for Black House Spiders?

If you notice lots of webs or spiders around your home, or feel uncomfortable dealing with them, it’s a good idea to call a pest control professional.

Final Thoughts:

The Black House Spider may look scary at first, but the truth is—it’s mostly harmless. These spiders are shy, non-aggressive, and actually help by eating household pests like flies and mosquitoes.

Unless you’re dealing with an infestation or have allergies to spider bites, there’s usually no reason to panic. They prefer to stay hidden in their webs and are not interested in humans or pets.

That said, if you’re uncomfortable with spiders in your home, you can take simple, natural steps to keep them away. And if the problem becomes too much to handle, professional pest control is always an option.

In short, the Black House Spider is more of a quiet roommate than a real threat. With a little knowledge and preventive care, you can live spider-free—or at least in peace!

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About the author

Dr. James Andrews

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