Identification
Physical Characteristics
Size: Females are the larger sex, with a body length of up to 18mm. Males are considerably smaller, reaching about 9-10mm.
Coloration: The carapace and legs are typically dark brown to charcoal grey or black. The abdomen is dark grey or black with lighter, mottled markings on the dorsal side, though these can be faint in older or darker specimens. The overall appearance is robust and velvety.
Key Features: The most reliable identifying feature is not the spider itself, but its web: a messy, tangled, lacy construction, often with bluish-white silk, built in structural corners. The spider has a robust, dark, velvety appearance.
Biology & Lifecycle
Development & Reproduction
Reproduction Rate: Females can produce multiple egg sacs throughout the summer months, leading to a rapid increase in population in ideal conditions.
Lifecycle Details
Egg Stage
After mating, the female constructs several white, fluffy egg sacs within the safety of her web's retreat. Each sac can contain dozens of eggs. She will guard these eggs until they hatch.
Larval Stage
Spiderlings emerge from the egg sac but may remain in the maternal web for a short period before dispersing.
Pupal Stage
Spiders do not undergo metamorphosis and therefore have no pupal stage.
Adult Stage
Females can live for up to two years, tending to and expanding their web. Males have a much shorter lifespan and typically die after mating. They are often seen wandering in search of females.
Reproduction Rate
Females can produce multiple egg sacs throughout the summer months, leading to a rapid increase in population in ideal conditions.
Generations Per Year
Typically one to two generations per year, with development being faster in warmer climates.
Development Time
The time from egg to adult can be several months, heavily influenced by temperature and the availability of prey.
Seasonal Cycle
They are active year-round in warmer climates. In cooler areas, activity peaks in the warmer months (spring and summer) when insect prey is abundant. Wandering males are most common in late summer and autumn.
Environmental Factors
The primary factor is the availability of suitable web-building sites with adjacent crevices for a retreat. Prey availability is also key to population growth.
Habitat & Distribution
Preferred Habitats
- Cracks in window frames and door frames.
- Under the eaves and gables of houses.
- In sheds, garages, and outdoor toilets.
- On fences, rock walls, and the bark of trees.
- Anywhere that provides a crevice for a retreat and open space for a web.
Distribution Patterns
Australian Distribution
Found throughout Australia, including Tasmania. It is one of the country's most widespread spider species.
Climate Zones
- Tropical
- Subtropical
- Temperate
- Arid
- Mediterranean
Urban vs Rural Distribution
Extremely common in urban and suburban environments due to the abundance of ideal web-building structures. Also found in rural and bushland settings.
Native Range
Native to Australia.
Introduced Range
It has been accidentally introduced to New Zealand.
Introduction History
Not applicable in Australia.
Current Spread
The species is ubiquitous and stable across almost the entire continent.
Limiting Factors
Very few limiting factors, though they are less common in extremely cold alpine regions.
Behavior & Diet
Activity Pattern
Predominantly nocturnal. They remain in their silken retreat during the day and emerge at night to repair their web or wait for prey.
Dietary Preferences
Feeding Habits
A classic web-building spider that waits for prey to come to it.
Health Risks
Always consult healthcare professionals for medical concerns related to pest exposure.
Disease Transmission
- No evidence of disease transmission.
Allergens and Respiratory Issues
The accumulation of dust and insect debris in old webs may potentially aggravate asthma or allergies in sensitive individuals.
Contamination Risk
Negligible. They do not seek out food products.
Vulnerable Populations
- People with specific sensitivities may experience a more severe local reaction.
- Individuals cleaning out sheds or areas with many webs are at higher risk of a defensive bite.
- Small children who may accidentally disturb a web.
- Gardeners and maintenance workers.
- Generally, the risk to all populations is low.
Symptoms of Exposure
- Immediate, sharp pain at the bite site.
- Localised swelling, redness, and itching.
- Nausea, vomiting, and sweating have been reported in rare cases but are not typical.
- Symptoms usually subside within 24-48 hours.
- The main risk is secondary infection if the bite area is not kept clean.
Transmission Methods
- A defensive bite is the only method of venom transmission.
Risk Severity
Low. The bite is painful but not considered medically significant or dangerous.
Economic Impact
Treatment Costs
Professional Treatment
$200-$450 for a general pest spray for spiders, which is highly effective against Black House Spiders.
Prevention Costs
$20-$50 annually for DIY surface sprays and brushes.
Diy Treatment
$20-$60 for a can of surface spray and a long-handled brush for web removal.
Property Damage
Structural Damage
None. Their webs are superficial.
Garden Damage
None. They are beneficial predators of garden insect pests.
Food Contamination
None.
Equipment Damage
Can build webs inside machinery or equipment stored for long periods, but rarely cause functional damage.
Business Impact
Restaurant Issues
The presence of messy webs on windows or outdoor dining areas can create a poor impression of cleanliness.
Retail Impact
Similar to restaurants, webs on shopfronts can deter customers.
Reputation Damage
Significant for hospitality and retail businesses, as a spider-infested appearance suggests poor maintenance and hygiene.
Operational Disruption
Minimal, but may require temporary closure of an area for cleaning or pest control treatment.
Agricultural Impact
Crop Damage
None.
Yield Loss
None.
Beneficial Aspects
Highly beneficial in gardens, agricultural settings, and around the home, as they consume large quantities of pest insects like flies and mosquitoes.
Economic Loss
The primary economic impact is negative and relates to the cost of control for aesthetic reasons in urban settings, and potential reputation damage to businesses.
Indirect Costs
Healthcare Costs
Minimal. A bite would typically only require basic first aid and possibly a visit to a GP if symptoms are persistent or infection occurs.
Cleanup Costs
Costs associated with regular cleaning of windows, eaves, and fences to remove unsightly webs.
Replacement Costs
None.
Preventive Maintenance
The cost of regular pest control services or DIY products to keep buildings free of webs.
Detection & Signs
Visual Signs
- The presence of their characteristic messy, lacy webs.
- Webs accumulating dust and becoming more noticeable over time.
- Seeing the spider at the entrance of its funnel, especially at night.
- An increase in the number of webs around the property.
- Finding small, fluffy white egg sacs tucked into the web's retreat.
Physical Evidence
- The webs themselves are the primary physical evidence.
- Fine, white or bluish silk strands forming a sheet.
- A visible funnel or tube leading into a crack or crevice.
- Tiny insect husks (remains of prey) caught in the web.
- Over time, black streaks or stains may appear on surfaces below the web from spider droppings.
Behavioral Signs
- Seeing a spider dash back into its funnel retreat when you approach.
- Observing the spider at night repairing or adding to its web.
- Wandering males may be seen inside the house in autumn, looking for females.
- Rapid vibration or shaking of the web when prey is caught.
- They are largely sedentary, so the web's presence implies the spider is nearby.
Seasonal Indicators
- Webs become larger and more numerous over the summer as spiders grow.
- Wandering males are more frequently sighted indoors during late summer and autumn.
- Populations peak at the end of summer.
- A 'spring clean' of the property often reveals the extent of an infestation.
- New, small webs appear in spring as spiderlings disperse and establish themselves.
Early Warning Signals
- The appearance of a few small, lacy webs in window corners.
- Noticing one or two spiders on external walls at night.
- An increase in small flying insects around the property can predict a future increase in these spiders.
- An 'infestation' simply means their numbers have become aesthetically unacceptable.
- The first webs appearing on a new building.
Prevention
Sanitation Measures
- Regularly brush away webs from windows, eaves, and fences.
- Reduce clutter around the house, especially against walls, to minimise hiding spots.
- Keep vegetation trimmed back from the house to reduce insect numbers.
- There are no specific food waste sanitation measures needed for this spider.
- Frequent cleaning of sheds, garages, and outdoor furniture.
Exclusion Methods
- Seal cracks and crevices in walls, window frames, and foundations to deny them a place for their retreat.
- Install and maintain good-quality fly screens on windows and doors.
- Use weather strips on external doors.
- While they often live outside, sealing entry points prevents wandering males from coming inside.
- Repair any damaged siding or roofing where they could find entry.
Landscaping Tips
- Trim trees and shrubs so they do not touch the house, as this creates a bridge for spiders and insects.
- Choose plants that attract fewer insects if planting near the house.
- Position outdoor lighting away from doorways and windows to avoid attracting the insects that these spiders feed on.
- Keep the area around the foundation clear of debris and vegetation.
- Regularly high-pressure hose outdoor surfaces to destroy webs and spiders.
Monitoring Strategies
- Perform regular visual inspections of the building's exterior, paying close attention to corners, eaves, and window frames.
- A simple 'web check' every few weeks can keep populations under control.
- Note any areas where webs reappear quickly after being removed.
- Use a torch at night to easily spot spiders and their webs.
- Monitoring is straightforward: the webs are the sign.
Environmental Modification
- Change outdoor light bulbs to yellow or sodium vapor lights, which are less attractive to the flying insects that spiders prey upon.
- Reduce moisture by fixing leaking taps, as this attracts insects.
- Promote airflow around the building exterior.
- The most effective modification is simply making the structure inhospitable by sealing cracks and regular cleaning.
- Remove any unnecessary fixtures or decorative items on walls that provide ideal nesting sites.
Control Methods
Professional Treatment Methods
Chemical Control
A professional surface spray with a residual insecticide is highly effective. The technician will treat common harbourage areas like eaves, window frames, fences, and sheds.
Biological Control
The White-tailed Spider (Lampona cylindrata) is a known predator of Black House Spiders, but introducing one predator to control another is not a viable or recommended strategy.
Physical Control
Physically removing webs with a brush or vacuum cleaner is a key part of control.
Integrated Approach
The best approach is a combination of physical web removal, sealing entry points, modifying lighting, and applying a professional residual surface spray for long-term prevention.
DIY Treatment Options
Natural Remedies
Spraying a mixture of water and vinegar or essential oils like peppermint or eucalyptus may deter spiders temporarily, but it has limited and short-lived effectiveness.
Home Made Traps
Sticky traps can catch wandering males but will not control the population of web-bound females.
Deterrent Methods
Regularly brushing away webs is the best non-chemical deterrent, as the spider will eventually move on if its web is constantly destroyed.
Mechanical Control
A vacuum cleaner is an excellent tool for removing both the web and the spider safely. A long-handled brush is also very effective.
Treatment Effectiveness
Success Rate
Professional treatments are very successful, often providing control for up to 12 months. DIY methods require constant repetition to be effective.
Timeframe
A professional spray provides immediate knockdown and long-lasting residual protection. DIY cleaning needs to be done every few weeks.
Follow Up Required
An annual professional treatment is usually sufficient to keep numbers very low.
Seasonal Considerations
The best time for a preventative treatment is in spring, to control spiders before they multiply during the summer.
Application Techniques
- Thorough application of residual insecticide to all external surfaces, especially around windows, doors, and under eaves.
- Use of a brush to apply insecticidal dust into cracks and crevices.
- Directly spraying spiders and webs for immediate control.
- Combining a chemical spray with a physical brush-down of all existing webs.
Professional Services
Professional Treatment Services
Chemical Control
A professional surface spray with a residual insecticide is highly effective. The technician will treat common harbourage areas like eaves, window frames, fences, and sheds.
Biological Control
The White-tailed Spider (Lampona cylindrata) is a known predator of Black House Spiders, but introducing one predator to control another is not a viable or recommended strategy.
Physical Control
Physically removing webs with a brush or vacuum cleaner is a key part of control.
Integrated Approach
The best approach is a combination of physical web removal, sealing entry points, modifying lighting, and applying a professional residual surface spray for long-term prevention.
Professional Treatment Costs
$200-$450 for a general pest spray for spiders, which is highly effective against Black House Spiders.
Treatment Success Rates
Professional treatments are very successful, often providing control for up to 12 months. DIY methods require constant repetition to be effective.
Treatment Timeframe
A professional spray provides immediate knockdown and long-lasting residual protection. DIY cleaning needs to be done every few weeks.
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Browse All ProvidersSeasonal Patterns
Spring Activity
Young spiders establish new webs. Existing spiders become more active and start feeding more as insect populations increase.
Summer Activity
Peak season for feeding, growth, and reproduction. Webs become much larger and more noticeable. Populations are at their highest.
Autumn Activity
Mating season. Males leave their webs and wander in search of females, often entering homes by accident. Females are guarding egg sacs.
Winter Activity
Activity slows significantly in colder regions. Spiders remain dormant in their retreats, living off stored energy. In warmer climates, activity may continue at a reduced rate.
Breeding Season
Primarily summer and early autumn.
Peak Activity Period
Infestations (i.e., the number and visibility of webs) are most prominent in late summer and autumn.
Environmental Factors
Temperature Effects
Warm temperatures accelerate growth and reproduction. Cold temperatures induce inactivity.
Humidity Effects
They are tolerant of a wide range of humidity levels.
Photoperiod Effects
Day length may influence the timing of mating and dispersal.
Weather Patterns
They are largely unaffected by weather as they live in sheltered locations. Heavy rain may destroy exposed webs, forcing them to rebuild.
Legal Considerations
Pest Status
Considered a common nuisance or domestic pest due to its webs and proximity to humans.
Control Regulations
Standard regulations for the use of domestic and commercial pesticides apply, as set by the APVMA.
Professional Requirements
Pest control technicians must be licensed to apply chemical treatments to homes and businesses.
Environmental Considerations
When treating exteriors, care should be taken to avoid spray drift onto flowering plants to protect bees and other beneficial insects.
Compliance Requirements
- Adherence to the instructions on the pesticide label is a legal requirement.
- Professionals must follow all state and territory licensing and safety regulations.
- No specific permits are required for control.
- Homeowners using DIY products should ensure they are registered for use in Australia.
- Proper storage and disposal of unused chemicals is required.
Frequently Asked Questions
Are Black House Spiders dangerous to have around my home?
Black House Spiders (*Badumna insignis*) are not considered dangerous. While they can bite, and the bite can be quite painful with localized swelling and redness, their venom is not medically significant and does not cause systemic illness in humans. They are timid by nature and will only bite in self-defence if they are cornered or pressed against the skin, for instance when cleaning a window frame. The primary issues they cause are aesthetic; their messy webs accumulate dust and can make a house look untidy. In fact, they are beneficial predators, helping to control populations of flies, mosquitoes, and other nuisance insects. So, while you may want to remove them for cleanliness, you don't need to fear for your safety.
Why do I have so many Black House Spiders on my property?
A high population of Black House Spiders is usually an indicator that your property offers an ideal environment for them. There are two main factors. First, your building likely has plenty of perfect nesting sites: small cracks and crevices in window frames, under eaves, in brickwork, or behind pipes, where they can create the funnel-like retreat for their web. Second, there is likely an abundant food source of insects. This can be caused by outdoor lighting near doors and windows, which attracts moths and flies at night, or nearby vegetation that harbours insects. Because these spiders are so common and their young disperse by wind, almost any building is susceptible. An 'infestation' simply means the conditions are right for them to thrive.
What is the best way to get rid of Black House Spider webs?
The most effective way to get rid of Black House Spiders and their webs is a two-step physical and chemical approach. First, physically remove the spiders and their webs using a vacuum cleaner with a long nozzle attachment or a stiff brush with a long handle. This provides an immediate clean-up. For a more lasting solution, a residual surface spray can be applied. You can use a DIY product from a hardware store or hire a professional pest controller. The spray should be applied to the areas where spiders build their webs, such as window frames, eaves, and doorways. This creates a barrier that will deter new spiders from settling and will eliminate any that try. Regular removal of new webs as they appear is also a key part of keeping them under control.
How can I prevent Black House Spiders from coming back?
Prevention focuses on making your home less attractive to them. Start by sealing up their hiding places. Use caulk or sealant to fill cracks and crevices around windows, doors, and utility pipes. Next, address their food source. Consider changing outdoor light bulbs to yellow 'bug lights', which are less attractive to the flying insects that spiders eat. Keep vegetation trimmed away from the house. Regular cleaning is also crucial; frequently brushing down eaves and window corners to remove the beginnings of new webs will encourage spiders to move elsewhere. Combining these habitat and food source reduction strategies with a preventative surface spray in spring is the most comprehensive way to keep them from returning.
Is the Black House Spider related to the Funnel-web spider?
No, they are not closely related, and it's a very important distinction to make. The similar-sounding name can cause confusion, but they belong to entirely different spider families and have vastly different behaviours and levels of danger. The Black House Spider (*Badumna insignis*) builds lacy, aerial webs on structures and is not dangerous. The Sydney Funnel-web spider (*Atrax robustus*) is a ground-dwelling mygalomorph that lives in burrows and is medically significant. They look very different: the Black House Spider is dark grey and velvety, while the Funnel-web is glossy black with large fangs and spinnerets. The only thing they share is a funnel-shaped retreat, but the Black House Spider's is part of an external web, while the Funnel-web's is the entrance to an underground burrow.
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