Adelaide Trapdoor Spider

Physical Characteristics

Size: Females are the larger sex, with a body length of up to 25-30mm. Males are smaller and more slender, typically around 15-20mm.

Coloration: The body is typically a uniform brown to dark chocolate brown. The cephalothorax (carapace) often has a distinct golden or coppery sheen, which is the inspiration for its scientific name 'aurea' (golden). The abdomen is darker, often with faint, lighter markings.

Key Features: Key features are the golden sheen on the carapace, their medium size for a trapdoor, and the construction of a burrow with a thick, plug-like or wafer-like lid that sits flush with the ground. Unlike some other trapdoors, they are not 'shield-backed'.

Disease Transmission

• There is no evidence that Adelaide Trapdoor Spiders can transmit diseases to humans.
• They are not vectors for any known human pathogens.
• Their subterranean lifestyle minimizes contact with disease-causing agents.
• Bacterial contamination risk from a bite is possible, as with any puncture wound, but not from the spider itself.
• No risk of viral or parasitic transmission.

Allergens and Respiratory Issues

Allergic reactions to trapdoor spider venom are not well-documented but are theoretically possible, as with any spider bite. Anaphylaxis would be extremely unlikely.

Contamination Risk

The risk of food or surface contamination is effectively zero. They live underground and wandering males do not seek out human food.

Vulnerable Populations

• Small children who may accidentally disturb a burrow or corner a wandering male.
• Gardeners are most likely to encounter them while digging.
• Anyone walking barefoot at night during the autumn mating season is at a slightly increased risk of encountering a wandering male.
• Pets may be bitten if they harass a spider, but the outcome is unlikely to be serious.
• Immunocompromised persons should take care to clean any bite wound thoroughly to prevent secondary infection.

Symptoms of Exposure

• A bite will cause immediate, sharp pain due to the mechanical action of their large fangs.
• Localized swelling, redness, and itching at the bite site are common.
• Nausea and lethargy have been occasionally reported but are not typical.
• Symptoms usually subside within a few hours to a day.
• Seek medical attention for any persistent or severe symptoms, or if the person bitten is a small child.

Transmission Methods

• The only health risk is from a direct, defensive bite.
• This requires direct contact, either by digging up a burrow or cornering a wandering male.
• There are no other pathways for any health impacts.
• Food contamination is not a risk.
• They are not a disease vector.

Risk Severity

The health risk is rated as Low. While the fangs are large and a bite would be painful, the venom is not considered dangerously toxic to humans.

Treatment Costs

Professional Treatment

$200-$400 for a general pest spray focused on creating a perimeter barrier to deter wandering males from entering the home. Direct treatment of burrows is often ineffective and not recommended.

Prevention Costs

$30-$80 for weather seals, door sweeps, and insect screens to block entry points for wandering males.

Diy Treatment

$40-$100 for a can of surface spray and gap filler for DIY exclusion efforts.

Property Damage

Structural Damage

They cause no structural damage to buildings.

Garden Damage

The main 'damage' is cosmetic. Their burrows can create small, sometimes numerous, holes in manicured lawns, which can be an aesthetic concern for some homeowners. They do not harm plants.

Food Contamination

No risk of food contamination.

Equipment Damage

No risk of equipment damage, although wandering males are frequently found dead in swimming pool skimmer boxes, requiring cleanup.

Business Impact

Restaurant Issues

Negligible, as wandering males are a residential issue. A male wandering into an outdoor dining area would be a rare and isolated incident.

Retail Impact

None.

Reputation Damage

None.

Operational Disruption

None.

Agricultural Impact

Crop Damage

No impact on commercial crops.

Yield Loss

None.

Beneficial Aspects

In gardens and natural ecosystems, they are beneficial predators that help control populations of insects and other invertebrates, contributing to soil health through aeration.

Economic Loss

There is no direct economic loss associated with this species. The only costs are related to nuisance control in residential settings.

Indirect Costs

Healthcare Costs

Extremely low. Costs would only be incurred in the rare event of a bite requiring medical consultation.

Cleanup Costs

Minor costs associated with lawn repair if a homeowner is highly concerned about the appearance of burrows, or the time taken to remove dead spiders from pool filters.

Replacement Costs

None.

Preventive Maintenance

The main cost is for materials and labour for exclusion methods, such as sealing gaps around the home.

Visual Signs

• The most obvious sign is finding the burrows: neat, circular holes in lawns or garden beds, sometimes with a visible, soil-camouflaged lid.
• Finding wandering male spiders inside the house, particularly in autumn.
• Small mounds of excavated soil around a new burrow.
• Spiders found in swimming pools or pool filters.
• Observing a spider at the entrance of its burrow at night with a torch.

Physical Evidence

• The burrow lid itself, which may be disturbed or ajar after hunting.
• Discarded exoskeletons near a burrow entrance after moulting, though this is rare to see.
• Remains of insect prey (e.g., beetle wing casings) around the burrow opening.
• Wandering males that have died indoors.
• Fine silk lining visible just inside the burrow entrance.

Behavioral Signs

• The sudden disappearance of the spider into its burrow when approached.
• Observing a male spider actively walking across a patio or floor at night.
• A defensive threat display (rearing up) if the spider is cornered or unearthed.
• The lid of the burrow being held shut from underneath if you try to pry it open.
• This is not a social spider, so you will not see group activity.

Seasonal Indicators

• A sudden increase in sightings of male spiders indoors during autumn (March-June).
• Male activity often peaks immediately following an autumn rain shower.
• Burrows may be more visible after mowing the lawn.
• Juvenile spiders may disperse and create tiny new burrows in late spring or summer.
• Females remain in their burrows year-round and are rarely seen.

Early Warning Signals

• Finding a single wandering male in the house is an early warning that there is a local population and more could enter.
• Discovering one or two burrows in the garden suggests more are likely present.
• Noticing small, freshly dug holes in the lawn could be juvenile spiders establishing themselves.
• Your neighbour mentioning they have trapdoor spiders is a good indicator they are in the area.

Sanitation Measures

• Indoor sanitation is not a factor as they are not attracted to food waste.
• Keeping the area around the house perimeter clear of thick leaf litter and debris can make it less attractive for wandering males to shelter.
• Reduce outdoor clutter like woodpiles or stored items near the house.
• There are no specific sanitation measures that prevent burrow construction in lawns.
• Water source elimination is not a primary control method, but reducing excessive irrigation might make lawns slightly less attractive.

Exclusion Methods

• This is the most important prevention strategy. Install high-quality weather seals on the bottom of all external doors.
• Use door sweeps to close the gap between the door and the threshold.
• Check for and seal any cracks or holes in the foundation, walls, or around pipes and utility lines where spiders could enter.
• Ensure insect screens on windows and screen doors are in good repair, with no holes or gaps.
• Install fine mesh guards over weep holes in brickwork to prevent entry while maintaining airflow.

Landscaping Tips

• It is very difficult to prevent burrows in a lawn without damaging the lawn itself.
• Creating a gravel or pebble border (at least 30cm wide) around the foundation of the house can deter wandering males from approaching and finding entry points.
• Keep grass mown to a reasonable height to make burrows more visible and the environment less sheltered.
• Avoid using thick organic mulches right up against the house foundation.
• Embrace biodiversity; in a large garden, having trapdoors in a back corner is a sign of a healthy ecosystem.

Monitoring Strategies

• During autumn, conduct nightly checks around doorways and on patios with a torch to spot wandering males.
• Regularly inspect door seals and screens for any damage or gaps.
• Place sticky blunder traps along walls in garages or sheds to monitor for wandering males, but be aware they will catch other creatures too.
• If you live in a known trapdoor area, be vigilant after the first autumn rains.
• Educate family members to keep doors closed, especially at night during the peak season.

Environmental Modification

• Modifying the outdoor environment to eliminate them is generally not feasible or desirable.
• Reducing outdoor lighting can decrease the number of insects, which may slightly reduce the food source, but is unlikely to have a major impact.
• Improving drainage to prevent waterlogged soil might help, but these spiders are well-adapted to typical garden soil moisture.
• The focus should be on modifying the structure of the house (exclusion) rather than the garden.

Professional Treatment Methods

Chemical Control

A professional may apply a residual insecticide barrier spray around the perimeter of the house, on paths, and around entry points. This acts as a deterrent and can kill wandering males that cross it. Direct poisoning of individual burrows is generally ineffective and not recommended, as it rarely reaches the spider deep inside.

Biological Control

There are no commercial biological controls for trapdoor spiders.

Physical Control

Physical removal of wandering males found indoors using the 'container and card' method is the most common and immediate solution. Professionals will do this and also implement exclusion measures.

Integrated Approach

The best professional approach is Integrated Pest Management (IPM): inspect the property to identify entry points, install physical barriers (exclusion), use targeted chemical barriers if necessary, and provide advice to the homeowner on monitoring.

DIY Treatment Options

Natural Remedies

There are no proven effective natural repellents for trapdoor spiders.

Home Made Traps

Sticky traps can be placed in garages or along walls to catch wandering males.

Deterrent Methods

The best deterrent is exclusion. Sealing entry points is far more effective than any repellent.

Mechanical Control

If a wandering male is found inside, the safest method is to place a sturdy container over it, slide a piece of stiff cardboard underneath, and then release it outside, away from the house. Alternatively, a vacuum cleaner can be used for removal if you are not comfortable with the container method.

Treatment Effectiveness

Success Rate

Exclusion methods have a very high success rate at preventing indoor incursions. Chemical barriers can be effective but require reapplication and may have non-target impacts.

Timeframe

Exclusion provides an immediate and long-lasting solution once all gaps are sealed. Chemical barriers are effective for 1-3 months depending on the product and weather.

Follow Up Required

Annual inspection of seals and barriers is recommended. Chemical treatments may need to be reapplied before the start of each autumn season.

Seasonal Considerations

The best time for preventative treatments (applying barriers, checking seals) is in late summer, just before the male wandering season begins in autumn.

Application Techniques

• Perimeter spraying: A licensed professional applies a band of residual insecticide to the external foundation walls, around doors, windows, and along paths.
• Gap sealing: Using caulking guns or fillers to seal cracks and crevices.
• Door seal installation: Fitting weather strips and door sweeps.
• Safety protocols: When using DIY sprays, follow the label directions precisely and wear appropriate PPE. Keep children and pets away until the spray has dried.

Spring Activity

Juvenile spiders may be establishing new burrows. Females are in their burrows. Minimal activity is observed by homeowners.

Summer Activity

Spiders remain deep in their burrows to escape the heat and dry conditions. Activity is very low.

Autumn Activity

This is the PEAK season. Triggered by cooler temperatures and rain, males leave their burrows en masse to wander at night in search of females. This is when they are most commonly found inside homes.

Winter Activity

Male wandering may continue into early winter. Spiders become less active as temperatures drop further, retreating deep into their burrows to conserve energy.

Breeding Season

The breeding season is autumn and early winter, coinciding with the male wandering period.

Peak Activity Period

The peak time for 'infestation' (i.e., indoor encounters with males) is autumn, from March to June in South Australia.

Environmental Factors

Temperature Effects

Cooler autumn temperatures stimulate male activity. Extreme heat or cold leads to inactivity.

Humidity Effects

Rainfall is a major trigger for male wandering, as it increases humidity and softens the ground, making travel easier.

Photoperiod Effects

Shorter day length in autumn is a key biological trigger for males to begin their search for mates.

Weather Patterns

The first significant autumn rainstorm often results in a large number of male sightings over the following nights.

Pest Status

They have no official pest status and are a native species. They are only considered a 'nuisance pest' in residential contexts.

Control Regulations

There are no specific regulations for controlling them. However, any professional applying pesticides must adhere to state and federal regulations regarding chemical use.

Professional Requirements

Pest control technicians must be licensed by the relevant South Australian authority (e.g., SA Health) to apply pesticides commercially.

Environmental Considerations

Responsible pest management aims to minimize pesticide use to avoid harming non-target species. Exclusion is always the preferred first step.

Compliance Requirements

• Adherence to the specific instructions and safety data sheets for any pesticides used.
• Pest controllers must keep records of their chemical applications.
• Compliance with general environmental protection laws.
• No permits are required for their control.
• Professional pest managers should follow the industry Code of Practice.