Grey House Spider, Window Spider
Badumna longinqua
Desidae (Intertidal and House Spiders), Order Araneae. Key characteristics include cribellate or ecribellate respiration, three claws, and a distinctive social or retreat-building habit often found around human habitations.
Physical Description
Robust body with a dark brown to greyish carapace and a velvety, oval abdomen that is often lighter grey with mottled markings. The cephalothorax is broad and glossy, and the chelicerae are strong and prominent.
Size Estimate
Body length typically ranges from 9 to 18 mm for females, with a leg span of around 30 to 40 mm. The specimen appears to be an adult.
Coloration & Markings
Dark brown to charcoal head region with a greyish-brown abdomen featuring indistinct lighter markings, chevron patterns, or mottling. The legs are uniformly dark and lack distinct banding.
Web Type
Tangle or sheet web with a distinct tubular retreat, commonly built in corners of windows, doors, and crevices around buildings.
Eye Arrangement
Eight eyes arranged in two rows of four across the broad front of the carapace, typical of cribellate spiders, with similar sizes assisting in forward and lateral vision.
Leg Characteristics
Robust, moderately long legs with dense claw tufts and visible hairs, held close to the body in a compact posture when resting near the tubular retreat.
Venom & Safety Information
Venom Information
Contains neurotoxic components. Envenomation is generally mild in humans, though bites can be painful.
Medical Significance
Not considered dangerously venomous to humans, but bites can cause local pain, swelling, and occasionally nausea or sweating if the bite is deep. First aid involves cold compresses and antiseptic.
Safety Recommendations
Avoid direct handling. If found near a doorway, it can be gently relocated using a container and a piece of card. Seal entry points if you wish to keep them out of living areas.
Habitat & Behavior
Habitat & Range
Native to Australia, now widely introduced globally including New Zealand, parts of the Americas, and Europe. Prefers artificial structures, window frames, door corners, tree bark, and wooden fences.
Behavior & Temperament
Nocturnal ambush hunters that spend daylight hours inside their silken retreat tubes, waiting for prey to strike the web. Generally non-aggressive, but females may bite defensively if trapped or cornered.
Diet & Prey
Insects including flies, moths, beetles, mosquitoes, and ants that happen to land or crawl onto the tangled sheet web.
Seasonal Activity
Active year-round in temperate indoor environments, with peak web-building and foraging activity occurring during the warmer spring and summer months.
Description
The Grey House Spider is a familiar companion around human habitations, recognized by its characteristic lacy web and silk-lined retreat tube near doors and windows. Though sometimes alarming due to its dark, robust appearance, it plays a useful role in controlling household insect populations.
Key Features
Robust dark body, velvety greyish-brown patterned abdomen, and the creation of a dense, messy sheet web featuring a prominent funnel-shaped retreat tube near architectural angles.
Similar Species
Tegenaria or Eratigena species (Funnel-web grass spiders/Giant house spiders), which generally have longer legs and faster running speeds, or Amaurobius species.
Life Cycle
Females construct silken egg sacs hidden within the retreat. Spiderlings disperse via ballooning after hatching. They molt multiple times to reach adulthood and can live for several years in favorable conditions.
Ecological Importance
Acts as a natural pest control agent by reducing populations of flying and crawling insects around buildings and gardens.
Conservation Status
Not evaluated by the IUCN, but highly secure and expanding globally due to human-modified habitats.
Interesting Facts
Despite originating in Australia, this species has successfully hitchhiked via global commerce to establish thriving urban populations worldwide, often coexisting closely with human activity.
Photography Tips
Photograph from the side or slightly above to capture the robust carapace and leg posture. Use macro settings and indirect lighting to reveal the texture of the abdomen without startling the spider into its retreat.
User Notes
Found in a building by door outside
Identified: 2026-09-15T12:32:48.954035