Grey House Spider, Australian House Spider
Badumna longinqua
Desidae (Intertidal and House Spiders), Order Araneae
Physical Description
Stout-bodied with a robust, somewhat flattened cephalothorax and a high, oval-shaped abdomen. The body is covered in fine, velvety hairs giving it a matte texture, though the legs and cephalothorax may show a subtle sheen.
Size Estimate
Body length ranges from 9 mm to 18 mm for females, with males slightly smaller around 6 mm to 12 mm. Total leg span can reach up to 30 mm to 40 mm.
Coloration & Markings
Characterized by a charcoal grey to dark brown base color. The abdomen typically features a mottled or patterned dorsal stripe with lighter grey or yellowish markings, while the legs display faint dark banding.
Web Type
Builds a characteristic messy, dense, lacy sheet web with a funnel-like retreat tube leading into a crevice, bark crack, or corner of a window frame.
Eye Arrangement
Eight small eyes arranged in two slightly curved, nearly parallel rows across the broad front of the cephalothorax, typical of cribellate spiders.
Leg Characteristics
Robust and moderately long legs with distinct dark banding. Equipped with specialized comb-like structures (calamistrum) on the hind legs used for spinning the cribellate silk.
Venom & Safety Information
Venom Information
Possesses mild neurotoxic venom designed to immobilize small insect prey. Bites to humans are uncommon and typically cause localized pain, swelling, and redness.
Medical Significance
Not medically significant. Bites may cause localized discomfort and mild swelling similar to a bee sting, but systemic effects are extremely rare. In very rare cases, an open sore or localized necrosis has been anecdotally reported from secondary infection or hypersensitivity.
Safety Recommendations
To avoid bites, wear gloves when cleaning outdoor furniture or clearing debris near exterior walls. If found inside, gently capture and release the spider outdoors using a cup and card.
Habitat & Behavior
Habitat & Range
Native to Australia but introduced globally to New Zealand, parts of North America (especially California), and Europe. Frequently found on exterior walls of buildings, window frames, fences, and tree bark.
Behavior & Temperament
Non-aggressive and secretive, spending most of its time hidden inside its funnel retreat. It emerges onto the sheet web primarily at night to wait for prey. Will bite defensively only if trapped or firmly pressed against the skin.
Diet & Prey
Generalist predator feeding primarily on flying insects such as flies, moths, mosquitoes, beetles, and occasionally other spiders that blunder into its web.
Seasonal Activity
Active year-round in temperate climates, with peak activity and web-building observed during the warmer spring and summer months.
Description
The Grey House Spider is a familiar urban dweller, often noticed by the distinctive untidy, lace-like webs spun around window frames and corners. As a master of architectural hiding, it constructs a dense silken retreat leading into crevices where it lies in wait for unsuspecting nocturnal insects. Though their webs can accumulate dust and appear untidy, these resilient spiders act as excellent natural pest controllers around human habitations.
Key Features
Robust dark grey to brown body, distinct lacy sheet web ending in a funnel-shaped retreat, and a preference for human-made structures and crevices.
Similar Species
Badumna insignis (Black House Spider), which is darker, larger, and prefers similar urban habitats; can be distinguished by its much darker, almost black coloration.
Life Cycle
Females produce round to lens-shaped egg sacs enclosed within the webbing retreat. Spiderlings hatch and disperse via ballooning or crawling. Adults can live for several years under favorable conditions.
Ecological Importance
Acts as an effective biological control agent in urban and suburban ecosystems by reducing populations of nuisance flying insects like mosquitoes and flies.
Conservation Status
Not evaluated by the IUCN, but populations are stable and thriving, frequently expanding their range through human transport.
Interesting Facts
Despite being native to Australia, the Grey House Spider has successfully hitchhiked via international cargo to establish thriving populations in coastal regions of North America and Europe.
Photography Tips
Photograph from a slightly elevated side angle to capture the texture of the velvety carapace and the patterning on the abdomen. Use natural side lighting or a diffused macro flash to highlight leg banding.
Identified: 2026-09-15T12:47:00.080201