Black House Spider, Window Spider
Badumna insignis
Desidae (Intertidal and House Spiders), Order Araneae. Key family characteristics include three-clawed tarsi, cribellate or ecribellate silk production, and typical arrangement of eight eyes in two rows.
Physical Description
Robust, dark-colored body with a densely hairy, velvety texture. The prosoma (cephalothorax) is dark brown to black and pear-shaped, while the opisthosoma (abdomen) is oval, slightly depressed, and covered in fine, velvety setae.
Size Estimate
Body length ranges from 9 to 18 mm for females, with males slightly smaller around 9 to 11 mm. Leg span is approximately 30 mm.
Coloration & Markings
Dark charcoal-grey to black overall coloration. The dorsal abdomen often features a faint, lighter patterned dorsal stripe or chevron markings, though older specimens can appear uniformly jet black.
Web Type
Constructs a characteristic messy, lacy, funnel-shaped sheet web with a tubular retreat, frequently built in crevices, window frames, and corners of buildings.
Eye Arrangement
Eight eyes arranged in two slightly curved rows across the front of the carapace, consisting of small, dark, uniform lenses typical of cribellate spiders.
Leg Characteristics
Moderately robust and covered in dark hair, with the first and fourth pairs typically being the longest. They lack prominent banding and are held close to the body when resting inside the tubular web retreat.
Venom & Safety Information
Venom Information
Possesses mild neurotoxic venom used to immobilize insect prey. Envenomation in humans is uncommon and rarely causes severe systemic effects.
Medical Significance
Not medically significant. A bite may cause localized pain, swelling, and redness, and in rare cases, sweating or nausea, but symptoms typically resolve without medical intervention.
Safety Recommendations
Wear gloves when clearing old webs from outdoor furniture or window frames, shake out outdoor shoes, and gently relocate spiders outdoors using a container if found indoors.
Habitat & Behavior
Habitat & Range
Native to Australia and New Zealand, widely introduced globally. Found primarily around human habitation, on rough tree bark, rock crevices, brick walls, and window corners.
Behavior & Temperament
Reclusive, nocturnal ambush hunter. Generally non-aggressive, retreating into its tubular funnel when disturbed, though females guarding egg sacs may bite if handled.
Diet & Prey
Feeds on a wide variety of flying and crawling insects, including flies, moths, beetles, butterflies, and ants, captured when they land on the sticky sheet web.
Seasonal Activity
Active year-round in temperate climates, with peak visibility during warmer months when females mature and maintain their webs.
Description
The Black House Spider is a familiar yet reclusive urban dweller, easily recognized by its dark, velvety body and messy funnel webs spun in corners. As an adept predator of household pests, it plays a quiet but valuable ecological role around homes and gardens.
Key Features
Robust dark body, velvety texture, and the distinctive messy funnel-shaped sheet web with a tubular retreat built in structural crevices.
Similar Species
Funnel-web spiders (Atrax and Hadronyche spp.) and House Spiders (Tegenaria/Eratigena spp.). Distinguished by web structure, habitat, and lack of aggressive posture.
Life Cycle
Females construct several white, papery egg sacs within the web retreat, containing up to several hundred eggs. Spiderlings disperse via ballooning after hatching. Lifespan can reach up to two years.
Ecological Importance
Acts as an effective natural pest control agent by reducing populations of flying and crawling insects around human structures.
Conservation Status
Not evaluated by the IUCN, but populations are secure, highly adaptable, and thriving globally alongside urban development.
Interesting Facts
Black House Spiders frequently share their webs with small scavenging theridiid spiders that steal leftovers, and they are known to maintain the same web site for years.
Photography Tips
Photograph from above or a slight side angle in natural indirect light to highlight the velvety texture of the abdomen without disturbing the spider inside its retreat.
Identified: 2026-09-23T21:14:15.396841