Black House Spider, Window Spider
Badumna insignis
Desidae (Intertidal and House Spiders), Order Araneae
Physical Description
Robust and dark-bodied with a bulky, somewhat flattened cephalothorax and an oval-shaped, velvety abdomen. Females are notably larger and more robust than males. The body texture appears matte and finely haired, giving it a dark, charcoal-like appearance.
Size Estimate
Body length ranges from 9 mm to 18 mm for females, with males slightly smaller around 9 mm to 11 mm. Total leg span can reach up to 30 mm.
Coloration & Markings
Charcoal grey to jet black throughout the body and legs. The dorsal abdomen may feature a faint, dull patterned stripe or lighter markings, though specimens often appear uniformly dark or nearly black, especially when mature.
Web Type
Builds a characteristic messy, lacy, sheet-like web with a funnel-like retreat tube leading into a crevice, crack, or hole.
Eye Arrangement
Eight small eyes arranged in two rows across the front of the broad cephalothorax, typical of cribellate spiders, closely grouped together.
Leg Characteristics
Strong, moderately long, and covered in fine dark setae. The legs are held in a typical stance adapted for rapid movement around the mouth of their funnel retreats.
Venom & Safety Information
Venom Information
Possesses mild to moderate neurotoxic venom. A bite can cause localized pain, swelling, and sometimes systemic symptoms such as sweating, nausea, and headache, though severe reactions are uncommon.
Medical Significance
Bites are uncommon due to their reclusive nature. While painful and occasionally resulting in local tissue necrosis or flu-like symptoms if the bite site becomes infected or untreated, they are generally not considered medically dangerous in the way a funnel-web or widow spider bite is.
Safety Recommendations
Avoid putting bare hands into dark crevices, woodpiles, or window corners where webs may be present. If relocating indoors, gently guide the spider into a container using a piece of card. Standard first aid involves ice packs and antiseptic for any bite.
Habitat & Behavior
Habitat & Range
Native to Australia and New Zealand, but introduced globally in temperate urban environments. Frequently found in crevices of walls, window frames, bark of trees, fences, and corners of buildings.
Behavior & Temperament
Reclusive, sedentary web-builders that spend most of their time inside their funnel retreats. They are nocturnal hunters, waiting at the mouth of the web for prey to trigger the silk lines. Generally non-aggressive, but females guarding egg sacs may bite if cornered or trapped against skin.
Diet & Prey
Feeds on a wide variety of flying and crawling insects, including flies, moths, beetles, butterflies, and ants, which become entangled in the cribellate silk.
Seasonal Activity
Active year-round in temperate regions, with peak web-building and foraging activity occurring during the warmer spring and summer months.
Description
The Black House Spider is a familiar sight around urban homes and gardens, recognizable by its dark, velvety body and messy, funnel-shaped webs built in corners and window frames. While somewhat intimidating due to its dark coloration and robust build, this species plays a valuable role in keeping nuisance insect populations in check.
Key Features
Robust dark body, velvety black or dark charcoal coloration, and a distinctive messy sheet web featuring a tubular funnel retreat.
Similar Species
Funnel-web spiders (Atrax and Hadronyche spp.) and House Spiders (Tegenaria/Eratigena spp.), distinguished by web structure, eye arrangement, and specific habitat niches.
Life Cycle
Females construct white, papery egg sacs hidden within the retreat webbing, containing dozens of eggs. Spiderlings disperse via ballooning upon hatching. Lifespan can be up to two years or more for females.
Ecological Importance
Acts as an effective natural pest controller in residential and natural environments, regulating populations of flies, mosquitoes, and beetles.
Conservation Status
Not threatened; highly adaptable and thriving alongside human development in urban and suburban landscapes.
Interesting Facts
Black house spiders often share their webs with tiny pirate spiders or scavengers. Their cribellate silk has a unique woolly texture that lacks sticky glue droplets, capturing insects purely through mechanical entanglement.
Photography Tips
Photograph from a safe distance using macro lenses in natural daylight or with a diffused flash to highlight the fine velvety texture of the body without harsh shadows.
Identified: 2026-10-12T15:10:39.902761