Black House Spider, Window Spider
Badumna longinqua (or Badumna insignis)
Desidae (Intertidal and Funnel-web House Spiders), Order Araneae. Key family characteristics include three-clawed tarsi and cribellate or ecribellate silk production, often building messy sheet or funnel webs.
Physical Description
Robust, dark-colored spider with a compact body. The cephalothorax is dark brown to black, and the abdomen is oval, covered in dense, velvety dark hair, sometimes featuring a faint lighter dorsal pattern.
Size Estimate
Body length ranges from 9 to 18 mm for females (males are slightly smaller, around 6 to 11 mm), with a leg span of approximately 30 to 40 mm. This appears to be an adult specimen.
Coloration & Markings
Uniformly dark charcoal, dark brown, or jet black across both the cephalothorax and abdomen. Some individuals may show a subtle, lighter zig-zag or scalloped pattern down the center of the dorsal abdomen.
Web Type
Messy, lacy sheet web with a tubular retreat, commonly built in corners of windows, door frames, or crevices in brickwork. The silk has a characteristic bluish or greyish-white tinged, fuzzy texture.
Eye Arrangement
Eight small eyes arranged in two transverse rows across the broad head region, typical of cribellate spiders, with lateral eyes often touching or closely grouped.
Leg Characteristics
Moderately long, robust, and covered in fine dark setae. The legs are held in a splayed, slightly crouched posture typical of ambush hunters waiting near their retreat.
Venom & Safety Information
Venom Information
Mycotoxic venom. While a bite can be painful, causing local swelling, redness, and occasionally nausea or sweating, it is generally not medically significant unless an allergic reaction occurs.
Medical Significance
Low to moderate. Bites are uncommon due to their shy nature. Symptoms of envenomation include localized pain and swelling, and in rare cases, superficial skin lesions if secondary infection occurs. First aid includes ice packs and simple analgesics.
Safety Recommendations
Avoid direct handling. If found indoors, gently guide the spider into a container using a piece of card and release it outdoors. Seal gaps around windows and doors to prevent entry.
Habitat & Behavior
Habitat & Range
Native to Australasia (Australia and New Zealand), but introduced to parts of North America, Japan, and South America. Highly adapted to urban environments, commonly found in crevices of buildings, window frames, fences, and bark.
Behavior & Temperament
Reclusive, nocturnal ambush hunter. It spends most of its time hidden inside its silken retreat, only emerging onto the web surface when prey triggers the trip lines. Timid towards humans, biting only when persistently provoked or trapped against the skin.
Diet & Prey
Primarily preys on flying insects such as flies, moths, mosquitoes, butterflies, and beetles that blunder into its sturdy web.
Seasonal Activity
Active year-round in temperate climates, with peak visibility during the warmer months when males leave their retreats to search for mates.
Description
The Black House Spider is a familiar urban dweller, often noticed nesting quietly in the corners of window frames and dark crevices around homes. With its velvety black coat and robust build, it is a master of building intricate funnel-like webs that trap unwary insects. While their shadowy presence and sudden appearances can startle homeowners, they act as effective pest controllers, quietly reducing indoor insect populations.
Key Features
Robust black or dark brown body, velvety texture, and association with messy, lacy funnel webs built in structural crevices or window corners.
Similar Species
Funnel-web spiders (Atracidae) and house spiders (Tegenaria/Eratigena species). Distinguished by web placement, eye pattern, and geographic distribution.
Life Cycle
Females construct several papery, white egg sacs hidden within the retreat. Spiderlings disperse via ballooning upon hatching. Lifespan can reach up to two years, with females living longer than males.
Ecological Importance
Serves as an important natural predator of household pests, helping to keep populations of flies, mosquitoes, and moths in check.
Conservation Status
Not evaluated by the IUCN, but populations are secure and thriving, particularly benefiting from human structures.
Interesting Facts
Black House Spiders are frequently preyed upon by the white-tailed spider (Lampona cylindrata), which specializes in hunting other spiders.
Photography Tips
Use macro lenses with a ring flash or diffused natural light. Photograph from above and slightly to the side to capture the body shape and leg posture clearly while maintaining a safe distance.
Identified: 2026-08-27T00:56:46.863107