Black Lace-weaver
Amaurobius ferox
Amaurobiidae (Hacklemesh Weavers), Order Araneae
Physical Description
Robust, dark-colored spider with a smooth, glossy cephalothorax and a velvety, oval abdomen. Females are generally larger and more robustly built than males.
Size Estimate
Body length ranges from 10 to 16 millimeters, with a leg span up to 30 millimeters. This appears to be an adult specimen.
Coloration & Markings
Deep dark brown to blackish coloration, sometimes with faint yellowish or reddish markings on the anterior part of the abdomen, though often appearing uniformly dark.
Web Type
Cribellate (hacklemesh) retreat web, typically built in crevices, under bark, or in dark corners around structures. The web has a distinctive bluish, woolly texture.
Eye Arrangement
Eight eyes arranged in two transverse rows of four, relatively uniform in size, characteristic of cribellate spiders.
Leg Characteristics
Strong, moderately long legs with distinct spines and a specialized structure called a calamistrum on the hind metatarsus used to comb cribellate silk.
Venom & Safety Information
Venom Information
Contains mild neurotoxic or proteolytic venom used to immobilize insect prey. Not considered lethal or dangerous to humans.
Medical Significance
Not medically significant. A bite may cause localized pain, redness, and mild swelling akin to a bee sting, but symptoms typically resolve quickly without medical intervention.
Safety Recommendations
Avoid handling with bare hands. If found indoors, gently guide it into a container using a piece of cardstock and relocate it outdoors. Wash any accidental bite site with soap and water.
Habitat & Behavior
Habitat & Range
Native to Europe and introduced to North America. Prefers dark, humid microhabitats such as bark, stone walls, and basements or cellars in human habitations.
Behavior & Temperament
Nocturnal ambush hunter that remains hidden in its silken retreat during the day. Generally non-aggressive but can deliver a defensive bite if cornered or trapped against skin.
Diet & Prey
Predominantly feeds on crawling insects such as beetles, cockroaches, woodlice, and flies that stumble into its woolly retreat web.
Seasonal Activity
Active year-round in sheltered indoor environments, with peak wandering behavior in males seeking females during late autumn.
Description
The Black Lace-weaver is a fascinating dark-hued dweller of crevices and dark corners. Known for its signature woolly blue-tinged cribellate silk, this robust spider plays a quiet yet effective role in natural pest control around homes and gardens.
Key Features
Velvety dark brown to black body, robust proportions, preference for crevice-dwelling, and the production of woolly, cribellate silk.
Similar Species
Tegenaria species (Funnel-web weavers) and Steatoda species (False widows), which can be distinguished by web structure and closer abdominal and leg patterning.
Life Cycle
Females construct silken egg sacs containing hundreds of eggs and often guard them until hatching. Spiderlings undergo multiple molts over a multi-year lifespan, often exhibiting matriphagy in some related species.
Ecological Importance
Acts as an effective predator of household and garden arthropods, helping to regulate populations of crawling insect pests.
Conservation Status
Not evaluated by the IUCN; widespread, abundant, and frequently thriving alongside human habitations as an introduced species.
Interesting Facts
They possess a specialized comb-like organ called a calamistrum used to pull silk from the cribellum plate, creating a woolly nano-fiber web that mechanically snags insect setae without sticky glue.
Photography Tips
Use macro lighting to capture the texture of the velvety abdomen and the unique blue sheen of the woolly web. Maintain a safe distance and photograph from a side angle to highlight body proportions.
Identified: 2026-10-05T03:54:45.426028