Eratigena atrica

Distinguished from co-occurring Eratigena species (E. duellica, E. saeva) by palp morphology in males and epigyne structure in females; these relatives are morphologically identical in overall appearance and life cycles. Males have legs approximately three times body length, females twice body length. Overall coloration is brownish-grey with paler abdominal patches forming anterior-facing chevrons toward the rear.

Human habitation and environs; also thrives under stones and logs, in tree cavities, and beneath overhanging earth banks far from immediate human influences.

Native to continental Europe; widespread across Europe and northern Asia (excluding China). Introduced to North America, with established populations in Canada (British Columbia) and USA (Pacific Northwest). In Britain, self-sustaining populations occur in Newcastle-upon-Tyne area and Perth/Dundee region of eastern Scotland, likely from accidental importation via ports.

Adults mature August–September; males emerge slightly before females. Spiderlings emerge in fall (contrasting with E. agrestis, which emerges in spring).

Egg sacs laid in spring, each containing approximately 60–80 eggs. Both sexes overwinter as half-grown juveniles, mature the following August–September. Mating occurs in the female's web; males may cohabit briefly before dying. Females overwinter with stored sperm and commence laying egg sacs in spring. Some females survive for a third winter. Males live approximately 18 months; females typically two years or more.

Makes sudden apparent appearances during late summer and autumn when adults mature. Constructs funnel-shaped webs.

Frequently encountered in human dwellings, earning the common name "Giant House Spider." Often mistaken for more dangerous species due to large size and rapid movements.

• Eratigena agrestisCo-occurs in Pacific Northwest; distinguished by spring emergence of spiderlings versus fall emergence in E. atrica
• Eratigena duellicaMorphologically identical in overall appearance and life cycle; distinguished by palp and epigyne features only
• Eratigena saevaMorphologically identical in overall appearance and life cycle; distinguished by palp and epigyne features only; E. atrica shows no evidence of hybridization with this species unlike potential hybridization between E. duellica and E. saeva

• spider
• funnel weaver
• house spider
• introduced species
• Europe
• North America

• BugGuide
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Bug Eric: Missing Sector Orbweaver, Zygiella x-notata
• Life-history data for the funnel weavers Eratigena agrestis and Eratigena atrica (Araneae: Agelenidae) in the Pacific Northwest of North America
• The genome sequence of the house spider, Eratigena atrica (C.L.Koch, 1843) (Araneae: Agelenidae).