Cobweb weaver vs Common Kidney-Vetch

Steatoda nobilis compared with Anthyllis vulneraria

Key Differences

Cobweb weaver is Not Evaluated while Common Kidney-Vetch is Vulnerable.

Taxonomic Classification

Rank	Cobweb weaver	Common Kidney-Vetch
Kingdom	Animalia (Animals)	Plantae (Plants)
Phylum	Arthropoda (Arthropods)	Magnoliophyta (Flowering Plants)
Class	Arachnida (Arachnids)	Magnoliopsida (Dicots)
Order	Araneae (Araneae)	Fabales (Legumes & Allies)
Family	Theridiidae	Fabaceae
Genus	Steatoda	Anthyllis
Species	Steatoda nobilis	Anthyllis vulneraria

Conservation Status

Cobweb weaver

NE — Not Evaluated

Common Kidney-Vetch

VU — Vulnerable

Physical Characteristics

Attribute	Cobweb weaver	Common Kidney-Vetch
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Cobweb weaver

Habitat

Typically found in terrestrial habitats from forests to deserts.

Range

Widely distributed across Europe (7 countries), North America (United States), and South America (Ecuador).

Common Kidney-Vetch

Habitat

Found across multiple habitat types including tropical and subtropical moist broadleaf forests, temperate broadleaf and mixed forests, and temperate coniferous forests, among 6 distinct biome types spanning the Indomalayan and Oceanian and Palearctic realms. Populations are also found in montane and highland environments at higher elevations.

Range

Widely distributed across Africa (Libya), Asia (Japan), Europe (9 countries), North America (Canada, United States), and Oceania and the Pacific (Australia). Currently classified as Vulnerable on the IUCN Red List, this species faces significant conservation challenges across its range.

Cobweb weaver

The noble false widow (Steatoda nobilis) is a theridiid spider that has attracted considerable media attention in the British Isles and along the Atlantic coast of Europe due to its painful but rarely dangerous bite and its rapid range expansion facilitated by human activity. Originally native to the Canary Islands and Madeira, the species arrived in southern England during the 19th century, likely via banana shipments, and has since spread northward through Britain and westward into Ireland, while also establishing populations along the Iberian Peninsula and Atlantic France. Females are robust, with a dark brown carapace and a distinctive cream-colored pattern on the bulbous abdomen that varies between individuals; females reach 8.5–14 millimeters in body length, making this one of the larger European theridiids. The species constructs persistent, tangled cobwebs in sheltered locations outside buildings—under window ledges, in door frames, and in garden walls—as well as within homes in cooler seasons. It is a generalist predator, capturing insects and other invertebrates, and has been reported to occasionally subdue prey considerably larger than itself, including small lizards. Steatoda nobilis venom produces steatodism, which can cause localized pain, swelling, and in rare cases systemic symptoms. Its conservation status has not been formally assessed, but its expanding range demonstrates considerable resilience.

Common Kidney-Vetch

Common Kidney-Vetch (<em>Anthyllis vulneraria</em>) is a flowering plant in the legume family Fabaceae, assessed as Vulnerable on the IUCN Red List due to habitat degradation and agricultural intensification across parts of its range. It is widely distributed across Africa (Libya), Asia (Japan), Europe (nine countries), North America (Canada and the United States), and Oceania (Australia), occupying six distinct biome types and occurring within the Indomalayan and Oceanian biogeographic realms. The species typically grows in dry, calcareous grasslands, coastal cliffs, sand dunes, and rocky slopes, often favoring nutrient-poor soils. It is an important larval food plant for certain butterfly species, particularly the Small Blue butterfly in Europe, and contributes to soil fertility through nitrogen fixation via root nodules. Its cheerful yellow, orange, or red flower heads make it a recognizable component of chalk and limestone grassland communities. Biological traits of this species remain poorly documented in the scientific literature.