Cobweb weaver vs Common corncockle

Steatoda nobilis compared with Agrostemma githago

Key Differences

Cobweb weaver is Not Evaluated while Common corncockle is Critically Endangered.

Taxonomic Classification

Rank	Cobweb weaver	Common corncockle
Kingdom	Animalia (Animals)	Plantae (Plants)
Phylum	Arthropoda (Arthropods)	Magnoliophyta (Flowering Plants)
Class	Arachnida (Arachnids)	Magnoliopsida (Dicots)
Order	Araneae (Araneae)	Caryophyllales (Caryophyllales)
Family	Theridiidae	Caryophyllaceae
Genus	Steatoda	Agrostemma
Species	Steatoda nobilis	Agrostemma githago

Conservation Status

Cobweb weaver

NE — Not Evaluated

Common corncockle

CR — Critically Endangered

Physical Characteristics

Attribute	Cobweb weaver	Common corncockle
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 corncockle

Habitat

Found across multiple habitat types including montane grasslands and shrublands, tropical and subtropical moist broadleaf forests, and temperate coniferous forests, among 13 distinct biome types. Populations are also found in montane and highland environments at higher elevations.

Range

Widely distributed across Africa (Lesotho), Asia (7 countries), Europe (24 countries), North America (Canada, Mexico, United States), Oceania and the Pacific (Australia), and South America (Brazil, Chile). Currently classified as Critically Endangered 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 corncockle

<em>Agrostemma githago</em>, commonly known as common corncockle, is an annual flowering plant in the family Caryophyllaceae. Once a widespread weed of cereal crops across Europe, Asia, and beyond, this species is now Critically Endangered on the IUCN Red List due to the dramatic decline caused by modern agricultural practices, particularly improved grain cleaning and herbicide use. Corncockle is a tall, slender plant covered in silky white hairs, bearing large, solitary pink to purple flowers with distinctive dark veining. Its seeds contain toxic saponin compounds called githagins, which historically contaminated grain supplies. The species now survives primarily in wildflower conservation areas, seed banks, and traditional farmland conservation schemes. It typically grows in open, disturbed arable soils with full sun exposure. Biological traits of this species remain poorly documented in the scientific literature.