Broom Flat-body vs Cobweb weaver

Agonopterix scopariella compared with Steatoda nobilis

Key Differences

• Broom Flat-body is Near Threatened while Cobweb weaver is Not Evaluated.

Taxonomic Classification

Rank	Broom Flat-body	Cobweb weaver
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum same	Arthropoda (Arthropods)	Arthropoda (Arthropods)
Class	Insecta (Insects)	Arachnida (Arachnids)
Order	Lepidoptera (Butterflies & Moths)	Araneae (Araneae)
Family	Depressariidae	Theridiidae
Genus	Agonopterix	Steatoda
Species	Agonopterix scopariella	Steatoda nobilis

Evolutionary Relationship

Broom Flat-body and Cobweb weaver share a common ancestor at the Phylum level: Arthropoda. (Arthropods)

Conservation Status

Broom Flat-body

NT — Near Threatened

Cobweb weaver

NE — Not Evaluated

Physical Characteristics

Attribute	Broom Flat-body	Cobweb weaver
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Broom Flat-body

Habitat

Typically found in virtually all terrestrial and freshwater habitats.

Range

Distributed across Belgium, Denmark, Norway, Portugal, and Sweden. Listed as Near Threatened, this species requires ongoing monitoring to prevent population decline.

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).

Broom Flat-body

The Broom Flat-Body (Agonopterix scopariella) is a species in the genus Agonopterix. It is currently classified as Near Threatened on the IUCN Red List. Typically found in virtually all terrestrial and freshwater habitats.

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.

Shared Countries

Both species can be found in 3 countries:

🇧🇪 Belgium 🇩🇰 Denmark 🇵🇹 Portugal