Cobweb weaver vs Fly Agaric

Steatoda nobilis compared with Amanita muscaria

Key Differences

Cobweb weaver is Not Evaluated while Fly Agaric is Least Concern.

Taxonomic Classification

Rank	Cobweb weaver	Fly Agaric
Kingdom	Animalia (Animals)	Fungi (Fungi)
Phylum	Arthropoda (Arthropods)	Basidiomycota (Club Fungi)
Class	Arachnida (Arachnids)	Agaricomycetes (Mushrooms)
Order	Araneae (Araneae)	Agaricales (Gilled Mushrooms)
Family	Theridiidae	Agaricaceae (Agarics)
Genus	Steatoda	Amanita (Amanitas)
Species	Steatoda nobilis	Amanita muscaria

Conservation Status

Cobweb weaver

NE — Not Evaluated

Fly Agaric

LC — Least Concern

Trend: Stable →

Physical Characteristics

Attribute	Cobweb weaver	Fly Agaric
Diet	—	Decomposer
Average Lifespan	—	1 years
Average Length	—	20 cm
Average Weight	—	100 g

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).

Fly Agaric

Habitat

Typically found in forest floors, decomposing wood, and soil ecosystems.

Range

Widely distributed across Europe (4 countries), North America (United States), Oceania and the Pacific (New Zealand), and South America (Brazil, Chile, Colombia).

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.

Fly Agaric

Among the most iconic and recognizable fungi on Earth, fly agaric mushrooms display striking red caps with white flecked warts across boreal forests of the Northern Hemisphere. Despite their fairy-tale appearance, they contain potent psychoactive compounds including muscimol and ibotenic acid and are moderately toxic. They form critical mycorrhizal symbioses with birch, pine, and spruce trees, exchanging mineral nutrients for carbon and playing essential roles in boreal forest nutrient cycling.