cobweb spiders vs Fly Agaric

Steatoda grossa compared with Amanita muscaria

Taxonomic Classification

Rank	cobweb spiders	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 grossa	Amanita muscaria

Conservation Status

cobweb spiders

LC — Least Concern

Fly Agaric

LC — Least Concern

Trend: Stable →

Physical Characteristics

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

Habitat & Geographic Range

cobweb spiders

Habitat

Typically found in terrestrial habitats from forests to deserts.

Range

Widely distributed across Africa (South Africa), Europe (29 countries), North America (Canada, 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 spiders

The false black widow (Steatoda grossa) is a cosmopolitan cobweb spider in the family Theridiidae, often mistaken for the true black widow due to its similarly dark, globose abdomen, though it lacks the red hourglass marking. Females reach 6–10 millimeters in body length and display a deep purplish-brown to nearly black coloration with faint pale markings on the dorsal abdomen. Originally native to western Europe, Steatoda grossa has spread globally through human commerce, establishing populations in Australia, New Zealand, North America, and other regions where it thrives in human structures including homes, sheds, and outbuildings. The spider constructs a persistent, tangled cobweb in sheltered corners and recesses, where it captures woodlice, ants, beetles, and other arthropods—notably targeting invertebrates that many other spiders avoid. The venom of S. grossa causes steatodism, a syndrome of localized pain, sweating, and systemic discomfort that is rarely serious but can cause significant distress. Interestingly, the antivenin produced for Latrodectus (true widow) spider bites has been shown to effectively treat Steatoda envenomations, underscoring the phylogenetic relatedness of these genera. Females produce several egg sacs during a season, each containing dozens of eggs wrapped in distinctive silken cocoons. The species is classified as Least Concern given its expanding global distribution facilitated by human activity.

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.