Birch Sober vs Große Fettspinne

Anacampsis blattariella compared with Steatoda grossa

Taxonomic Classification

Rank	Birch Sober	Große Fettspinne
Kingdom same	Animalia (Tier)	Animalia (Tier)
Phylum same	Arthropoda (Gliederfüßer)	Arthropoda (Gliederfüßer)
Class	Insecta (Insekten)	Arachnida (Spinnentiere)
Order	Lepidoptera (Schmetterlinge)	Araneae (Webspinnen)
Family	Gelechiidae	Theridiidae
Genus	Anacampsis	Steatoda
Species	Anacampsis blattariella	Steatoda grossa

Evolutionary Relationship

Birch Sober and Große Fettspinne share a common ancestor at the Phylum level: Arthropoda. (Gliederfüßer)

Conservation Status

Birch Sober

LC — Least Concern

Große Fettspinne

LC — Least Concern

Physical Characteristics

Attribute	Birch Sober	Große Fettspinne
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Birch Sober

Habitat

Typically found in virtually all terrestrial and freshwater habitats.

Range

Distributed across Belgium, Denmark, Norway, and Sweden.

Große Fettspinne

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).

Birch Sober

The Birch Sober (Anacampsis blattariella) is a species in the genus Anacampsis. It is currently classified as Least Concern on the IUCN Red List. Typically found in virtually all terrestrial and freshwater habitats.

Große Fettspinne

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.

Shared Countries

Both species can be found in 3 countries:

🇧🇪 Belgium 🇩🇰 Denmark 🇸🇪 Sweden