Cobweb spider vs common bubble snail

Enoplognatha thoracica compared with Akera bullata

Key Differences

• Cobweb spider is Vulnerable while common bubble snail is Least Concern.

Taxonomic Classification

Rank	Cobweb spider	common bubble snail
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum	Arthropoda (Arthropods)	Mollusca (Mollusks)
Class	Arachnida (Arachnids)	Gastropoda (Gastropoda)
Order	Araneae (Araneae)	Aplysiida (Aplysiida)
Family	Theridiidae	Akeridae
Genus	Enoplognatha	Akera
Species	Enoplognatha thoracica	Akera bullata

Evolutionary Relationship

Cobweb spider and common bubble snail share a common ancestor at the Kingdom level: Animalia. (Animals)

Conservation Status

Cobweb spider

VU — Vulnerable

common bubble snail

LC — Least Concern

Physical Characteristics

Attribute	Cobweb spider	common bubble snail
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Cobweb spider

Habitat

Typically found in terrestrial habitats from forests to deserts.

Range

Found across Europe (4 countries) and North America (Canada, United States). Currently classified as Vulnerable on the IUCN Red List, this species faces significant conservation challenges across its range.

common bubble snail

Habitat

Typically found in terrestrial and aquatic habitats including forests and freshwater.

Range

Distributed across Denmark, Norway, Portugal, and Sweden.

Cobweb spider

Enoplognatha thoracica is a slender cobweb spider in the family Theridiidae, a widespread group of three-dimensional web-building spiders found across the temperate regions of Europe and North America. This small spider, typically measuring 3–5 millimeters in body length, constructs irregular, tangled cobwebs in low vegetation, hedgerows, meadow margins, and scrubby habitats where it captures small flying and crawling arthropods. The body is pale yellowish-brown to creamy white with darker markings on the abdomen, and the legs are long and slender relative to body size, adapted for navigating the three-dimensional structure of its web. Like other theridiids, Enoplognatha thoracica uses a gum-foot trap technique in which sticky vertical threads attached to the substrate at their lower ends snap insects upward when disturbed, immobilizing prey effectively. The species occupies a range spanning much of Europe eastward into temperate Asia and has established populations in parts of North America, likely through accidental human-mediated dispersal. Females produce egg sacs that are guarded within the web until hatching. The species is associated with disturbed and edge habitats and tolerates moderate agricultural landscapes. It is classified as Vulnerable by some assessments, reflecting localized population pressures from habitat loss and intensification of land use in parts of its range, though other evaluations consider it more broadly secure.

common bubble snail

The common bubble snail (<em>Akera bullata</em>) is a marine gastropod mollusc found in the coastal waters of Denmark, Norway, Portugal, and Sweden. This species typically inhabits terrestrial and aquatic environments including forests and freshwater-adjacent marine areas, often occurring in shallow subtidal and intertidal zones of temperate European seas. It is classified as Least Concern on the IUCN Red List. As a member of the family Akeridae, the common bubble snail is characterized by its thin, fragile shell and its ability to swim briefly by flapping its large, wing-like parapodia. The species often forages on algae and detritus in sandy and muddy seafloor habitats, particularly in sheltered bays and estuaries. The common bubble snail typically aggregates in large numbers during the spawning season, producing gelatinous egg masses. Biological traits of this species remain poorly documented in the scientific literature.

Shared Countries

Both species can be found in 3 countries:

🇩🇰 Denmark 🇳🇴 Norway 🇸🇪 Sweden