cobweb spiders vs Common Yellow Conch

Steatoda grossa compared with Agapeta hamana

Taxonomic Classification

Rank	cobweb spiders	Common Yellow Conch
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum same	Arthropoda (Arthropods)	Arthropoda (Arthropods)
Class	Arachnida (Arachnids)	Insecta (Insects)
Order	Araneae (Araneae)	Lepidoptera (Butterflies & Moths)
Family	Theridiidae	Tortricidae
Genus	Steatoda	Agapeta
Species	Steatoda grossa	Agapeta hamana

Evolutionary Relationship

cobweb spiders and Common Yellow Conch share a common ancestor at the Phylum level: Arthropoda. (Arthropods)

Conservation Status

cobweb spiders

LC — Least Concern

Common Yellow Conch

LC — Least Concern

Physical Characteristics

Attribute	cobweb spiders	Common Yellow Conch
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

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).

Common Yellow Conch

Habitat

Typically found in virtually all terrestrial and freshwater habitats.

Range

Distributed across Belgium, Denmark, Norway, and Sweden.

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.

Common Yellow Conch

<em>Agapeta hamana</em>, the common yellow conch moth, is a small moth in the family Tortricidae. It is widely distributed across Europe and central Asia, ranging from Britain and Scandinavia eastward through much of the Palearctic region. The species inhabits dry grasslands, heathlands, chalk downlands, and scrubby habitats where its larval host plants are found. Adult moths display distinctive pale yellow to golden-yellow forewings with irregular brown or reddish-brown markings near the wingtip, forming a pattern that resembles the shell of a conch, lending the species its common name. The wingspan typically measures around 15–22 mm. Biological traits such as average adult lifespan, precise body weight, and detailed population data remain poorly documented in consolidated scientific literature. Larvae feed internally on the roots of thistles and knapweeds, particularly <em>Centaurea</em> and <em>Cirsium</em> species. Adults fly from June to August and are frequently attracted to light. <em>Agapeta hamana</em> has been investigated as a potential biological control agent for invasive knapweed species in North America, where it has been introduced experimentally. The species is assessed as Least Concern given its broad distribution and stable habitat associations.

Shared Countries

Both species can be found in 3 countries:

🇧🇪 Belgium 🇩🇰 Denmark 🇸🇪 Sweden