Coastal wattle vs cobweb spiders

Acacia cyclops compared with Steatoda grossa

Taxonomic Classification

Rank	Coastal wattle	cobweb spiders
Kingdom	Plantae (Plants)	Animalia (Animals)
Phylum	Magnoliophyta (Flowering Plants)	Arthropoda (Arthropods)
Class	Magnoliopsida (Dicots)	Arachnida (Arachnids)
Order	Fabales (Legumes & Allies)	Araneae (Araneae)
Family	Fabaceae	Theridiidae
Genus	Acacia	Steatoda
Species	Acacia cyclops	Steatoda grossa

Conservation Status

Coastal wattle

LC — Least Concern

cobweb spiders

LC — Least Concern

Physical Characteristics

Attribute	Coastal wattle	cobweb spiders
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Coastal wattle

Habitat

Found across multiple habitat types including tropical and subtropical moist broadleaf forests, tropical and subtropical dry broadleaf forests, and tropical and subtropical grasslands and savannas, among 8 distinct biome types spanning the Afrotropic and Palearctic realms. Populations are also found in montane and highland environments at higher elevations.

Range

Widely distributed across Africa (13 countries), Asia (Israel), Europe (4 countries), and North America (United States).

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).

Coastal wattle

Coastal wattle (Acacia cyclops) is a dense, fast-growing shrub in the family Fabaceae, native to the southwestern and southern coastal regions of Western Australia, from Shark Bay south to the Nullarbor Plain. It grows on coastal dunes, sandy scrubland, and limestone substrates near the sea, where it tolerates salt spray, wind, and summer drought. Coastal wattle produces distinctive circular seeds with bright red arillate coatings, making them highly attractive to birds. Although valued in its native range for coastal stabilisation and revegetation, the species has become highly invasive in southern Africa, particularly South Africa, where it was introduced for dune stabilisation in the 19th century and has since spread extensively across the Cape Floristic Region, displacing native fynbos vegetation. It is listed among the 100 worst invasive species globally by the IUCN Invasive Species Specialist Group. In Australia, it is assessed as Least Concern. Management of invasive populations in South Africa involves mechanical removal and biological control efforts aimed at protecting the critically threatened fynbos biome.

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.