Cobweb weaver vs Colonial bentgrass

Steatoda nobilis compared with Agrostis capillaris

Key Differences

Cobweb weaver is Not Evaluated while Colonial bentgrass is Least Concern.

Taxonomic Classification

Rank	Cobweb weaver	Colonial bentgrass
Kingdom	Animalia (Animals)	Plantae (Plants)
Phylum	Arthropoda (Arthropods)	Magnoliophyta (Flowering Plants)
Class	Arachnida (Arachnids)	Liliopsida (Monocots)
Order	Araneae (Araneae)	Poales (Grasses)
Family	Theridiidae	Poaceae (Grass Family)
Genus	Steatoda	Agrostis
Species	Steatoda nobilis	Agrostis capillaris

Conservation Status

Cobweb weaver

NE — Not Evaluated

Colonial bentgrass

LC — Least Concern

Physical Characteristics

Attribute	Cobweb weaver	Colonial bentgrass
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Cobweb weaver

Habitat

Typically found in terrestrial habitats from forests to deserts.

Range

Widely distributed across Europe (7 countries), North America (United States), and South America (Ecuador).

Colonial bentgrass

Habitat

Inhabits tropical and subtropical moist broadleaf forests within the Neotropic biogeographic realm.

Range

Widely distributed across Europe (8 countries), North America (Canada, Costa Rica, United States), Oceania and the Pacific (Australia, New Zealand), and South America (5 countries).

Cobweb weaver

The noble false widow (Steatoda nobilis) is a theridiid spider that has attracted considerable media attention in the British Isles and along the Atlantic coast of Europe due to its painful but rarely dangerous bite and its rapid range expansion facilitated by human activity. Originally native to the Canary Islands and Madeira, the species arrived in southern England during the 19th century, likely via banana shipments, and has since spread northward through Britain and westward into Ireland, while also establishing populations along the Iberian Peninsula and Atlantic France. Females are robust, with a dark brown carapace and a distinctive cream-colored pattern on the bulbous abdomen that varies between individuals; females reach 8.5–14 millimeters in body length, making this one of the larger European theridiids. The species constructs persistent, tangled cobwebs in sheltered locations outside buildings—under window ledges, in door frames, and in garden walls—as well as within homes in cooler seasons. It is a generalist predator, capturing insects and other invertebrates, and has been reported to occasionally subdue prey considerably larger than itself, including small lizards. Steatoda nobilis venom produces steatodism, which can cause localized pain, swelling, and in rare cases systemic symptoms. Its conservation status has not been formally assessed, but its expanding range demonstrates considerable resilience.

Colonial bentgrass

<em>Agrostis capillaris</em>, colonial bentgrass, is a perennial grass in the family Poaceae with an extensive native range across Europe and naturalised populations in North America, South America, and Oceania, including Australia and New Zealand. This species is highly adaptable, colonising tropical and subtropical moist broadleaf forests, temperate grasslands, disturbed soils, roadsides, and cultivated landscapes within the Neotropical realm. It is assessed as Least Concern by the IUCN. Colonial bentgrass is a fine-leaved, low-growing species often used in lawn and sports turf applications due to its tolerance for close mowing and its capacity to form dense, even swards. Its panicle inflorescences bear numerous small spikelets on delicate, hair-like branches, giving the species a feathery appearance when in flower. In its naturalised range, <em>Agrostis capillaris</em> can become invasive, competing with native grass species in acid grasslands and open heathlands. The species tolerates acidic and nutrient-poor soils, attributes that contribute to its widespread persistence in degraded landscapes. Biological traits of this species remain poorly documented in the scientific literature.