Cobweb Spiders vs Common Fieldcap

Parasteatoda tepidariorum compared with Agrocybe pediades

Taxonomic Classification

Rank	Cobweb Spiders	Common Fieldcap
Kingdom	Animalia (Animals)	Fungi (Fungi)
Phylum	Arthropoda (Arthropods)	Basidiomycota (Club Fungi)
Class	Arachnida (Arachnids)	Agaricomycetes (Mushrooms)
Order	Araneae (Araneae)	Agaricales (Gilled Mushrooms)
Family	Theridiidae	Strophariaceae
Genus	Parasteatoda	Agrocybe
Species	Parasteatoda tepidariorum	Agrocybe pediades

Conservation Status

Cobweb Spiders

LC — Least Concern

Common Fieldcap

LC — Least Concern

Physical Characteristics

Attribute	Cobweb Spiders	Common Fieldcap
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), Asia (Taiwan), Europe (7 countries), North America (Canada, United States), and South America (Colombia).

Common Fieldcap

Habitat

Typically found in forest floors, decomposing wood, and soil ecosystems.

Range

Found across Europe (5 countries) and North America (United States).

Cobweb Spiders

The common house spider (Parasteatoda tepidariorum) is one of the most cosmopolitan of all spider species, having followed human civilization to virtually every inhabited corner of the globe. A member of the family Theridiidae, this small to medium-sized spider—females reaching 5–8 millimeters, males somewhat smaller—constructs the characteristic messy, three-dimensional cobwebs in sheltered corners of buildings, under eaves, in cellars, and in other human-modified structures worldwide. Originally native to North and South America, the species has spread through commerce and human transport to Europe, Asia, Africa, and beyond, where it thrives in the stable temperature and prey-rich conditions provided by human habitation. The web design is deceptively effective: irregular sticky threads radiate in all directions from a silk retreat, ensnaring flies, mosquitoes, ants, and other arthropods that blunder into the structure. Females are long-lived—surviving several years—and produce multiple egg sacs containing hundreds of eggs during a lifetime, contributing to the species' population resilience. Parasteatoda tepidariorum has become an important laboratory model organism for arachnid developmental biology, with its genome sequenced to facilitate studies of spider gene expression, venom evolution, and silk production. It is broadly classified as Least Concern given its cosmopolitan distribution and remarkable adaptation to anthropogenic environments.

Common Fieldcap

The Common Fieldcap (<em>Agrocybe pediades</em>) is a saprotrophic fungus belonging to the genus Agrocybe within the family Strophariaceae. It typically produces small, tan to pale brown cap-shaped fruiting bodies and is often found growing in clusters or scattered on lawns, grassy areas, forest floors, decomposing wood, and soil-rich ecosystems. The species typically inhabits forest floors, decomposing wood, and soil ecosystems, obtaining nutrients by breaking down dead organic matter. Its geographic range includes several European countries — Belgium, Denmark, Norway, Portugal, and Sweden — as well as the United States in North America. <em>Agrocybe pediades</em> is assessed as Least Concern on the IUCN Red List, reflecting its broad distribution and apparent stability. Biological traits of this species, including specific data on fruiting body size, lifespan, and ecological preferences, remain poorly documented in the scientific literature. Like other members of its genus, it typically fruits during warmer months and often appears after rainfall in nutrient-rich grassland and woodland habitats.