Grass Spider, American Grass Spider, Funnel Weaver
Agelenopsis sp.
Family Agelenidae (Funnel Weavers), Order Araneae
Physical Description
Elongated, pear-shaped cephalothorax with a teardrop-shaped abdomen. The body is covered in fine hairs (setae) and features two prominent, long spinnerets extending from the tail end of the abdomen, which is a diagnostic trait for this genus.
Size Estimate
Body length is approximately 10-20mm for females, with a leg span of 25-50mm. This appears to be an adult specimen based on proportions and distinct markings.
Coloration & Markings
Features two prominent dark longitudinal stripes running the length of the cephalothorax on a light tan or greyish background. The abdomen has a darker central band with lighter chevron-like patterns or mottling on the sides.
Web Type
A horizontal, non-sticky sheet web that leads into a funnel-shaped retreat in a crevice or corner. The webs are often visible in the morning when covered in dew (heavy 'cobwebs' on lawns).
Eye Arrangement
Eight eyes arranged in two rows that appear highly arched, often described as a 'frowny face' or 'horseshoe' shape when viewed from the front.
Leg Characteristics
Long, slender legs with visible spines (macrosetae). The legs typically show light and dark banding or mottling, and the spider is built for extreme speed on its sheet web.
Venom & Safety Information
Venom Information
The venom contains agelenotoxins, which are neurotoxic to insects. However, the venom is not considered medically significant to humans.
Medical Significance
Low. Bites are rare due to the spider's timid nature. If a bite occurs, it typically results in mild localized pain, swelling, and redness similar to a bee sting. No specialized treatment is usually required.
Safety Recommendations
Harmless and beneficial. If found in the home, they can be easily relocated using a cup and a piece of paper. They pose no threat to pets or children.
Habitat & Behavior
Habitat & Range
Found throughout North America (USA and Canada). They are common in low-lying vegetation, gardens, window wells, and between rocks or woodpiles.
Behavior & Temperament
Extremely fast runners as their primary defense. They are ambush predators that wait in the funnel retreat for vibrations on the sheet web. They are generally shy and will retreat deeper into their funnel if disturbed by humans.
Diet & Prey
Primarily feeds on ground-dwelling insects like crickets, beetles, and moths that land on the horizontal sheet web. The spider dashes out, bites the prey, and drags it back into the funnel.
Seasonal Activity
Populations peak in late summer and early autumn (August through October in most of North America) when the spiders are largest and webs are most visible.
Description
A classic garden dweller, the Grass Spider is a master of the ambush. Known for its incredible speed and the architectural beauty of its morning dew-covered webs, it is a vital part of the backyard ecosystem.
Key Features
Two dark longitudinal stripes on the carapace and exceptionally long, multi-segmented spinnerets protruding from the rear of the abdomen.
Similar Species
Wolf Spiders (Lycosidae) are often confused with them but lack the long spinnerets and build no webs. Fishing Spiders (Dolomedes) are much larger and usually found near water.
Life Cycle
Females lay egg sacs in the autumn in sheltered crevices. The adults typically die after the first hard frost, while the eggs overwinter and hatch in the spring. Average lifespan is about one year.
Ecological Importance
They are highly effective at controlling garden pests and serve as a major food source for birds, wasps, and larger predatory insects.
Conservation Status
Not evaluated by the IUCN, but populations are stable and common throughout their range.
Interesting Facts
Despite the large webs, they are not 'orb-weavers'; their silk is not sticky. They rely entirely on their lightning-fast reflexes to catch prey before it crawls off the sheet.
Photography Tips
Shoot from a top-down angle to capture the stripes and spinnerets for ID. Using a flash can help highlight the fine threads of the sheet web against dark rocks.
Identified: 2026-06-22T03:53:10.768374