Desert Grass Spider, Funnel Weaver
Agelenopsis aperta
Agelenidae (Funnel-Weavers), Order Araneae
Physical Description
Elongated body with a distinct tapered abdomen, prominent spinnerets extending from the rear, and long, spiny legs adapted for rapid running.
Size Estimate
Body length ranges from 10 to 18 mm, with a leg span up to 40 mm; the specimen appears to be an adult or sub-adult.
Coloration & Markings
Tan to brownish-grey base coloration with distinctive longitudinal dark stripes running along the dorsal side of the cephalothorax and pale margins on the abdomen.
Web Type
Horizontal sheet web terminating in a tubular retreat or funnel where the spider waits for prey.
Eye Arrangement
Eight small eyes arranged in two slightly curved, more or less parallel rows across the front of the carapace.
Leg Characteristics
Long, slender legs covered with prominent bristles and spines, held flat against the surface in a splayed, alert posture ready for immediate dash.
Venom & Safety Information
Venom Information
Neurotoxic venom specialized for subduing insect prey quickly, relatively mild and generally ineffective against human skin.
Medical Significance
Not medically significant; bites are rare, cause minimal localized pain or swelling, and require no special medical intervention.
Safety Recommendations
Keep areas around foundations clear of debris, shake out shoes left outside, and gently relocate individuals outdoors using a cup and card if found indoors.
Habitat & Behavior
Habitat & Range
Common throughout the western United States, including Texas, inhabiting arid regions, grasslands, gardens, and around human structures.
Behavior & Temperament
Extremely fast and skittish; retreats rapidly into its funnel when disturbed, rarely aggressive toward humans.
Diet & Prey
Insects and other small arthropods that blunder onto the horizontal sheet web, which the spider subdues with a rapid rush.
Seasonal Activity
Most active during spring and summer months, with mating occurring in late summer and early autumn.
Description
The Desert Grass Spider is a swift and agile hunter, constructing sheet-like webs over grass or crevices that end in a secure silken funnel. Known for their incredible speed, these spiders dart across their webs with lightning quickness to capture unwary insects, making them fascinating yet elusive residents of dry environments.
Key Features
Prominent rear spinnerets, longitudinal dark stripes on the cephalothorax, and construction of a sheet web ending in a funnel.
Similar Species
Wolf spiders (Lycosidae), which can be distinguished by their active roaming behavior and lack of sheet webs with funnels.
Life Cycle
Females construct tough, disc-shaped egg sacs in protected crevices during autumn, overwintering as eggs or immatures with a lifespan of about one year.
Ecological Importance
Act as effective biological control agents by consuming large quantities of agricultural and household insect pests.
Conservation Status
Not evaluated by the IUCN, but populations are secure, abundant, and widespread across their natural range.
Interesting Facts
Grass spiders can sense the vibrations of potential prey on their sheet webs within milliseconds and react faster than the blink of an eye.
Photography Tips
Use a macro lens with a fast shutter speed, as these spiders move abruptly; photograph from above the web while avoiding vibrations that trigger their escape response.
User Notes
Middle Conger, San Angelo Area
Identified: 2026-09-12T21:14:48.659386