Feather-legged Orb-Weaver, Feather-legged Spider, Hackled Orb-Weaver
Uloborus glomosus
Family Uloboridae (Feather-legged Orb-Weavers), Order Araneae. Key family characteristics include complete lack of venom glands, presence of a cribellum and calamistrum for spinning hackled silk, and distinct leg postures.
Physical Description
Small spider with an elongated abdomen that often possesses small humps or tufts of setae. The cephalothorax is relatively flat, and the legs are slender with prominent feathery tufts of hairs on the tibiae of the first pair of legs. Extremely sexually dimorphic, with females being significantly larger than males.
Size Estimate
Female body length approximately 3 to 5 mm, male body length approximately 2 to 3 mm. Total leg span around 10 to 15 mm. The specimen in the image appears to be an adult female stationed at the hub of her web.
Coloration & Markings
Variable coloration ranging from pale tan, cream, gray, to dark brown or blackish-grey, often with subtle longitudinal stripes on the carapace and mottle patterns on the abdomen. Legs frequently feature light and dark banding.
Web Type
Builds a classic, circular orb web that is typically oriented horizontally or at a steep diagonal angle. Unlike typical orb-weavers, it uses non-sticky, woolly, cribellate silk (hackled silk) to trap prey rather than sticky silk droplets. Small zigzag stabilimenta or tufts of silk may occasionally be present.
Eye Arrangement
Eight small eyes arranged in two transverse rows on the front of the cephalothorax. Posterior eye row is gently recurved, and anterior eyes are small and evenly spaced.
Leg Characteristics
Leg pair I is distinctly longer and stouter than the others, featuring dense, brush-like tufts of fine setae (feathery hairs) on the tibiae. Legs are frequently held extended straight forward and backward in a tight line when resting on the web.
Venom & Safety Information
Venom Information
Completely non-venomous. Uloboridae is one of the extremely rare spider families that completely lack venom glands and cheliceral venom apparatus.
Medical Significance
Harmless to humans and pets. Poses zero medical risk because it cannot inject venom.
Safety Recommendations
No safety precautions required. If found indoors, relocate gently using a small container and paper to an outdoor garden or shrubbery where it can assist with pest control.
Habitat & Behavior
Habitat & Range
Widespread across eastern and central North America. Frequently found in low vegetation, shrubs, tree branches, woodland understories, agricultural fields, as well as under porch eaves, outdoor lighting, and inside shaded garden structures.
Behavior & Temperament
Extremely docile, non-aggressive spider that relies on camouflage and cryptic resting postures. When disturbed, it may jerk its web rapidly to confuse predators or drop to the ground on a safety line.
Diet & Prey
Feeds on small flying and crawling insects such as gnats, mosquitoes, midges, fruit flies, and small moths. Traps prey using woolly cribellate silk and wraps them extensively in silk to immobilize them before consuming them.
Seasonal Activity
Most active during late spring through autumn, with mature females and webs commonly observed during summer months.
Description
The feather-legged orb-weaver is a fascinating arachnid distinguished by its lack of venom and its remarkable web construction techniques. Instead of relying on sticky glue, it carding fine strands of silk with a specialized cribellum to create mechanical mesh traps. Sitting head-down in the center of a horizontal orb web, its unique leg tufts give it a distinctive silhouette.
Key Features
Feathery hair tufts on the first pair of legs, horizontal orb web made of non-sticky hackled silk, resting posture with front legs extended, small body size (<5mm), and complete absence of venom glands.
Similar Species
Araneid orb-weavers (such as Larinioides or Neoscona) which possess sticky orb webs and venom glands, and Tetragnatha (long-jawed orb weavers) which have very long chelicerae and elongated bodies.
Life Cycle
Females construct distinct papery, star-shaped or elongated grey egg sacs, which they guard near or within their web. Spiderlings hatch and disperse via ballooning. Lifespan is typically around one year.
Ecological Importance
Serves as an effective natural pest control agent by consuming huge quantities of small flying pests such as mosquitoes and gnats around homes and garden ecosystems.
Conservation Status
Not evaluated by IUCN, but widespread, abundant, and secure throughout its native range.
Interesting Facts
Uloborid spiders are among the very few spiders in the world that have no venom glands whatsoever. They digest their prey entirely by wrapping it thoroughly in hundreds of meters of silk and regurgitating digestive fluids onto the silk-wrapped package.
Photography Tips
Photograph from a side or angled top profile under ambient light or soft backlighting to highlight the web structure and the feathery leg brush details. Macro lens recommended due to its small body size.
Identified: 2026-07-25T01:13:52.203020