Jorō Spider, Yellow-legged Orb-weaver
Trichonephila clavata
Araneidae (Orb-Weavers), Order Araneae. Key family characteristics include the construction of vertical, wheel-like orb webs and robust bodies with strong visual camouflage or warning coloration.
Physical Description
Elongated, cylindrical abdomen with striking coloration and a distinct cephalothorax. Marked by pronounced sexual dimorphism where females are vastly larger and brightly colored, while males are tiny and brownish.
Size Estimate
Females typically have a body length of 17-25 mm and a leg span reaching up to 70-100 mm. This specimen is an adult female.
Coloration & Markings
Bright yellow and dark grey or black transverse bands on the abdomen, interspersed with red patches on the underside and rear. Legs feature distinct yellow and black banding with prominent hairy brushes.
Web Type
Large, permanent vertical orb web composed of golden-hued silk, often accompanied by a complex barrier web above and below the main wheel.
Eye Arrangement
Eight eyes arranged in two rows, typical of orb-weavers, with lateral eyes grouped closely and median eyes situated on a slight tubercle.
Leg Characteristics
Long, slender legs with distinct black and yellow banding. Characterized by dense tufts of stiff hair (setae) along the tibia and metatarsus, lacking large spines but visually striking.
Venom & Safety Information
Venom Information
Neurotoxic venom typical of orb-weavers, but specifically evolved to subdue invertebrate prey. It poses no chemical threat to humans.
Medical Significance
Harmless to humans. A bite may cause minor localized pain, redness, or swelling comparable to a mosquito bite, but they rarely bite unless tightly squeezed or trapped against skin.
Safety Recommendations
Leave undisturbed when outdoors. If found near doorways, gently relocate using a stick or broom to guide the spider into a safe wooded area. No pest control required.
Habitat & Behavior
Habitat & Range
Native to East Asia including Japan, Korea, Taiwan, and China; recently introduced and expanding in the southeastern United States. Prefers forested areas, woodland edges, gardens, and utility poles where it can anchor large webs.
Behavior & Temperament
Docile and non-aggressive. Sits motionless at the center of its web facing downward, retreating only when heavily disturbed.
Diet & Prey
Generalist predator feeding primarily on flying insects such as mosquitoes, flies, beetles, butterflies, and occasionally larger wasps or cicadas caught in its durable orb web.
Seasonal Activity
Most active and visible during late summer and autumn when females reach full adult size. Overwinters in the egg stage.
Description
The Jorō Spider is a magnificent and brightly colored orb-weaver renowned for its brilliant yellow and black striped body and golden silk webs. Originally from Asia, it has captured public attention as an invasive yet surprisingly beneficial resident of southeastern US gardens, where it acts as an efficient predator of garden pests.
Key Features
Elongated yellow-and-black striped abdomen, distinctive yellow and black banded legs with brush-like setae, and massive golden-colored vertical orb webs.
Similar Species
Argiope aurantia (Black and Yellow Garden Spider) and Trichonephila clavipes (Golden Silk Spider), but distinguished by the specific bright yellow transverse banding and reddish markings on the ventral side of T. clavata.
Life Cycle
Females produce an egg sac containing several hundred eggs in the autumn. Spiderlings hatch in spring, undergo multiple molts, and mature by late summer through early autumn.
Ecological Importance
Acts as a primary regulator of flying insect populations, controlling pest numbers without harming plants or posing risks to larger animals.
Conservation Status
Not evaluated by the IUCN, but populations are robust and actively expanding their invasive range in North America without immediate threats.
Interesting Facts
Jorō spiders are capable of 'ballooning' as juveniles, using silk threads to catch the wind and travel long distances. Their silk shines a brilliant golden color in sunlight, which researchers believe helps attract prey.
Photography Tips
Use a macro lens with a fast shutter speed to capture leg details and dorsal patterns. Early morning is ideal when dew catches the golden web threads, providing striking contrast.
Identified: 2026-10-03T18:29:16.540892