Jorō Spider, Joro spider
Trichonephila clavata
Araneidae (Orb-Weavers), Order Araneae. Characterized by robust bodies, excellent vision, and the creation of vertical orb webs using sticky silk.
Physical Description
Elongated, cylindrical abdomen with distinct tapering towards the rear, paired with a relatively compact cephalothorax. The female exhibits pronounced sexual dimorphism, being much larger and more vividly colored than the male.
Size Estimate
Body length of adult females ranges from 17 to 25 millimeters, with a leg span extending up to 7 to 10 centimeters. This appears to be an adult or sub-adult female specimen.
Coloration & Markings
Striking yellow and blue-cyan horizontal stripes across the dorsal side of the abdomen, accented with darker tones. The underside often features vivid red or orange patches near the spinnerets.
Web Type
Large, permanent, three-dimensional orb web constructed with characteristically golden-hued silk. The web often spans wide gaps between structural timbers, trees, or vegetation.
Eye Arrangement
Eight relatively small eyes arranged in two rows on a slightly raised cephalic area, typical of orb-weaving spiders to monitor prey movement in the web.
Leg Characteristics
Long, slender legs featuring distinct black and yellow or greenish-yellow banding. Legs are often held in pairs when resting on the web in an X-shape.
Venom & Safety Information
Venom Information
Neurotoxic venom tailored specifically for immobilizing insect prey. It has very low potency relative to humans and mammals.
Medical Significance
Harmless to humans. A bite is extremely rare and typically causes no more than minor localized pain, redness, or mild swelling, similar to a mosquito bite.
Safety Recommendations
No special safety measures required as they are harmless. If relocation is desired, gently guide the spider into a container using a soft brush.
Habitat & Behavior
Habitat & Range
Native to East Asia (Japan, Korea, China, Taiwan) and recently established in the Southeastern United States. Prefers wooded areas, gardens, and human-made structures like porches and eaves.
Behavior & Temperament
Docile and non-aggressive. They remain stationary in the center of their webs during the day, dropping out of the web or retreating only when severely disturbed.
Diet & Prey
Generalist predator feeding primarily on flying insects such as mosquitoes, flies, beetles, and butterflies caught in its sticky web.
Seasonal Activity
Peak activity occurs during late summer and autumn when females reach full adult size and construct their massive webs. Overwintering occurs strictly in the egg stage.
Description
The Jorō spider is a breathtaking and conspicuous orb-weaver renowned for its brilliant yellow and cyan banded body and voluminous golden silk web. As an introduced species in North America, it has captured public fascination due to its size and docile nature, peacefully coexisting near human dwellings while performing valuable pest control.
Key Features
Elongated yellow-and-blue striped abdomen, banded black and yellow legs, and a massive, distinctive golden-colored orb web.
Similar Species
Trichonephila clavipes (Golden Silk Orb-Weaver), which features a more reddish-brown body with tufts of hair on the legs, unlike the vivid cyan and yellow stripes of T. clavata.
Life Cycle
Females produce an egg sac containing several hundred eggs in the autumn. Spiderlings hatch in the spring, disperse via ballooning, and mature through successive molting stages over one season.
Ecological Importance
Acts as an effective natural pest controller by intercepting large quantities of nuisance flying insects and agricultural pests within its extensive web.
Conservation Status
Not evaluated by the IUCN, highly abundant throughout its native and introduced ranges with expanding populations.
Interesting Facts
Jorō spiders are capable of 'ballooning' long distances as juveniles using silk threads to catch the wind. Their silk exhibits exceptional tensile strength and a striking golden sheen derived from pigment proteins.
Photography Tips
Photograph from the side or slightly above to capture the full abdominal stripe pattern and leg banding. Utilize a macro lens in natural indirect light with a dark background to highlight the golden silk.
Identified: 2026-09-18T21:20:41.436157