The invasive spider species, the silver spider, has been discovered in Pennsylvania for the first time.
According to the interactive tracking system JoroWatch, six of the giant, colorful spiders, which have already spread to Northeastern states including New York and New Jersey, were spotted in a Bucks County yard on September 5, after which a state entomologist visited to confirm their location and species.
This species, Trichonephila clavata, is found in East Asia, primarily in Japan. It can grow up to 4 inches (10 cm) in body length, with a leg span of 8 inches (20 cm), and can spin large, golden nests up to 10 feet (3 m) wide.
According to JoroWatch, females can be identified by their yellow underside, broad blue-green stripes down their backs, and yellow and red markings on their undersides. Females also have long black legs that are often striped with yellow.
The male is smaller and mostly brown with two long yellow stripes down each side of the abdomen and a darker brown stripe down the middle.
The Jorog spider was first discovered in northern Georgia, USA, in 2014, though it likely arrived in a shipping container years earlier. Unlike its closely-related relative, the golden silk spider, the Jorog spider has twice the metabolic rate and a 77% higher heart rate, according to a 2022 University of Georgia study.
As a result, unlike the golden silk spider, which migrated from the tropics to the southeastern United States 160 years ago but was unable to survive the cold and spread, the water lily spider can now survive freezes.
Despite their intimidating appearance, Joros are considered to be fairly timid and harmless towards people and pets.
Last year, scientists at the University of Georgia compared the reactions of more than 450 spiders from 10 different species to a mild disturbance — a couple of puffs of air at the spider. Most stopped moving and resumed normal activity within a minute, but the orb-weaver spiders remained motionless for over an hour.
“They basically shut down and wait for the disturbance to go away,” Andy Davis, lead author of the study, told the university newspaper. “These spiders are afraid of humans, rather than us being afraid of them.”
