A venomous eight-inch-long spider native to Asia, whose palm-sized females cannibalize their male mates, is flying up America’s east coast and spreading out west.
Experts say the Jorō spider can fly 50 to 100 miles at a stretch, using their webbing as a parasail to glide in the wind, and it’s now also hitching rides up east coast highways — but the creatures aren’t known to pose a threat to humans or pets.
However, the jury is still out on the impact that this giant spider, which is believed to have first arrived in the US a decade ago via shipping containers arriving in Georgia, might have on local wildlife.
One thing that is certain, according to an ecologist at Rutgers University’s Lockwood Lab in New Jersey, who spoke with DailyMail.com: ‘Soon enough, possibly even next year, they should be in New Jersey and New York.’
‘Because their main methods of dispersal are to either ‘balloon’ with the wind, or hitch rides on cars,’ PhD student and ecologist José R. Ramírez-Garofalo told DailyMail.com, ‘they are generally going to spread to where the wind blows, or where humans are.’
Ramírez-Garofalo, who currently conducts research for Rutgers’ Lockwood Lab, added that while the Jorō spider will likely be able to take advantage of warming temperatures along the northeastern seaboard, their hitchhiking and parachuting methods are sure to take them farther than some other invasives.
‘Their range expansion is more complicated than the typical northward expansion that you see with a lot of species under current climate conditions,’ Ramírez-Garofalo told DailyMail.com.
‘Right now, we are seeing them dispersing into Maryland,’ as the ecologist recently told Staten Island Advance. ‘It is a matter of when, not if.’
Last month, other ecological and entomological researchers in New York, Tennessee, Texas and South Carolina pooled their resources in an effort to predict just how fast and how far the invasive Jorō spider was likely to spread.
The short answer is far and wide across the continental United States, Canada and even parts of Mexico.
Their findings, published in the journal Ecology and Evolution, ‘add evidence that T. clavata [the short form of the Jorō’s species name, Trichonephila clavata] is an invasive species and deserves much more ecological scrutiny,’ they wrote:
‘While impacts of T. clavata on human or pet health have not been documented,’ they said, ‘our data show that their ecological impacts may not be similarly benign.’
The researchers hope their estimates — based on captured spiders and climate comparisons between North American regions and the Jorō’s habitats in Japan, China, Korea and Taiwan — will spur action to protect domestic spider species.
‘These patterns should strongly motivate funding institutions and researchers alike to turn their attention toward this invasion,’ they wrote, ‘and consider ways to mitigate its impacts on native communities.’
But Ramírez-Garofalo at Rutgers, who also serves as vice president of Protectors of Pine Oak Woods on Staten Island, expressed caution about overly demonizing the Jorō or panicking over its possible ecosystem impacts.
‘While this is always a concern with newly invasive species,’ Ramírez-Garofalo told DailyMail.com, ‘the Jorō spider does not seem to be a major threat to the native biodiversity.’
While Jorōs are venomous, experts have stated that they are not a threat to humans, dogs or cats, and won’t bite unless they are feeling very threatened.
‘In fact, if you look at the literature,’ Ramírez-Garofalo told DailyMail.com, ‘there have been no documented fatalities, nor any notable medically significant bites.’
‘Taken together with their behavior (they are very reluctant to bite) and the evidence from the literature, they really pose no threat to humans or our pets,’ he said.
In contrast, the Jorō spider mostly preys on flies, mosquitos and stink bugs — with the latter being not only a threat to crops, but a threat that currently enjoys free reign without natural predators in many parts of the US.
Researchers say that the Jorō could be a blessing in disguise for farmers and that they should be left alone.
‘There’s really no reason to go around actively squishing them,’ said University of Georgia researcher Benjamin Frick.
‘Humans are at the root of their invasion,’ Frick said. ‘Don’t blame the Jorō.’
More than 150 years ago, a cousin of the Jorō spider called the golden silk spider also made its way to the United States from South America and the Caribbean.
However, unlike the Jorō, these spiders do not have the same body-like features to spread in different climates across the country as they mainly stay in the southeast of the US.
The lifecycle of Jorō spiders usually ends by late autumn or early winter, albeit with one newly discovered catch: a high percentage of Jorō spiders (74 percent) were found to be capable of surviving a two-minute freeze at 32 degrees Fahrenheit.
‘Jorō spiders had a higher survival during brief periods of below-zero temperature,’ Frick and is colleagues wrote of their findings last year, ‘which would be akin to a light frost during late-fall.’
Colorful, venomous palm-sized Joro spiders are set to take over the east coast
The Joro spider is one of many types of orb-weaver spiders belonging to the trichonephila genus. It can be found throughout Japan, South Korea, Taiwan and China, and now in the US, noticeably in South Carolina and Georgia, since 2014.
Joro females have colorful yellow, blue and red markings on their bodies and are well-liked in Japan. They are roughly 0.66 to 0.98 inches (1.7 – 2.5 cm), but the ones found in Georgia can measure three inches (8 cm) in length when their legs are fully extended, according to anypest.com.
Male Joros are much plainer and they only have a brown body. They are smaller than their counterparts and roughly measure between 0.27 to 0.39 inches (0.70 – 1cm).
Joro spiders can be easily observed through spring, summer and fall, before the end of their one-year lifecycle in the winter (November & December).
They are venomous but do not pose as a threat to humans or house pets and won’t bite them unless they feel in danger. Their fangs are also not long and sharp enough to penetrate human skin.
The eight-legged insects also suppress mosquitoes and biting flies. They are one of the few spiders that will catch and eat stink bugs, which are serious pests to many crops.
The Joros have about double the metabolism of the golden silk spider and a 77 percent higher heart rate, which enables them to live in the cold, unlike most spiders.
They use a ‘ballooning’ technique that allows them to catch air with their web, allowing them to travel 50-100 miles. Most often, Joro spiders can be found in groups and not far away from forests.
They are also great stowaways as they came to the U.S. by hanging on to cargo ships in 2014.
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This article by Matthew Phelan was first published by The Daily Mail on 6 December 2023. Lead Image: A venomous 8-inch-long spider native to Asia, whose palm-sized females cannibalize their male mates, is flying up America’s east coast and even spreading out west.
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