Meet the 'giant', 'flying' Joro spider set to arrive in New York. Here's what experts say about its spread across the US

"Giant" spiders invading one of the world's largest cities sounds like the stuff of horror movies.

Headlines in news outlets across the United States are warning of the "Joro spider".

"Giant venomous spiders that can fly headed to East Coast," according to NewsNation.

Scientific American took a different approach: "Millions of Joro Spiders Are Moving Up the East Coast".

Here's what the experts have to say.

What are Joro spiders? 

Joro spiders, a type of orb weaver native to East Asia, were first spotted in the United States more than a decade ago.

Females grow to be about 1.7-2.5cm in body length, with a leg span of 7-10cm. Males are typically about half that size.

Compare that to your average huntsman spider, which can have a leg span of up to 15cm, according to the Australian Museum.

Australia's largest orb weaver, the giant golden orb weaver, also has a leg span of up to 15cm, and a body length of about up to 4cm long.

Jose Ramirez Garofalo, an ecologist with Rutgers University, said conditions in the US were "really, really" similar to the creature's native habitat.

"The climate here actually mimics their habitat in their native range," he told NBC.

"So they can exist all the way from the south of the US all the way north into Canada.

"Across the eastern US they're probably here to stay for the long term."

Daniel Kronauer, an associate professor at Rockefeller University, told Reuters the spiders tended to do very well in parks, gardens and car parks.

"There's a good chance that maybe this summer we'll see some of them in New York," he said.

"They're pretty cold tolerant ... That's why we can expect them to mover further north."

How did they get to the US? 

It's suspected they may have been carried to the US on a cargo ship.

They were first confirmed to live in North America in 2014, when they were recorded by scientists in Georgia.

The research team at the time said — after they first discovered the spider — they enlisted the public for help.

"Almost as soon as a press release appeared in a local newspaper in late October ... we heard almost immediately from several concerned citizens throughout a three-county area of north-east Georgia," they said in a 2015 report.

"Accidental human transport of spiders and their egg masses on or within cargo containers, on plant nursery stock and on crates and pallets [is] the probably means of transport."

Since then they've been recorded in South Carolina, North Carolina, Tennessee and other states, including as far north as New Jersey.

Ecologist Linda Hernandez Duran, an adjunct research associate at James Cook University, said the main concern was what impact the species would have on the environment.

"They have been spreading for a while," she said.

"We need more ecological studies to determine whether it's actually affecting other species, and so far they haven't reported anything.

"It needs long-term study [on] whether there's actually competition or any damage to native animals.

"But they are in cities, in urban areas, so I don't think they're going to be a problem."

Can spiders really 'fly'? 

Not really.

Dr Hernandez Duran said the Joro spider used a strategy called "ballooning" to spread further.

"What they do, when they're spiderlings to avoid competition with other spiderlings … they reach a highest point in a branch or in a tree," she said.

"They release silk, and the currents of air just help them to disperse. They can reach a wide range of distribution thanks to that."

The strategy is also called "kiting".

In 2021, Gippsland in Victoria became covered in silk webs after floodwater forced spiders to escape to higher ground.

Are they dangerous? 

Joro spiders have venom like all spiders, but they aren't deadly or even medically relevant to humans.

At worst, a Joro bite might itch or cause an allergic reaction.

"They're not dangerous. They're not aggressive. Even if you ... go after the spider and harass it to such an extent that it would bite you, it wouldn't be an issue," said Professor Kronauer.

They're also unlikely to go after pets, preferring mosquitoes, roaches, wasps and other insects that may fall into their web.

Joro spiders actually have a reputation for being shy.

A University of Georgia research scientist, Andy Davis, told the New York Times last year he had experimented by blowing air on different spiders with a turkey baster.

“They don’t like that, and they freeze,” he told the outlet.

“You can time how long they stay in that position.”

Other species remained frozen for two minutes. The joro spiders he tested didn't move for an hour.

Asked whether the influx of media coverage was due to Americans being confronted by the reality of of a very large, brightly coloured spider, Dr Hernandez Duran said: "Exactly."

She said it was important for scientific communities to share "information that is real and not based on fears".

"Of course, everyone can get in a panic, but then once the media clarifies ... it's a lack of understanding and it's fair enough they feel panic if they don't know," she said.

"They have venom, but they're harmless to humans."

Biology professor David Nelsen told the AP: "My sense is people like the weird and fantastic and potentially dangerous.

"This is one of those things that sort of checks all the boxes for public hysteria."

ABC/AP/Reuters