WASHINGTON (AFP) – Big and scary-looking Joro spiders have spread from Asia to the southern United States (US) and are now poised to colonise the country’s cooler climes – but they’re nothing to fear and might end up actually helping local ecosystems. That’s according to scientists who have been studying the arachnid invaders since they first arrived in Georgia around 2013.
In a few short years, the golden webs spun by the bright yellow, dark blue and red spiders have become a common sight throughout the state, and new research suggests they will clamber up the Eastern Seaboard next.
“The reason we got involved in this project was because they literally fell in our lap,” an ecologist at the University of Georgia Andy Davis told AFP on Friday.
“They’re kind of everywhere here in North Georgia, they’re all over my backyard.”
Davis set about studying the new resident, comparing it to the golden silk spider, which came to the southeastern US some 160 years ago from the tropics.
Writing in a paper published in the journal Physiological Entomology, he and his co-author Ben Frick found similarities but also striking differences between the relatives.
The Joro spider’s metabolic rate is about double that of its cousin, its heart beats 77 per cent faster, and it can survive brief freezes. They also grow faster.
Together, these traits mean it can better survive colder climates, which is not completely surprising, given that it is native to temperate Japan. They’re also adept at gliding – spinning webs that act like parachutes and catch air currents – allowing them to fly up to 160 kilometres.
The paper examined records from iNaturalist, which tracks sightings of animals, and found that the spider’s range had already spread far beyond Georgia to encompass the nearby states of South Carolina, North Carolina and Tennessee.
