What is unusual—but not unheard of—is for spiders to establish populations at their destinations. When this happens, as with Steatoda nobilis in southern California, it's normally near large ports; but the Georgian counties are nowhere near a port.
Instead, study leader Hoebeke suspects that a shipment moving through the East Coast's busy I-85 corridor contained Joro egg sacs, which likely hatched spiderlings after the shipment arrived.
"Spiderlings of this particular group are really good dispersers because of the way they're able to spin a piece of silk," Hoebeke says. "It kind of acts like a parachute, if you will, and gets dragged by the prevailing wind currents."
Finding Joro
It's too soon to say how big the North American N. clavata population is and whether the spider is likely to compete with native species. The vibrant new arrival does have an American relative: Nephila clavipes, a golden silk orb weaver that's native to the southern U.S.
"I suspect it may be more widespread than what our data is initially indicating," Hoebeke says. "It could be anywhere where there are major importing warehouses."
Now, with winter waning and spring on the way, the spiders are about to emerge from their egg sacs. They'll grow over the next few months and be easiest to spot in late summer or early fall.
Hoebeke is hoping for some help in finding them.
"We can't be everywhere looking for this thing, but we can have people take a close look and let us know," he says.
"This is really citizen science at its best.