GIANT, INVASIVE SPIDERS APPEAR BUILT TO THRIVE IN THE U.S.

Massive Joro spiders are likely to continue their march across the United States thanks to their ability to adapt to human-dominated environments, a new analysis suggests.

The spiders, which are native to East Asia, have large yellow-and-black bodies, long legs and an ability to spin orblike webs. First confirmed in the United States in 2014, in northeast Georgia, they have since spread across the Southeast.

They also build unique webs that can be more than 6 feet across and appear golden when they reflect sunlight. Female Joros, which can grow to around 3 inches across — around double the size of males — also have blue stripes and red patches on their predominantly yellow abdomens.

The study, published in the journal Arthropoda, tracked their behavior in northeast Georgia; the authors argue that part of the spiders’ success in the United States may turn on their ability to tolerate busy roads.

To measure the ways in which traffic affects the spiders’ behavior, the researchers conducted more than 350 trials across 20 roads with different levels of traffic. They touched the spiders’ webs with a tuning fork vibrating at 128 hertz, simulating prey and attempting to stimulate the creatures’ usual attack mechanism.

Overall, the spiders attacked the simulated prey 59 percent of the time. But spiders near busier roads were not as likely to attack as those near quieter roads. Those near traffic attacked about half the time vs. 65 percent of the time among spiders with webs in lower-traffic areas.