The predominately yellow spider, which can get as big as the palm of your hand, was first spotted in Georgia in 2013. In less than 10 years, the species has spread across Georgia and other parts of the Southeast. Comparing the Joro spider to its relative, the golden silk spider — also known as the "banana spider," — scientists have concluded that the Joro spider has the ability to survive colder climates and may begin moving up the east coast.
Linda Rayor, an ecologist specializing in the social behavior of spiders, says Joro’s spread is not alarming and it presents a wonderful opportunity for people in northern states to watch this beautiful spider in their own yards.
“The Joro spider, Trichonephila clavata, is a close relative of the native Golden Orb Weaver, Trichonephila clavipes, which is found all over the southeastern US (especially Louisiana, Florida, Georgia). Both of these species are large, gorgeous orb weavers that build very large orb webs with additional barrier webs designed to capture large insects, like grasshoppers.
“The Joro spider is notable in that it didn’t originate in North America and appears to be more tolerant of colder weather, indicating it will establish itself in more northern climates. And it appears to build webs near other Joro spiders somewhat more densely than the Golden orb weaver. There is no evidence that this spider presents any sort of an ecological risk or risk to people or pets of being bitten. The only way you get bitten by orb weavers is if you put your fingers in their faces, and even then, it is rare.
“This is a wonderful opportunity for those of us further north to watch this stunningly beautiful spider in our yards. The entire group of golden orb weavers in the genus Trichonephila have terrifically interesting behavior! The adult females are almost 100 times the size of the males. The males are tiny little things that are smaller than the size the prey the female eats. This sexual size dimorphism, or difference in the size of the females and males, is some of the most extreme of all other animals. What is interesting, is that if the males are relatively larger, the females are more likely to kill them. It is believed that the females are relative giants so that they can lay bigger egg sacs. You can easily watch these tiny males jousting in female’s webs to have the chance to mate with her. I should add that it is fun tossing big moths or grasshoppers into these large webs and watching the spider capture the prey.
“Not only that, but their silk is also some of the strongest known. Spider silk is already one of the strongest biopolymers known, but the Trichonephila produce some of the very strongest silks. Think about light weight body armor that could protect against bullets or parachutes that don’t tear – that is why there is so much interest in figuring out how to use spider silks or produce them through biotechnology.
“I hope that people will keep an open mind about these spiders and recognize that they are going to be more fun than frightening to see. I can hardly wait to start taking photos of them, myself.”