This story was originally published in March 2022.
Take a breath. It’s not going to be raining spiders over Maine this summer.
There is a slight chance that a warm, southerly breeze could bring the invasive but harmless joro spider into the state, but entomologists here said it’s nothing to worry about.
Joro spiders, Trichonephila clavata, made the news following publication of a study out of Georgia that said the spider is capable of withstanding the cold temperatures of New England and could quickly spread throughout the region.
Joros are native to Asia and have been in the southern United States for about a decade. They are on the large side — about 3 inches when their legs are fully extended — and colorful and travel through the air by spinning small silk, balloon-like threads.
Like the spider, the story has grown legs and quickly began circulating with predictions of biblical size hordes of joros parachuting into northern states looking like the opening scene from “Red Dawn.”
Nothing could be further from the truth, according to spider experts.
“Just think of the black and yellow garden spider we are all familiar with,” said Jim Dill, entomologist and pest management specialist with University of Maine Cooperative Extension. “The joro is very similar to that — maybe more elongated and with longer legs.”
Joros are in the spider family Araneidae and often referred to as orb weavers. It’s the most common group, and they are the ones that build those spiral-shaped webs seen in the corners of buildings and outside in gardens, fields and forests.
Like all orb weavers, baby joro spiders — called spiderlings — disperse by weaving a small strand of silk that acts like a kite and carries the tiny arachnid on the wind.
“When they are ‘parachuting’ they will be very small,” said Allison Kanoti, state entomologist with the Maine Department of Agriculture, Conservation and Forestry. “They are just cute little babies.”
Despite the fact joros have been labeled venomous, entomologists said they pose little danger to humans. For one thing, the mandibles of an adult joro simply are not strong enough to pierce human skin. For another, any venom they possess is not considered toxic to humans.
“All spiders are venomous,” Dill said. “How venomous is this one? Not really, unless you are allergic.”
If joros make it to Maine, Dill predicts it will be by land rather than air. Like many invasives, they are quick to exploit humans for their travel needs.
“Like so many spiders they come from the south into the north, and they are expected to arrive in Pennsylvania this summer,” Dill said. “It could then hitch a ride on a car or piece of wood coming here and all of a sudden it’s in Maine.”
If they do arrive, they will likely become part of the state’s food chain.
“Spiders are predators so they have the potential to disrupt the food web,” Kanoti said of the joros, “[but] they have not observed any negative effects in the south. Because they are predators they have the potential to have more impacts on some of our pests and that can be a positive around our homes — they are nothing to be scared of.”
