An invasive species is causing havoc in the Tennessee Valley, United States. It is the Joro spider (Trichonephila clavata), native to Asian countries such as China, Japan, and South Korea, quite unpleasant to look at. It first appeared in 2014 in Georgia, was reported again in 2023 in Chattanooga, and has continued spreading to other states. Its appearance is quite intimidating, as it can reach the size of a human hand and has a red mark on its abdomen, with long, striped legs.
However, according to Dr. David Nelsen, a biology professor at Southern Adventist University, it is a completely harmless species to both humans and animals, but its presence can be unpleasant. The main problem with its presence is its impact on local ecosystems, as although it can control some insect pests, it can also eliminate native species in the areas it occupies.
Joro spider (Trichonephila clavata)
The spider Jojo, whose scientific name is Trichonephila clavata, belongs to the genus Trichonephila. It is a species native to East Asia, especially China, Japan, Korea, and Taiwan. Since the 2010s, it has reached North America, spreading across several states. It is a completely harmless species and poses no risk to humans or animals. It has bright yellow and black coloring with a red spot on its abdomen. They can grow up to 10 centimeters long, with long legs that can reach up to 15 centimeters.
Joro Spider in the United States
Although it originates from countries such as China, Japan, or Korea, specimens have been recorded in the United States as far as it has managed to spread. The first record occurred in 2014 in Georgia, and in 2021 it appeared again in the Chattanooga area. More and more specimens are being found by Americans in their homes, including the Tennessee Valley. According to the biology professor at Southern Adventist University, Dr. David Nelsen, “When fully mature, it has this large red spot on its abdomen and tends to have striped legs – black and yellow.
Our population seems to come from China.” He also explains that it is a completely harmless species and does not pose a threat to humans or pets. “Any kind of pesticide sprayed on them… will kill them. So if you want to get rid of them, you can. But it is not necessary,” he said. Furthermore, if you are worried about their bites, he also explained, “The risk of being bitten is really minimal. Even if you walk into a web, the spider will either flee or fall. That is its first response.” He also compares the bite to that of a mosquito, to give us an idea.
Invasive Species
An invasive species can be a plant, an animal, or a foreign microorganism that has been artificially and forcibly introduced into a new ecosystem. There, it manages to establish itself, reproduce, and spread uncontrollably, which poses a threat to native species as well as to the environment and human health. This is precisely what has happened with the Jojo spider. It has been artificially introduced into the ecosystems of the regions where it is appearing, causing havoc among native species.
In response to this situation, Dr. Nelsen has been studying its presence and the effects it is causing for 4 years. According to him, although it has been useful for controlling insect pests, its interaction with the species is still being studied. “It seems that the longer they have been established in an area, the fewer native species we see. We have been studying this for four years, moving into five, and we will see if this trend continues”.