The issue of invasive species is frequently discussed across all taxonomic groups, especially in terms of how to address species that impact ecosystems, agriculture, fisheries, or pose health risks to humans. For example, in recent years, insects such as the fire ant, which is highly toxic, the red-haired cicada moth, which harms cherry blossom and peach trees, and the yellow-legged hornet, which negatively affects beekeeping, have been receiving particular attention.

In the case of spiders, the *Joro spider* ( *Trichonephila clavata*) native to Australia is well-known. However, there are numerous other invasive spider species that have established themselves in Japan. Through investigation and research, interesting cases have been discovered, which we will introduce in this article.

## *Joro spider* Migration Route: Movement by Vehicle

First discovered in Osaka in 1995, the *Joro spider* quickly gained widespread media attention and became known throughout Japan. Initially, the media highlighted the spider's potent venom, capable of causing fatalities in those bitten, earning it the moniker of "killer spider". However, over time, it became clear that the likelihood of serious complications from a bite was lower than initially believed (no actual deaths have been recorded in Japan). As a result, it no longer receives the same level of attention. However, the *Joro spider* remains a risk for infants, the elderly, and those with allergies. Therefore, it is designated as an invasive wild plant or animal, and eradication efforts and strategies to prevent its spread continue. Currently, the *Joro spider* has been found in 45 prefectures in Japan, excluding Aomori and Akita. However, the degree of its establishment varies by region. Based on numerous sightings, it is widely believed that the primary cause of the *Joro spider*'s spread is its ability to hitchhike on vehicles such as automobiles. Information gathered from *Joro spider* investigations conducted at the request of local municipalities and other entities has confirmed that this species has been transported attached to vehicles.

While the *Joro spider* is known for its potent venom, cases of human fatalities from bites are rare. However, bites can cause severe pain, and in severe cases, the neurotoxin can lead to symptoms like respiratory distress, increased blood pressure, and elevated heart rate. Therefore, it is essential to exercise caution when encountering a *Joro spider* and avoid touching or handling it. Children and the elderly should be particularly vigilant to prevent bites.

*Joro spiders* prefer warm, humid environments and build their nests in low-lying areas. Therefore, it is important to be aware of your surroundings and avoid approaching nests if discovered. If you encounter a *Joro spider*, contact the local government or an environmental protection organization for assistance.