Jorō spiders, a nonnative species known as Trichonephila clavata, have been thriving in urban areas across the southeastern United States, according to a recent study published in Arthropoda. Unlike typical spiders, Jorō spiders seem to be unaffected by the noise and wind disturbance caused by busy roads, making them well-suited to urban environments. The study, conducted by researchers at the University of Georgia’s Odum School of Ecology, sheds light on why these spiders are regularly found in urban areas where native spiders do not inhabit.
Lead study author Andy Davis explains that Jorō spiders can tolerate living next to roadsides, which are typically harsh environments for animals. Davis states, “If you ever look at a spiderweb next to a road, they’re jiggling and shaking, and it’s a cacophony of stimuli… But Jorōs seem to be able to live next to them.” This unique ability has allowed the species to thrive in the United States since its introduction around 2013.
Jorō spiders are classified as orb weavers and use their giant, three-dimensional webs to catch prey. The spiders sit in the middle of their webs and wait for vibrations that indicate an insect has been caught. The researchers conducted over 350 tests on spiders across 20 roads, using a tuning fork to simulate prey behavior. Surprisingly, the tests revealed that spiders near moderate to heavy traffic roads were only slightly less likely to attack simulated prey compared to those near low-traffic roads. Spiders near heavy traffic attacked 51% of the time, while those in less busy areas attacked 65% of the time.
Floyd Shockley, collections manager for the Department of Entomology at the Smithsonian National Museum of Natural History, comments on the Jorō spider’s natural tolerance for being around cars and people. He explains that while most spider species prefer wooded areas, Jorō spiders specifically move into urban habitats to take advantage of easy hunting and access to prey. Shockley adds, “They’re not particularly interested in us; they’re interested in the fact that we make the condition super easy for them to get the prey that they need to complete their life cycle.”
The researchers note that Jorō spiders seem to prefer making their webs on structures where lights are nearby, such as between buildings or on telephone poles. This is because the light attracts the insects that the spiders feed on. While past studies have shown that roads negatively impact insect abundance and diversity, Jorō spiders and other Trichonephila species are surprisingly tolerant of urban environments and choose to build their homes near busy areas.
Although the researchers are unsure why Jorō spiders are better suited to city life than other species, they plan to conduct future studies on the spiders’ physiology and response to stress. Davis hopes to find answers regarding the unique ways in which Jorō spiders react to stress and how they can live in stressful environments.
As the nonnative Jorō spider continues to spread, it poses a threat to native spider species that are beneficial to the environment. However, the researchers found evidence of Jorō spiders coexisting with native spiders during their study. While Jorō spiders are venomous, their fangs are incapable of breaking human skin. Therefore, it is advised to leave them alone as they eat both beneficial and harmful insect species.
In conclusion, the study reveals the adaptability of Jorō spiders in urban areas and their ability to thrive despite the harsh conditions caused by busy roads. Their tolerance for noise and wind disturbance sets them apart from native spider species, allowing them to spread rapidly across the southeastern United States. Future research aims to uncover the physiological and behavioral traits that enable Jorō spiders to thrive in stressful environments. As these nonnative spiders continue to multiply, they may displace native species, highlighting the need for further monitoring and conservation efforts.
