The Jorō spider (Trichonephila clavata) in the southeastern U.S.: an opportunity for research and a call for reasonable journalism

Abstract

Trichonephila clavata, also known as the Jorō spider, was first discovered in Georgia, USA in 2014. Its arrival from Asia and subsequent range expansion across the southeastern U.S. has received much media coverage, spanning from factual to sensational. Here, we describe T. clavata's invasion potential and known invasive range, and review its biology, dispersal abilities, potential impacts, and management strategies. As of October 2022, T. clavata's range spans at least 120,000 km2, occurring across Georgia, South Carolina, North Carolina, and Tennessee, with additional reports in Alabama, Maryland, Oklahoma, and West Virginia. Its pattern of spread suggests it is primarily driven by natural dispersal mechanisms, such as ballooning, though human-mediated transport cannot be discounted. Like other large-bodied orb-weavers, T. clavata captures and feeds on flying insects and potentially other small animals, and we suggest thirteen co-occurring spider species that should be monitored for competition with T. clavata for resources and web-building sites. Since T. clavata is spreading across both natural and urban habitats, management options are limited. Overall, very little is known about this species in its new North American range, especially its impacts within this novel ecosystem. Thus, we advise journalists and experts alike against exaggerating its potential environmental impact or uncritical acceptance of the spider as ecologically harmless. Instead, T. clavata's rapid spread should be carefully monitored, and we should take a cautious, evidence-based approach when determining next steps.

Fine Structural Characteristics of the Chorionic Microspheres on the Egg Surface of the Orb Web Spider Trichonephila clavata

“…This idea could also be applicable to further biological studies on the egg secretion of silk-producing arthropods. It would be interesting to investigate whether there is a correlation between the amount of CM secretion and the average winter climate in the area, in relation to the proliferation and northward expansion of T. clavata (Chuang et al 2023), which has been introduced into the United States.…”

Veni, vidi, vici? Future spread and ecological impacts of a rapidly expanding invasive predator population

“…There are over 6700 “research grade” observations of T. clavata globally as of May 2023 (i.e., including a photograph and multiple user verifications of species identity), nearly half of which are from the non‐native range. These observations first allowed us to make preliminary estimates of its range boundaries (Chuang et al., 2023), and here we further use them to construct a SDM to determine future range predictions and assess how it compares to T. clavata 's current range expansion rate.…”

“…org). The rate at which these non-native arthropods are spreading appears to be increasing exponentially (Chuang et al, 2023), following a lag time typical of invasive species (Sakai et al, 2001), with their presence in at least ~120,000 km 2 as of summer 2022 (Chuang et al, 2023).…”

“…The exact method of introduction is unknown but their arrival as stowaway hitchhikers on international shipping cargo is the most likely scenario (Hoebeke et al., 2015). Jorō spiders have now spread into at least four states in the southeastern United States, with breeding populations likely occurring in several additional states (Chuang et al., 2023, http://www.inaturalist.org). The rate at which these non‐native arthropods are spreading appears to be increasing exponentially (Chuang et al., 2023), following a lag time typical of invasive species (Sakai et al., 2001), with their presence in at least ~120,000 km 2 as of summer 2022 (Chuang et al., 2023).…”

“…These observations first allowed us to make preliminary estimates of its range boundaries (Chuang et al, 2023), and here we further use them to construct a SDM to determine future range predictions and assess how it compares to T. clavata's current range expansion rate. Trichonephila clavata's large size may facilitate detection, which can aid in monitoring its ecological impacts as it spreads, despite the relative recency of invasion.…”