Russell James E, Mizera Nicholas, Brown Christopher G, Chuang Angela, Coyle David R, Nelsen David R
Department of Biological Sciences, Georgia Gwinnett College, Lawrenceville, GA, United States of America.
Department of Forestry and Environmental Conservation, Clemson University, Clemson, SC, United States of America.
PeerJ. 2025 Sep 15;13:e19952. doi: 10.7717/peerj.19952. eCollection 2025.
The introduction of (L. Koch, 1878) (Araneae: Araneidae: subfamily Nephilinae) in the United States was first recorded in Georgia in 2014. Since its introduction, has become a prominent feature of the arthropod fauna in several southeastern US states. Many questions regarding the introduction event(s) remain unanswered; for instance, was the introduction a single discrete event followed by rapid spread, or were there multiple introductions? The mitochondrial cytochrome c oxidase subunit one gene region (COI), which was used to characterize the initial observation in the US, has also been used to characterize within- and between-population genetic variation. One confounding factor for COI as a population genetic molecular marker, though, is the presence of cytoplasmic agents of selection such as intracellular bacteria in the genus . Given that infections have been detected in potential source populations of , the present study sought to characterize mitochondrial genetic diversity and the status of infection in the North American population(s) closest to the originally proposed introduction site in Georgia. DNA sequencing revealed no mitochondrial genetic variation in the population sampled in North America, and an exact sequence match to the previously reported in Georgia and a sequence sample from Yunnan, China. was detected in the North American samples. However, phylogenetic analysis on a concatenated multi-locus type sequence suggested two distinct clades, one represented by samples collected in Georgia and another represented by a single sample collected in South Carolina. Sequence analyses of the multi-locus gene regions suggested that the Georgia may be infected with two strains of (super-infection), and the South Carolina sample represented a separate single infection. The study's results emphasize the need for further research, including expanded sampling in the introduced and potential source population regions, as well as a more detailed molecular characterization of the populations.
（L. Koch，1878年）（蜘蛛目：园蛛科：络新妇亚科）于2014年首次在美国佐治亚州被记录。自引入以来，已成为美国东南部几个州节肢动物区系的一个显著特征。关于引入事件的许多问题仍未得到解答；例如，引入是一次单一的离散事件后迅速传播，还是有多次引入？线粒体细胞色素c氧化酶亚基一基因区域（COI），曾被用于表征在美国的最初观察结果，也被用于表征种群内和种群间的遗传变异。然而，COI作为种群遗传分子标记的一个混杂因素是存在细胞质选择因子，如属内的细胞内细菌。鉴于在的潜在源种群中已检测到感染，本研究旨在表征最接近佐治亚州最初提议引入地点的北美种群的线粒体遗传多样性和感染状况。DNA测序显示在北美采集的种群中没有线粒体遗传变异，并且与之前在佐治亚州报道的以及来自中国云南的一个序列样本完全匹配。在北美样本中检测到了。然而，对串联多位点类型序列的系统发育分析表明有两个不同的进化枝，一个由在佐治亚州采集的样本代表，另一个由在南卡罗来纳州采集的单个样本代表。多位点基因区域的序列分析表明，佐治亚州的可能感染了两种菌株（双重感染），而南卡罗来纳州的样本代表一种单独的单一感染。该研究结果强调了进一步研究的必要性，包括在引入区域和潜在源种群区域扩大采样，以及对种群进行更详细的分子表征。
