Majors in Plant Resource Sciences and Environment, College of Applied Life Science, SARI, Jeju National University, Jeju, 63243, Republic of Korea.
The Research Institute for Subtropical Agriculture and Biotechnology, Jeju National University, Jeju, Republic of Korea.
Sci Rep. 2020 Oct 12;10(1):16952. doi: 10.1038/s41598-020-73344-1.
The Japanese pine sawyer, Monochamus alternatus Hope (Coleoptera: Cerambycidae), transfers the pine wood nematode, Bursaphelenchus xylophilus (Steiner and Buhrer) that causes pine wilt disease (PWD), especially in Asian countries. The key for the control of PWD is primarily focused on vector management. Thus, understanding the exact life history of M. alternatus is required. Since the late 1980s, the life cycle of M. alternatus has been accepted under the assumption that the final larvae pass four instars in the field. This study is revising the previous error for the life cycle hypothesis of M. alternatus by finding various instar pathways, which pathway is defined as the number of instars that larvae pass through prior to pupation. We confirm experimentally that the overwintered fourth or fifth instar larvae directly pupate to emerge as adults, indicating the presence of four and five instar pathways, respectively. The selection of instar pathway might be determined primarily by habitat temperature. This information will be useful to explain the variation of life history in M. alternatus populations worldwide based on the thermal environments, and also can be served to predict the northern distribution limit by applying the threshold degree-days for the completion of four instar pathway.
日本松褐天牛，Monochamus alternatus Hope（鞘翅目：天牛科），传播松材线虫，Bursaphelenchus xylophilus（Steiner and Buhrer），引起松材线虫病（PWD），特别是在亚洲国家。控制 PWD 的关键主要集中在媒介管理上。因此，需要了解 M. alternatus 的准确生活史。自 20 世纪 80 年代末以来，M. alternatus 的生命周期被认为是假设野外的最后幼虫经过四个龄期。本研究通过发现各种龄期途径，修正了之前关于 M. alternatus 生命周期假说的错误，其中途径定义为幼虫化蛹前经过的龄期数。我们通过实验证实，越冬的第四或第五龄期幼虫直接化蛹为成虫，分别表明存在四龄期和五龄期途径。龄期途径的选择可能主要由栖息地温度决定。这些信息将有助于根据热环境解释 M. alternatus 种群生活史的变化，也可以通过应用完成四龄期途径的阈值度日来预测北方分布极限。
