Understanding how invasive species respond to novel environments is limited by a lack of sensitivity and throughput in conventional biomonitoring methods. Arthropods in particular are often difficult to monitor due to their small size, rapid lifecycles, and/or visual similarities with co-occurring species. This is true for the agromyzid leafminer fly, Liriomyza sativae, a global pest of vegetable and nursery industries that has recently established in Australia. A robust method based on environmental DNA (eDNA) was developed exploiting traces of DNA left inside “empty” leaf mines, which are straightforward to collect and persist longer in the environment than the fly. This extends the window of possible diagnosis to at least 28 days after a leaf mine becomes empty. The test allowed for visually indistinguishable leafmining damage caused by L. sativae to be genetically differentiated from that of other flies. Field application resulted in the identification of new local plant hosts for L. sativae, including widely distributed weeds and common garden crops, which has important implications for the pest's ability to spread. Moreover, the test confirmed the presence of a previously unknown population of L. sativae on an island in the Torres Strait. The developed eDNA method is likely to become an important tool for L. sativae and other leafmining species of biosecurity significance, which, historically, have been difficult to detect, diagnose and monitor. More generally, eDNA is emerging as a highly sensitive and labour-efficient surveillance tool for difficult to survey species to improve outcomes for agricultural industries, global health, and the environment.

中文翻译：

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一种用于生物监测外来植物害虫的分子方法：环境 DNA 的叶挖掘

了解入侵物种如何对新环境做出反应受到传统生物监测方法缺乏灵敏度和吞吐量的限制。由于节肢动物体型小、生命周期快和/或与共生物种的视觉相似性，节肢动物尤其难以监测。这是agromyzid潜叶蛾飞翔，真正的美洲斑潜蝇，一种最近在澳大利亚建立的全球蔬菜和苗圃行业害虫。开发了一种基于环境 DNA (eDNA) 的稳健方法，利用留在“空”叶雷中的 DNA 痕迹，这些痕迹比苍蝇更容易收集并在环境中持续更长时间。这将可能的诊断窗口延长至叶雷变空后至少 28 天。该测试允许由L引起的视觉上无法区分的采叶损害。 sativae与其他果蝇的遗传差异。现场应用导致鉴定了L的新本地植物宿主。 苜蓿，包括广泛分布的杂草和常见的园艺作物，这对害虫的传播能力具有重要意义。此外，该测试证实了先前未知的L种群的存在。 美洲斑潜蝇在托雷斯海峡的岛屿。开发的 eDNA 方法很可能成为L的重要工具。 斑潜蝇和生物安全的意义，这在历史上，已经很难检测，诊断和监测等leafmining品种。更一般地说，eDNA 正在成为一种高度敏感和劳动效率高的监测工具，用于难以调查的物种，以改善农业、全球健康和环境的结果。