Data from: Inadvertent biological control: an Australian thrips killing an invasive New Zealand tree in California

Transport hubs of international trade and tourism are sites of unprecedented long-distance dispersal of species and novel ecological interactions. In cases of invasive plants released from their specialist natural enemies, novel interactions with both resident enemies and new arrivals can accumulate and potentially reduce weed competitiveness. I present here one dramatic example of this, where an invasive woody weed in southern California is being rapidly controlled by an accidentally introduced genus-specialist herbivorous insect. The New Zealand native shrub/small tree, Myoporum laetum, is a long-time popular ornamental plant in California and has become an invasive woody weed. In 2005, a Myoporum-specific thrips, Klambothrips myopori, was discovered (and described) in California feeding on M. laetum leaves. Several searches have failed to find K. myopori in New Zealand and a population has recently been discovered in Tasmania, Australia, feeding on Myoporum insulare. In 5 years, K. myopori has killed off about half of southern Californian M. laetum with almost all surviving individuals being gradually defoliated. Inadequate border biosecurity has resulted in inadvertent biological control, in a rapid timeframe, caused by a novel enemy. Unfortunately, K. myopori has subsequently been accidentally transported from California to Hawaii where it is now killing off Hawaiian native Myoporum sandwicense. Transport hubs can both connect weeds with natural enemies and disperse those enemies more widely.国际贸易与旅游的交通枢纽，是促成物种实现前所未有的长距离扩散，并催生新型生态相互作用的核心场所。当入侵植物脱离其专性天敌后，其与本土天敌及新入侵天敌间的新型相互作用会持续累积，进而可能削弱入侵杂草的竞争优势。本文将展示一则极具代表性的实例：加利福尼亚南部的一种入侵木本杂草，正被一种意外引入的属专性植食性昆虫快速抑制。新西兰原生灌木/小乔木银叶苦槛蓝（Myoporum laetum）长期以来都是加利福尼亚州广受欢迎的观赏植物，现已演变为入侵性木本杂草。2005年，研究人员在加利福尼亚州发现了一种专性侵害苦槛蓝属的蓟马——苦槛蓝蓟马（Klambothrips myopori），并对其完成了分类描述，该昆虫以银叶苦槛蓝的叶片为食。多次搜寻均未在新西兰发现苦槛蓝蓟马的踪迹，而近期在澳大利亚塔斯马尼亚州发现了该物种的种群，其寄主为澳洲苦槛蓝（Myoporum insulare）。短短五年间，苦槛蓝蓟马已导致加利福尼亚南部约半数的银叶苦槛蓝死亡，剩余存活个体也几乎全部逐渐落叶枯萎。边境生物安全防控的疏漏，使得一种新型天敌意外引入，进而在短时间内实现了生物防治效果。不幸的是，苦槛蓝蓟马随后又意外从加利福尼亚传入夏威夷群岛，当前正导致夏威夷原生物种夏威夷苦槛蓝（Myoporum sandwicense）大量死亡。交通枢纽既能为入侵杂草与天敌搭建联结桥梁，也能助力天敌实现更广泛的扩散。