Introduced species can become invasive, damaging ecosystems and disrupting economies through explosive population growth. One mechanism underlying population expansion in invasive populations is ‘enemy release’, whereby the invader experiences relaxation of agonistic interactions with other species, including parasites. However, direct observational evidence of release from parasitism during invasion is rare. We mimicked the early stages of invasion by experimentally translocating populations of mite-parasitized slender anole lizards (Anolis apletophallus) to islands that varied in the number of native anoles. Two islands were anole-free prior to the introduction, whereas a third island had a resident population of Gaige's anole (Anolis gaigei). We then characterized changes in trombiculid mite parasitism over multiple generations post-introduction. We found that mites rapidly went extinct on one-species islands, but that lizards introduced to the two-species island retained mites. After three generations, the two-species island had the highest total density and biomass of lizards, but the lowest density of the introduced species, implying that the ‘invasion’ had been less successful. This field-transplant study suggests that native species can be ‘enemy reservoirs’ that facilitate co-colonization of ectoparasites with the invasive host. Broadly, these results indicate that the presence of intact and diverse native communities may help to curb invasiveness.

引入的物种可能会通过人口爆炸性增长而成为侵入性的、破坏生态系统和扰乱经济的。入侵种群中种群扩张的一种机制是“敌人释放”，入侵者由此与其他物种（包括寄生虫）的激动相互作用放松。然而，在入侵期间从寄生虫释放的直接观察证据很少见。我们通过实验将寄生了螨的细长 anole 蜥蜴 ( Anolis apletophallus )种群转移到本地anole数量不同的岛屿来模拟入侵的早期阶段。在引入之前，两个岛屿没有 anole，而第三个岛屿有 Gaige's anole ( Anolis gaigei)的常住种群）。然后，我们描述了引入后多代 trombiculid 螨寄生的变化。我们发现螨虫在一个物种岛上迅速灭绝，但引入到两个物种岛上的蜥蜴保留了螨虫。三代后，两物种岛蜥蜴的总密度和生物量最高，但引进物种的密度最低，表明“入侵”不太成功。这项田间移植研究表明，本地物种可以成为促进外寄生物与入侵宿主共同定殖的“敌人蓄水池”。从广义上讲，这些结果表明完整和多样化的本地社区的存在可能有助于遏制入侵。