Russello Michael A, Avery Michael L, Wright Timothy F
Department of Biology and Physical Geography, University of British Columbia Okanagan, Kelowna, British Columbia V1V 1V7, Canada.
BMC Evol Biol. 2008 Jul 24;8:217. doi: 10.1186/1471-2148-8-217.
Severe ecological and economic impacts caused by some invasive species make it imperative to understand the attributes that permit them to spread. A notorious crop pest across its native range in South America, the monk parakeet (Myiopsitta monachus) has become established on four other continents, including growing populations in the United States. As a critical first step to studying mechanisms of invasion success in this species, here we elucidated the geographical and taxonomic history of the North American invasions of the monk parakeet. Specifically, we conducted a genetic assessment of current monk parakeet taxonomy based on mitochondrial DNA control region sequences from 73 museum specimens. These data supported comparative analyses of mtDNA lineage diversity in the native and naturalized ranges of the monk parakeet and allowed for identification of putative source populations.
There was no molecular character support for the M. m. calita, M. m. cotorra, and M. m. monachus subspecies, while the Bolivian M. m. luchsi was monophyletic and diagnosably distinct. Three haplotypes sampled in the native range were detected within invasive populations in Florida, Connecticut, New Jersey and Rhode Island, the two most common of which were unique to M. m. monachus samples from eastern Argentina and bordering areas in Brazil and Uruguay.
The lack of discrete morphological character differences in tandem with the results presented here suggest that M. m. calita, M. m. cotorra and M. m. monachus are in need of formal taxonomic revision. The genetic distinctiveness of M. m. luchsi is consistent with previous recommendations of allospecies status for this taxon. The geographic origins of haplotypes sampled in the four U.S. populations are concordant with trapping records from the mid-20th century and suggest that propagule pressure exerted by the international pet bird trade contributed to the establishment of invasive populations in the United States.
一些入侵物种造成了严重的生态和经济影响，因此有必要了解促使它们扩散的特性。和尚鹦鹉（Myiopsitta monachus）在其南美洲原生范围内是一种臭名昭著的农作物害虫，现已在其他四大洲站稳脚跟，包括在美国数量不断增加。作为研究该物种入侵成功机制的关键第一步，我们在此阐明了和尚鹦鹉北美入侵的地理和分类历史。具体而言，我们基于73个博物馆标本的线粒体DNA控制区序列，对当前和尚鹦鹉的分类进行了遗传评估。这些数据支持了对和尚鹦鹉原生和归化范围内线粒体DNA谱系多样性的比较分析，并有助于识别推定的源种群。
没有分子特征支持M. m. calita、M. m. cotorra和M. m. monachus亚种，而玻利维亚的M. m. luchsi是单系的且在诊断上有明显区别。在佛罗里达州、康涅狄格州、新泽西州和罗德岛州的入侵种群中检测到了在原生范围内采样的三种单倍型，其中两种最常见的单倍型是M. m. monachus来自阿根廷东部以及巴西和乌拉圭边境地区样本所特有的。
缺乏离散的形态特征差异以及此处呈现的结果表明，M. m. calita、M. m. cotorra和M. m. monachus需要进行正式的分类修订。M. m. luchsi的遗传独特性与先前对该分类单元的同种异名状态的建议一致。在美国四个种群中采样的单倍型的地理起源与20世纪中叶的捕获记录一致，这表明国际宠物鸟贸易施加的繁殖体压力促成了美国入侵种群的建立。
