Rawlings Timothy A, Hayes Kenneth A, Cowie Robert H, Collins Timothy M
Department of Biological Sciences, Florida International University, University Park, Miami, Florida 33199, USA.
BMC Evol Biol. 2007 Jun 26;7:97. doi: 10.1186/1471-2148-7-97.
Since the mid 1990s populations of non-native apple snails (Ampullariidae) have been discovered with increasing frequency in the continental United States. Given the dramatic effects that introduced apple snails have had on both natural habitats and agricultural areas in Southeast Asia, their introduction to the mainland U.S. is cause for concern. We combine phylogenetic analyses of mtDNA sequences with examination of introduced populations and museum collections to clarify the identities, introduced distributions, geographical origins, and introduction histories of apple snails.
Based on sampling to date, we conclude there are five species of non-native apple snails in the continental U.S. Most significantly, we recognize three species within what has been called the channeled apple snail: Pomacea canaliculata (California and Arizona), Pomacea insularum, (Florida, Texas, and Georgia) and Pomacea haustrum (Florida). The first established populations of P. haustrum were discovered in the late 1970s in Palm Beach County Florida, and have not spread appreciably in 30 years. In contrast, populations of P. insularum were established in Texas by 1989, in Florida by the mid to late 1990s, and in Georgia by 2005, and this species continues to spread rapidly. Most introduced P. insularum haplotypes are a close match to haplotypes from the Río Uruguay near Buenos Aires, indicating cold tolerance, with the potential to spread from Florida, Georgia, and Texas through Louisiana, Alabama, Mississippi, and South Carolina. Pomacea canaliculata populations were first discovered in California in 1997. Haplotypes of introduced P. canaliculata match native-range haplotypes from near Buenos Aires, Argentina, also indicating cold tolerance and the potential to establish farther north.
The term "channeled apple snail" is descriptive of a morphology found in many apple snail species. It does not identify a single species or a monophyletic group. Clarifying species identifications permits a more accurate assessment of introduction histories and distributions, and provides a very different picture of the tempo and pattern of invasions than was inferred when the three species with channeled sutures were considered one. Matching introduced and native-range haplotypes suggests the potential for range expansion, with implications for native aquatic ecosystems and species, agriculture, and human health.
自20世纪90年代中期以来，在美国大陆发现非本地苹果螺（瓶螺科）种群的频率越来越高。鉴于引进的苹果螺对东南亚的自然栖息地和农业地区都产生了巨大影响，它们被引入美国大陆令人担忧。我们将线粒体DNA序列的系统发育分析与对引进种群和博物馆藏品的研究相结合，以阐明苹果螺的身份、引进分布、地理起源和引进历史。
根据迄今为止的采样，我们得出结论，美国大陆有五种非本地苹果螺。最重要的是，我们在所谓的有沟苹果螺中识别出三个物种：加州苹果螺（加利福尼亚州和亚利桑那州）、岛生苹果螺（佛罗里达州、得克萨斯州和佐治亚州）和瓶形苹果螺（佛罗里达州）。瓶形苹果螺的第一批定居种群于20世纪70年代末在佛罗里达州棕榈滩县被发现，并且在30年里没有明显扩散。相比之下，岛生苹果螺种群在1989年于得克萨斯州建立，在20世纪90年代中期至后期于佛罗里达州建立，在2005年于佐治亚州建立，并且这个物种仍在迅速扩散。大多数引进的岛生苹果螺单倍型与布宜诺斯艾利斯附近乌拉圭河的单倍型非常匹配，表明其耐寒性，有可能从佛罗里达州、佐治亚州和得克萨斯州扩散到路易斯安那州、亚拉巴马州、密西西比州和南卡罗来纳州。加州苹果螺种群于1997年首次在加利福尼亚州被发现。引进的加州苹果螺单倍型与阿根廷布宜诺斯艾利斯附近的本地单倍型匹配，也表明其耐寒性以及在更北地区建立种群的潜力。
“有沟苹果螺”一词描述的是许多苹果螺物种中发现的一种形态。它并不能识别单一物种或一个单系类群。明确物种身份有助于更准确地评估引进历史和分布，并提供了一幅与将具有沟状缝合线的三个物种视为一个物种时所推断的入侵速度和模式截然不同的图景。匹配引进和本地单倍型表明了范围扩张的可能性，这对本地水生生态系统、物种、农业和人类健康都有影响。
