First evidence for an established Marmorkrebs (Decapoda, Astacida, Cambaridae) population in Southwestern Germany, in syntopic occurrence with Orconectes limosus (Rafinesque, 1817)
First evidence for an established Marmorkrebs (Decapoda, Astacida, Cambaridae) population in Southwestern Germany, in syntopic occurrence with Orconectes limosus (Rafinesque, 1817)
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DOI：
10.3391/ai.2010.5.4.10
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发表时间：
2010-12-01
影响因子：
1.6
通讯作者：
Pfeiffer, Michael
中科院分区：
文献类型：
--
作者：
Chucholl, Christoph;Pfeiffer, Michael
Marmorkrebs是目前在中欧水域发现的12种已知的非本地小龙虾（NICS）之一。它的独特之处在于，只有雌性进行孤雌生殖，即卵子发育不受精，所有后代的基因都相同。Marmorkrebs于20世纪90年代中期在德国水族馆贸易中首次被发现，从那时起就成为一种非常常见的宠物物种。在这里，我们提出了第一个证据，证明在弗赖堡（德国）附近的上莱茵河流域的一个小湖泊中有一个成熟的Marmorkrebs种群。该种群与另一种入侵莱茵河系统的NICS，大约50年前入侵莱茵河系统的Orconectes limmosus同步发生。对2010年7月3日捕获的12只Marmorkrebs标本进行了形态测量和卵巢重量测量。在德国萨克森州捕获的一个自由生活的个体身上发现了明显的讲台旋转。卵巢发育阶段（促性腺指数）呈异质性，6月上旬至7月下旬为单果雌虫，可能存在非同步繁殖习性。两种小龙虾的相对丰度和分布分别在夜间进行了两次目测计数。这两个物种在整个湖缘都达到了相当的中等密度。Marmorkrebs是浅沼泽生境斑块上的主要物种，这可能与它的自然主要栖息地相似。尽管有一个已经存在的O. limosus种群，但成功建立Marmorkrebs强调了Marmorkrebs的竞争能力。除了最近提出的假设，即Marmorkrebs可能在欧洲大部分地区受到温度限制，我们认为也有必要考虑其可能的自然主要栖息地和生命周期：Marmorkrebs可能能够在中欧大部分地区的夏季温暖、缓慢的栖息地定居。
Marmorkrebs are one of 12 currently known non-indigenous crayfish species (NICS) to be found in Central European waters. It is unique in the manner that there exist only females which reproduce parthenogenetically, i.e. eggs develop unfertilized and all offspring are genetically identical. Marmorkrebs have been first discovered in the German aquarium trade in the mid 1990s and became a very common pet species since then. Here, we present first evidence for a well established Marmorkrebs population in a small lake in the Upper Rhine catchment near Freiburg (Germany). The population occurs syntopically with Orconectes limosus, another NICS which invaded the Rhine system about 50 years ago. Morphometric and ovary weight measurements were taken from 12 Marmorkrebs specimens that were captured on July 3, 2010. The rostrum spination was pronounced and resembled the one found on a free-living individual captured in Saxony (Germany). Ovary development stages (Gonadosomatic Index) were heterogeneous and single berried females were found from early June to late July, which might indicate an asynchronous breeding habit. The relative abundance and distribution of both crayfish species were assessed by visual counts at nighttime at two occasions. Both species attained a comparable, moderate density throughout the lake margin. The Marmorkrebs was the prevalent species on shallow, swampy habitat patches, which are presumably similar to its natural prime habitats. The successful establishment of Marmorkrebs despite a pre-existing O. limosus population, stresses the competitive ability of Marmorkrebs. In addition to the recently suggested hypothesis that Marmorkrebs might be temperature limited in most parts of Europe, we feel that it is also necessary to consider its probable natural prime habitats and life cycle: Marmorkrebs are presumably able to colonize summer-warm, lentic habitats in most parts of Central Europe.