Phytophagous insect community assembly through niche conservatism on oceanic islands
Phytophagous insect community assembly through niche conservatism on oceanic islands
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DOI：
10.1111/j.1365-2699.2012.02792.x
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发表时间：
2013-02-01
影响因子：
3.9
通讯作者：
Gillespie, Rosemary G.
中科院分区：
文献类型：
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作者：
Hembry, David H.;Okamoto, Tomoko;Gillespie, Rosemary G.
目的确定海洋岛屿上的植食昆虫群落（以波利尼西亚东南部的Glochidion树为食的昆虫群）主要是通过生态位保守性还是适应性辐射聚集的。位于库克群岛和法属波利尼西亚的波利尼西亚东南部的岛屿（库克群岛南部、Austral群岛、Society群岛、Tuamotu-Gambier群岛和Marquesas群岛）。方法采集波利尼西亚东南部20个岛屿上23种Glochidion （Euphorbiaceae s.l., Phyllanthaceae: Phyllanthus s.l.）特有树种的幼虫，进行饲养鉴定。将饲养记录与亚洲和澳大拉西亚近缘分类群的文献和博物馆收藏的寄主记录进行了比较。结果收集到的昆虫标本中，90%属于亚洲和大洋洲（= 6000 km）已知的攻击Glochidion的5个分类群，表明该群落的聚集具有很强的生态位保守性。其中三个分类群，两种取食种子的飞蛾（细叶蛾科：表翅目；圆叶蛾科：三翅目）和一种采叶飞蛾（细叶蛾科：白蛉目）仅在大陆的千叶蛾科或大戟科中发现。另外两个分类群，另一种采叶蛾（细叶蛾科：Caloptilia）和一种卷叶蛾（Tortricidae: Dudua），包含了许多只在大陆上从千层蛾科中已知的物种，并且很可能代表了生态位保守性的例子。相反，在大陆上已知的许多在数量上占优势的昆虫类群（如寄生性膜翅目昆虫）在波利尼西亚东南部没有报道。这表明岛屿群落代表了大陆群落中那些分类群的一个子集，这与已建立的太平洋多样性梯度相一致。这些发现表明，尽管专业化可能会对成功建立植食昆虫群落造成限制，但生态位保守性在海洋岛屿上的植食昆虫群落的聚集中起着重要作用。由于这种生态位保守性，这些群落可能代表物种较少的热带大陆群落，而不是非类似的岛屿生态系统。
Aim To determine whether a community of phytophagous insects on oceanic islands (the fauna of insects feeding internally on Glochidion trees in south-eastern Polynesia) was assembled predominantly through niche conservatism or adaptive radiation. Location The islands of south-eastern Polynesia (southern Cook, Austral, Society, Tuamotu-Gambier and Marquesas archipelagos) in the Cook Islands and French Polynesia. Methods Internally feeding insects were collected as larvae from 23 endemic species of Glochidion (Euphorbiaceae s.l., Phyllanthaceae: Phyllanthus s.l.) trees on 20 islands in south-eastern Polynesia, reared and identified. Rearing records were compared with host records previously known from the literature and museum collections of closely related taxa in Asia and Australasia. Results Ninety per cent of insect specimens collected fall into five taxa previously known to attack Glochidion in Asia and Australasia (= 6000 km distant), indicating a strong role for niche conservatism in the assembly of this community. Three of these taxa, two seed-feeding moths (Gracillariidae: Epicephala; Tortricidae: Tritopterna) and a leaf-mining moth (Gracillariidae: Diphtheroptila) are only known from Phyllanthaceae or Euphorbiaceae s.l. on continents. Two more taxa, another leaf-mining moth (Gracillariidae: Caloptilia) and a leaf-rolling moth (Tortricidae: Dudua), contain many species known only from Phyllanthaceae on continents, and are also very likely to represent examples of niche conservatism. Conversely, many numerically dominant insect taxa known from Glochidion on continents (such as parasitoid Hymenoptera) are not reported from south-eastern Polynesia. This indicates that the insular community represents a subset of those taxa from the continental community, consistent with the well-established Pacific diversity gradient. Main conclusions These findings indicate that niche conservatism can play an important role in the assembly of phytophagous insect communities on oceanic islands, despite the constraints that specialization might be expected to pose on successful establishment. As a result of this niche conservatism, these communities may represent less species-rich versions of continental tropical communities rather than non-analogue insular ecosystems.