Ecological modules and roles of species in heathland plant-insect flower visitor networks
Ecological modules and roles of species in heathland plant-insect flower visitor networks
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DOI：
10.1111/j.1365-2656.2008.01501.x
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发表时间：
2009-03-01
影响因子：
4.8
通讯作者：
Olesen, Jens M.
中科院分区：
文献类型：
--
作者：
Dupont, Yoko L.;Olesen, Jens M.
1.共存的植物和访花动物往往形成复杂的相互作用网络。生态学和进化生物学中一个长期存在的问题是如何检测这种网络中强相互作用物种的非随机子集（隔间，块，模块）。在这里，我们使用网络分析方法（i）检测授粉网络中的模块性，（ii）调查模块的物种组成，以及（iii）评估跨站点模块的稳定性。虫媒植物和他们的花游客之间的相互作用，记录在整个开花季节在三个石楠在丹麦，分开>= 10公里。在网站之间，植物群落相似，但组成的访花昆虫区系不同。访客物种的访问频率被记录为昆虫丰度的量度。3.定性（存在-不存在）的互动网络进行了测试的模块化。模块被识别，物种被分类为拓扑角色（外围设备，连接器，或枢纽）使用“模拟退火功能制图”，一种最近由Guimera & Amaral（2005 a）开发的方法。所有网络都是模块化的。每个模块由1-6种植物和18-54种昆虫组成。相互作用集中在一个或两个枢纽植物物种周围，这在三个研究地点基本相同。昆虫物种被分类在分类组，主要是在目的水平。当按访问频率加权时，每个模块由一个或几个昆虫类群主导。这种模式在各研究中心是一致的。我们的研究进一步支持了这样一个结论，即某些植物物种和访花者群体是非随机和重复关联的。在一个网络中，这些强烈相互作用的物种亚群可能会对彼此施加相互的选择压力。因此，模块可能是长期寻求的共同进化的关键单元的候选者。
1. Co-existing plants and flower-visiting animals often form complex interaction networks. A long-standing question in ecology and evolutionary biology is how to detect nonrandom subsets (compartments, blocks, modules) of strongly interacting species within such networks. Here we use a network analytical approach to (i) detect modularity in pollination networks, (ii) investigate species composition of modules, and (iii) assess the stability of modules across sites.2. Interactions between entomophilous plants and their flower-visitors were recorded throughout the flowering season at three heathland sites in Denmark, separated by >= 10 km. Among sites, plant communities were similar, but composition of flower-visiting insect faunas differed. Visitation frequencies of visitor species were recorded as a measure of insect abundance. 3.Qualitative (presence-absence) interaction networks were tested for modularity. Modules were identified, and species classified into topological roles (peripherals, connectors, or hubs) using 'functional cartography by simulated annealing', a method recently developed by Guimera & Amaral (2005a).4. All networks were significantly modular. Each module consisted of 1-6 plant species and 18-54 insect species. Interactions aggregated around one or two hub plant species, which were largely identical at the three study sites.5. Insect species were categorized in taxonomic groups, mostly at the level of orders. When weighted by visitation frequency, each module was dominated by one or few insect groups. This pattern was consistent across sites.6. Our study adds support to the conclusion that certain plant species and flower-visitor groups are nonrandomly and repeatedly associated. Within a network, these strongly interacting subgroups of species may exert reciprocal selection pressures on each other. Thus, modules may be candidates for the long-sought key units of co-evolution.