Medan Diego, Perazzo Roberto P J, Devoto Mariano, Burgos Enrique, Zimmermann Martín G, Ceva Horacio, Delbue Ana M
Cátedra de Botánica, Facultad de Agronomía de la Universidad de Buenos Aires, Av. San Martín 4454, 1417DSE Buenos Aires, Argentina.
J Theor Biol. 2007 Jun 7;246(3):510-21. doi: 10.1016/j.jtbi.2006.12.033. Epub 2007 Jan 8.
It has been observed that mutualistic bipartite networks have a nested structure of interactions. In addition, the degree distributions associated with the two guilds involved in such networks (e.g., plants and pollinators or plants and seed dispersers) approximately follow a truncated power law (TPL). We show that nestedness and TPL distributions are intimately linked, and that any biological reasons for such truncation are superimposed to finite size effects. We further explore the internal organization of bipartite networks by developing a self-organizing network model (SNM) that reproduces empirical observations of pollination systems of widely different sizes. Since the only inputs to the SNM are numbers of plant and animal species, and their interactions (i.e., no data on local abundance of the interacting species are needed), we suggest that the well-known association between species frequency of interaction and species degree is a consequence rather than a cause, of the observed network structure.
据观察，互利共生的二分网络具有嵌套的相互作用结构。此外，与此类网络中涉及的两个群落（例如植物与传粉者或植物与种子传播者）相关的度分布大致遵循截断幂律（TPL）。我们表明，嵌套性和TPL分布紧密相连，并且这种截断的任何生物学原因都叠加在有限大小效应上。我们通过开发一种自组织网络模型（SNM）进一步探索二分网络的内部组织，该模型再现了大小差异很大的授粉系统的实证观察结果。由于SNM的唯一输入是植物和动物物种的数量及其相互作用（即不需要关于相互作用物种局部丰度的数据），我们认为观察到的网络结构导致了相互作用物种频率与物种度之间众所周知的关联，而不是相反。
