Laboratorio de Parasitología, Departamento de Biología, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata- CONICET, Funes 3350, 7600 Mar del Plata, Argentina.
Int J Parasitol. 2011 Mar;41(3-4):309-16. doi: 10.1016/j.ijpara.2010.10.002. Epub 2010 Nov 26.
Whereas the effect of parasites on food webs is increasingly recognised and has been extensively measured and modelled, the effect of food webs on the structure of parasite assemblages has not been quantified in a similar way. Here, we apply the concept of decay in community similarity with increasing distance, previously used for parasites in geographical, phylogenetic and ontogenetic contexts, to differences in the trophic level (TL) based on diet composition of fishes. It is proposed as an accurate quantitative method to measure rates of assemblage change as a function of host feeding habits and is applied, to our knowledge for the first time, across host species in marine waters. We focused on a suite of 15 species of trophically-transmitted and non-specific larval helminths across 16 fish species (1783 specimens, six orders, 14 families) with different sizes and TLs, gathered from the same ecosystem. Not all host species harboured the same number and types of parasites, reflecting the differences in their ecological characteristics. Using differences in TL and body length as measurements of size and trophic distances, we found that similarity at both infracommunity and component community levels showed a very clear decay pattern, based on parasite abundance and relative abundance, with increasing distance in TL, but was not related to changes in fish size, with TL thus emerging as the main explanatory factor for similarity of parasite assemblages. Furthermore, the relationships between host TL and assemblage similarity allowed identification of fishes for which the TL was under- or over-estimated and prediction of the TL of host species based on parasite data alone.
尽管寄生虫对食物网的影响越来越受到重视，并已得到广泛的测量和建模，但食物网对寄生虫组合结构的影响尚未以类似的方式进行量化。在这里，我们应用了基于饮食组成的鱼类营养水平（TL）差异的群落相似性随距离增加而衰减的概念，该概念以前在寄生虫的地理、系统发育和个体发育背景下得到了广泛应用。我们提出了一种准确的定量方法，用于测量组合变化率作为宿主摄食习惯的函数，并首次将其应用于海洋水域的宿主物种。我们集中研究了 16 种鱼类（1783 个样本，六个目，14 个科）中 15 种具有不同大小和 TL 的营养传递和非特异性幼虫期蠕虫，这些鱼类来自同一生态系统。并非所有宿主物种都携带相同数量和类型的寄生虫，这反映了它们生态特征的差异。使用 TL 和体长的差异作为大小和营养距离的测量值，我们发现基于寄生虫丰度和相对丰度，在 TL 上的距离增加时，亚社区和组件社区水平的相似性均显示出非常明显的衰减模式，但与鱼类大小的变化无关，因此 TL 成为寄生虫组合相似性的主要解释因素。此外，宿主 TL 和组合相似性之间的关系允许识别 TL 被低估或高估的鱼类，并根据寄生虫数据预测宿主物种的 TL。
