Loiseau Claire, Melo Martim, Lobato Elisa, Beadell Jon S, Fleischer Robert C, Reis Sandra, Doutrelant Claire, Covas Rita
CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBio, Laboratório Associado, University of Porto. Campus Agrário de Vairão, 4485-661 Vairão, Portugal.
Biology Department, Science Faculty, University of Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal.
J Biogeogr. 2017 Nov;44(11):2607-2617. doi: 10.1111/jbi.13060. Epub 2017 Jul 11.
Lower species diversity, increased population densities and ecological niche enlargement are common characteristics of island faunas. However it remains to be determined if they extend to the parasite community. We tested if Haemosporidia parasite pressure varies between islands and the mainland with two different levels of analysis: i) at the host community level, and ii) with paired-species comparisons between islands and the mainland.
Gulf of Guinea, West Africa.
We used molecular-based methods to identify avian Haemosporidian parasites (, and ) to describe their diversity, prevalence, host specificity and their phylogenetic relationships in five islands of the Gulf of Guinea and in nearby mainland areas.
We found reduced Haemosporidia diversity on islands for and , but not for . In addition, lower parasite prevalence on islands was found using a paired-species approach. Although the mean host specificity of the parasite community on islands did not differ from the mainland, we found a very distinct parasite species assemblage on the islands, which was composed of both the most generalist and the most specialist lineages.
This study supports the hypothesis that parasite pressure is reduced on islands. Colonization is made by generalists with high host switching capacities, with some subsequently evolving into highly specialised parasites. This suggests that 'taxon cycle' dynamics may explain the assemblage of insular parasite communities.
物种多样性降低、种群密度增加以及生态位扩大是岛屿动物群的共同特征。然而，这些特征是否适用于寄生虫群落仍有待确定。我们通过两种不同层面的分析来检验疟原虫寄生虫压力在岛屿和大陆之间是否存在差异：i）在宿主群落层面；ii）在岛屿和大陆之间进行配对物种比较。
西非几内亚湾。
我们采用基于分子的方法来鉴定鸟类疟原虫寄生虫（、和），以描述它们在几内亚湾的五个岛屿及附近大陆地区的多样性、流行率、宿主特异性及其系统发育关系。
我们发现，对于和而言，岛屿上的疟原虫多样性降低，但对于则不然。此外，采用配对物种方法发现岛屿上的寄生虫流行率较低。尽管岛屿上寄生虫群落的平均宿主特异性与大陆没有差异，但我们在岛屿上发现了一个非常独特的寄生虫物种组合，它由最具普遍性和最具特异性的谱系组成。
本研究支持岛屿上寄生虫压力降低的假说。定殖是由具有高宿主转换能力的泛化种完成的，其中一些随后进化为高度特化的寄生虫。这表明“分类群循环”动态可能解释岛屿寄生虫群落的组合。
