Department of Biology, Zaporizhzhia National University, Zhukovskogo 66, 69063 Zhaporizhzhia, Ukraine.
Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, PO Box 22 085, 46071 Valencia, Spain.
Int J Parasitol. 2019 Jan;49(1):83-91. doi: 10.1016/j.ijpara.2018.10.004. Epub 2018 Dec 1.
A number of hypotheses exist to explain aggregated distributions, but they have seldom been used to investigate differences in parasite spatial distribution between native and introduced hosts. We applied two aggregation models, the negative binomial distribution and Taylor's power law, to study the aggregation patterns of helminth populations from Liza haematocheilus across its native (Sea of Japan) and introduced (Sea of Azov) distribution ranges. In accordance with the enemy release hypothesis, we predicted that parasite populations in the introduced host range would be less aggregated than in the native host area, because aggregation is tightly constrained by abundance. Contrary to our expectation, aggregation of parasite populations was higher in the introduced host range. However, the analyses suggested that the effect of host introduction on parasite aggregation depends on whether parasite species, or higher level taxonomic groups, were acquired in or carried into the new area. The revealed similarity in the aggregation parameters of co-introduced monogeneans can be attributed to the repeatability and identity of the host-parasite systems. In contrast, the degree of aggregation differed markedly between regions for higher level taxa, which are represented by the native parasites in the Sea of Japan versus the acquired species in the Sea of Azov. We propose that the host species plays a crucial role in regulating infra-population sizes of acquired parasites due to the high rate of host-induced mortality. A large part of the introduced host population may remain uninfected due to their resistance to native naïve parasites. The core concept of our study is that the comparative analysis of aggregation patterns of parasites in communities and populations, and macroecological relationships, can provide a useful tool to reveal cryptic relationships in host-parasite systems of invasive hosts and their parasites.
有许多假说可以解释聚集分布，但它们很少被用于研究原生宿主和引入宿主之间寄生虫空间分布的差异。我们应用了两种聚集模型，负二项分布和泰勒幂律，来研究从花鲈（Liza haematocheilus）跨越其原生分布范围（日本海）和引入分布范围（亚速海）的寄生虫种群的聚集模式。根据敌人释放假说，我们预测引入宿主范围内的寄生虫种群的聚集程度会低于原生宿主区域，因为聚集受到丰度的严格限制。与我们的预期相反，引入宿主范围内寄生虫种群的聚集程度更高。然而，分析表明，宿主引入对寄生虫聚集的影响取决于寄生虫物种，或者更高分类群的寄生虫是在新地区获得的还是带入的。共同引入的单殖吸虫的聚集参数的相似性可以归因于宿主-寄生虫系统的可重复性和同一性。相比之下，对于更高分类群，区域之间的聚集程度差异明显，这是由日本海的原生寄生虫与亚速海的获得物种代表的。我们提出，由于宿主诱导的死亡率较高，宿主物种在调节获得寄生虫的亚种群大小方面起着关键作用。由于其对原生寄生虫的抗性，很大一部分引入宿主种群可能仍然未被感染。我们研究的核心概念是，对寄生虫在群落和种群中的聚集模式以及宏观生态学关系的比较分析，可以为揭示入侵宿主及其寄生虫的宿主-寄生虫系统中的隐蔽关系提供有用的工具。
