Galipaud Matthias, Bollache Loïc, Lagrue Clément
Department of Evolutionary Biology, Bielefeld University, Konsequenz 45, 33615 Bielefeld, Germany.
UMR 6249 Chrono-environment, Université Bourgogne Franche-Comté, 6 Boulevard Gabriel, 21000 Dijon, France.
Int J Parasitol Parasites Wildl. 2017 Apr 25;6(3):439-447. doi: 10.1016/j.ijppaw.2017.04.005. eCollection 2017 Dec.
Shared parasites can strongly influence the outcome of competition between congeneric, sympatric hosts, and thus host population dynamics. Parasite-mediated competition is commonly hypothesized as an important factor in biological invasion success; invasive species often experience lower infection levels and/or parasite-induced mortality than native congeneric hosts. However, variation in infection levels among sympatric hosts can be due to contrasting abilities to avoid infection or different parasite-induced mortality rates following infection. Low parasite infection levels in a specific host can be due to either factor but have drastically different implications in interaction outcomes between sympatric hosts. We assessed acanthocephalan infection levels (prevalence and abundance) among cryptic molecular taxonomic units (MOTU) of the native / species complex from multiple populations where they occur in sympatry. We concomitantly estimated the same parameters in the invasive commonly found in sympatry with / MOTUs. We then tested for potential differences in parasite-induced mortality among these alternative hosts. As expected, the invasive showed relatively low infection level and was not subject to parasite-induced mortality. We also found that both acanthocephalan infection levels and parasite-induced mortality varied greatly among cryptic MOTUs of the native amphipods. Contrary to expectations, some native MOTUs displayed levels of resistance to their local parasites similar to those observed in the invasive . Overall, cryptic diversity in native amphipods coupled with high levels of variability in infection levels and parasite-induced mortality documented here may strongly influence inter-MOTU interactions and native population dynamics as well as invasion success and population dynamics of the congeneric invasive .
共享的寄生虫会强烈影响同属、同域宿主之间的竞争结果，进而影响宿主种群动态。寄生虫介导的竞争通常被认为是生物入侵成功的一个重要因素；入侵物种通常比本地同属宿主经历更低的感染水平和/或寄生虫诱导的死亡率。然而，同域宿主之间感染水平的差异可能是由于避免感染的能力不同，或者感染后寄生虫诱导的死亡率不同。特定宿主中较低的寄生虫感染水平可能是由于这两个因素中的任何一个，但对同域宿主之间的相互作用结果有截然不同的影响。我们评估了来自多个同域分布种群的本地物种复合体的隐秘分子分类单元（MOTU）中的棘头虫感染水平（患病率和丰度）。我们同时估计了与本地MOTU同域常见的入侵物种中的相同参数。然后，我们测试了这些替代宿主之间寄生虫诱导死亡率的潜在差异。正如预期的那样，入侵物种显示出相对较低的感染水平，并且没有受到寄生虫诱导的死亡影响。我们还发现，本地双足类动物的隐秘MOTU之间，棘头虫感染水平和寄生虫诱导的死亡率都有很大差异。与预期相反，一些本地MOTU对其本地寄生虫的抗性水平与入侵物种中观察到的相似。总体而言，本地双足类动物的隐秘多样性，加上此处记录的感染水平和寄生虫诱导死亡率的高度变异性，可能会强烈影响MOTU间的相互作用和本地种群动态，以及同属入侵物种的入侵成功和种群动态。
