Krasnovyd Vadym, Vetešník Lukáš, Gettová Lenka, Civáňová Kristína, Šimková Andrea
Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic.
Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, v.v.i., Květná 8, 603 65 Brno, Czech Republic.
Int J Parasitol. 2017 Jul;47(8):471-483. doi: 10.1016/j.ijpara.2017.01.003. Epub 2017 Mar 3.
Hybrids and their parasite diversity represent interesting models for evolutionary ecology. The modified immune response, shifted ecology, inheritance, and maternal ancestry of hybrid host fish are supposed to affect the diversity of their parasite communities. The pattern of metazoan parasite distribution in non-congeneric cyprinids - common bream (Abramis brama) and roach (Rutilus rutilus) (species with different morphology and ecology, and harbouring different specific parasites) - and their hybrids was analysed. Four static alternative scenarios based on parasite infection levels in hybrids and parental taxa are known. The hybrid resistance scenario predicts that hybrids are more resistant than parental taxa, resulting in low parasite infection in hybrids. This scenario is principally consistent with hybrid heterosis advantage. In accordance with this prediction, metazoan parasite abundance and prevalence were higher in parental species when compared with their hybrids. Alternatively, the dynamic Red Queen scenario of infection in hybridising systems predicts parasite adaptation to common hosts. Temporal (six sampling events) and spatial (two sampling sites) aspects as possible factors influencing parasite distribution were analysed. We found no support for this hypothesis, i.e. no changes in the frequency of hybrids or their parental species and no changes in parasite infection in parental species or hybrids were found in the different time periods. The effect of maternal ancestry on infection level was evident; hybrids exhibiting common bream mtDNA were more strongly parasitized by digeneans and crustaceans than hybrids exhibiting roach mtDNA. Hybrids harboured a majority of the specific parasites of both parental species; however, the level of infection of common bream-specific parasites (especially monogeneans) in hybrids was low. Such an asymmetrical distribution of parental species-specific parasites in hybrids may suggest the limited inheritance of protective immunological mechanisms from one parental species and reveal stronger coadaptation between common bream and its specific parasites.
杂交种及其寄生虫多样性是进化生态学中有趣的研究模型。杂交宿主鱼类的免疫反应改变、生态位转移、遗传以及母系血统被认为会影响其寄生虫群落的多样性。分析了非同属鲤科鱼类——欧鳊（Abramis brama）和拟鲤（Rutilus rutilus）（形态和生态不同且携带不同特异性寄生虫的物种）及其杂交种体内后生动物寄生虫的分布模式。基于杂交种和亲本分类群中寄生虫感染水平，已知有四种静态替代情景。杂交抗性情景预测杂交种比亲本分类群更具抗性，导致杂交种体内寄生虫感染率较低。这种情景主要与杂交优势相符。根据这一预测，与杂交种相比，亲本物种体内后生动物寄生虫的丰度和患病率更高。另外，杂交系统中感染的动态红皇后情景预测寄生虫会适应共同宿主。分析了时间（六个采样事件）和空间（两个采样地点）方面作为影响寄生虫分布的可能因素。我们没有找到支持这一假设的证据，即在不同时间段内，杂交种或其亲本物种的频率没有变化，亲本物种或杂交种体内的寄生虫感染也没有变化。母系血统对感染水平的影响很明显；表现出欧鳊线粒体DNA的杂交种比表现出拟鲤线粒体DNA的杂交种更容易受到复殖吸虫和甲壳类动物的寄生。杂交种携带了两个亲本物种的大多数特异性寄生虫；然而，杂交种中欧鳊特异性寄生虫（尤其是单殖吸虫）的感染水平较低。杂交种中亲本物种特异性寄生虫的这种不对称分布可能表明来自一个亲本物种的保护性免疫机制的遗传有限，并揭示了欧鳊与其特异性寄生虫之间更强的共同适应。
