1. Introgressive hybridisation between two invasive species has the potential to contribute to their invasion success and provide genetic resiliency to rapidly adapt to new environments. Additionally, differences in the behaviour of hybrids may lead to deleterious ecosystem effects that compound any negative impacts of the invading parental species.
2. Invasive silver carp (Hypophthalmichthys molitrix) and bighead carp (Hypophthalmichthys nobilis) provide an opportunity to evaluate how hybridisation may influence the behaviour, dispersal, and spread of an invasive species introgressive complex. In order to investigate the role hybrids may have in the invasion ecology of bigheaded carps, we examined the distribution, movements, and environmental cues for movement of two invasive fishes and their hybrids in the Illinois River (U.S.A.).
3. Early generation hybrids (e.g. F₁,F₂, and first‐generation backcross individuals) composed a greater proportion of the population at the invasion front where abundances of bigheaded carp were low. A greater proportion of early hybrids passed through dams upstream towards the invasion front than did other hybrids and parental species.
4. The movements and environmental cues for movement of late‐generation backcrosses (more genetically similar to parental genotype) were not different from the parental species with which they shared the most alleles. Although the direction of the relationship between movement and environment was sometimes different for the parental species and associated advanced generation hybrids, these results indicate that management for parental species will also affect most hybrids.
5. Although early generation hybrids are rare, our results indicate they may disperse towards low‐density population zones (i.e. invasion fronts) or are produced at greater frequency in low‐density areas. These rare hybrids have the potential to produce a variety of unique genetic combinations that could result in more rapid adaptation of a non‐native population to their invaded range potentially facilitating the establishment of invasive species.

中文翻译：

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早期杂交种可能会推动两条入侵鱼类的范围扩展

1. 两个入侵物种之间的渐渗杂交可能有助于其入侵成功并提供遗传适应力，以迅速适应新环境。此外，杂种行为的差异可能会导致有害的生态系统影响，从而加剧入侵的亲本物种的任何负面影响。
2. 外来入侵silver鱼（Hypophthalmichthys molitrix）和big鱼（Hypophthalmichthys nobilis）提供了一个机会来评估杂交可能如何影响侵入性物种渗入性复合体的行为，传播和传播。为了研究杂种在in鱼入侵生态学中的作用，我们研究了伊利诺伊河（美国）中两种入侵鱼类及其杂种的运动的分布，运动和环境线索。
3. 早杂种（例如F ₁，F ₂和第一代回交个体）在big头丰盛度较低的入侵前沿种群中所占比例较高。与其他杂种和亲本物种相比，早期杂种通过上游大坝向入侵前沿传播的比例更大。
4. 晚期回交（在遗传上更类似于亲本基因型）的运动和环境提示与它们共享最多等位基因的亲本物种没有区别。尽管对于亲本物种和相关的先进杂种而言，运动与环境之间关系的方向有时会有所不同，但这些结果表明，对亲本物种的管理也会影响大多数杂种。
5. 尽管早期杂交种很少见，但我们的研究结果表明它们可能分散到低密度种群区（即入侵前沿），或者在低密度地区以更高的频率产生。这些稀有杂种具有产生各种独特遗传组合的潜力，这些组合可能导致非本地种群更快速地适应其入侵范围，从而有可能促进入侵物种的建立。