美国北卡罗莱纳大学Karin S. Pfennig和Catherine Chen研究组合作报告，进行适应性杂交的雌性蟾蜍更喜欢高质量的异种交配。这一成果于2020年3月20日发表在《科学》。

通常认为杂交（种间杂交）是随机发生在两个物种的成员之间。与预期相反，雌性平原蟾蜍（Spea bombifrons）可以通过优先与另一物种雄性墨西哥蟾蜍（Spea multiplicata）的优质雄性交配，以此来提高其进化适应性。

墨西哥雄性蟾蜍的交配方面可以预测他们的杂交后代的健康状况，由于这些特性，平原雌性蟾蜍更偏向墨西哥雄性蟾蜍，但仅在杂交适应性强的种群和生态条件下发生。

通过选择另一物种适应性增强的伴侣，雌性会增加杂交的益处，并在整个物种之间进行性选择。物种之间的非随机交配因此可以增加物种间适应性基因流动的可能性，因此适应性基因渗入不是简单的偶然事件。

附：英文原文

Title: Female toads engaging in adaptive hybridization prefer high-quality heterospecifics as mates

Author: Catherine Chen, Karin S. Pfennig

Issue&Volume: 2020/03/20

Abstract: Abstract

Hybridization—interbreeding between species—is generally thought to occur randomly between members of two species. Contrary to expectation, female plains spadefoot toads (Spea bombifrons) can increase their evolutionary fitness by preferentially mating with high-quality males of another species, the Mexican spadefoot toad (Spea multiplicata). Aspects of Mexican spadefoot males’ mating calls predict their hybrid offspring’s fitness, and plains spadefoot females prefer Mexican spadefoot males on the basis of these attributes, but only in populations and ecological conditions where hybridization is adaptive. By selecting fitness-enhancing mates of another species, females increase hybridization’s benefits and exert sexual selection across species. Nonrandom mating between species can thereby increase the potential for adaptive gene flow between species so that adaptive introgression is not simply happenstance.

DOI: 10.1126/science.aaz5109

Source: https://science.sciencemag.org/content/367/6484/1377