Data from: Sequential mate choice and sexual isolation in threespine stickleback species

Sequential mate choice strategies predict how females should alter their choosiness based on the availability of attractive males. While there are many studies on sequential mate choice within species, few have asked if females apply these strategies to interactions between species and how these strategies may affect hybridization. We tested how previous interactions with conspecific and heterospecific males affect mate preference and sexual isolation in two threespine stickleback species (benthics and limnetics: Gasterosteus spp.). Consistent with previous work, we found that within species, stickleback females gauge male attractiveness relative to previously encountered males. If females extend these decision rules between species, we predicted that previous interactions with conspecifics should make heterospecifics less attractive, while interactions with heterospecifics should make conspecifics more attractive. However, females found heterospecifics less attractive after prior experience, largely independent of the species of male first encountered. Thus, sequential mate choice strategies are used within but not between species in sticklebacks. Further, learning from prior courtship interactions acts to enhance existing sexual isolation between species.序列择偶策略（Sequential mate choice strategies）阐释了雌性个体应如何依据有吸引力雄性的可获得性，调整自身择偶严苛程度。尽管已有诸多针对物种内序列择偶行为的研究，但鲜有探讨雌性是否会将此类策略应用于跨物种互动，以及这类策略可能对杂交产生何种影响。本研究以两种三棘刺鱼（底栖棘鱼与浮游棘鱼：Gasterosteus spp.）为实验对象，探究雌性与同种（conspecific）、异种（heterospecific）雄性的先前互动经历，如何影响其择偶偏好与性隔离（sexual isolation）。与此前研究结果一致，本研究发现：同种场景下，棘鱼雌性会依据此前遭遇过的雄性，评估当前雄性的吸引力。若雌性将此类决策规则延伸至跨物种互动，我们曾预测：先前与同种雄性的互动会降低异种雄性的吸引力，而先前与异种雄性的互动则会提升同种雄性的吸引力。但实验结果显示，雌性在拥有先前互动经历后，会认为异种雄性吸引力更低，且这一效应基本不受首次接触的雄性物种类型影响。由此可见，棘鱼仅在同种个体间使用序列择偶策略，跨物种互动中则不会采用此类策略。此外，从先前求偶互动中获得的学习经验，可进一步强化物种间已有的性隔离屏障。