Data from: Environmental change mediates mate choice for an extended phenotype, but not for mate quality

Sexual cues, including extended phenotypes, are expected to be reliable indicators of male genetic quality and/or provide information on parental quality. However, the reliability of these cues may be dependent on stability of the environment, with heterogeneity affecting how selection acts on such traits. Here we test how environmental change mediates mate choice for multiple sexual traits, including an extended phenotype – the structure of male-built nests – in stickleback fish. First, we manipulated the dissolved oxygen (DO) content of water to create high or low DO environments in which male fish built nests. Then we recorded the mate choice of females encountering these males (and their nests), under either the same or reversed DO conditions. Males in high DO environments built more compact nests than those in low DO conditions and males adjusted their nest structure in response to changing conditions. Female mate choice for extended phenotype (male nests) was environmentally-dependent (females chose more compact nests in high DO conditions), while female choice for male phenotype was not (females chose large, vigorous males regardless of DO level). Examining mate choice in this dynamic context suggests that females evaluate the reliability of multiple sexual cues, taking into account environmental heterogeneity.

性信号（包括扩展表型（extended phenotype））被认为是雄性遗传质量的可靠指示因子，同时也能提供亲本质量相关信息。然而，这类信号的可靠性可能依赖于环境稳定性，环境异质性会影响选择作用于这些性状的方式。本研究以棘鱼（stickleback）为对象，探究环境变化如何介导雌性对多种雄性性性状的配偶选择，其中包括一项扩展表型——雄性构筑的巢穴结构。首先，我们通过调控水体的溶解氧（dissolved oxygen, DO）含量，构建高溶解氧与低溶解氧两种环境，让雄性棘鱼在此环境中构筑巢穴。随后，我们在与筑巢环境相同或相反的溶解氧条件下，记录雌性棘鱼对这些雄性（及其巢穴）的配偶选择行为。相较于低溶解氧环境，高溶解氧环境中的雄性构筑的巢穴更为紧凑，且雄性会根据环境变化调整其巢穴结构。雌性对扩展表型（雄性巢穴）的配偶选择具有环境依赖性（在高溶解氧环境中，雌性更倾向选择巢穴更紧凑的雄性），而雌性对雄性自身表型的选择则无此环境依赖性——无论溶解氧水平如何，雌性均会选择体型更大、活力更强的雄性。在这一动态情境下开展的配偶选择研究表明，雌性会综合考量环境异质性，以此评估多种性信号的可靠性。