Colour Cues That Are Not Directly Attached to the Body of Males Do Not Influence the Mate Choice of Zebra Finches

Mate choice decisions of female zebra finches are generally thought to rely on the assessment of male quality, which includes the specific ornamentation of males. A commonly used paradigm to experimentally manipulate a male’s attractiveness is to add a coloured leg ring to the bird. Some studies have shown that female zebra finches prefer or alter their investment in males that have an additional red leg ring compared with males with green leg rings. Whether the coloured artificial ornaments need to be attached to the male’s body or whether environmental colouration could have a similar effect on male attractiveness remains unclear. Here, I investigated this novel context to determine whether female choice between males is affected by environmental colour cues that are not directly attached to the male’s body in four experiments involving 220 zebra finches (Taeniopygia guttata).A first experiment revealed that females chose males with red colour cues in the environmental background over males with green cues in the background. Based on this finding, I conducted follow-up experiments to obtain a deeper understanding of how environmental colour cues affect mate choice. Therefore, I examined whether female choice behaviour or male behaviour was altered in two additional experiments. Both experiments failed to show any effects of environmental colour cues on female choice or on male behaviour. Therefore, I replicated the initial experiment in a fourth experiment. Again replication failed; thus, the initial results indicating that environmental colouration affects mate choice behaviour of female zebra finches were not supported by the three subsequent experiments; thus, the outcome of the first experiment seems to be a false positive. Taking my results together, I found no robust support for the idea that environmental colour cues that are not directly attached to the body of male zebra finches affect female mate choice decisions.雌性斑胸草雀（zebra finch）的择偶决策通常被认为依赖于对雄性质量的评估，其中涵盖雄性的特定装饰特征。实验性操控雄性吸引力的常用范式，是为其佩戴彩色脚环。已有研究表明，相较于佩戴绿色脚环的雄性，雌性斑胸草雀更偏爱佩戴红色脚环的雄性，或会对其增加繁殖投入。目前仍存在两个尚未明确的问题：一是这类人工彩色装饰是否必须附着于雄性体表，二是环境色彩本身能否对雄性吸引力产生同等影响。本研究针对这一全新研究场景展开探究，通过包含220只斑胸草雀（Taeniopygia guttata）的四项实验，验证未直接附着于雄性体表的环境色彩线索是否会影响雌性的择偶选择。首项实验结果显示，相较于环境背景带有绿色色彩线索的雄性，雌性更倾向于选择环境背景带有红色色彩线索的雄性。基于这一发现，本研究开展了后续实验以深入解析环境色彩线索对择偶决策的影响机制。为此，我们额外开展了两项实验，考察雌性择偶行为或雄性行为是否会因环境色彩线索发生改变。两项实验均未发现环境色彩线索对雌性择偶行为或雄性行为存在任何显著影响。因此，本研究在第四项实验中重复了首项实验的操作。此次重复实验仍未得到预期结果；换言之，后续三项实验均未支持首项实验中"环境色彩会影响雌性斑胸草雀择偶行为"的结论，首项实验的结果疑似为假阳性结果。综合所有实验结果，本研究未找到可靠证据表明，未直接附着于雄性斑胸草雀体表的环境色彩线索会影响雌性的择偶决策。