Experimentally impaired female condition does not affect biliverdin-based egg colour

It has been proposed that blue-green egg coloration is a condition-dependent female sexual trait that may modify paternal care in a post-mating sexual selection scenario. This pattern may arise because the pigment responsible for eggshell colouration (biliverdin) may be a costly and limited resource, whose availability is linked to female health state. Thus, it can be predicted that females whose condition is compromised should be constrained in their capacity to deposit biliverdin in the eggshell, thus producing paler clutches. To test this hypothesis, we performed a handicapping experiment by clipping some feathers of female spotless starlings before egg laying and measuring the colour of their clutches. We expected the handicapping treatment to increase flying costs, impairing female overall condition and resulting in paler clutches. Our experiment was successful in lowering the weight gain of handicapped with respect to control females. However, in contrast to our expectations, we f...已有研究提出，蓝绿色卵色是一种依赖于个体状态的雌性性征，在交配后性选择情境中可影响父本抚育行为。该模式的产生可能源于决定卵壳颜色的色素（胆绿素，biliverdin）是一种稀缺且成本高昂的资源，其可获得性与雌性健康状况直接相关。因此可以推测，身体状态受损的雌性，其在卵壳中沉积胆绿素的能力会受到限制，进而产出颜色更浅的卵窝。为验证这一假说，我们开展了一项累赘处理实验：在产卵前对雌性无斑椋鸟的部分羽毛进行修剪，并测量其卵窝的颜色。我们预期该处理会提升飞行能耗，损害雌性整体身体状态，最终导致卵窝颜色变浅。相较于对照组雌性，本实验成功降低了处理组个体的体重增量。然而，与我们的预期相悖的是，我们……