Am Nat. 2022 May;199(5):705-718. doi: 10.1086/719030. Epub 2022 Mar 29.
AbstractDynamic signals can convey distinct information to a receiver on different timescales, making assessment of how quickly signal strength changes important for understanding signal function. Here, we combine repeated measures of offspring begging behavior of western bluebirds with assessments of fitness as well as quantitative genetic analyses of cross-fostered offspring to investigate whether variation in begging behavior conveys information about hunger, need, or quality or has no signaling function. Begging intensity increased with food deprivation, supporting the signal-of-hunger hypothesis. However, after controlling for this variation, multiple lines of evidence showed that begging also signaled need but not quality. Specifically, begging intensity was repeatable only on short timescales, and nestlings that begged more intensely were in poorer condition. Moreover, variation in mean begging intensity was not strongly related to measures of fitness. In general, we found that begging behavior is a highly flexible trait that appears to be unconstrained by both genetic and early developmental influences, as indicated by the cross-fostering experiment that confirmed that the nest environment, not genetic relatedness, explained variation in begging behavior. Together, these results support the idea that begging dynamically signals shorter-term information: hunger and need. More generally, they show the importance of assessing the timescale of signal change to understand its function.
动态信号可以在不同的时间尺度上向接收者传达不同的信息，因此评估信号强度变化的速度对于理解信号功能非常重要。在这里，我们结合了西方蓝鸟后代乞食行为的重复测量，以及对交叉寄养后代的适应性以及数量遗传学分析，以调查乞食行为的变化是否传递了饥饿、需求或质量的信息，或者没有信号功能。乞食强度随着食物剥夺而增加，支持饥饿信号假说。然而，在控制了这种变化后，有多种证据表明乞食也传递了需求的信息，但不是质量的信息。具体来说，乞食强度只能在短时间尺度上重复，乞食强度较高的雏鸟状况较差。此外，平均乞食强度的变化与适应性的测量值没有很强的关系。总的来说，我们发现乞食行为是一种高度灵活的特征，似乎不受遗传和早期发育的影响，这一点可以通过交叉寄养实验来证实，该实验证实了巢环境而不是遗传关系解释了乞食行为的变化。这些结果共同支持了乞食行为动态地传递短期信息（饥饿和需求）的观点。更普遍地说，它们表明评估信号变化的时间尺度对于理解其功能的重要性。
