Sanz J J, Moreno J
Departamento de Ecología Evolutiva, Museo Nacional de Ciencias Naturales (CSIC), José Gutierrez Abascal 2, E-28006, Madrid, Spain.
Oecologia. 1995 Aug;103(3):358-364. doi: 10.1007/BF00328625.
We performed a food provisioning experiment in a population of Pied Flycatchers Ficedula hypoleuca breeding at high altitude in central Spain to test if food availability before and during laying determines clutch size. Food was provided to one of two pairs with the same date of initiation of nest-building (15 dyads of subsequently reproducing pairs were thus created). Food provisioning began on the day of initiation of nest-building and ended on the day after the last egg was laid. Although laying date was unaffected by the experiment, clutch size in the experimental treatment was significantly larger. This result could indicate that food availability at laying (1) proximately constrained clutch size or (2) that females evaluated future conditions for incubating eggs and feeding nestlings based on food availability at laying. Reproductive success (proportion of eggs that resulted in fledged young) was significantly reduced in the experimental treatment. This effect suggest that supplemented females were tricked by the experiment into laying more eggs than the number of eggs they were able to incubate with success and the number of nestlings they were able to feed, a source of error in clutch size adjustment which could be common in non-experimental situations.
我们在西班牙中部高海拔地区繁殖的斑姬鹟种群中进行了一项食物供应实验，以测试产卵前和产卵期间的食物供应是否决定窝卵数。在开始筑巢日期相同的两对斑姬鹟中，对其中一对提供食物（由此创建了15组随后繁殖的配对）。食物供应从筑巢开始之日起，一直持续到产下最后一枚卵后的第二天。虽然产卵日期不受该实验影响，但实验处理组的窝卵数显著更多。这一结果可能表明，产卵时的食物供应（1）直接限制了窝卵数，或者（2）雌性根据产卵时的食物供应情况评估了未来孵化卵和喂养雏鸟的条件。实验处理组的繁殖成功率（孵出幼鸟的卵的比例）显著降低。这种效应表明，得到补充食物的雌性被实验误导，产下了比它们能够成功孵化的卵数和能够喂养的雏鸟数更多的卵，这是窝卵数调整中的一个误差来源，在非实验情况下可能很常见。
