Segers Francisca H I D, Taborsky Barbara
Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, Hinterkappelen, Switzerland.
Proc Biol Sci. 2012 Mar 22;279(1731):1241-8. doi: 10.1098/rspb.2011.1290. Epub 2011 Oct 5.
When females anticipate a hazardous environment for their offspring, they can increase offspring survival by producing larger young. Early environmental experience determines egg size in different animal taxa. We predicted that a higher perceived predation risk by juveniles would cause an increase in the sizes of eggs that they produce as adults. To test this, we exposed juveniles of the mouthbrooding cichlid Eretmodus cyanostictus in a split-brood experiment either to cues of a natural predator or to a control situation. After maturation, females that had been confronted with predators produced heavier eggs, whereas clutch size itself was not affected by the treatment. This effect cannot be explained by a differential female body size because the predator treatment did not influence growth trajectories. The observed increase of egg mass is likely to be adaptive, as heavier eggs gave rise to larger young and in fish, juvenile predation risk drops sharply with increasing body size. This study provides the first evidence that predator cues perceived by females early in life positively affect egg mass, suggesting that these cues allow her to predict the predation risk for her offspring.
当雌性动物预期其后代将面临危险环境时，它们可以通过产出更大的幼崽来提高后代的存活率。早期的环境经历决定了不同动物类群的卵的大小。我们预测，幼年时感知到更高的捕食风险会导致它们成年后产出的卵的大小增加。为了验证这一点，我们在一项分窝实验中，将口孵丽鱼蓝纹埃氏丽鱼的幼鱼暴露于自然捕食者线索或对照环境中。成熟后，曾接触过捕食者的雌鱼产出的卵更重，而一窝卵的数量本身不受处理的影响。这种效应不能用雌鱼不同的体型来解释，因为捕食者处理并未影响生长轨迹。观察到的卵质量增加可能具有适应性，因为较重的卵会孵出更大的幼鱼，而在鱼类中，幼鱼的捕食风险会随着体型的增加而大幅下降。这项研究提供了首个证据，即雌性动物在生命早期感知到的捕食者线索会对卵的质量产生积极影响，这表明这些线索使她能够预测后代面临的捕食风险。
