Two size classes of 0+ year perch: is phenotypic plasticity based on food resources?
Two size classes of 0+ year perch: is phenotypic plasticity based on food resources?
复制标题
0年鲈的两个尺寸等级：表型可塑性基于食物资源吗？
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
J. Borcherding
中科院分区：
文献类型：
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作者：
L. Heermann;P. Beeck;J. Borcherding
分别于6月（单峰大小分布）和7月（双峰大小分布）在一个砾石坑湖中捕获0岁以上的河鲈，分析两个生长队列的形态差异。与大小无关，0年以上的鲈鱼发育出更深的身体，大种群的鲈鱼比小种群的鲈鱼有更深的身体。这可能是对鱼类或浮游生物的适应，但也可能是一种暗示，即小群体的0岁以上的鲈鱼营养不良，它们的发展轨迹与大群体的个体不同。在第二步，研究扩展了一个中观实验。这部分研究的目的是在忽略栖息地利用等其他因素的情况下，为形态变化在多大程度上可能是由于不同食物资源的消耗而提供初步证据。4种中生态系统的2组0岁以上鲈鱼分别饲喂相同生物量的浮游生物和鲤类，饲喂40 d。虽然实验结束时的实验组在大小上没有差异，但在形态上却有所不同。0岁以上的鱼食性鲈鱼的嘴部变大，胸鳍和后腹部的质心向后移动。这些结果提供了进一步的证据，证明食物的类型是重要的，并可能导致进一步的形态学功能适应。
Perch Perca fluviatilis of age 0+ years were caught in a gravel pit lake in June (unimodal size distribution) and in July (bimodal size distribution) to analyse morphological differences between the two growth cohorts. Independent of size, 0+ year perch developed a deeper body and perch of the large size cohort had an even deeper body than perch of the small size cohort. This might have been adaptations to either piscivory or planktivory, but might also be a hint that 0+ year perch of the small size cohort were undernourished and that they developed on a different trajectory than individuals of the large size cohort. In a second step the study was extended with a mesocosm experiment. This part of the study was designed to provide preliminary evidence for the extent to which morphological variations may be due to the consumption of different food resources when other factors such as habitat use could be neglected. Two groups of 0+ year perch in four mesocosms were fed for 40 days with the same biomass of either plankton or cyprinids. Although the experimental groups at the end of the experiment did not differ in size, they differed in morphology. The mouth of the piscivorous 0+ year perch became larger, the pectoral fins and the centre of mass of the posterior abdomen were shifted backwards. These results provide further evidence that the type of food is important and might lead to further functional adaptations in morphology.