Herrel Anthony, Van Wassenbergh Sam, Wouters Sarah, Adriaens Dominique, Aerts Peter
Dept Biology, University of Antwerp, Universiteitsplein 1, B-2610 Antwerpen, Belgium.
J Exp Biol. 2005 Jun;208(Pt 11):2091-102. doi: 10.1242/jeb.01604.
Effects of size are pervasive and affect nearly all aspects of the biology of animals and plants. Theoretical scaling models have been developed to predict the effects of size on the functioning of musculo-skeletal systems. Although numerous experimental studies have investigated the effects of size on the movements of skeletal elements during locomotion and feeding in vertebrates, relatively little is known about the scaling of the muscles and bones responsible for the actual movements. Here, we examine the scaling of external morphology, skeletal elements of the feeding system, and a number of cranial muscles to understand how this may affect the movements observed during suction feeding in the African catfish, Clarias gariepinus. The results show that neither the head nor the cranial elements themselves scale according to geometric similarity models. Relative to head size, distinct changes in the mass and configuration of the feeding structures takes place. Unexpectedly, different cranial muscles show different scaling patterns that ultimately all lead to a positive allometry of muscle cross-sectional area relative to fish head size. This suggests that (1) the scaling of the cranial elements cannot be predicted a priori based on the scaling of external head dimensions and (2) the scaling of the feeding system is optimised towards high force output in the larger animals. An analysis of the consequences of the observed changes in morphology with size on performance traits, including bite force and jaw closing velocity, suggests a tight link between the scaling of the feeding system and the natural diet of these fish. Whereas for smaller size classes the system is tuned towards high bite forces, for animals with cranial lengths greater than 65 mm the scaling of the feeding system appears to be dictated by the hydrodynamic constraints on suction feeding.
体型的影响无处不在，几乎影响着动植物生物学的各个方面。人们已经建立了理论比例模型来预测体型对肌肉骨骼系统功能的影响。尽管众多实验研究调查了体型对脊椎动物运动和进食过程中骨骼元素运动的影响，但对于负责实际运动的肌肉和骨骼的比例关系却知之甚少。在此，我们研究非洲鲶鱼（Clarias gariepinus）外部形态、摄食系统骨骼元素以及一些头部肌肉的比例关系，以了解其如何影响吸食摄食过程中观察到的运动。结果表明，头部和颅骨元素本身均不符合几何相似模型的比例关系。相对于头部大小，摄食结构的质量和形态发生了明显变化。出乎意料的是，不同的头部肌肉呈现出不同的比例模式，最终所有这些模式都导致肌肉横截面积相对于鱼头大小呈正异速生长。这表明：（1）颅骨元素的比例关系无法根据外部头部尺寸的比例关系预先预测；（2）摄食系统的比例关系朝着使较大动物产生高力量输出的方向优化。对观察到的形态随体型变化对性能特征（包括咬合力和颌骨闭合速度）的影响进行分析，结果表明摄食系统的比例关系与这些鱼类的自然食性之间存在紧密联系。对于较小体型的鱼类，该系统倾向于产生高咬合力，而对于颅骨长度大于65毫米的动物，摄食系统的比例关系似乎受吸食摄食过程中的流体动力学限制所支配。
