Van Wassenbergh Sam, Herrel Anthony, Adriaens Dominique, Aerts Peter
Department of Biology, University of Antwerp, B-2610 Antwerpen, Belgium.
J Exp Zool A Comp Exp Biol. 2006 Jul 1;305(7):559-69. doi: 10.1002/jez.a.293.
Species with narrow or limited diets (trophic specialists) are expected to be less flexible in their feeding repertoire compared to species feeding on a wide range of different prey (trophic generalists). The ability to modulate prey capture kinematics in response to different prey types and prey position, as well as the overall variability in prey capture kinematics, is evaluated in four clariid species ranging from trophic generalist (Clarias gariepinus) to species with morphological specializations and a narrow diet (Channallabes apus and Gymnallabes typus). High-speed video recordings were made of prey captures on two prey that differ in shape, attachment strength and hardness. While the observed amount of strike-to-strike variability in prey capture kinematics is similar for all species and not influenced by prey type, only the two less specialized species showed the ability to modulate their prey capture kinematics in function of the presented prey types. All species did, however, show positional modulation during the strike by adjusting the magnitude of neurocranial elevation. These results indicate that the narrow dietary breadth of trophic specialists is indeed indicative of functional stereotypy in this group of fishes. Although most studies focussing on prey processing found a similar result, the present study is one of the few that was able to demonstrate this relationship when focussing on prey capture mechanics. Possibly, this relationship is less frequently observed for prey capture compared to prey processing because, regardless of prey type, the initial capture of prey requires a higher amount of variability.
与以广泛不同猎物为食的物种（营养通才）相比，食性狭窄或有限的物种（营养专家）预计在其捕食技能方面灵活性较差。对四种胡子鲶科鱼类进行了评估，它们从营养通才（埃及塘鲺）到具有形态学特化和狭窄食性的物种（阿氏新胡鲶和典型裸臀鲶），评估了它们根据不同猎物类型和猎物位置调节猎物捕获运动学的能力，以及猎物捕获运动学的总体变异性。对捕获两种形状、附着强度和硬度不同的猎物的过程进行了高速视频记录。虽然所有物种在猎物捕获运动学中观察到的逐次攻击变异性数量相似，且不受猎物类型影响，但只有两个不太特化的物种表现出根据所呈现的猎物类型调节其猎物捕获运动学的能力。然而，所有物种在攻击过程中确实通过调整神经颅抬高的幅度表现出位置调节。这些结果表明，营养专家狭窄的食性广度确实表明了这组鱼类的功能刻板性。尽管大多数关注猎物处理的研究都得出了类似的结果，但本研究是少数在关注猎物捕获机制时能够证明这种关系的研究之一。与猎物处理相比，猎物捕获中这种关系可能较少被观察到，因为无论猎物类型如何，猎物的初始捕获都需要更高的变异性。
