Perevolotsky Tal, Brotman-Krass Jacob M, Ratner Yarden, Avigad Yael, Summers Adam P, Donatelli Cassandra M, Holzman Roi
School of Zoology, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv 69978, Israel.
The Interuniversity Institute for Marine Sciences in Eilat, Eilat 88103, Israel.
Integr Org Biol. 2025 Jul 25;7(1):obaf032. doi: 10.1093/iob/obaf032. eCollection 2025.
Across teleosts, feeding by biting substrate-attached prey has evolved multiple times and is associated with convergent morphologies that include a deep body and an elongated, tapered head. However, the functional role of these morphologies in substrate-biting fish is not established. Here, we tested the hypothesis that these morphologies function as control surfaces that affect feeding kinematics during biting. To test this hypothesis, we used simplified physical models of substrate-biting reef fish and examined the role of head, body, and fin morphology in determining feeding kinematics that facilitate the removal of substrate-attached prey. Models simulated the swift lateral movement of the head, previously documented in species biting substrate-attached algae. Using models that capture the natural morphological variation of biters, we tested (i) how different head morphologies affect the speed of the head and (ii) how different body morphologies affect the stability of the body during head movements. We found that the moment of inertia (MOI) of the head and body explained most of the variation in head speed and body displacement. A decrease in head MOI resulted in faster lateral head movements, known to facilitate removal of attached prey. An increase in body MOI, relative to that of the head, stabilized the lateral displacement of the body during bites. Overall, our results suggest that the laterally compressed bodies and tapered snouts function as control surfaces during feeding in substrate-biting fish. We propose that a selective pressure to extend the lateral surface area underlies the prevailing morphological convergence of biting reef fishes.
在硬骨鱼中，通过啃咬附着在基质上的猎物来进食的行为已经多次进化，并且与趋同形态相关，这些形态包括深体和细长的锥形头部。然而，这些形态在啃咬基质的鱼类中的功能作用尚未确定。在这里，我们测试了这样一个假设，即这些形态作为控制表面，在啃咬过程中影响进食运动学。为了验证这一假设，我们使用了啃咬基质的珊瑚礁鱼类的简化物理模型，并研究了头部、身体和鳍的形态在决定有助于去除附着在基质上的猎物的进食运动学中的作用。模型模拟了头部快速的横向运动，这在啃咬附着在基质上的藻类的物种中已有记录。使用捕捉啃咬者自然形态变化的模型，我们测试了（i）不同的头部形态如何影响头部速度，以及（ii）不同的身体形态如何在头部运动过程中影响身体的稳定性。我们发现，头部和身体的转动惯量（MOI）解释了头部速度和身体位移的大部分变化。头部转动惯量的降低导致头部横向运动更快，这有助于去除附着的猎物。相对于头部，身体转动惯量的增加稳定了啃咬过程中身体的横向位移。总体而言，我们的结果表明，在啃咬基质的鱼类进食过程中，侧向压缩的身体和锥形口鼻部起到了控制表面的作用。我们提出，扩大侧面表面积的选择压力是啃咬珊瑚礁鱼类普遍形态趋同的基础。
