Takeuchi Yuichi, Hori Michio, Tada Shinya, Oda Yoichi
Department of Anatomy, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.
Graduate School of Science, Nagoya University, Aichi, Japan.
PLoS One. 2016 Jan 25;11(1):e0147476. doi: 10.1371/journal.pone.0147476. eCollection 2016.
The scale-eating cichlid Perissodus microlepis with asymmetric mouth is an attractive model of behavioral laterality: each adult tears off scales from prey fishes' left or right flanks according to the direction in which its mouth is skewed. To investigate the development of behavioral laterality and mouth asymmetry, we analyzed stomach contents and lower jaw-bone asymmetry of various-sized P. microlepis (22 ≤ SL<115 mm) sampled in Lake Tanganyika. The shapes of the pored scales found in each specimen's stomach indicated its attack side preference. Early-juvenile specimens (SL<45 mm) feeding mainly on zooplankton exhibited slight but significant mouth asymmetry. As the fish acquired scale-eating (45 mm ≤ SL), attack side preference was gradually strengthened, as was mouth asymmetry. Among size-matched individuals, those with more skewed mouths ate more scales. These findings show that behavioral laterality in scale-eating P. microlepis is established in association with development of mouth asymmetry which precedes the behavioral acquisition, and that this synergistic interaction between physical and behavioral literalities may contribute to efficient scale-eating.
具有不对称口型的食鳞丽鱼（Perissodus microlepis）是行为偏侧性的一个引人关注的模型：每只成年个体根据其口型倾斜的方向，从猎物鱼的左侧或右侧撕下鳞片。为了研究行为偏侧性和口型不对称的发育情况，我们分析了在坦噶尼喀湖采集的不同大小（22≤标准体长<115毫米）的食鳞丽鱼的胃内容物和下颌骨不对称性。在每个标本胃中发现的有孔鳞片的形状表明了其攻击侧偏好。主要以浮游动物为食的早期幼体标本（标准体长<45毫米）表现出轻微但显著的口型不对称。随着鱼开始捕食鳞片（45毫米≤标准体长），攻击侧偏好逐渐增强，口型不对称也随之增强。在大小匹配的个体中，口型更偏斜的个体吃掉的鳞片更多。这些发现表明，食鳞丽鱼的行为偏侧性是与行为获得之前口型不对称的发育相关联而建立的，并且这种身体和行为偏侧性之间的协同相互作用可能有助于高效地捕食鳞片。
