Department of Marine and Environmental Sciences, Graduate School of Engineering and Science, University of the Ryukyus, Senbaru, Nishihara, Okinawa, 903-0213, Japan.
Department of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan.
J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2024 May;210(3):381-398. doi: 10.1007/s00359-023-01654-6. Epub 2023 Jul 29.
The spatial position of individuals within a social group, which provides the group members with benefits and costs, is determined by several physical and physiological factors. Lateralization (left and right asymmetry of morphology and behavior) could also be factors determining the individual's positions within a group. However, this possibility has been documented in some fish species, but never in an invertebrate species. This study investigates the association between spatial positions and lateralization in oval squid, Sepioteuthis lessoniana, which displays social behavior, such as schooling and lateralization for eye use (visual lateralization). The direction and strength of visual lateralization were determined for single squid by observing which eye was used to detect the prey, predators, and conspecifics. The spatial positions of individuals were determined by identifying whether the squids were in the left or right side from the center of the school. When the prey was presented to schooling squids, strongly lateralized squids against prey positioned themselves on the right side, whereas weakly lateralized squids positioned themselves on the left side. When the predator was presented to squids, the strongly lateralized squids against the conspecifics positioned themselves on the right side, and the weakly lateralized squids positioned themselves on the left side. When no targets were presented, the strongly lateralized squids against the predator positioned themselves on the right side, whereas the weakly lateralized squids positioned themselves on the left side. The strength of visual lateralization of oval squid could offer the defensive and offensive functions of schools with specific individual positions.
个体在社会群体中的空间位置为其成员提供了利益和成本，这取决于几个物理和生理因素。偏侧性（形态和行为的左右不对称）也可能是决定个体在群体中位置的因素。然而，这种可能性仅在一些鱼类物种中得到证实，而在无脊椎动物物种中从未得到证实。本研究调查了空间位置与卵形鱿鱼（Sepioteuthis lessoniana）的偏侧性之间的关联，该鱿鱼表现出社会行为，例如群体游动和用眼的偏侧性（视觉偏侧性）。通过观察鱿鱼用来检测猎物、捕食者和同种个体的眼睛，确定了单个鱿鱼的偏侧性方向和强度。通过识别鱿鱼在群体中的位置是在左侧还是右侧，确定了个体的空间位置。当猎物呈现给游动的鱿鱼时，强烈偏侧性的鱿鱼会将自己定位在右侧，而较弱偏侧性的鱿鱼会将自己定位在左侧。当捕食者呈现给鱿鱼时，强烈偏侧性的鱿鱼会将自己定位在右侧，而较弱偏侧性的鱿鱼会将自己定位在左侧。当没有目标呈现时，强烈偏侧性的鱿鱼会将自己定位在右侧，而较弱偏侧性的鱿鱼会将自己定位在左侧。卵形鱿鱼的视觉偏侧性强度可以为具有特定个体位置的群体提供防御和进攻功能。
