Sexually immature green chromides exhibit choice-based decision making in the context of social preferences

In most animals, the decision to join a group is influenced by the cost-to-benefit ratio of social preferences for an organism under a given set of conditions. Social preferences show large variations across species, populations and even at the levels of individuals and may be linked to evolutionary fitness. In this study, we demonstrated social preferences in sexually immature individuals of green chromide by using choice-based setups and different types of stimuli. We investigated the mechanistic underpinnings, in terms of the involved sensory modalities, for the observed social preferences. Our results demonstrated that chromides showed significant preferences toward conspecifics that too for similar body size and large group sizes. The pattern of social preferences in green chromides was also similar between ‘olfaction excluded’ and ‘all senses included’ setups, and thus, it can be speculated that the preference is possibly derived majorly via visual signals. Overall, the study provides primal findings on social preferences of a cichlid species that is widely distributed across several Asian countries.在多数动物类群中，个体加入群体的决策会受特定条件下其社交偏好的成本-收益比调控。社交偏好存在显著的种间、种群间乃至个体间差异，且可能与进化适合度相关。本研究通过基于选择的实验范式与多种刺激类型，证实了未性成熟绿慈鲷（green chromide）的社交偏好，并从所涉及的感官通道角度，探究了上述社交偏好的机制基础。研究结果显示，绿慈鲷对体型相近的同种个体以及大群体表现出显著偏好。在“嗅觉阻断”与“全感官保留”的实验范式中，绿慈鲷的社交偏好模式并无显著差异，由此可推测该偏好主要通过视觉信号介导。综上，本研究为一种广泛分布于多个亚洲国家的慈鲷物种的社交偏好提供了基础性研究发现。