不同群体规模德玛森小岩鲷在逃逸过程中群体决策选择研究
GROUP DECISION-MAKING IN DIFFERENT POPULATION SIZE OF CICHLIDS (CHINDONGO DEMASONI) DURING ESCAPE
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摘要: 为探究短时间内德玛森小岩鲷(Chindongo demasoni)在模拟捕食刺激下对路标线索的利用能力, 以及不同群体规模对群体决策的影响, 实验选取喜好集群的德玛森小岩鲷幼鱼为研究对象, 考察不同鱼群规模 (3、6和9尾), 在自然状态及经过短时间对路标和隐蔽场所建立联系后遭遇模拟捕食刺激下做出的群体决策情况。实验设置了1个6臂辐射迷宫为竞技场, 包含一条具有路标、挡板和水草作为隐蔽场所的隐蔽场所臂、1条只有挡板的误导臂和4条空白臂。以鱼群在自然状态和应激状态下首次选择臂占比和首次到达各臂的时间等参数作为评估指标。在自然状态下鱼群首次选择不同类型臂的概率是均等的, 经过短时间的空间探索后在应激状态下, 3种不同群体规模的鱼群首次选择隐蔽场所臂的占比都显著增加(P<0.05), 首次到达隐蔽场所臂的时间均显著减少(P<0.05); 随着群体规模的增大, 在应激状态下首次选择隐蔽场所臂的占比减少(P<0.05), 在两种状态下鱼群在隐蔽场停留时间占比均有所减少(P<0.05), 这是可能是因为随着群体的增大其反捕食策略发生变化。研究表明: 德玛森小岩鲷能够在短时间内利用搜集到的路标线索与隐蔽场所建立联系, 在遇到捕食刺激时能准确且快速的找到避难场所。并且随着群体规模增大, 在模拟捕食刺激下群体的决策准确性呈现下降趋势。Abstract: Group decision-making plays a crucial role in fish anti-predation. The ability to utilize landmarks may be closely related to group decision-making choices during anti-predation in fish. In this study, the cichlid (Chindongo demasoni) was selected as the study model. A 6-arm radial maze was set up as an arena, consisting of a shelter arm (with landmark, baffle, and weed as shelter), a misleading arm (with only a baffle), and four normal arms. We examined group decision-making in shoals of different sizes (consisting of 3, 6, and 9 fish) under both natural and stress conditions after a short period of establishing contact with landmarks and shelter. Parameters such as the proportion of first-selected arms and the time taken to first reach each arm were used as evaluation indices. Under natural conditions, the first-selected arm was evenly distributed among the options. However, under stress conditions, following a brief period of spatial exploration, the proportion of fish selecting the shelter arm first increased significantly across all group sizes, and the time taken to reach each arm decreased significantly. As group size increased, the proportion of fish selecting the shelter arm first decreased under stress conditions, and the dwell time in the shelter arm decreased under both conditions, suggesting a change in their anti-predator strategies. Our results suggest that Cichlid can utilize collected landmark cues to establish contact with shelter within a short period and can accurately and quickly locateshelter when encountering a predator stimulus. Additionally, the accuracy of group decision-making under simulated predation stimuli was found to decrease with increasing group size.