Shirasaki Riku, Tanaka Ryoya, Takekata Hiroki, Shimada Takashi, Ishikawa Yuki, Kamikouchi Azusa
Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan.
Center for Strategic Research Project, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213, Japan.
R Soc Open Sci. 2022 Aug 24;9(8):220042. doi: 10.1098/rsos.220042. eCollection 2022 Aug.
Many animal species form groups. Group characteristics differ between species, suggesting that the decision-making of individuals for grouping varies across species. However, the actual decision-making properties that lead to interspecific differences in group characteristics remain unclear. Here, we compared the group formation processes of two Drosophilinae fly species, and , which form dense and sparse groups, respectively. A high-throughput tracking system revealed that flies formed groups faster than flies, and the probability of remaining in groups was far higher than that of . flies joined groups even when the group size was small, whereas flies joined groups only when the group size was sufficiently large. flies attenuated their walking speed when the inter-individual distance between flies became small, whereas such behavioural properties were not clearly observed in . Furthermore, depriving flies of visual input affected grouping behaviours, resulting in a severe reduction in group formation. These findings show that decision-making regarding grouping, which greatly depends on vision, is significantly different from , leading to species-specific group formation properties.
许多动物物种会形成群体。不同物种的群体特征存在差异，这表明个体关于形成群体的决策在不同物种间有所不同。然而，导致群体特征种间差异的实际决策特性仍不清楚。在这里，我们比较了两种果蝇亚科果蝇的群体形成过程，分别是形成密集群体的物种A和形成稀疏群体的物种B。一个高通量追踪系统显示，物种A的果蝇比物种B的果蝇更快形成群体，并且物种A留在群体中的概率远高于物种B。物种A的果蝇即使在群体规模较小时也会加入群体，而物种B的果蝇只有在群体规模足够大时才会加入群体。当果蝇个体间距离变小时，物种A的果蝇会降低其行走速度，而在物种B中未明显观察到这种行为特性。此外，剥夺物种A果蝇的视觉输入会影响群体形成行为，导致群体形成严重减少。这些发现表明，物种A关于群体形成的决策极大地依赖视觉，与物种B有显著不同，从而导致了物种特异性的群体形成特性。
