Data from: Commuting fruit bats beneficially modulate their flight in relation to wind

NOTE: An updated and larger version of this dataset is available. See https://doi.org/10.5441/001/1.k8n02jn8. ABSTRACT: When animals move, their tracks may be strongly influenced by the motion of air or water, and this may affect the speed, energetics and prospects of the journey. Flying organisms, such as bats, may thus benefit from modifying their flight in response to the wind vector. Yet, practical difficulties have so far limited the understanding of this response for free-ranging bats. We tracked nine straw-coloured fruit bats (Eidolon helvum) that flew 42.5+17.5km (mean + s.d.) to and from their roost near Accra, Ghana. Following detailed atmospheric simulations, we found that bats compensated for wind drift, as predicted under constant winds, and decreased their airspeed in response to tailwind assistance such that their groundspeed remained nearly constant. In addition, bats increased their airspeed with increasing crosswind speed. Overall, bats modulated their airspeed in relation to wind speed at different wind directions in a manner predicted by a two-dimensional optimal movement model. We conclude that sophisticated behavioural mechanisms to minimize the cost of transport under various wind conditions have evolved in bats. The bats’ response to the wind is similar to that reported for migratory birds and insects, suggesting convergent evolution of flight behaviours in volant organisms.

注意：本数据集存在更新且规模更大的版本，详见 https://doi.org/10.5441/001/1.k8n02jn8。

摘要：动物移动时，其行进轨迹可能受到空气或水流运动的强烈影响，进而作用于行进速度、能量消耗与行程表现。因此，蝙蝠等飞行生物可通过调整飞行策略以响应风矢量（wind vector）。但截至目前，实际研究的诸多挑战限制了学界对自由活动蝙蝠此类行为响应的认知。
我们对9只 straw-coloured 果蝠（straw-coloured fruit bat, Eidolon helvum）进行了追踪，这些蝙蝠往返于加纳阿克拉附近的栖所，单程飞行距离为42.5±17.5千米（均值±标准差）。通过精细化大气模拟分析，我们发现蝙蝠会如恒定风场条件下的预测那般补偿风致漂移，并借助顺风助力降低自身空速（airspeed），使对地速度（groundspeed）维持近乎恒定。此外，随着侧风（crosswind）风速升高，蝙蝠会提升空速。总体而言，蝙蝠会依据不同风向下的风速调整空速，该模式与二维最优运动模型（two-dimensional optimal movement model）的预测结果一致。
综上，蝙蝠已演化出复杂的行为机制，可在各类风况下最小化运输成本。蝙蝠对风的响应与迁徙鸟类和昆虫的相关研究报道相似，这表明飞行类生物的飞行行为存在趋同演化（convergent evolution）现象。