一项研究发现，蜜蜂通过让正在接近的着陆地点在它们的视野中扩大的速率保持恒定从而减速并在表面上安全着陆。
安全着陆可以说是飞行最具挑战的一个方面，它需要在触地的时候减速到接近0速度，而飞机是由经过训练的飞行员以及精密仪器引导的，让动物实现这种技艺的机制仍然不清楚。
为了分析蜜蜂用于在垂直表面降落的线索，Emily Baird及其同事设计了一些实验，使用旋转的螺旋图案去模拟着陆地点的运动模式，结果发现这些蜜蜂通过接近着陆表面的时候让着陆表面扩大的表观速率保持恒定，从而平滑地降低了速度。
这组作者开发了一个复制了这种技术的数学模型，然后证明了这种技术可以有效引导在任何方向上在表面上平滑着落。这组作者报告说，这种着陆导航的生物策略——这种机制很可能被其他飞行动物利用——并不需要了解到表面的距离或者飞行速度。这组作者说，这种方法的简单性可能提供了一个理想的解决方案，可以由飞行机器人的自动导航系统实施。（生物谷Bioon.com）
生物谷推荐的英文摘要
Proceedings of the National Academy of the Sciences of the United States of America doi: 10.1073/pnas.1314311110
A universal strategy for visually guided landing
Emily Bairda，1， Norbert Boeddekerb， Michael R. Ibbotsonc，d， and Mandyam V. Srinivasane，f
Landing is a challenging aspect of flight because， to land safely， speed must be decreased to a value close to zero at touchdown. The mechanisms by which animals achieve this remain unclear. When landing on horizontal surfaces， honey bees control their speed by holding constant the rate of front-to-back image motion (optic flow) generated by the surface as they reduce altitude. As inclination increases， however， this simple pattern of optic flow becomes increasingly complex. How do honey bees control speed when landing on surfaces that have different orientations？ To answer this， we analyze the trajectories of honey bees landing on a vertical surface that produces various patterns of motion. We find that landing honey bees control their speed by holding the rate of expansion of the image constant. We then test and confirm this hypothesis rigorously by analyzing landings when the apparent rate of expansion generated by the surface is manipulated artificially. This strategy ensures that speed is reduced， gradually and automatically， as the surface is approached. We then develop a mathematical model of this strategy and show that it can effectively be used to guide smooth landings on surfaces of any orientation， including horizontal surfaces. This biological strategy for guiding landings does not require knowledge about either the distance to the surface or the speed at which it is approached. The simplicity and generality of this landing strategy suggests that it is likely to be exploited by other flying animals and makes it ideal for implementation in the guidance systems of flying robots.
