Optimal strategies for insects migrating in the flight boundary layer: mechanisms and consequences.
Optimal strategies for insects migrating in the flight boundary layer: mechanisms and consequences.
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昆虫在飞行边界层迁徙的最佳策略：机制和后果。
DOI：
10.1093/icb/icn011
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发表时间：
2007
影响因子：
2.6
通讯作者：
R. Dudley
中科院分区：
文献类型：
--
作者：
R. B. Srygley;R. Dudley
定向空中位移要求飞行生物的空速超过环境风速。对于生物相关的高度，风速随着离地高度的增加而呈指数增加。因此，大多数昆虫的传播受到大气条件的影响。然而，靠近地球表面飞行的昆虫在昆虫空速相对较高的飞行边界层内移动。在过去的17年里，我们通过跟踪个体在加勒比海和巴拿马运河上的迁徙来研究边界层昆虫。虽然大多数移民逃避干旱或寒冷，nymphalid和pierid蝴蝶在雨季开始时穿越巴拿马。Pantala属的蜻蜓在10月与锋面天气系统同时迁移。迁移最远，因此也是最难研究的，昼行蛾Urania fulgens在中美洲和南美洲之间迁移。迁徙的蝴蝶和蜻蜓能够在多变的风中朝着一个首选的罗盘方向定向移动，而飞蛾则随风在水上漂流。蝴蝶利用全局和局部线索来定位。与最佳迁移理论相一致，蝴蝶和蜻蜓以最大化单位燃料迁移距离的方式调整它们的飞行速度，而飞蛾则不然。此外，只有蝴蝶调整其飞行速度与内源性脂肪储备。这些昆虫很可能使用光流来测量它们的速度和漂移，因此必须迁移到它们可以看到地球表面足够细节的地方。蝴蝶和蜻蜓调整水面飞行速度的能力表明，它们具有与迁徙相关的复杂控制和引导系统。
Directed aerial displacement requires that a volant organism's airspeed exceeds ambient wind speed. For biologically relevant altitudes, wind speed increases exponentially with increased height above the ground. Thus, dispersal of most insects is influenced by atmospheric conditions. However, insects that fly close to the Earth's surface displace within the flight boundary layer where insect airspeeds are relatively high. Over the past 17 years, we have studied boundary-layer insects by following individuals as they migrate across the Caribbean Sea and the Panama Canal. Although most migrants evade either drought or cold, nymphalid and pierid butterflies migrate across Panama near the onset of the rainy season. Dragonflies of the genus Pantala migrate in October concurrently with frontal weather systems. Migrating the furthest and thereby being the most difficult to study, the diurnal moth Urania fulgens migrates between Central and South America. Migratory butterflies and dragonflies are capable of directed movement towards a preferred compass direction in variable winds, whereas the moths drift with winds over water. Butterflies orient using both global and local cues. Consistent with optimal migration theory, butterflies and dragonflies adjust their flight speeds in ways that maximize migratory distance traveled per unit fuel, whereas the moths do not. Moreover, only butterflies adjust their flight speed in relation to endogenous fat reserves. It is likely that these insects use optic flow to gauge their speed and drift, and thus must migrate where sufficient detail in the Earth's surface is visible to them. The abilities of butterflies and dragonflies to adjust their airspeed over water indicate sophisticated control and guidance systems pertaining to migration.