Vision complements echolocation in an aerial-hawking bat
Vision complements echolocation in an aerial-hawking bat
复制标题
DOI：
10.1007/s00114-003-0464-x
复制
发表时间：
2003-09
影响因子：
--
通讯作者：
J. Rydell;J. Eklöf
中科院分区：
文献类型：
--
作者：
J. Rydell;J. Eklöf
北方蝙蝠Eptesicus nilssonii通常使用频率调制的回声定位呼叫在空中捕食昆虫。它还能发现并捕捉在草茎间低空盘旋的视觉上显眼的猎物（白色飞蛾）。为了克服草地上的声音干扰目标回波探测的问题，蝙蝠除了利用回声定位外，还利用视觉线索。因此，我们调查了猎物的最小尺寸，蝙蝠可以区分使用视觉，通过提出蝙蝠与不同大小的死亡和传播蛾。我们发现，只有当飞蛾的翼展至少为5厘米时，视觉才能增加被发现的机会。较小的目标被发现使用回声定位单独。蝙蝠的平均探测距离为3.5 m，表明蝙蝠需要49′弧的视觉敏锐度才能发现猎物。这与密切相关物种的视动反应测试和视网膜神经节细胞计数的结果一致。我们的研究结果表明，视觉敏锐度ofEptesicusbats可能不足以在正常条件下的猎物检测，但蝙蝠可以使用视觉时，猎物是异常大和显眼。北方蝙蝠在猎物探测技术上表现出灵活性，这在以前的空中鹰蝠中是没有的，它们能够在野外充分利用自己的视觉能力。
The northern batEptesicus nilssoniinormally hunts flying insects in the air using frequency-modulated echolocation calls. It is also known to detect and catch visually conspicuous prey (white moths) hovering low among grass stalks. To overcome the problem with acoustic clutter from the grass, which interferes with target echo detection, the bats make use of visual cues in addition to those of echolocation. We therefore investigated the minimum size of prey that the bats could distinguish by using vision, by presenting the bats with different sized dead and spread moths. We found that vision increased the chance of detection only when the moths had a wingspan of at least 5 cm. Smaller targets were detected using echolocation alone. The mean detection range was 3.5 m, suggesting that the bats need a visual acuity of 49′ of arc to detect the prey. This is consistent with results of optomotor response tests and counts of retinal ganglion cells in closely related species. Our results suggest that the visual acuity ofEptesicusbats may not be adequate for prey detection under normal conditions, but that the bats can use vision when the prey is unusually large and conspicuous. The northern bats display a flexibility in prey detection techniques not previously recognised among aerial-hawking bats and they are able to use their full visual capacity in the field.