Muchhala Nathan, Serrano Diana
Department of Biology, University of Missouri St. Louis, St. Louis, Missouri, United States of America.
Escuela de Ciencias Biologicas, Pontificia Universidad Católica del Ecuador, Quito, Ecuador.
PLoS One. 2015 Oct 7;10(10):e0136657. doi: 10.1371/journal.pone.0136657. eCollection 2015.
Given their small size and high metabolism, nectar bats need to be able to quickly locate flowers during foraging bouts. Chiropterophilous plants depend on these bats for their reproduction, thus they also benefit if their flowers can be easily located, and we would expect that floral traits such as odor and shape have evolved to maximize detection by bats. However, relatively little is known about the importance of different floral cues during foraging bouts. In the present study, we undertook a set of flight cage experiments with two species of nectar bats (Anoura caudifer and A. geoffroyi) and artificial flowers to compare the importance of shape and scent cues in locating flowers. In a training phase, a bat was presented an artificial flower with a given shape and scent, whose position was constantly shifted to prevent reliance on spatial memory. In the experimental phase, two flowers were presented, one with the training-flower scent and one with the training-flower shape. For each experimental repetition, we recorded which flower was located first, and then shifted flower positions. Additionally, experiments were repeated in a simple environment, without background clutter, or a complex environment, with a background of leaves and branches. Results demonstrate that bats visit either flower indiscriminately with simple backgrounds, with no significant difference in terms of whether they visit the training-flower odor or training-flower shape first. However, in a complex background olfaction was the most important cue; scented flowers were consistently located first. This suggests that for well-exposed flowers, without obstruction from clutter, vision and/or echolocation are sufficient in locating them. In more complex backgrounds, nectar bats depend more heavily on olfaction during foraging bouts.
由于体型小且新陈代谢快，花蜜蝙蝠在觅食期间需要能够迅速找到花朵。虫媒植物依靠这些蝙蝠进行繁殖，因此如果它们的花朵能够容易被找到，这些植物也会受益，并且我们预计气味和形状等花部特征已经进化到能够最大化被蝙蝠察觉。然而，对于觅食期间不同花部线索的重要性，我们了解得相对较少。在本研究中，我们对两种花蜜蝙蝠（长尾果蝠和杰氏果蝠）和人造花进行了一系列飞行笼实验，以比较形状和气味线索在定位花朵中的重要性。在训练阶段，向一只蝙蝠展示一朵具有特定形状和气味的人造花，其位置不断变化以防止依赖空间记忆。在实验阶段，展示两朵花，一朵具有训练花的气味，另一朵具有训练花的形状。对于每次实验重复，我们记录哪朵花先被找到，然后改变花的位置。此外，实验在简单环境（没有背景干扰）或复杂环境（有树叶和树枝背景）中重复进行。结果表明，在简单背景下，蝙蝠对两朵花都不加区分地访问，它们先访问训练花的气味还是训练花的形状没有显著差异。然而，在复杂背景下，嗅觉是最重要的线索；有气味的花总是先被找到。这表明对于暴露良好、没有杂物阻挡的花朵，视觉和/或回声定位足以找到它们。在更复杂的背景下，花蜜蝙蝠在觅食期间更依赖嗅觉。
