Nicotine in floral nectar pharmacologically influences bumblebee learning of floral features.
Nicotine in floral nectar pharmacologically influences bumblebee learning of floral features.
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DOI：
10.1038/s41598-017-01980-1
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发表时间：
2017-05-16
影响因子：
4.6
通讯作者：
Chittka L
中科院分区：
文献类型：
--
作者：
Baracchi D;Marples A;Jenkins AJ;Leitch AR;Chittka L
许多植物通过其组织中的化学威慑物来保护自己免受食草动物的侵害，花蜜中存在这种物质意味着传粉者在觅食时经常遇到它们。这些物质对传粉者觅食行为的影响知之甚少。在严格控制的实验室环境中使用人造花，我们研究了生物碱尼古丁对大黄蜂觅食性能的影响。我们发现，同时面对两种同等回报的含尼古丁和不含尼古丁的花朵类型的大黄蜂，只会被不自然的高尼古丁浓度所阻止。这种威慑消失，甚至变成吸引力在较低的花蜜相关的浓度。生物碱以剂量依赖的方式对学习有深刻的影响。在高自然剂量下，蜜蜂学习含尼古丁的花朵类型的颜色比具有相同卡路里值但不含尼古丁的花朵类型更快。此外，在体验过含有任何测试浓度尼古丁的花朵后，越来越多的大黄蜂对这些花朵更加忠诚，即使它们在奖励方面成为次优选择。这些结果表明生物碱增强了传粉者的花恒常性，为植物和传粉者之间的协同进化过程开辟了新的视角。
Many plants defend themselves against herbivores by chemical deterrents in their tissues and the presence of such substances in floral nectar means that pollinators often encounter them when foraging. The effect of such substances on the foraging behaviour of pollinators is poorly understood. Using artificial flowers in tightly-controlled laboratory settings, we examined the effects of the alkaloid nicotine on bumblebee foraging performance. We found that bumblebees confronted simultaneously with two equally rewarded nicotine-containing and nicotine-free flower types are deterred only by unnaturally high nicotine concentrations. This deterrence disappears or even turns into attraction at lower nectar-relevant concentrations. The alkaloid has profound effects on learning in a dose-dependent manner. At a high natural dose, bees learn the colour of a nicotine-containing flower type more swiftly than a flower type with the same caloric value but without nicotine. Furthermore, after experiencing flowers containing nicotine in any tested concentration, increasing numbers of bumblebees stay more faithful to these flowers, even if they become a suboptimal choice in terms of reward. These results demonstrate that alkaloids enhance pollinator flower constancy, opening new perspectives in co-evolutionary process between plants and pollinators.