Slippery flowers as a mechanism of defence against nectar-thieving ants
Slippery flowers as a mechanism of defence against nectar-thieving ants
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滑花是抵御花蜜蚂蚁的防御机制
DOI：
10.1093/aob/mcaa168
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发表时间：
2021
期刊：
影响因子：
4.2
通讯作者：
Kawakita Atsushi
中科院分区：
文献类型：
--
作者：
Takeda Kazuya;Kadokawa Tomoki;Kawakita Atsushi
背景与目的动物传粉植物花部特征的多样性通常被认为是植物和传粉者共同进化相互作用的结果。花卉拮抗剂，如花蜜窃贼，也有可能对花卉特性的选择产生影响，但对花卉拮抗剂的适应性相对较少引起注意。我们发现，黄蜂传粉的轮叶党参的花冠和蜜蜂传粉的贝母花被片对生活在植物栖息地的盗蜜蚂蚁来说是滑滑的；由于这两种植物的花都暴露了蜜腺，滑滑的花被片可能起到防御盗蜜蚂蚁的作用。方法我们进行了行为实验，并用扫描电子显微镜观察花被片表面的微观结构，以探讨滑滑的机制。通过田间试验验证了光滑的花被是否能阻止蚂蚁进入花朵，以及蚂蚁在花内是否会影响授粉。当用正己烷擦拭时，花被就失去了它的滑滑性。使用防滑材料对光滑的表面进行人工桥接，使蚂蚁能够更频繁地进入花朵。将活蚂蚁引入党参花卉的试验，驱逐了黄蜂传粉者，缩短了传粉者访问的时间。然而，有蚂蚁和没有蚂蚁的花的果实或种子没有统计学差异。结论滑脱的花被很可能是基于表皮层蜡晶，阻止了蚂蚁进入花朵，从而对传粉者的行为产生了负面影响。基于光滑表面的花朵防御的实验证据很少见，但这种防御模式可能在开花植物中广泛存在。
Background and AimsThe great diversity of floral characteristics among animal-pollinated plants is commonly understood to be the result of coevolutionary interactions between plants and pollinators. Floral antagonists, such as nectar thieves, also have the potential to exert an influence upon the selection of floral characteristics, but adaptation against floral antagonists has attracted comparatively little attention. We found that the corollas of hornet-pollinatedCodonopsis lanceolata(Campanulaceae) and the tepals of bee-pollinatedFritillaria koidzumiana(Liliaceae) are slippery to nectar-thieving ants living in the plant’s habitat; because the flowers of both species have exposed nectaries, slippery perianths may function as a defence against nectar-thieving ants.MethodsWe conducted a behavioural experiment and observed perianth surface microstructure by scanning electron microscopy to investigate the mechanism of slipperiness. Field experiments were conducted to test whether slippery perianths prevent floral entry by ants, and whether ant presence inside flowers affects pollination.Key ResultsScanning electron microscopy observations indicated that the slippery surfaces were coated with epicuticular wax crystals. The perianths lost their slipperiness when wiped with hexane. Artificial bridging of the slippery surfaces using non-slippery materials allowed ants to enter flowers more frequently. Experimental introduction of live ants to theCodonopsisflowers evicted hornet pollinators and shortened the duration of pollinator visits. However, no statistical differences were found in the fruit or seed sets of flowers with and without ants.ConclusionsSlippery perianths, most probably based on epicuticular wax crystals, prevent floral entry by ants that negatively affect pollinator behaviour. Experimental evidence of floral defence based on slippery surfaces is rare, but such a mode of defence may be widespread amongst flowering plants.