Fluid physico-chemical properties influence capture and diet in Nepenthes pitcher plants
Fluid physico-chemical properties influence capture and diet in Nepenthes pitcher plants
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DOI：
10.1093/aob/mcu266
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发表时间：
2015-03-01
期刊：
影响因子：
4.2
通讯作者：
Gaume, Laurence
中科院分区：
文献类型：
--
作者：
Bazile, Vincent;Le Moguedec, Gilles;Gaume, Laurence
猪笼草猪笼草已经进化出具有光滑表面和酶液体的改良叶片，其捕获和消化猎物、粪便和/或植物碎屑。虽然流体的贡献，昆虫捕获的认可，所涉及的物理化学性质仍然未充分探索，可能会有所不同的物种，影响他们的饮食类型。本研究以4种猪笼草（Nepenthes）为研究对象，研究了在不同营养策略下，酸性和粘弹性对2种蚂蚁和2种蝇类捕集效率的影响。rafflesiana、小刺牛肝菌N. gracilis、N. hemsleyana和N.壶腹从生长在田间的植物的不同年龄的罐中收集液体，并立即转移到玻璃小瓶中，并将单个蚂蚁（Campotini部落，Fomicinae）和苍蝇（Calliphora vomitoria和Drosophila melanogaster）放入并观察5分钟。使用适用于右删失观察的模型分析生存期和寿命数据。进行了额外的实验室实验，其中C。呕吐蝇浸泡在pH值控制的水溶液中，观察5分钟。关键结果猪笼草物种之间的投手液不同昆虫保留能力和时间杀死，与猎物类型之间观察到的差异。只有据说是食虫物种的流体是非常酸性和/或粘弹性的，并保留了显着更多的昆虫比水控制。粘弹性液体对苍蝇是致命的，能够捕获最广泛的昆虫。年轻的粘弹性流体表现出更好的保留能力比老的流体，虽然与快速杀死能力，这表明化学作用后的机械之一。昆虫滞留指数增加流体粘弹性，这发生得更突然，在一个较低的阈值相比，蚂蚁苍蝇。如果苍蝇落入背上的陷阱，它们的翅膀就会被弄湿，从而更容易被留住。昆虫滞留和死亡率随流体酸度增加而增加，蚂蚁的阈值低于苍蝇，杀灭时间随酸度增加而减少。实验室实验表明，更少的苍蝇逃脱酸性溶液相比，水。结论除了粘弹性，投手的流体酸度和润湿能力的影响昆虫的命运，因此猪笼草的饮食。这些植物可能会通过操纵其瓶状液中H+离子和多糖的分泌来选择它们保留的猎物。这反过来又可能参与可能的适应性辐射这一属的营养封存策略。这些植物甚至可能在结构上影响昆虫的下落方向和捕获概率，激发了害虫控制的仿生设计。
Background and Aims Nepenthes pitcher plants have evolved modified leaves with slippery surfaces and enzymatic fluids that trap and digest prey, faeces and/or plant detritus. Although the fluid's contribution to insect capture is recognized, the physico-chemical properties involved remain underexplored and may vary among species, influencing their diet type. This study investigates the contributions of acidity and viscoelasticity in the fluid's capture efficiency of two ant and two fly species in four Nepenthes species with different nutrition strategies.Methods Four Nepenthes species were studied, namely N. rafflesiana, N. gracilis, N. hemsleyana and N. ampullaria. Fluid was collected from pitchers of varying ages from plants growing in the field and immediately transferred to glass vials, and individual ants (tribe Campotini, Fomicinae) and flies (Calliphora vomitoria and Drosophila melanogaster) were dropped in and observed for 5 min. Water-filled vials were used as controls. Survival and lifetime data were analysed using models applied to right-censored observations. Additional laboratory experiments were carried out in which C. vomitoria flies were immersed in pH-controlled aqueous solutions and observed for 5 min.Key Results Pitcher fluid differed among Nepenthes species as regards insect retention capacity and time-to-kill, with differences observed between prey types. Only the fluids of the reputedly insectivorous species were very acidic and/or viscoelastic and retained significantly more insects than the water controls. Viscoelastic fluids were fatal to flies and were able to trap the broadest diversity of insects. Younger viscoelastic fluids showed a better retention ability than older fluids, although with less rapid killing ability, suggesting that a chemical action follows a mechanical one. Insect retention increased exponentially with fluid viscoelasticity, and this happened more abruptly and at a lower threshold for flies compared with ants. Flies were more often retained if they fell into the traps on their backs, thus wetting their wings. Insect retention and death rate increased with fluid acidity, with a lower threshold for ants than for flies, and the time-to-kill decreased with increasing acidity. The laboratory experiments showed that fewer flies escaped from acidic solutions compared with water.Conclusions In addition to viscoelasticity, the pitcher's fluid acidity and wetting ability influence the fate of insects and hence the diet of Nepenthes. The plants might select the prey that they retain by manipulating the secretion of H+ ions and polysaccharides in their pitcher fluid. This in turn might participate in possible adaptive radiation of this genus with regard to nutrient sequestration strategy. These plants might even structurally influence insect fall-orientation and capture-probability, inspiring biomimetic designs for pest control.