It takes two to tango but three is a tangle:: mutualists and cheaters on the carnivorous plant Roridula
It takes two to tango but three is a tangle:: mutualists and cheaters on the carnivorous plant Roridula
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DOI：
10.1007/s00442-002-0998-1
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发表时间：
2002-08-01
期刊：
影响因子：
2.7
通讯作者：
Midgley, JJ
中科院分区：
文献类型：
--
作者：
Anderson, B;Midgley, JJ
齿捕蝇与半翅目昆虫有亲缘关系，半翅目昆虫能促进昆虫对氮的同化。R. dentata也与蜘蛛有关，它们在消化中的作用尚不清楚。我们通过“间接消化”来量化捕虫从昆虫中吸收的氮的大致数量。“使用δ（15）N，我们然后确定半翅目昆虫的氮吸收是否随蜘蛛密度的变化而不同。这样，我们就可以确定它们的营养作用。在低蜘蛛密度，猎物的间接消化约占70%的植物氮。这些值与在其他食肉植物中发现的直接猎物消化方法相当。然而，蜘蛛减少半翅目昆虫的数量栖息捕虫植物，也降低了高达30%的间接猎物消化效率。我们推断蜘蛛是骗子，因为它们利用植物的奖励而不提供任何回报。然而，当半翅目昆虫密度最低时，间接食肉仍然足够有效，确保互利共生不会崩溃。
Roridula dentata is associated with hemipterans, which facilitate nitrogen assimmilation from insects. R. dentata is also associated with spiders and their role in digestion is unknown. We quantify approximately how much nitrogen Roridula assimilates from insects through "indirect digestion." Using delta(15)N we then determine whether nitrogen absorption from hemipteran insects differs with varying spider densities. In this way, we are able to determine their nutritional role. At low spider densities, indirect digestion of prey accounts for approximately 70% of plant nitrogen. These values are comparable to methods of direct prey digestion found in other carnivorous plants. However spiders decrease the numbers of hemipteran individuals inhabiting Roridula plants and also decrease efficiency of indirect prey digestion by up to 30%. We deduce that spiders are cheaters as they exploit plant rewards without offering any rewards in return. However, indirect carnivory is still efficient enough when hemipteran densities are at their lowest, ensuring that the mutualism does not break down.