Mutualism exploitation: predatory drosophilid larvae sugar-trap ants and jeopardize facultative ant-plant mutualism.
Mutualism exploitation: predatory drosophilid larvae sugar-trap ants and jeopardize facultative ant-plant mutualism.
复制标题
互利共生利用：捕食性果蝇幼虫捕食糖蚁并危害兼性蚂蚁与植物的互利共生。
作者：
Mayra C. Vidal;S. Sendoya;P. Oliveira
在蚂蚁-植物兼性互利共生的进化生态学中，一个悬而未决的问题是相关群落的其他成员如何影响相互作用，以至于互惠互利被破坏。热带稀树草原蚂蚁在拜访夸利亚大花灌木丛时，在花外蜜腺收集糖分奖励，它们阻止了食草动物，减少了对叶子的损害。在这里，我们表明，幼虫的苍蝇Rhinoleucophenga myrmecophaga，这对花外蜜腺的发展，引诱潜在的互惠互利，花蜜喂养的蚂蚁和猎物。觅食的蚂蚁在苍蝇出没的树叶上花费的时间更少。田间试验表明，蝇幼虫对蚂蚁的捕食（或捕食的威胁）通过三个营养级产生级联效应，导致叶片上的保护性蚂蚁减少，咀嚼食草动物数量增加，叶片损害更大。这些结果揭示了一个无证的互惠互利的剥削模式，由一个机会主义的捕食者在植物提供的食物来源，危害蚂蚁衍生的保护服务的植物。我们的研究记录了一个相当不寻常的情况下捕食成年蚂蚁的双翅目物种，并证明了自上而下的营养级联广义蚂蚁植物互惠共生。
An open question in the evolutionary ecology of ant-plant facultative mutualism is how other members of the associated community can affect the interaction to a point where reciprocal benefits are disrupted. While visiting Qualea grandiflora shrubs to collect sugary rewards at extrafloral nectaries, tropical savanna ants deter herbivores and reduce leaf damage. Here we show that larvae of the fly Rhinoleucophenga myrmecophaga, which develop on extrafloral nectaries, lure potentially mutualistic, nectar-feeding ants and prey on them. Foraging ants spend less time on fly-infested foliage. Field experiments showed that predation (or the threat of predation) on ants by fly larvae produces cascading effects through three trophic levels, resulting in fewer protective ants on leaves, increased numbers of chewing herbivores, and greater leaf damage. These results reveal an undocumented mode of mutualism exploitation by an opportunistic predator at a plant-provided food source, jeopardizing ant-derived protection services to the plant. Our study documents a rather unusual case of predation of adult ants by a dipteran species and demonstrates a top-down trophic cascade within a generalized ant-plant mutualism.