Risk of spider predation alters food web structure and reduces local herbivory in the field
Risk of spider predation alters food web structure and reduces local herbivory in the field
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DOI：
10.1007/s00442-015-3226-5
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发表时间：
2015-06-01
期刊：
影响因子：
2.7
通讯作者：
Entling, Martin H.
中科院分区：
文献类型：
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作者：
Bucher, Roman;Menzel, Florian;Entling, Martin H.
捕食者可以通过抑制食草动物来间接提高植物的性能，猎物的消耗和猎物性状的变化（例如觅食行为的变化）都会导致食草动物的减少。我们进行了一项现场实验，以确定这种非消耗性影响的程度，其中包括反复将蜘蛛（Pisaura mirabilis）放置在封闭的植物（Urtica dioica）上以进行线索沉积。对照植物以相同的方式封闭，但没有蜘蛛。线索沉积后，将外壳移除，让节肢动物在植物上定居并以植物为食。在随后的蜘蛛沉积或控制围栏之前，将节肢动物从植物中除去。在六个封闭周期中，我们量化了植物叶子的损伤。第七个周期后，对定殖节肢动物进行采样，以确定与蜘蛛线索存在/不存在相关的群落组成。我们发现化学触觉蜘蛛信号的存在可将叶片损伤减少 50%。此外，蜘蛛线索导致了节肢动物群落的变化：较小的蜘蛛避开了有蜘蛛线索的植物。相比之下，照顾蚜虫的蚂蚁在带有线索的植物上招募了更多的工蚁，这可能是为了保护蚜虫。我们的研究结果表明，蜘蛛捕食的风险可以减少对野生植物的食草行为，并且还表明，捕食者群体中的非消耗性影响可能特别强烈。
Predators can indirectly enhance plant performance via herbivore suppression, with both prey consumption and changes in prey traits (e.g. changes in foraging behaviour) contributing to the reduction in herbivory. We performed a field experiment to determine the extent of such non-consumptive effects which consisted of repeatedly placing spiders (Pisaura mirabilis) on enclosed plants (Urtica dioica) for cue deposition. Control plants were enclosed in the same way but without spiders. After cue deposition, the enclosures were removed to allow arthropods to colonize the plants and feed on them. Arthropods were removed from the plants before the subsequent spider deposition or control enclosure. During six cycles of enclosure, we quantified leaf damage on the plants. After a seventh cycle, the colonizing arthropods were sampled to determine community composition in relation to the presence/absence of spider cues. We found that the presence of chemotactile spider cues reduced leaf damage by 50 %. In addition, spider cues led to changes in the arthropod community: smaller spiders avoided plants with spider cues. In contrast, the aphid-tending ant Myrmica rubra showed higher recruitment of workers on cue-bearing plants, possibly to protect aphids. Our results show that the risk of spider predation can reduce herbivory on wild plants and also demonstrate that non-consumptive effects can be particularly strong within the predator guild.