Not just the usual suspects: Insect herbivore populations and communities are associated with multiple plant nutrients
Not just the usual suspects: Insect herbivore populations and communities are associated with multiple plant nutrients
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DOI：
10.1890/11-1142.1
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发表时间：
2012-05-01
期刊：
影响因子：
4.8
通讯作者：
Behmer, Spencer T.
中科院分区：
文献类型：
--
作者：
Joern, Anthony;Provin, Tony;Behmer, Spencer T.
植物养分含量与植食性昆虫种群和群落结构之间的关系一直是生态学家感兴趣的问题。食草昆虫需要多种营养素，但生态学家主要关注氮（植物蛋白质含量的估计值），最近又关注磷（P）;其他营养素很少受到关注。在这里，我们记录的营养变化，草和B样本从草原栖息地在内布拉斯加州中部使用元素的方法，在总的12个元素（N和P，加上S，B，Ca，Mg，Na，K，Zn，Fe，Mn和Cu），我们测量叶面浓度。我们检测到显着的变异N，P，Mg，Na，K和Cu的网站之间。接下来，我们使用模型选择的方法来探索这种营养变化和植物生物量与蝗虫密度（集体和在饲养公会水平），和主成分分析，探讨营养与蝗虫群落物种组成的相关性。当所有蝗虫汇集，密度不同的网站，但只有P与丰富的元素显示不同的网站之间。不同的反应发生在饲养公会水平。对于草专家，密度与N，加上P，Mg和Na有关。对于杂类草专家，N和P往往与密度，但协会与Na和K也观察到。最后，混合饲养丰度与生物量密切相关，并在较小程度上P，Mg，Na和Cu。在群落水平上，B、Ca、Zn和Cu加上生物量解释了>30%的物种组成变化。我们的结果证实了氮和磷与食草昆虫种群的正相关性，同时表明镁、钠和钾具有潜在的作用。它们还表明了在饲养公会一级探索影响的重要性。我们希望我们的数据能激励生态学家在考虑植物营养对食草昆虫的影响时超越N和P，并呼吁研究食草昆虫对Mg，Na和K的饮食操作的功能反应。最后，我们的研究结果表明，营养物质和物种组合的变化之间的相关性，但与植物营养质量或生物量无关的因素可能解释了大部分观察到的变化。
The relationship between plant nutrient content and insect herbivore populations and community structure has long interested ecologists. Insect herbivores require multiple nutrients, but ecologists have focused mostly on nitrogen (an estimate of plant protein content), and more recently phosphorus (P); other nutrients have received little attention. Here we document nutrient variation in grass and forb samples from grassland habitats in central Nebraska using an elemental approach; in total we measured foliar concentrations of 12 elements (N and P, plus S, B, Ca, Mg, Na, K, Zn, Fe, Mn, and Cu). We detected significant variability among sites for N, P, Mg, Na, K, and Cu. We next used a model selection approach to explore how this nutritional variation and plant biomass correlate with grasshopper densities (collectively and at the feeding-guild level), and principal component analysis to explore nutrient correlations with grasshopper community species composition. When all grasshoppers were pooled, densities varied among sites, but only P was associated with abundance of the elements shown to vary between sites. Different responses occurred at the feeding-guild level. For grass specialists, densities were associated with N, plus P, Mg, and Na. For forb specialists, N and P were often associated with density, but associations with Na and K were also observed. Finally, mixed-feeder abundance was strongly associated with biomass, and to a lesser extent P, Mg, Na, and Cu. At the community level, B, Ca, Zn, and Cu, plus biomass, explained >30% of species composition variation. Our results confirm the positive association of N and P with insect herbivore populations, while suggesting a potential role for Mg, Na, and K. They also demonstrate the importance of exploring effects at the feeding-guild level. We hope our data motivate ecologists to think beyond N and P when considering plant nutrient effects on insect herbivores, and make a call for studies to examine functional responses of insect herbivores to dietary manipulation of Mg, Na, and K. Finally, our results demonstrate correlations between variation in nutrients and species assemblages, but factors not linked to plant nutrient quality or biomass likely explain most of the observed variation.