Kent Dylan R, Lynn Joshua S, Pennings Steven C, Souza Lara A, Smith Melinda D, Rudgers Jennifer A
Department of Biology University of New Mexico Albuquerque NM USA.
Present address: Department of Biology University of Bergen Bergen Norway.
Ecol Evol. 2020 May 26;10(13):6385-6394. doi: 10.1002/ece3.6374. eCollection 2020 Jul.
Patterns of insect herbivory may follow predictable geographical gradients, with greater herbivory at low latitudes. However, biogeographic studies of insect herbivory often do not account for multiple abiotic factors (e.g., precipitation and soil nutrients) that could underlie gradients. We tested for latitudinal clines in insect herbivory as well as climatic, edaphic, and trait-based drivers of herbivory. We quantified herbivory on five dominant grass species over 23 sites across the Great Plains, USA. We examined the importance of climate, edaphic factors, and traits as correlates of herbivory. Herbivory increased at low latitudes when all grass species were analyzed together and for two grass species individually, while two other grasses trended in this direction. Higher precipitation was related to more herbivory for two species but less herbivory for a different species, while higher specific root length was related to more herbivory for one species and less herbivory for a different species. Taken together, results highlight that climate and trait-based correlates of herbivory can be highly contextual and species-specific. Patterns of insect herbivory on dominant grasses support the hypothesis that herbivory increases toward lower latitudes, though weakly, and indicates that climate change may have species-specific effects on plant-herbivore interactions.
昆虫食草模式可能遵循可预测的地理梯度，在低纬度地区食草现象更为严重。然而，昆虫食草的生物地理学研究往往没有考虑到可能构成这些梯度基础的多种非生物因素（如降水和土壤养分）。我们测试了昆虫食草的纬度梯度以及食草的气候、土壤和基于性状的驱动因素。我们在美国大平原地区的23个地点对五种优势草种的食草情况进行了量化。我们研究了气候、土壤因素和性状作为食草相关因素的重要性。当将所有草种一起分析以及单独分析两种草种时，低纬度地区的食草现象增加，而另外两种草种也呈现出这种趋势。较高的降水量与两种草种的食草现象增加相关，但与另一种草种的食草现象减少相关，而较高的比根长与一种草种的食草现象增加相关，与另一种草种的食草现象减少相关。综合来看，结果表明食草的气候和基于性状的相关因素可能具有高度的情境性和物种特异性。优势草种上的昆虫食草模式支持了食草现象向低纬度地区增加的假设，尽管这种趋势较弱，并表明气候变化可能对植物 - 食草动物相互作用产生物种特异性影响。
