Classic research on elevational gradients in plant–herbivore interactions holds that insect herbivore pressure is stronger under warmer climates of low elevations. However, recent work has questioned this paradigm, arguing that it oversimplifies the ecological complexity in which plant–insect herbivore interactions are embedded. Knowledge of antagonistic networks of plants and herbivores is however crucial for understanding the mechanisms that govern ecosystem functioning. We examined herbivore damage and insect herbivores of eight species of genus Ficus (105 saplings) and plant constitutive defensive traits of two of these species, along a rain forest elevational gradient of Mt. Wilhelm (200–2,700 m a.s.l.), in tropical Papua New Guinea. We report overall herbivore damage 2.4% of leaf area, ranging from 0.03% in Ficus endochaete at 1,700 m a.s.l. to 6.1% in F. hombroniana at 700 m a.s.l. Herbivore damage and herbivore abundances varied significantly with elevation, as well as among the tree species, and between the wet and dry season. Community‐wide herbivore damage followed a hump‐shaped pattern with the peak between 700 and 1,200 m a.s.l. and this pattern corresponded with abundance of herbivores. For two tree species surveyed in detail, we observed decreasing and hump‐shaped patterns in herbivory, in general matching the trends found in the set of plant defenses measured here. Our results imply that vegetation growing at mid‐elevations of the elevational gradient, that is at the climatically most favorable elevations where water is abundant, and temperatures still relatively warm, suffers the maximum amount of herbivorous damage which changes seasonally, reflecting the water availability.

中文翻译：

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巴布亚新几内亚雨林海拔梯度上的昆虫食草和榕树食草动物

关于植物与草食动物相互作用的海拔梯度的经典研究认为，在低海拔的温暖气候下，昆虫食草动物的压力更大。但是，最近的工作对此范式提出了质疑，认为它过分简化了嵌入植物-昆虫食草动物相互作用的生态复杂性。然而，了解植物和草食动物的拮抗网络对于了解控制生态系统功能的机制至关重要。我们研究了八种榕属的食草动物危害和昆虫食草动物沿山地的雨林海拔梯度，这些树种有105种幼树和105种本构防御性状。威廉（200–2,700 m升），位于巴布亚新几内亚热带地区。我们报告了总体草食动物损害占叶面积的2.4％，从榕树在1,700 m asl的0.03％到F. hombroniana的6.1％在海拔700 m处，草食动物的损害和草食动物的丰度随海拔，树木种类以及在干湿季节之间的变化而显着变化。社区范围内的草食动物损害呈驼峰状，峰值在700至1200 m asl之间，并且这种模式与草食动物的数量相对应。对于详细调查过的两种树种，我们观察到草食性的减少和驼峰状模式，总体上与此处测量的植物防御体系中发现的趋势相匹配。我们的结果表明，植被生长在海拔梯度的中部高度，即在气候最有利的海拔高度，那里的水量充沛，温度仍然相对温暖，遭受的草食性损害最大，随季节变化，反映了水的可利用性。