Local adaptation to herbivory within tropical tree species along a rainfall gradient

In tropical forests, insect herbivores exert significant pressure on plant populations. Adaptation to such pressure is hypothesized to be a driver of high tropical diversity, but direct evidence for local adaptation to herbivory in tropical forests is sparse. At the same time, herbivore pressure has been hypothesized to increase with rainfall in the tropics, which could lead to differences among sites in the degree of local adaptation. To assess the presence of local adaptation and its interaction with rainfall, we compared herbivore damage on seedlings of local vs non-local populations at sites differing in moisture availability in a reciprocal transplant experiment spanning a rainfall gradient in Panama. For 13 native tree species, seeds collected from multiple populations along the rainfall gradient were germinated in a shadehouse and then transplanted to experimental sites within the species range. We tracked the likelihood of herbivore attack over 1.5 years and quantified the perce...在热带森林生态系统中，植食性昆虫对植物种群施加着显著的选择压力。学界假说认为，针对此类压力的适应性演化是推动热带地区维持高生物多样性的潜在驱动力，但目前热带森林中针对植食作用的本地适应性的直接实证研究仍较为匮乏。与此同时，有假说提出热带地区的植食压力会随降雨量增加而升高，这可能导致不同样地间本地适应性的程度产生差异。为评估本地适应性的存在及其与降雨量的交互作用，我们在巴拿马的一条降雨梯度上开展了互惠移植实验，在水分有效性各异的样地中，对比了本地种群与非本地种群幼苗所遭受的植食损伤情况。针对13种本土乔木物种，我们从该降雨梯度沿线的多个种群采集种子，在荫棚中完成育苗后，将幼苗移植至该物种分布范围内的实验样地。我们在1.5年的周期内追踪了幼苗遭受植食性昆虫侵袭的概率，并量化了其可观测的（原文未完整表述）