Carvalho Mónica R, Wilf Peter, Barrios Héctor, Windsor Donald M, Currano Ellen D, Labandeira Conrad C, Jaramillo Carlos A
Department of Geosciences, Pennsylvania State University, University Park, Pennsylvania, United States of America; Department of Plant Biology, Mann Library Building, Cornell University, Ithaca, New York, United States of America.
Department of Geosciences, Pennsylvania State University, University Park, Pennsylvania, United States of America.
PLoS One. 2014 May 2;9(5):e94950. doi: 10.1371/journal.pone.0094950. eCollection 2014.
The fossil record demonstrates that past climate changes and extinctions significantly affected the diversity of insect leaf-feeding damage, implying that the richness of damage types reflects that of the unsampled damage makers, and that the two are correlated through time. However, this relationship has not been quantified for living leaf-chewing insects, whose richness and mouthpart convergence have obscured their value for understanding past and present herbivore diversity. We hypothesized that the correlation of leaf-chewing damage types (DTs) and damage maker richness is directly observable in living forests. Using canopy access cranes at two lowland tropical rainforest sites in Panamá to survey 24 host-plant species, we found significant correlations between the numbers of leaf chewing insect species collected and the numbers of DTs observed to be made by the same species in feeding experiments, strongly supporting our hypothesis. Damage type richness was largely driven by insect species that make multiple DTs. Also, the rank-order abundances of DTs recorded at the Panamá sites and across a set of latest Cretaceous to middle Eocene fossil floras were highly correlated, indicating remarkable consistency of feeding-mode distributions through time. Most fossil and modern host-plant pairs displayed high similarity indices for their leaf-chewing DTs, but informative differences and trends in fossil damage composition became apparent when endophytic damage was included. Our results greatly expand the potential of insect-mediated leaf damage for interpreting insect herbivore richness and compositional heterogeneity from fossil floras and, equally promisingly, in living forests.
化石记录表明，过去的气候变化和物种灭绝显著影响了昆虫取食叶片造成损害的多样性，这意味着损害类型的丰富程度反映了未被采样的造成损害的昆虫的丰富程度，并且二者在时间上具有相关性。然而，对于现存的咀嚼式口器昆虫，这种关系尚未得到量化，它们的丰富程度和口器趋同现象使其在理解过去和现在的食草动物多样性方面的价值变得模糊不清。我们推测，在现存森林中可以直接观察到咀嚼式口器造成的损害类型（DTs）与造成损害的昆虫丰富程度之间的相关性。利用巴拿马两个低地热带雨林地区的树冠通道起重机对24种寄主植物进行调查，我们发现所收集的咀嚼式口器昆虫物种数量与在取食实验中观察到由同一物种造成的DTs数量之间存在显著相关性，这有力地支持了我们的推测。损害类型的丰富程度在很大程度上是由造成多种DTs的昆虫物种驱动的。此外，在巴拿马地区以及从一组最新白垩纪到始新世中期的化石植物群中记录的DTs的排序丰度高度相关，这表明取食模式分布在时间上具有显著的一致性。大多数化石和现代寄主植物对其咀嚼式口器造成的DTs显示出较高的相似性指数，但当纳入内生损害时，化石损害组成中的信息性差异和趋势就变得明显了。我们的研究结果极大地扩展了昆虫介导的叶片损害在解释化石植物群以及同样有前景的现存森林中昆虫食草动物丰富程度和组成异质性方面的潜力。
