关键词: 植物防御, 生态系统功能, 单宁含量, 植物-昆虫互作, 系统发育主成分, 植物权衡策略

Abstract: Aims Differences in herbivory among plant species can greatly affect the functioning of forest ecosystems. However, little is known about the main drivers causing interspecific differences in herbivore damage among tree species. The growth-defence trade-off hypothesis posits that intrinsic growth rate of plant species governs resource allocation between defense and growth, thereby shaping interspecific variation in herbivory. However, the validity of this hypothesis is extensively debated, especially in highly species-rich subtropical forests. Methods We quantified leaf herbivore damage in 27 native tree species in a tree species diversity experiment conducted in subtropical China. Concurrently, we measured 12 leaf traits associated with insect palatability and relative growth rates of 27 tree species. Using a combination of phylogenetic multivariate analyses, we assessed trade-offs between leaf traits and the relative effect of these traits on leaf herbivore damage. Important findings We found 1) neither phylogenetic principal component analysis nor hierarchical cluster analysis supported the idea that species displayed one-dimensional trade-off; 2) Conventional strategies, such as condensed tannins, are not strongly involved as a defence against herbivores; 3) No significant trade-off between plant intrinsic growth rate and chemical defence traits for the 27 studied tree species. Our results do not support arguments for growth-defense trade-off hypothesis. Rather, plants display a range of combinations of leaf traits. We suggest this lack of a one-dimensional trade-off may be adaptive, resulting from selective pressure to adopt a different combination of defences to coexisting species.

Key words: plant defense, ecosystem function, tannin content, plant-insect interactions, phylogenetic principal components, trade-off strategies