Insect herbivores and leaf damage along successional and vertical gradients in a tropical dry forest.

摘要

The availability and quality of resources for herbivores in tropical dry forests (TDFs) vary in time and space, affecting herbivore guilds differently across spatial scales (both horizontally and vertically), with consequences to the distribution of leaf damage in these forests. We attempted to elucidate the distribution patterns of herbivorous insect guilds and leaf damage throughout the secondary succession and vertical stratification along the rainy season in a Brazilian TDF. With the advance of the succession, a greater richness and abundance of herbivorous insects were found, resulting in higher leaf damage in intermediate and late stages. This pattern, however, was not observed for the frequency of leaf miners. At a smaller spatial scale, the host tree height positively affected the richness and abundance of insects. The higher leaf damage was found in canopy, which also harbored a greater richness and abundance of chewing herbivores compared to the understory at both the beginning and the end of the rainy season. Although for sap-sucking insects, this was only true at the beginning of the season. We detected a decrease in insect richness and abundance at the end of the rainy season, probably due to a synchronization of insect activity with the availability of young, highly nutritious plant tissues. These results are consistent with other studies that found a general trend of increasing richness and abundance of herbivorous insects and leaf damage throughout the secondary succession (early to late stages) and between vertical strata (understory to canopy), suggesting that forest complexity positively affects herbivores.