Patterns and correlates of interspecific variation in foliar insect herbivory and pathogen attack in Brazilian cerrado

Patterns of insect herbivore and leaf pathogen attack are described for 25 plant species (10 trees, 10 shrubs and five herbs) at a Brazilian savanna ( cerrado) site. Plant and leaf traits were correlated with interspecific var iation in attack by herbivores and pathogens in order to account for differ ences among plant species. Across all species, pathogen damage was 1.5 time s higher than insect damage (17.3% vs. 6.8%, respectively). Most insect dam age occurred to young leaves while they were expanding (end of the dry seas on). In contrast, pathogen attack was low on young expanding leaves at the end of the dry season, increased as those leaves matured in the wet season, but continued to increase through the next dry season. Protein-binding cap acity was negatively associated with interspecific differences in insect da mage to mature leaves. Protein availability and plant height were positive predictors of pathogen attack among plant species, while leaf expansion rat e was a significant negative predictor. Interspecific differences in leaf p henology had little effect on the amount of damage caused by either insects or pathogens. However, new leaves produced during the wet season suffered less insect damage than leaves produced during the dry season, the time of greatest leaf production. Timing of young leaf production affected pathogen attack but the season of escape depended on plant species. In contrast, th ere was no evidence for escape in space as common species were less likely to suffer high pathogen attack than rare species. New and mature leaf tough ness, and time for a leaf to reach full expansion all increased from herbs to shrub to trees, while mature leaf nitrogen decreased in that order.