Responses of subtropical deciduous and evergreen trees to varying intensities of herbivory

AimsGenerally, deciduous and evergreen trees coexist in subtropical forests, and both types of leaves are attacked by numerous insect herbivores. However, trees respond to and defend themselves from herbivores in different ways, and these responses may vary between evergreen and deciduous species. To understand tree responses to leaf herbivore attack under varying intensities of herbivory.MethodsWe examined both the percentage of leaf area removed by herbivores as well as the percentage of leaves attacked by herbivores to evaluate leaf herbivore damage across 15 subtropical deciduous and evergreen trees, quantified plant responses to varying intensities of herbivory and analyzed both leaf herbivore attack and leaf traits among species.ResultsWe have found that there was a higher intensity of herbivory on deciduous species than evergreen species, both as percentage of leaf area removed and the percentage of leaves attacked. In addition, leaf herbivory was positively correlated with defensive traits (concentrations of tannin and lignin), and negatively correlated with nutrient content (ratios of NSC:lignin and NSC:cellulose), which may be largely attributed to long-term and frequent insect herbivore stress and potentially evolutionary arms races between plants and insects.ConclusionsThis study highlights that leaf responses to varying intensities of herbivory differed widely among subtropical plant species and there was a stronger defensive response for deciduous trees to leaf herbivore attack than that of evergreen trees. These results have implications for better understanding plant responses and defenses to varying intensities of herbivory, and reveal several underlying relationships between leaf traits and herbivory.