Relationships between herbivory and plant defense characters among selected trees in La Mesa Watershed.

Abstract

Existing herbivory studies mostly focus on the ecosystem level, while physiological and morphological parameters affecting this community interaction are left understudied. The study of the success of invasive species lacks focus on the physiological and morphological mechanisms employed by these plants against their possible predators. Grazing rates, leaf toughness, and phenol content were measured in three native (Antidesma bunius, Ficus septica, and Bischofia javanica) and two exotic (Acacia auriculiformis and Swietenia macrophylla) replanted tree species in La Mesa Watershed during the dry season. The differences in leaf toughness and phenol content were attributed to differences in species and age of leaves. Type of species, whether native or exotic, does not cause differences in grazing rates. In A. bunius, F. septica, and A. auriculiformis, as leaf toughness increases, phenol content decreases. Meanwhile, in B. javanica, as leaf toughness increases, phenol content also increases. In the case of S. macrophylla, as phenol content increases, grazing rate also increases. For A. auriculiformis, B. javanica and S. macrophylla, carbon allocation is preferred for construction of leaf toughness in mature leaves and increasing phenol content in young leaves. There are no significant differences in grazing rates on native and exotic species, suggesting that plant defenses have minimal effect on deterring herbivores.