Interactions between chilean matorral shrubs and phytophagous insects.

Lithraea caustica (Mol.) H. et Arn. and Colliguaya odorifera Mol. are two sclerophyllous shrubs of the scrub vegetation in Central Chile. These two species commonly grow in close association on equator-facing slopes. Leaves of L. caustica are severely predated upon by phytophagous insects while those of C. odorifera are rarely attacked. Leaf growth dynamics, leaf loss, and leaf predation by insects were correlated through the year with leaf phenolic compounds. Leaf structural properties (cuticle thickness, density, sclerenchymatic fibers, leaf thickness) were similar between the two species, while leaf phenol content differed significantly. The higher phenol content in C. odorifera may influence leaf palatability, and thus account for the observed lower leaf area loss in that species due to insect damage.