GENOTYPIC VARIATION IN LEAF DAMAGE IN PIPER-ARIEIANUM (PIPERACEAE) BY A MULTISPECIES ASSEMBLAGE OF HERBIVORES

Piper arieianum has a diverse herbivore fauna (95 species) in Costa Rican rain forest. Damage patterns were measured for 2 plots, 4 genotypes per plot. There were significant differences among genotypes in total leaf area missing throughout the 2-5 yr study period. Rankings of genotypes based on overall damage remained constant over time in plot 1 but changed in plot 2. Certain herbivore species caused significantly higher damage in some genotypes than in others; the change in genotype rankings in plot 2 was associated with increased damage to particular genotypes by specific herbivore groups. Resistance to one herbivore species did not necessarily confer resistance against all species; herbivore species causing the greatest proportion of damage for a given plant changed over time. Because total damage resulted from the summation of losses to individual herbivore species, whether an individual plant lost more leaf area than its neighbors depended on the relative abundance of the herbivore species at any one time for a portion of the study period in each plot, more heavily damaged clones grew less than lesser damaged clones. The herbivores of P. arieianum represent a selective force for changes in resistance, but this selective force changes both in intensity and quality over time. -from Author