Effects of ants and an ant-tended herbivore on seed production of a neotropical herb.

Focused on 1) a neotropical perennial plant, Calathea ovandensis (Marantaceae), that produces extrafloral nectar, 2) ants that visit the nectaries, 3) an ant-tended specialist herbivore, Eurybia elvina (Lepidoptera: Riodinidae), that feeds on buds, flowers, and fruits, and 4) other herbivores of reproductive tissues. The lowest seed production (mean 6) was for inflorescences with Eurybia but without ants. Highest seed production (mean 21) was for inflorescences with ants, but without Eurybia. In the presence of ants, Eurybia lowered mean seed production by 33%. In the absence of ants, Eurybia lowered mean seed production by 66%. The 8 ant species differed greatly in the magnitude of their beneficial effects on seed production. Ants were not equally distributed over sites, and spatial heterogeneity in seed production by Calathea reflected differences in ant communities among sites. -from Authors