Rapid asymptotic species accumulation in phytophagous insect communities: the pests of cacao.

The number of cacao insect pests is described by a species-area curve. Either annual cacao productivity or area in cultivation of the crop predicts the number of associated insect pest species, when the world's cacao-producing regions are compared. Analysis of covariance does not discriminate different species-area regressions for native as opposed to nonnative cacao-producing regions; the numbers of insect pest species per unit area of cacao in regions of long-standing cultivation do not exceed the numbers in regions of recent introduction. This demonstrates that the number of cacao insect pest species rises rapidly to an asymptote set by the area in cultivation in each region.