Species Richness, Species Packing, and Evolution in Insect-Plant Systems

Abstract

A literature review on species richness in phytophagous insects is presented, with details of the morphological complexity of host plant species, their size and range, habitat heterogeneity, cumulative host abundance during evolutionary time and effects of taxonomic isolation of the host plant. This is followed by an analysis of parameters which determine the species richness of the distinct and ecologically diverse community of insect inhabitants of Cardueae flower heads, and the adaptations of phytophages to different dimensions of Cardueae flower heads, varying between 120 mm3 for Centaurea diffusa and 180 000 mm3 for Cynara scolymus.