Chapter 111 – Grassland Habitats

Publisher Summary This chapter discusses grassland habitats for insects. Plant and insect communities of grasslands greatly differ depending on climate, soil type, and management practices. Some marked differences are apparent between the plant – insect communities of temperate and tropical habitats. Plant species richness, which determines much of the insect diversity, may be only 10–15 species in intensively managed and highly fertilized grasslands, but 50–70 in extensively managed and low-input temperate grasslands. In contrast, tropical grasslands may contain over 200 plant species. Grasses make up the largest portion of the grassland biomass; consequently, the insect communities of grasslands are determined more by the monocotyledonous Poaceae than by the dicotyledonous herb families. Grasses differ from the Dicotyledonae in that their architecture is simple, and the intercalary meristems, which substitute for growth from terminal buds, are protected by hard leaf sheaths. Most grasses lack the variety of secondary compounds that deter herbivory in most dicotyledons. Insect diversity in grassland ecosystems can be best predicted by floral diversity or related characteristics of vegetation structure, especially biomass and structural heterogeneity of the plant community.