The Role of Sclerophyllous Leaves in Determining Insect Grazing Damage

Abstract

The vegetation of mediterranean-climate ecosystems is dominated by shrubs with sclerophyllous leaves. These evergreen, hard, leathery leaves, low in nutrient and water content and rich in secondary compounds are also characteristic of plants in nutrient-impoverished and/or droughty environments (Mooney and Dunn 1970; Dement and Mooney 1974; Janzen 1974). Convergence on the sclerophyllous leaf type is generally considered to be the result of an adaptation to limited availability of water (Cunningham and Strain 1969; Orians and Solbrig 1977) or a physiological response to low levels of nutrients, particularly phosphorus (Loveless 1961; Beadle 1966; Monk 1966; Small 1972; Grubb 1977). IT has also been suggested that sclerophylly is an adaptation to the biotic stress imposed by herbivorous animals (Mooney and Dunn 1970; Janzen 1974; Schlesinger and Chabot 1977; Reader 1979).