Folivory

Folivory is a feeding strategy in which animals derive most or all of their nutrition from consuming leaves. It is observed in diverse groups, including mammals such as koalas and howler monkeys, and a large array of insects, notably caterpillars, beetles, and leaf-cutting ants. Folivores may specialize on particular plant species or forage more broadly.

Leaves are high in fiber and often contain secondary compounds such as tannins and alkaloids that reduce digestibility or are toxic. To cope, folivores have adaptations for processing fibrous matter and detoxifying chemicals, including extended digestive tracts, specialized dentition, and microbial symbionts. Some mammals rely on foregut fermentation, others on hindgut fermentation or microbial communities elsewhere in the gut.

Plants defend against folivory with structural barriers, chemical toxins, and induced defenses. The interaction between leaf chemistry and folivore biology drives coevolution and contributes to patterns of leaf choice, phenology, and plant community structure. Folivory also influences nutrient cycling and energy flow in ecosystems, particularly in forests where leaves form a large annual input.

Notable folivores include koalas (eucalyptus leaves), sloths, colobus and howler monkeys, leaf beetles, caterpillars, and leaf-cutting ants. The diversity of strategies—from selective feeding to social farming of plant material—reflects adaptation to varied plant defenses and environmental conditions.