herbivory

Herbivory is the ecological interaction in which animals feed on living or recently living plant material. It includes consumption of leaves, stems, roots, seeds, fruits, flowers, and plant sap. Herbivores may be specialists or generalists, and can be described by the plant parts they consume (folivores, granivores, frugivores, nectarivores) or by their feeding location (phloem or xylem feeders). It is distinct from predation or scavenging and encompasses a range of feeding strategies from chewing to sucking.

Ecological role: Herbivory transfers energy from plants to higher trophic levels and affects plant performance, growth, and reproduction. By preferentially eating certain tissues, herbivores can influence plant community composition and stimulate compensatory regrowth. Plant communities and herbivore populations interact with predators and pathogens, creating complex food webs and potential trophic cascades.

Plant defenses and herbivore adaptations: Plants deploy chemical defenses (alkaloids, tannins, terpenoids), physical barriers (thorns, trichomes, tough leaves), and timing strategies. Many herbivores adapt with detoxification enzymes, specialized mouthparts, and digestive systems suited to plant material, including foregut or hindgut fermentation in ruminants and certain insects, enabling them to extract nutrients from tough tissues.

Evolution and examples: Coevolution between plants and herbivores has led to matching traits, such as monarch caterpillars tolerating and sequestering milkweed toxins. Some insects feed on phloem sap while circumventing plant defenses.

Applications: Understanding herbivory is important in ecology and agriculture, where herbivore pressure affects crop yields and plant community dynamics; management includes habitat modification, predators, and integrated pest management.