polyphagy

Polyphagy is the feeding habit of organisms that consume a broad range of food items, rather than specializing on a single resource. In ecological and evolutionary contexts, it often refers to herbivores or omnivores that can utilize many plant species or other food types. The term is commonly contrasted with monophagy, organisms that specialize on a single host or food source, and oligophagy, which describes feeding on a limited set of related hosts.

Diet breadth is a key aspect of polyphagy. Researchers assess polyphagy by examining the number and diversity of hosts used in natural conditions, laboratory feeding trials, and food-web contexts. A truly polyphagous species may exploit hosts across multiple plant families or prey types, while some organisms appear polyphagous in certain environments but more restricted in others.

Mechanisms enabling polyphagy include physiological and sensory adaptations. Generalist detoxification systems (such as diverse cytochrome P450 enzymes), flexible digestive physiology, and broad gustatory and olfactory cues allow organisms to process chemically diverse food items. Behavioral strategies, learning, and phenotypic plasticity also promote successful exploitation of multiple foods. Trade-offs may exist, with generalists sometimes showing lower performance on any single host compared to specialists, but gaining greater resilience to environmental variation and resource loss.

Ecological and evolutionary implications are significant. Polyphagy can support wider geographic distribution, rapid colonization of new habitats, and increased pest potential in agricultural systems due to multiple available crops. Conversely, some polyphagous species can adapt to changing climates or disturbed ecosystems more readily than specialists.

Illustrative examples include certain moths and beetles, such as Helicoverpa armigera and Spodoptera frugiperda, which feed on numerous crop species, as well as omnivorous vertebrates like some birds and mammals.