oligophagous

Oligophagous is an ecological term used to describe organisms that feed on a limited range of food sources, typically a small number of host species or plant genera. It is most commonly applied to herbivorous insects and other parasites, though the concept can extend to other feeding relationships. Oligophagy sits between monophagy, which denotes feeding on a single species, and polyphagy, which denotes feeding on many species or genera.

The degree of specialization in oligophagous species often reflects adaptations to particular plant chemistry, nutrients, or defensive compounds. Such specialization can arise from coevolution with host plants, enabling efficient detoxification and digestion, but it also entails trade-offs, including reduced ability to exploit novel resources and heightened vulnerability to changes in host availability or habitat.

In practice, oligophagy is described by the number of host taxa used, with some researchers labeling a species oligophagous if it uses a few closely related plant species or genera rather than a broad diet. Examples include certain leaf beetles and aphids that preferentially feed on a narrow set of hosts, and some butterflies whose larvae require specific plant genera. The term can also apply to parasitoids or predators that attack a restricted range of prey species within a broader taxonomic group.

Etymology derives from Greek oligos, few, and phagein, to eat. Related concepts include stenophagy for very narrow specialization and polyphagy for broad feeding.