Biology · Ch 13 — Organisms and Populations
Commensalism
Commensalism
Commensalism is the interaction in which one species benefits while the other is neither harmed nor benefited. An orchid growing as an epiphyte on the branch of a mango tree is a good example -- the orchid gains physical support and space and benefits from the relationship, while the mango tree derives no benefit from hosting it (and is not harmed either). The cattle egret foraging alongside grazing cattle (Fig. 13.12) is another classic case of commensalism: cattle egrets characteristically forage close to cattle because, as the cattle move through grass, they flush out insects that the egrets would otherwise find much harder to locate and catch, so the egret benefits while the cattle are simply unaffected. …
What this figure shows. Two side-by-side illustrations, each showing a different commensal relationship. In the first, a white cattle egret stands close beside or on a grazing buffalo; as the buffalo moves through the grass it disturbs insects that fly or hop up, which the egret then catches, benefiting from the buffalo's movement while the buffalo itself is unaffected. In the second, an orange-and-white banded clown fish is shown nestled among the waving tentacles of a sea anemone, sheltering there for protection from predators that avoid the anemone's sting, without providing any visible benefit back …