6.1.1.2: Herbivory
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When an animal feed on parts of another organism (usually a plant), herbivory occurs. For example, the koala eats the eucalyptus leaves (figure \(\PageIndex{a}\)) or a cicada feeds a plant's sap (figure \(\PageIndex{b}\)). Like predators, herbivores may feed on multiple individuals over their lives; however, herbivores do not necessarily kill the plants that they eat.
Plant species have evolved numerous defenses that reduce herbivory. Thorns are an example of a mechanical defense that discourages large herbivores from feeding on a plant (Figure \(\PageIndex{c}\)-a). Many plant species produce secondary plant compounds that serve no function for the plant except that they are toxic to animals and discourage consumption, acting as a chemical defense. For example, the foxglove produces several compounds, including digitalis, that are extremely toxic when eaten (Figure \(\PageIndex{c}\)-b). (Biomedical scientists have repurposed the chemical produced by foxglove as a heart medication, which has saved lives for many decades.)
Attribution
Modified by Melissa Ha from Community Ecology from Environmental Biology by Matthew R. Fisher (licensed under CC-BY)