Coumarins inPrunus mahaleb and its herbivore, the small ermine mothYponomeuta mahalebellus.

Larvae of the small ermine mothYponomeuta mahalebellus were reared on foliage ofPrunus mahaleb, a plant known to contain coumarins. Thin-layer chromatography and gas chromatography showed that coumarin, umbelliferone, and herniarin were present in leaves ofP. mahaleb and in pupae and adults ofY. mahalebellus. Overall concentrations of simple coumarins in the plant and insect were, respectively, 0.54% and 0.003-0.004% (dry weight). The possible role of coumarins in the chemical defense of both the plant and insect is discussed.