Leaf-tying by tortricid larvae as an adaptation for feeding on phototoxicHypericum perforatum.

Hypericin, an anthrone dimer inHypericum perforatum (Guttiferae), is shown for the first time to be phototoxic to generalist lepidopteran larvae; survivorship was reduced and development prolonged forHeliothis zea (Noctuidae) andPlatynota flavedana (Tortricidae) that consumed hypericin diets in the presence of light. Survivorship for both species is enhanced when photoactivating wavelengths are excluded by filters. In natureP. flavedana successfully survives onH. perforatum by tying together leaves and feeding inside the ties. Shielded from light, the larvae are protected by their mode of feeding from phototoxic compounds.