UV-B radiation and insect herbivory: preliminary observations on strawberry plants and the leaf beetle Galerucella sagittariae in Finland.

Enhanced UV-B (280-315 nm) radiation, as a result of stratospheric ozone depletion is known to increase UV-protective phenolics, especially flavonoids in plant tissues. We tested the hypothesis that the suitability of plant foliage to insect herbivores might be reduced due to higher amount of defence compounds produced by the host plant when exposed to enhanced UV-B radiation. Strawberry plants were exposed to supplementary UV-B and UV-A radiation in an open-field exposure system. The test animal was the leaf beetle (Galerucella sagittariae, Coleoptera, Chrysomelidae), which is known to damage strawberry leaves both in larval and adult stage. The tentative first-year results reported in this paper showed slight, but not statistically significant support for this hypothesis.