Ozone alters the feeding behavior of the leaf beetle Agelastica coerulea (Coleoptera: Chrysomelidae) into leaves of Japanese white birch (Betula platyphylla var. japonica)

High mixing ratios of ground-level O-3 threaten trophic interactions. In the present study, we conducted laboratory assays, where insect larvae and adults were not directly exposed to O-3, to test the feeding behavior and attraction of the coleopteran leaf beetle Agelastica coerulea to early and late leaves of Japanese white birch (Betula platyphylla var. japonica) treated with ambient or elevated O-3 levels. We found that overwintered adults were not deterred from grazing elevated O-3-treated leaves, but rather preferred them than ambient O-3-treated ones. We also found that the feeding behavior of 2nd instar larvae fed on early or late leaves was not influenced by the O-3 treatment of the leaves when larvae could choose leaves. These observations of the adults and larvae feeding preferences contradict prior observations in the field conditions where the insects avoided leaves in O-3-enriched atmosphere. Since adults preferred elevated O-3-exposed leaves in the present laboratory assays, it is worthy of further investigations whether adults change their grazing preference so as to ensure the leaf palatability as a feeding source for their larvae. Hence, new direction towards detailed ovipositional behavior surveys under field conditions is encouraged.