DIFFERENTIAL RESOURCE UTILIZATION AND COOCCURRENCE OF LEAF MINERS ON OAK (QUERCUS-DENTATA)

1. Spatial, temporal, and dietary differences in resource utilization and patterns of interspecific association on leaves were investigated for dominant and common leaf-mining species on an oak species, Quercus dentata Thunb., in Hokkaido, northern Japan. 2. Leaf miners were divided into two groups according to leaf tissues used for food: upper-layer-feeders which consume the palisade parenchymatous layer (Stigmella spp. and tenthredinid sp.), and full-depth-feeders which consume spongy and palisade parenchymatous layers (Phyllonorycter leucocorona (Kumata), P.similis Kumata, and Caloptilia sapporella (Matsumura)). 3. Differences in the position of mines on leaves were found among species: mines of P.similis were distributed more frequently in the middle section of leaves, whereas those of the remaining species were concentrated in the basal section. 4. Leaf size preference differed between species: C.sapporella and tenthredinid sp. tended to select larger leaves more frequently than did the other species. 5. Phenological differentiation was found among species: C.sapporella appeared earliest, followed by P.similis, P.leucocorona and a tenthredinid sp., and then Stigmella spp. 6. Each species showed a highly clumped distribution among leaves. Leaf miners of some species pairs co-occurred on leaves more frequently than expected by chance.