Influence of the leaf-mining and petiole-boring moth Neoshoenobia testacealis on the leaf longevity of the water lily Nuphar subintegerrimum

The leaf phenology of the water lily Nuphar subintegerrimum (Nymphaeaceae) and the seasonal occurrence of its specialist aquatic moth, Neoshoenobia testacealis (Lepidoptera: Crambidae), were studied at Midorogaike Pond, in Kyoto, Japan. The immature larvae of N. testacealis mine the floating leaves, while the mature larvae bore into the petioles. The percentages of leaves with eggs and of larvae-attacked leaves were 17.8% and 77.4%, respectively. When larvae attacked new leaves in August and late September, the attacks negatively affected leaf longevity. Although specialist herbivores were always able to feed on fresh plant tissue, they had to move between floating leaves due to the short leaf longevity of their host plants. These results suggest that larval movement is an adaptation to the short leaf longevity of their aquatic host plants.