Oviposition preferences of the Japanese Gypsy moth, <i>Lymantria dispar japonica</i> (Motschulsky, 1860) (Insecta: Lepidoptera: Erebidae: Lymantriinae), on evergreen broad-leafed tree leaves in Hiroshima Prefecture, Japan

Abstract

2 Abstract: Female gypsy moths, Lymantria dispar dispar (Linnaeus, 1758), commonly deposit their egg masses on tree trunks in Europe and North America. However, in northern Japan (Hokkaido and northern Honshu) females of L. umbrosa (Butler, 1881) and L. dispar japonica (Motschulsky, 1860) show a strong preference for white birch, Betula platyphylla Sukatschev var. japonica (Miq.) Hara (Betulaceae), trunks. In those areas of Japan where white birches are absent, it has been unclear where most oviposition occurs. In southern part of Hiroshima Prefecture, southwestern Japan, where evergreen broad-leafed trees exist, a preliminary egg mass survey failed to find egg masses on any tree trunks. Subsequently an intensive survey of 1115 individual trees (of 36 different species) in three broad-leafed forest plots found 126 egg masses of which 125 (99.2%) were on Quercus glauca (Thunb.) (Fagaceae), Camellia japonica L. (Theaceae), Eurya japonica Thunb. (Theaceae), or Ilex purpurea Hassk (Aquifoliaceae), and 111 egg masses were positioned on the undersurface of new- growth Q. glauca leaves. In southern part of Hiroshima Prefecture, gypsy moth egg mass surveys in the future should focus on the evergreen leaves of broad-leaved trees, especially Q. glauca.