Platypus quercivorus is a ambrosia beetle which cause Japanese oak wilt by transporting pathogenic fungus Raffaelea quercivora. The adult beetle emergence from infected trees lasts four to five months, and there exists a difference in the date of arrival to new host trees among beetles. Among beetles that flew to the same tree, a difference is also observed in the settlement order. Previous studies on the mountain pine beetle indicated that the reproductive success of the bettle was affected by both the arrival date and the settlement order. Besides these temporal variations, spatial variations in the reproductive success of P. quercivorus was also examined in this study.

In 2004, I marked the holes newly bored by P. quercivorus on 13 Quercus crispula at the secondary forest in Kyoto, Japan, in one week intervals, and the gallery length was measured for each hole in 2005 as an indicator of reproductive success. At a glance, temporal variations were observed in the gallery length: the length was longer in holes with early arrival and early order. A generalized additive mixed model was applied to the data to predict the gallery length, and the best-fit model included only the negative effect of the height. Results suggested that the observed temporal variations in the reproductive success of P. quercivorus was actually caused by the spatial variation.