Effects of attack time on the development and reproduction of the oak borer, Platypus quercivorus (Murayama)

We allowed the oak borer, Platypus quercivorus, to construct galleries in fresh logs of Pasania edulis in an evergreen broad-leaved forest during a period from June to December 1997 and counted the number of adults that emerged from each gallery in the autumn of 1997 and summer of 1998. Attack by this species, namely the start of gallery construction, was observed from early June to early October in 1997. The distribution patterns of entry holes changed from uniform to contagious with the increment of their density. Reproductive success was lower for galleries started after August than those started in June and July, from which new adults emerged in September and October 1997. The galleries started after the end of August did not develop well and failed to produce any new adults. These results suggest that the time of attack is very important for reproductive success of this species and that adults should start gallery construction by the end of July to produce a considerable number of new adult beetles. The construction of galleries by new adults in autumn may contribute little to the population dynamics of this species.