Abstract
We examined whether pre-dispersal feeding by insects (pre-insects) or the status of acorns facilitates acorn infestation by insects that feed on post-dispersal acorns (post-insects) of Quercus crispula. In an Abies-Tsuga natural forest, we sowed the acorns with different types of holes and germination status under the canopy of Q. crispula in late May 2009: germinated or ungerminated acorns with larval emergence holes of pre-insects, those with artificially bored holes, and those without holes. One month later, acorns were collected to check the infestation by post-insects. We found that the spermathophagpus scolytid beetles penetrated acorns regardless of the types of holes on the acorns or germination status, whereas infestation by moth larvae was concentrated on the germinated acorns or the ungerminated acorns with artificial holes. Therefore, emergence holes alone neither facilitate nor inhibit acorn infestation by post-insects, whereas post-insects tend to infest germinated acorns. In particular, germination facilitates acorn infestation by moth larvae.
