2023 Volume 105 Issue 12 Pages 365-374
Nut weevils (genus Curculio) are major pre-dispersal seed predators that determine subsequent Fagaceae tree recruitment. In this study, we investigated seed production, size, and germination in two oak species (Quercus serrata and Quercus crispula) and the chestnut Castanea crenata, as well as tree species preferences among larvae of different Curculio species. We collected a total of 105 seeds from beneath 10 trees of each species. Larvae emerging from the seeds were reared in pudding cups covered with rearing mats, and mature weevils were identified to species. The success or failure of germination of each acorn was recorded. The highest feeding damage rate was observed in C. crenata nuts (50.5％), followed by acorns of Q. crispula (41.0％) and Q. serrata (24.8％). In both Q. serrata and Q. crispula, acorn size was significantly positively correlated with the number of Curculio larvae that emerged from the acorns. Three nut weevil species (Curculio sikkimensis, Curculio dentipes, and Curculio distinguendus) matured from acorns of Q. serrata and Q. crispula, whereas only C. sikkimensis matured from nuts of C. crenata. Only the dominant weevil species, C. sikkimensis, selected C. crenata nuts. Germination success increased with acorn size in Q. serrata, with fewer acorn weevil larvae (indicating less feeding damage) in Q. crispula, and was not significantly affected by acorn size or number of acorn weevil larvae in C. crenata.
