Predispersal Seed Predation by Insects vs. Vertebrates in Six Dipterocarp Species in Sarawak, Malaysia1

Abstract

ABSTRACTWe investigated the predispersal survivorship of seeds of six dipterocarp species (Dipterocarpus globosus, D. tempehes, Dryobalanops aromatica, D. lanceolata, Shorea beccariana, and S. pilosa) during 2001–2002, when a general flowering occurred in Lambir Hills National Park, Sarawak, Malaysia. More immature seeds dropped during the first month in Dryobalanops and Shorea spp. than in Dipterocarpus spp. Insects attacked the seeds of all species during all developmental stages through to maturity, although temporal patterns varied among the dipterocarps. In contrast, arboreal vertebrates only occasionally ate seeds, and produced less damage than insects. In four species, insects damaged a significantly higher percentage of seeds than did vertebrates. Direct observations of seed survival patterns and bagging experiments using two sizes of mesh (cloth and wire) in the canopy of Dryobalanops aromatica identified insects as the principal seed predators during both the last phase, and overall. These results document the relative importance of insects as predispersal seed predators in these dipterocarp species.