Community structure of pre-dispersal seed predatory insects on eleven Shorea (Dipterocarpaceae) species

The Dipterocarpaceae in South-Last Asia are known for their strict mast fruiting. During fruiting, pre-dispersal seed predation by insects contributes to mortality of dipterocarp seeds. We documented the community structure of insect seed predators on 11 Shores species in Peninsular Malaysia. Fruits were sampled sequentially throughout seed development, and 21.44 and 1.655 individuals of seed predator weevils and moths were collected in two mast-fruiting events. Four weevils: Namphyes shoreae, nanophyid sp. 1., Alcidodes dipterocarpi and Alcidodes humeralis, and one moth Andrioplecta shoreae were abundant in seeds of the Shorea species. The proportion of N. shoreae to the total predators became larger in the latter fruiting event than the former while that of Alcidodes spp. became smaller. The predator species composition changed during seed development: nanophyid spp. emerged from immature fruits while Alcidodes spp. emerged from mature fruits. Andrioplecta shoreae emerged from both immature and mature fruits. The level of host specificity measured by Kullback-Leibler distance was low for most predator species in both events. Predator species composition of many Shores was similar to each other due to the dominance of N. shoreae though it might gradually differ with the phylogenetic distance between hosts. In conclusion. predator species composition of Shorea varied during seed development within a host rather than among hosts. Intermittent synchronized fruiting by congeneric Shorea trees would be advantageous to avoid pre-dispersal insect seed predators, and contribute to their reproduction.