Pollination biology in a lowland dipterocarp forest in Sarawak, Malaysia. I. Characteristics of the plant-pollinator community in a lowland dipterocarp forest

Flowerings and flower visitors were observed continuously in a lowland dipterocarp forest in Sarawak, Malaysia, for 53 mo in 1992-1996. Flower visitors of 270 plant species were observed or collected, and pollinators were assessed by observing body contact to stigmas and anthers. We recognized 12 categories of pollination systems. Among them, plants pollinated by social bees included the largest number of species (32%) and were followed by beetle-pollinated species (20%). Pollination systems were significantly related with some floral characters (flowering time of day, reward, and floral shape), but not with floral color. Based on the relationships between pollinators and floral characters, we described pollination syndromes found in a lowland dipterocarp forest. The dominance of social bees and beetles among pollinators is discussed in relation to the general flowering observed in dipterocarp forests of West Malesia. In spite of high plant species diversity and consequent low population densities of lowland dipterocarp forests, long-distance-specific pollinators were uncommon compared with the Neotropics.