Reproductive phenology of gingers in a lowland mixed dipterocarp forest in Borneo

Abstract

Reproductive phenology of 117 individuals from a total of 20 ginger species (Costaceae and Zingiberaceae) was monitored for up to 21 mo in a lowland mixed dipterocarp forest in the Lambir Hills National Park, Sarawak. Of these 20 species of iteroparous perennials, pollinated by either spiderhunters (Nectariniidae), medium-sized Amegilla bees (Anthophoridae), or small halictid bees (Halictidae), many reproduced more than once a year, or flowered continuously with short interruptions. Significant but weak synchronization in flowering events among conspecific individuals was detected for only two species out of the five examined (Etlingera aff. metriocheilos and Amomum somniculosum). The low synchronization within the population, the overlapping flowering among species sharing common pollinators, and the high flowering frequency for each species, contrast markedly with the reproductive phenology of hummingbird-pollinated and large bee-pollinated plants of related taxa in the Neotropics. Although the plants studied do not include all members of each pollination guild, at least one species within a guild was flowering at any time except in the spiderhunter-pollinated guild. Some bee-pollinated gingers may serve as keystone species for survival of the traplining bees living on floral nectar and pollen.