Six-Year Population Fluctuation of the Giant Honey Bee <I>Apis dorsata</I> (Hymenoptera: Apidae) in a Tropical Lowland Dipterocarp Forest in Sarawak

Abstract

The giant honey bee Apis dorsata F. inhabits lowland tropical rainforests in Southeast Asia, where a general, community-wide owering occurs at intervals of 4 yr on average. The numerical response by the honey bee population to the drastic increase of ower resources during general owering was investigated for 6 yr by monthly light-trapping and by nest counts in a lowland dipterocarp forest in Borneo. The numbers of A. dorsata workers obtained by light-trapping were highest during general owering periods, whereas very few workers were trapped in other periods. The abundance of A. dorsata nests showed temporal correspondence with the abundance of trapped workers, and the nests disappeared in the nonowering periods. These data suggest that the A. dorsata population increases rapidly in response to general owering and that this is initiated by nonseasonal, long-distance migration. Drones of A. dorsata were present during the general owering period, but there is no evidence that reproduction by A. dorsata occurs only in general owering periods. Fluctuation in abundance by the honey bee A. koschevnikovi Enderlein was also observed by monthly light-trapping. The temporal trend of this species was similar to that of A. dorsata, but sightings persisted even in the nonowering periods. Both honey bees responded numerically to oral resources, but long-distance migration in A. koschevnikovi was unlikely.