Six-year population fluctuation of the giant honey bee Apis dorsata (Hymenoptera : Apidae) in a tropical lowland dipterocarp forest in Sarawak

The giant honey Lee Al,is dorsata F. inhabits lowland tropical rainforests in Southeast Asia, where a general, community-wide flowering occurs at inte rvals of 4 yr on average. The numerical response by the honey bee populatio n to the drastic increase of newer resources during general flowering was i nvestigated for 6 Fr by monthly light-trapping and by nest counts in a lowl and dipterocarp forest in Borneo. The numbers of A. dorsata workers obtaine d by light-trapping were highest during general flowering 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 nonflowering periods. These data suggest that the A. dorsata population increases rapidly in response to general fl owering and that this is initiated by nonseasonal, long-distance migration. Drones of A. dorsata were present during the general flowering period, but there is no evidence that reproduction by A. dorsata occurs only in genera l flowering periods. Fluctuation in abundance by the honey bee A. koschevni kovi Enderlein was also observed by monthly light-trapping. The temporal tr end of this species was similar to that of A. dorsata, but sightings persis ted even in the nonflowering periods. Both honey bees responded numerically to floral resources, but long-distance migration in A. koschevnikovi was u nlikely.