Surfing the Sweet Wave: Migrating Giant Honey Bees (Hymenoptera: Apidae: Apis dorsata) Display Spatial and Temporal Fidelity to Annual Stopover Site in Thailand.

Apis dorsata F. (Hymenoptera: Apidae), the giant honey bee of southern Asia, is an important pollinator of crops and non-cultivated angiosperms, and a producer of honey and beeswax. Its populations are in decline in many areas. Colonies migrate seasonally between highland and lowland nesting sites, taking advantage of available food sources. In 2009, a stopover site was discovered in Thailand where numerous migrating colonies bivouacked near one another. Bivouacs used the site again in 2010. I went to the site in 2016 to test the hypothesis that bees use the site regularly as part of an annual migration. I witnessed many bivouacs, spanning almost precisely the same time period and occupying the same area as in 2010. Here I describe their migratory dances in preparation for departure and their subsequent flights as well as periodic mass flight and defensive behavior. Analysis of photographs indicated that the bivouacking bees aged slowly and may thus live long enough to be capable of intergenerational transmission of migratory route knowledge. I describe attributes of the stopover site, e.g., abundant food and water availability, its location along a major river, and other possible navigational cues. Although the site is the only one of its kind so far known to researchers, such stopover sites probably exist wherever giant honey bees undertake long seasonal migrations. I recommend searching for bivouacking sites, particularly along rivers, wherever giant honey bees migrate. Stopover sites are undoubtedly essential to the life history and health of migratory bee populations, and thus warrant conservation policies.

Migrating giant honey bees (Apis dorsata) congregate annually at stopover site in Thailand.

Giant honey bees (Apis dorsata) of southern Asia are vital honey producers and pollinators of cultivated crops and wild plants. They are known to migrate seasonally up to 200 km. It has been assumed their migrations occur stepwise, with stops for rest and foraging, but bivouacking bees have rarely been seen by scientists. Here I report discovery of a site in northern Thailand where bivouacs appeared in large congregations during the wet seasons of 2009 and 2010. The bivouac congregation stopover site is a small mango orchard along the Pai River. Bivouacs rested in branches of mango and other tree species in the immediate vicinity. Departures were preceded by dances indicating approximate direction and apparently, distance of flights. Such consistent stopover sites likely occur throughout southern Asia and may support critical, vulnerable stages in the life history of giant honey bees that must be conserved for populations of the species to survive.