Migration in honey bees

Migration studies include spectacular examples from vertebrates, such as birds, bats, and turtles. However, insect migration studies have lagged due to a restrictive definition of what entails migration and because of constraints in tracking insect movement. This has changed in recent times with studies on migratory butterflies, moths, and dragonflies. However, studies on collective migration by social insects such as honey bees are still largely lacking, despite their impact on ecosystem services, food security, and biodiversity. In this review, we synthesise findings from scattered studies on migration in a subset of honey bee species to better understand this phenomenon and to provide impetus for future research. As a general trend, migration in the genus Apis begins with a shift from a statary to a migratory phase within colonies, characterised by greater scout activity and consensus-building with respect to the direction of departure using migratory waggle dances. Once air-borne, the finer details of a swarm’s movement are unknown for any Apis species. Swarms reportedly make multiple stops, and while temporarily existing as comb-less clusters at these sites, the decision-making process occurs repeatedly, until nest-selection dances occur and the migratory phase finally culminates. We highlight the need for studies into the drivers and mechanisms of honey bee migration, as well as the promise of initiatives such as citizen science and tools such as pollen metabarcoding in studying migration in honey bees. This is particularly needed, given that rapidly changing habitats and climate could affect honey bee migration and the pollination services they provide.