Sleep maps: mapping dynamic patterns of sleep behavior in the lives of worker honey bees

Known to exhibit sleep, honey bees (Apis mellifera) face variables such as age and position of resources within the hive that may impact their sleep schedule, both spatially and temporally. We introduced individually marked, recently eclosed worker honey bees into observation hives, filmed them during 24h surveys with a thermal camera, and mapped bees’ temperature and sleep behavior as they aged and changed tasks. We also produced maps of the hive’s comb contents as the colony grew and the contents changed. Our aim was to produce “sleep maps,” which could serve as spatial and temporal guides to the organization of complex behaviors within a colony.

All worker bees exhibited sleep (i.e., state of relative immobility while discontinuously ventilating). Mapping sleep spatially: As bees aged, they slept more outside of comb cells than inside cells. Bees slept closer to the edge of the hive when outside of cells and slept closer to the central brood comb when inside cells. Mapping sleep temporally: The youngest worker bees slept arrhythmically, and older bees slept primarily at night. When asleep, foragers’ temperature decreased, and did not differ between day and night or with respect to location in the hive.

Understanding where and when different castes within a society sleep is the starting point from which to understand sleep and its impact on the behavior and ecology of societies, and the societally-based purpose(s) of sleep. Thermal and behavioral maps of honey bees may serve as a new means of scientifically visualizing sleep within a society.