Why do honeybees dance?
Image: Courtesy, Ken Hoare
Editor, South Shropshire Beekeeper
Keywords: Apis mellifera, communication, evolution, foraging, idiothetic movement, Meliponini.
JULIAN DAVID O'DEABiotechnology and R&D Policy Branch, Agriculture, Fisheries and Forestry Australia, GPO Box 858, Canberra ACT 2601, Australia, Julian.ODea@affa.gov.au
Received January 30, 2000, published February 7, 2000
When a honeybee (Apis mellifera L.) returns to the hive after a successful foraging trip, she often performs a "dance," a set of movements that reflects in miniature the details of her trip. The duration and orientation of the movements in the dance depend on the distance from, and the direction of, the bee's latest foraging site relative to the hive.
Professor von Frisch won a Nobel Prize for his studies on this behavior, and in particular for work leading him to conclude that the honeybee's dance communicates information about the location of a food source to hivemates, thereby enabling them to find and exploit the same resource (1). However, there has been persistent debate about this interpretation (2–11) and today it is generally believed that honeybees are guided to suitable foraging sites by odor cues, including those picked up from successful foragers, rather than by locational information contained in the dances of other foragers. If this is correct, the function of the dance, which embodies information without communicating it to other bees, remains unclear.
An explanation is suggested by consideration of the behavior of other species that perform so-called idiothetic movements: movements that reflect in miniature previous large-scale movements (12). For example, the io moth (Automeris io Fabricius) performs movements after flight that contain information about the flight's length (13). Some social stingless bees (Meliponini) also "dance" after foraging. These dances, like those of the honeybee, embody information about the bee's most recent flight, but this information is not used by the other stingless bees. However, the dances do "excite recruits to go out and search" (14). Likewise, africanized honeybees are known to perform dances that contain information about the location of food sources, but the dances do not recruit other bees, because foraging in this subspecies is an individual activity (15). Evidently, therefore, bees and other insects may perform information-laden movements that are not communicative.
Thus, to explain how the function of the honeybee's dance has evolved, I postulate, first, that idiothetic movements evolved in primitive bees, and served to reinforce the memory of locations recently visited. Then, as bees evolved group foraging, they came to rely on odors picked up from successful foragers as a guide to the location of resources. Finally, idiothetic behavior took on the new function of attracting the attention of foragers, making them aware of the odors picked up by successful hivemates. Thus, although the dance of the honeybee contains locational information about food sources, it is not necessary to assume that bee dances convey this information to other bees. However, the dance may communicate the success of a forager's most recent flight and draw attention to the odors associated with the food source.