Bees, particularly honeybees (Apis mellifera), are among the most sophisticated non-human communicators in the animal kingdom. One of the most remarkable features of their communication system is the waggle dance, a behavior used to convey information about the location of food sources. While the waggle dance is well known for encoding spatial information—such as direction and distance—less publicized but equally important is its role in conveying food quality. Understanding how bees encode this quality information provides insights into the complex social organization and foraging efficiency of bee colonies.
Overview of the Waggle Dance
The waggle dance is performed by a forager bee that has returned to the hive after discovering a profitable food source. The dance takes place on a vertical surface, typically inside the dark confines of the hive, often on the honeycomb itself. It consists of a figure-eight pattern with a central straight “waggle run,” during which the bee vibrates her body and moves forward.
The waggle dance encodes three main types of information:
- Direction – indicated by the angle of the waggle run relative to gravity (which correlates with the sun’s position).
→ Learn more about the waggle dance from the University of Illinois - Distance – encoded by the duration of the waggle phase.
- Quality – encoded by multiple factors, which will be detailed below.
How Bees Encode Food Quality Information
Unlike direction and distance, food quality is a more abstract and multifaceted concept. It can refer to sugar concentration, volume, ease of access, odor, or reliability of the food source. Bees encode quality through modulations in the dance’s intensity, duration, and accompanying behaviors.
1. Number of Dance Circuits
- Bees perform more dance circuits (repetitions of the waggle dance) for higher-quality food sources.
- A forager discovering a nectar source with high sucrose concentration (e.g., 50% sugar) may perform dozens of circuits, while a lower-quality source may elicit only a few.
2. Vigor and Duration of Waggle Runs
- The duration of the waggle portion of each circuit generally correlates with distance, but there is some evidence that longer dances may also indicate more valuable resources.
- A more vigorous waggle (stronger abdominal vibrations, more energetic movements) may be used to emphasize the profitability of the resource.
3. Recruitment Intensity
- A bee that finds a high-quality source will attract more followers through her enthusiastic dance.
- The buzzing sounds, body temperature, and pheromonal cues (especially from the Nasonov gland) can enhance the dance’s attractiveness.
4. Trophallaxis (Food Sharing)
- During or after the dance, the forager may share samples of the nectar with nearby bees.
- This tasting allows potential recruits to directly assess the sugar content, providing a chemical confirmation of the forager’s message.
5. Dance Persistence Over Time
- If the food source continues to be productive, the forager will return to the hive and dance multiple times over several foraging trips.
- A decline in quality usually leads to a cessation of dancing, indicating the dynamic nature of quality encoding.
→ PLOS Biology: Study on bee dance adaptation and food quality
The Role of Sugar Concentration
Bees are particularly sensitive to sugar concentration, a direct measure of nectar quality. Experimental studies show a clear correlation:
- Higher sucrose levels (35-50%) → more dance circuits, more recruits, more vigorous dances.
- Lower sucrose levels (10-20%) → fewer dances or even no dancing at all.
The forager’s internal assessment of the nectar involves gustatory receptors in the proboscis and pharynx. The perceived sweetness influences how enthusiastically the forager dances.
Contextual Factors
The encoding of food quality is also context-dependent:
- If food is scarce, bees may lower their quality threshold, dancing for food that would otherwise be considered suboptimal.
- In times of abundance, only highly rewarding sources elicit strong dances.
Other factors include:
- Colony hunger levels
- Time of day
- Presence of competitors or predators
Conclusion
Bees encode food quality in their dances using a combination of behavioral intensity, dance frequency, trophallactic interactions, and recruitment dynamics. This multi-modal communication system allows a honeybee colony to allocate its foraging workforce efficiently, ensuring survival and productivity.
The ability of bees to integrate environmental data and translate it into a dance that conveys complex, qualitative, and quantitative information exemplifies a remarkable evolutionary achievement. Studying this behavior not only helps us understand insect communication but also provides models for decentralized decision-making and efficient information flow in complex systems.