Animals use a variety of signals, including sounds, chemicals, visual signals, and vibrations, to convey information to other members of their species. In particular, the honeybee waggle dance is famous for transmitting information with a precision comparable to language. Let us learn about the evolutionary background of communication and representative examples.
Basic Knowledge
Honeybee language (von Frisch): A scout bee that discovers a nectar source communicates its direction, distance, and quantity to other bees through a dance inside the hive. ① Round dance = indicates a nearby nectar source (within 100 m). ② Waggle dance (figure-eight dance) = indicates a distant nectar source (100 m or more). The angle of the straight section indicates the direction of the nectar source relative to the sun, while the duration encodes the distance. On a vertical honeycomb, the direction of gravity substitutes for the direction of the sun.
Birdsong: Complex vocalizations used to declare territories and attract mates. It develops when young birds hear adult song during the sensitive period (an element of social learning is involved). It is characteristic of males (in many cases). Experiments with song sparrows show that song development is refined through repeated practice based on a vocalization template.
Chemical communication (pheromones): Chemicals that induce specific behaviors or physiological changes within a species. Types include sex pheromones (mate attraction, as in moths), alarm pheromones (recruiting ants to attack), trail pheromones (marking routes to food sources for ants), and aggregation pheromones.
Other means of communication: Visual displays (a peacock spreading its tail feathers = a signal of sexual selection), electrical signals (weakly electric fish), bioluminescence, and contact (mutual grooming). Warning coloration (red, yellow, and black in poisonous organisms = a visual warning to predators).
Explain how the honeybee waggle dance encodes the direction and distance of a nectar source.
Answer: The angle of the straight section of the figure-eight dance (the waggle run) indicates the direction of the nectar source relative to the sun, using the direction of gravity (downward) as the reference. For example, if the waggle run is vertically upward, the nectar source is in the direction of the sun. The duration of the waggle run (or its repetition rate) indicates the distance to the nectar source; a longer duration means a more distant source. In this way, two-dimensional information about direction and distance is transmitted accurately.
- Round dance = nearby nectar source (within 100 m)
- Waggle dance = distant source; angle = direction; duration = distance
- Von Frisch = deciphered the honeybee language and received the Nobel Prize
- Birdsong = territory, mate attraction, and development during the sensitive period
- Pheromones = chemical communication within a species
- Warning coloration = red, yellow, and black in poisonous organisms (warning to predators)
- Communication benefits both the sender and the receiver
Points to Note
① The angle of the waggle dance can be interpreted using “the direction of gravity = the direction of the sun” (so it functions even inside a dark hive). ② Pheromones differ from hormones (chemical substances in the body) because they act only within a species. ③ Birdsong is unique in that it has an innate template but is refined through social learning (imitation).
Practice
- Explain how the direction and distance of a nectar source are communicated in the honeybee waggle dance.
- State two differences between pheromones and hormones.
- Explain the evolution of warning coloration from the perspective of natural selection.