William F. Towne

Tactics of dance choice in honey bees : do foragers compare dances?

Summary(1) When a honey bee follows recruitment dances to locate a new food source, does she sample multiple dances representing different food sources and selectively respond to the strongest dance? (2) Several initial findings suggested that foragers might indeed compare dances. First, dance information is arrayed in the hive in a way that facilitates comparison-making: dances for different flower patches are performed close together in time and space. Second, food-source quality is coded in the dances, in terms of dance length (number of circuits per dance). Third, dances to natural food sources vary in length by more than 2 orders of magnitude, indicating that the quality of natural food sources varies greatly. Fourth, foragers seeking a new food source follow several dances before exiting the hive (though only one dance is followed closely). (3) Nevertheless, a critical test for comparison-making revealed that foragers evidently do not compare dances. A colony was given two feeders that were equidistant from the hive but different in profitability. If foragers do not compare dances, then the proportion of recruits arriving at the richer feeder should match the proportion of dance circuits for the richer feeder. This is the pattern that we found in all 11 trials of the experiment. (4) We suggest that the reason foragers do not compare dances is that a colonys foraging success is greater if its foragers distribute themselves among the various food sources being advertised in the hive than if they crowd themselves on the one, best source. (5) Food-source selection by honey bee colonies is a democratic decision-making process. This study reveals that this selection process is organized to function effectively even though each member of the democracy possesses incomplete information about the available choices.

The acoustic near field of a dancing honeybee

SummaryThe acoustic near field close to honeybees performing the wagging dance was investigated with pairs of small, matched microphones placed in various positions around the dancing bees. The dance ‘sounds’ are produced by the wings, which act as an asymmetrical dipole emitter. Close to the abdomen, the ‘sound’ pressures in the air spaces above and below the plane of the wings are totally out of phase. A zone of very intense acoustical short-circuiting exists close to the edges of the wings, where pressure gradients of about 1 Pa/mm are observed in the dorso-ventral direction (perpendicular to the plane of the wings). The pressure gradients drive air movements with velocity amplitudes up to about 1 m/s. The pressure gradients are much smaller in directions radially away from the bee and decrease rapidly with increasing distance from the wings. The ‘sound’ pressure detected by a stationary probe at one side of the bee is strongly modulated at 12–13 Hz as a result of the bees side-to-side wagging. Surprisingly little ‘sound’ is found near the dancers head. The positions of the follower bees reflect the properties of the acoustic field: The follower bees place their antennae in the zone of maximum acoustical short-circuiting where the air particle movements are most intense. These observations suggest 1) how follower bees can avoid mixing up the messages carried by the dance ‘sounds’ when two or more bees are dancing only a few cm apart and 2) how the followers might extract information about a dancers spatial orientation from the acoustic near field she produces. The observations also provide clues regarding the nature of the putative ‘sound’ receivers.

Acoustic and visual cues in the dances of four honey bee species

SummaryThe sounds produced during the dance of the European honey bee, Apis mellifera, are potentially important in the reception of the dance information by recruit bees. I have studied the dances of the three Asian honey bee species and have found that the single species which nests in dark cavities like A. mellifera produces similar sounds, while the two open-nesting species produce none. This and other evidence suggest that the different species may perceive their dances through different sensory channels.

Magnetic Field Sensitivity in Honeybees

In the past 15 years an abundance of evidence has accumulated suggesting that the behavior—particularly the orientation—of a variety of organisms is affected by the earth’s magnetic field. The orientation and navigation of pigeons and honeybees have been unusually well studied (see reviews by von Frisch, 1967; Keeton, 1974; Gould, 1982), and of all terrestrial animals, it is in these two that the effects of magnetic fields on orientation have been most clearly and abundantly documented. Gould (Chapter 12, this volume) reviews the pigeon findings. Here we review the evidence for an effect of the earth’s magnetic field on honeybee orientation. Where we see the evidence as weak, we say so and suggest experiments that should help to show whether or not the effects are real. We then discuss the nature and sensitivity of the receptor mechanism as inferred from behavioral observations and anatomical studies. Again, we suggest experiments which should help us to locate and understand the magnetic field detector.

Honey Bee Learning

Publisher Summary This chapter integrates behavioristic terminology and insights with the ethological perspective on learning. To illustrate this convergence, honeybee is chosen as a lot is known about its natural history and is a convenient experimental “wild” animal. Honeybees face the problem of learning to recognize and handle flowers with a useful set of predispositions and programs: they recognize flower-like targets innately, land on them, and explore them and if they provide food, they learn about them. Bees learn both to recognize and to handle flowers. Recognition learning is a case of classical conditioning in which a compound conditioned stimulus is committed to memory. Like many-probably most-cases of learning, the memorizing process is highly biased with some cues learned more easily than others and some that are easily perceived not learned at all. Bees store flower memory in a time-linked and time-exclusive set, in a mental array that must be prewired. These observations suggest that honeybee learning is organized in a manner very similar or identical to the circuitry that underlies alpha conditioning—that is, the inputs to the cell(s) responsible for storage-cells with specific time constraints in the case of bees come from a limited set of modalities, some more strongly represented and thus more easily learned than others.