Bee perception

Karl von Frisch's work
Karl von Frisch studied the [[Eurpopean honey bee.

Bee Perception
Sense of smell: Frisch discovered that bees can distinguish various blossoming plants by their scent, and that each bee is “flower constant”. Surprisingly, their sensitivity to a “sweet” taste is only slightly stronger than in humans. He thought it possible that a bee’s spatial sense of smell arises from the firm coupling of its olfactory sense with its tactile sense.

Optical perception: The power of resolution of a bee’s compound eyes is much poorer than in the case of human eyes. But its compound eye is especially well suited to detect motion because of its high temporal resolution. A bee’s color perception is comparable to that of humans, but with a shift away from the red toward the ultraviolet part of the spectrum. For that reason bees cannot distinguish red from black (colorless), but they can distinguish the colors white, yellow, blue and violet. Color pigments which reflect UV radiation expand the spectrum of colors which can be differentiated. For example, several blossoms which may appear to humans to be of the same yellow color will appear to bees as having different colors (multicolored patterns) because of their different proportions of ultraviolet.

Powers of orientation: Frisch’s investigation of a bee’s powers of orientation were significant. He discovered that bees can recognize the desired compass direction in three different ways: by the sun, by the polarization pattern of the blue sky, and by the earth’s magnetic field, whereby the sun is used as the main compass, with the alternatives reserved for the conditions arising under cloudy skies or within a dark beehive.

Polarization pattern: Light scattered in a blue sky forms a characteristic pattern of partially polarized light which is dependent on the position of the sun and invisible to human eyes. With a UV receptor in each of the lens units of a compound eye, and a UV filter oriented differently in each of these units, a bee is able to detect this polarization pattern. A small piece of blue sky is enough for a bee to recognize the pattern changes occurring over the course of a day. This provides not only directional but also temporal information.

Variations in the daytime position of the sun: Karl von Frisch proved that variations in the position of the sun over the course of a day provided bees with an orientation tool. They use this capability to obtain information about the progression of the day deep inside a dark beehive comparable to what is know from the position of the sun. This makes it possible for the bees to convey always up-to-date directional information during their waggle dance, without having to make a comparison with the sun during long dance phases. This provides them not only with alternative directional information, but also with additional temporal information.

Internal clock: Bees have an internal clock with three different synchronization or timekeeping mechanisms. If a bee knows the direction to a feeding place found during a morning excursion, it can also find the same location, as well as the precise time at which this source provides food, in the afternoon, based on the position of the sun.

Horizontal orientation of the honeycomb: Based on the magnetic field, the alignment of the plane of a honeycomb under construction (e.g., the new honeycomb of a swarm) will be the same as that of the home hive of the swarm, according to Karl von Frisch. By experiment, even deformed combs bent into a circle can be produced.

Sensing the vertical: The vertical alignment of the honeycomb is attributed by Karl von Frisch to the ability of bees to identify what is vertical with the help of their head used as a pendulum together with a ring of sensory cells in the neck.

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