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Excerpt from Chapter 8 “Cultivated intelligence”

from: J. Tautz, H. R. Heilmann (Photos): The Buzz About Bees, Springer 2008

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Half-baked” Sisters, or “Genetics Is Not Everything”

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In summary: worker bee pupae of honeybees (Fig. 8.22) receive individual and different “personal” heat treatments from heater bees.

Do these different treatments have consequences for the resulting bees?

The temperature of the brood nest is a controlling factor in the self-constructed environment with which bees influence the characteristics of their future sisters.

In summary: worker bee pupae of honeybees (Fig. 8.22) receive individual and different

The pupa phase of honeybees lasts about 9 days for the workers, about 10 days for the drones, and about 6 days for the queen. In this time, a bee transforms from a larva into an adult. The essential characteristics of the adult bee are established during this metamorphic change. These are typical of insects, and deviate less from the general basic form than is the case for many insects that are adapted to special ecological niches.

Behavioral plasticity is the distinguishing feature that tops the list for bees. During their lives, worker bees carry out a sequence of different tasks that depend on their age. There is a long list of tasks that bees undertake in an undisturbed colony. Arranged in the order of occurrence, these are: cell cleaning, capping the brood, caring for the brood, serving in the queen’s court, receiving nectar, production of honey, removal of detritus, pollen packing, comb building, ventilation, entrance guarding, and foraging. Behavioral studies employing technology that can focus on single, individual bees have extended the list to include the heater bees, and the filling station bees responsible for providing the energy support for the heater bees (Figs. 8.23–8.26).

Different activities require very different behavior, and behavior is determined by the nervous system. The nervous system of honeybees must therefore possess a highly developed capacity for change. Unusual for insects, the amount of juvenile hormone increases with the age of the bee. As implied by its name, the amount of juvenile hormone is normally highest in young insects, and decreases during the life of the adult. The increasing levels of juvenile hormone during the adult life of bees may be responsible for the older forager bees being better able to learn than are the young hive-bound bees. Bees send their seniors out into an unfriendly world to cope with the dangerous and challenging tasks outside the nest.

Individual bees do not always take part in all the occupations listed above. For example, only a few bees are needed for the queen’s court, or to guard the entrance to the nest; bees that are associated with a specific task perform it often, and their sensitivity to stimuli that evoke the task is critical. Highly sensitive individuals will react even to weak stimuli; insensitive bees will react only to strong stimulation, and be correspondingly less active (►Chap. 10).

A list can be drawn up for the frequency with which individual bees are engaged in various activities, and age and the social environment take on a primary role in determining their actual occupation. Here, too, a genetic component plays a role, but even more influential than the direct genetic contribution is the temperature at which the pupae developed into adult bees. Because the climate of the nest is controlled by the heater bees, whose own behavior and genetic disposition are determined by the conditions under which they developed, a highly complex interaction of environment and genome provides the colony with a high level of adaptability.

Artificially rearing bee pupae at the different temperatures normally existing in an undisturbed beehive has shown that the frequency of the specific behavioral activities they undertake is dependent on the temperature at which they were raised. Bees that emerge from cooler pupae primarily undertake tasks that differ from those of bees stemming from warm pupae. Communication is critical for the successful foraging of a colony, and bees that can precisely communicate their message turn out to be those that develop at temperatures close to 36°C, the highest that has been found in the brood nest. This group of bees also possesses better learning abilities, and better memories than do their cooler sisters.

The temperature at which bees are raised also influences their lifespan. Adult foragers usually live for about 4 weeks, and are called summer bees by beekeepers. Individuals that survive the winter (winter bees), and are again active in the following season as foragers, can live up to 12 months. Pupae raised at the lowest temperatures in the brood nest are the most likely to become winter bees.

Hier ein Vergleich des Energieaufwandes für die beiden anstrengendsten Tätigkeiten, die eine Honigbiene ausüben kann:

Für die Produktion von Wärme verbrennt eine Heizerbiene pro Sekunde 65 Millijoule unter gemäßigten äußeren Temperaturbedingungen.

Für einen Flug von einer Länge von einem Kilometer verbraucht eine Honigbiene 6.5 Joule an Energie. Setzt man die maximale Fluggeschwindigkeit von 30 km/h an, entspricht das einer Flugzeit von 120 Sekunden und somit einem Energieverbrauch von 54 Millijoule in jeder Flugsekunde.

Aus diesen Angaben lässt sich berechnen, dass in einer Heizperiode von 30 Minuten Dauer 117 Joule verbrannt werden und dass ein Flug von 20 Kilometern Distanz 130 Joule an Energie verbraucht.

Im Experiment ließ sich zeigen, dass eine Heizerbiene nach 30 Minuten ihre Tätigkeit energetisch erschöpft aufgeben muss.

Unter extremen Bedingungen lassen sich Bienen dazu bringen, sich bis zu 10 Kilometern vom Stock zu entfernen. Hin- und Rückflug addieren sich dabei zu 20 Kilometern. Auch diese Gesamtdistanz stellt das Maximum an Leistungsfähigkeit dar.

Die beiden Leistungsgrenzen für das Heizen und das Fliegen, die sich aus Beobachtungen ergeben, werden durch die oben skizzierten Berechnungen belegt. Dreißig Minuten heizen kostet die gleiche Energiemenge wie ein Flug von 20 Kilometern Länge.

Die Energie, die dafür bereitgestellt wird, stammt nicht direkt aus der Füllung des Kropfes mit Honig oder Nektar, sondern aus den Zuckermolekülen, die im Blut der Biene kreisen. 

Während alle bisher daraufhin untersuchten Insekten als Blutzucker die Trehalose verwenden, finden man bei den Bienen Glucose als Blutzucker. Auch hierin stimmen sie mit den Säugetieren überein.

Kleinhenz M, Bujok B, Fuchs S & J.Tautz: Hot bees in empty cells – broodnest heating from within. Journal of Experimental Biology 206: 4217-4231, 2003

Highlighted by K.Phillips in The Journal of Experimental Biology 206, 4181 (2003) Climate control, bee style

Bujok,B., Kleinhenz,M., Fuchs,S & J.Tautz: Hot spots in the bee hive.
Naturwissenschaften 89, 299-301, 2002

Kleinhenz M, Bujok B, Tautz J: Leben im Bienenstock. Unterricht Biologie 283 (27), 27-30 (Beihefter), 2003

Tautz,J, Kleinhenz M, Bujok B & F.Fuchs: Raumklimatisierung: Meisterleistung der Honigbienen. ADIZ 12, 8-10, 2003

Groh,C., Tautz,J. & W.Rössler: Synaptic organization in the adult honey-bee brain is influenced by brood-temperature control during pupal development.

Proc.Nat.Acad.Sci.USA 101, 4268-4273, 2004

Tautz J, Maier S, Groh C, Roessler W & A.Brockmann: Behavioral performance in adult honey bees is influenced by the temperature experienced during their pupal development. Proc.Nat.Acad.Sci.USA 100, 7343-7347, 2003.

(commented in Science News www.sciencenews.org/20030524/fob3.asp)

Fehler, Kleinhenz, M., Klügl, F., Puppe, F. & J.Tautz: Caps and gaps: a computer model for studies on brood incubation strategies in honeybees (Apis mellifera carnica)

Naturwissenschaften 94, 675-680, 2007