ALBERT

Notes: Summary 1) Auxiliary optical marks placed at the food goal serve as rank- and racespecific learning criteria and influence the orientation performance of theApis mellifera carnica andApis mellifera ligustica. 2) The bees are not conditioned race-specifically by optical marks placed at a longer distance from the food goal. The visual structure of the more distant surroundings and the absolute distance of the food goal determine the rise, gradient, and level of such learning curves. 3) When orientation cues from optical marks and the sun compass are lacking, both races are incapable of optically determining the exact position of the food goal (tests in a circular arena under totally overcast skies). 4) When there are no optical marks near the goal, polarization substitutes adequately for the sun compass. 5) When an artificial optical mark is removed from a formerly learned, complex set of marks, relearning is prohibited by pro-active processes during a particular latency phase. During this latency phase the stored information is forgotten; however, the first learning step is excluded from any forgetting process. Relearning an easier task, with the addition of an optical mark to the former set of marks, takes place without difficulty.

Notes: Summary If an insect is able to determine the direction of polarization in any point of the sky, this ability does not in itself guarantee that the insect can orientate unambiguously. Such would only be the case, if every point in the sky had its own exclusive direction of polarization. In thee-vector pattern of the sky, however, each direction of polarization is found at many different points. For compass orientation the insect has therefore to use some information on the geometry of thee-vector pattern in the sky. In general, eache-vector occurs twice at a given elevation (Fig. 1). The angular separation ω between the positions of identicale-vectors depends on the elevations of thee-vectors above the horizon and on the height of the sun. Except at sunrise and sunset, ω ≠ 180°. If a bee is trained to fly in a certain direction to a food source, the direction of its waggle dance on a horizontal comb points directly towards the goal (provided that the bee is able to view the sky). However, if the bee is only allowed to view a singlee-vector in the sky (or a single artificially adjustede-vector), it should perform ambiguous orientation. One expects the bee to prefer two dance directions separated by the proper angular distance ω. One of these two dance directions should point at the food source. The bees indeed dance in two directions. However, there are two unexpected results: (1) The angular distance between the two preferred directions invariably amounts to ω=180°. (2) One of the preferred directions points closely, but not exactly at the goal. What one can deduce from these single-e-vector tests is that the bee uses a rather generalized internal representation of thee-vector pattern in the sky. This paper describes the generale-vector characteristic applied by a dancing bee that only views a singlee-vector in the sky (diameter of the celestial patch or the artificially polarized light source ≦10°). This generale-vector characteristic of the bee (Fig. 9) more closely fits the meane-vector distribution near the zenith thane-vector distributions in other parts of the sky (Fig. 11).

Notes: Zusammenfassung 1. Rund- und Schwänzeltanz, wie sie v. Frisch für Apis mellifica beschrieben hatte, dienen auch den 3 übrigen Arten der Gattung Apis: Apis indica, Apis florea und Apis dorsata zur Verständigung über die Lage eines bestimmten Zieles. 2. In der Richtungs- und Entfernungsweisung durch diese Tänze zeigen sich einige artspezifische Unterschiede. Solche sind im wesentlichen. a) Apis indica kann den Futterplatz bereits von einer Entfernung von 2 m ab durch gerichtete Schwänzelläufe anzeigen, Apis florea von etwa 5 m ab und Apis dorsata von etwa 3 m ab. Nur unterhalb dieser Entfernungsgrenzen beobachtet man Rundtänze bzw. den Übergang von Sichel- zu Rundtanz. b) Die Richtungsweisung im Schwänzeltanz erfolgt bei Apis indica und Apis dorsata genauso wie bei Apis mellifica auf der vertikalen Wabenfläche, und zwar wird nach dem gleichen Schlüssel der Winkel zur Sonne auf die Schwerkraft transponiert, wie dies Apis mellifica tut. c) Apis florea hingegen kann die Richtung zum Futterplatz nicht auf die Schwerkraft transponieren; sie tanzt oben auf dem First der Wabe, wo sie auf horizontal gelegenem Tanzboden direkt die Richtung zum Ziel weist. Hierzu benötigt sie Ausblick zum Himmel, um sich beim Schwänzellauf in gleicher Richtung zur Sonne einstellen zu können, wie beim Flug zum Futterplatz. Der Tanz von Apis florea muß demnach als der phylogenetisch ältere innerhalb der Gattung Apis angesehen werden. d) In der Entfernungsweisung bestehen bei den genannten 3 indischen Bienenarten die gleichen Beziehungen zum Tanzrhythmus wie bei Apis mellifica: Mit zunehmender Entfernung wird der Rhythmus der sich folgenden Schwänzelläufe immer langsamer und die daraus sich ergebenden Entfernungskurven (vgl. Abb. 3) verlaufen bei allen 4 Arten konform. Die Ausgangswerte sind jedoch für jede Art spezifisch. Besonders bemerkenswert ist, daß das Endstück dieser Entfernungs-kurven sich jeweils der Flugweite der betreffenden Art anpaßt: vor Erreichen der Fluggrenze läuft sie flach, d. h. parallel zur X-Achse aus (Abb. 3). Die Flugweite beträgt bei Apis indica etwa 800 m, bei Apis florea etwa 350 m; jene von Apis dorsata ist noch zu bestimmen. 3. Es wurde auch ein Vertreter aus einer anderen Gattung (Trigona) auf die Möglichkeit hin geprüft, ob eine Verständigung über aufgefundene Futterquellen besteht. Bei Trigona iridipennis besteht eine solche, jedoch beruht sie nicht auf Tänzen, und ihre Verständigung ist wesentlich primitiver: die Stockbienen erhalten von den erfolgreichen Sammelbienen nur die Nachricht, daß es eine lohnende Futterstelle gibt, und des weiteren wird der Duft dieser Futterquelle mitgeteilt. Es wird jedoch keine Information über die Richtung und Entfernung des Zieles vermittelt. Die Wirkung der Alarmierung ist bei Trigona iridipennis demgemäß wesentlich schwächer als bei den Apis-Arten.

Notes: Summary 1. Bees were trained to a feeding station, where they obtained a 2-mol sucrose solution. The course of flight led across water and covered a distance of 247 m. The speed of the bees and their path of flight were observed. 2. When the water surface was mirror smooth, a great number of bees plunged into the water. They continually lost altitude until they crashed headlong into the water, wich thereby flipped them onto their backs. We were unable to observe this phenomenon when the water was rippled or, during smooth water, when the course was marked with a bridge of floating boards. 3. The bees always flew slower and lower over rippled water then over solid land or the floating bridge of boards. We measured without wind a flight-speed over water of 6.34 m/s (43 observations), over the floating bridge a flight-speed of 7.93 m/s (11 observations). The difference is significant. 4. The bees compensated for the velocity of the wind when flying over rippled water as well as over the bridge, so that their air-speed was greater when they were flying against the wind and less when they were flying with the wind. 5. The flight across water was disturbed to a great extent by crosswinds. The bees could maintain the correct angle to the cross-wind only near the banks. When they were farther than approximately 20 meters from the bank, they drifted in the wind. Even the presence of the floating bridge did not help them to hold the correct angle to the wind. The bees were driven across the bridge and followed it in a garland-like track on the lee-side. 6. A bee, wich was forced to make a detour to the feeding station did not return by the same route, but chose instead the most direct path to the hive. 7. The reasons for a bee flying slowly when close to the surface of the water are discussed.

Notes: Summary It has been possible — by transplantation of brain tissue (i.e. mushroom-bodies) — to perform an interindividual transfer of a learned time-signal in honeybees. The information of the donor bees becomes determinative for the temporal activity pattern of the recipients about 3 to 4 days following transplantation. As seen from histological investigations done in parallel, the donor tissue is treated as a xenograft by the recipient's organism including disintegration and encapsulation processes. These observations give evidence for a humoral transfer of information. The results are discussed from the point of view of the analysis of the mechanism of time reception.

Notes: Summary The behaviour of young honeybee queens and of worker bees was studied in an observation hive. Tooting and quacking signals emitted by the queens were recorded as airborne sound and as substrate vibrations of the combs by means of a microphone and a laser vibrometer, respectively. The fundamental frequency component is larger than the harmonics when the signals are measured as vibration velocity, and it is argued that the signals are carried mainly by the fundamental frequency component. The frequencies emitted depend on the queens' age, and the tooting syllables contain a frequency sweep. These observations may explain some of the very diverse frequency values reported in the literature. The fundamental carrier frequencies of the toots and quacks overlap, but the tooting syllables have longer rise times than the quacking syllables. Recordings of the vibration of cells in which queens were confined allowed us to measure the threshold for the release of quacking in the confined queens by artificial toots and by natural toots from emerged queens. Artificial toots with long syllable rise time are more efficient in releasing quacking responses than are toots with short syllable rise time. This observation may suggest that the bees recognize these signals mainly by their temporal structure. A comparison of the threshold, emission level, and attenuation with distance, suggests that these and other vibration signals are used by honey bees only for local communication within a restricted area of the comb.