ALBERT

Notes: Summary Number and distribution of sensilla and setae on the antennal flagellum of the honeybeeApis mellifera carnica were determined on whole antennal preparations. The following types of sensilla were distinguished according to their cuticular structure: Sensillum placodeum, S. ampullaceum, S. coeloconicum, S. basiconicum, S. campaniforme and 5 hair sensilla S.trichodeum A, B1, B2, C, D, as well as 4 types of probably non-innervated setae (A1–3, B). The names used here for the different types were compared with the previously used terms. Number and distribution of sensilla, the number of sensory cells and the function of the sensilla were discussed with respect to the data available from the literature. There is a notable dimorphism between the worker and drone with respect to the relative number of sensilla of each type and to the total number of sensory cells. The worker has far more of the presumably olfactory S. trichodea A and of the mechanoreceptive S. trichodea B1. The drone lacks the S. basiconica and has far more S. placodea than the worker. The flagellum surfarce of the drone is twice as large as that of the worker and has 5 times as many sensory cells. The worker flagellum has a poreplate-free zone on the side facing the head which is densely packed with non-innervated setae. In the corresponding zone the drone has a lower density of poreplates than elsewhere on its antennal flagellum. All other sensilla and setae are also characteristically distributed.

Notes: Summary 1. In diluted seawater (density 1.017) Bugula-zooids grow uniserially instead of biserially. Phototropic growth reactions have been measured with uniserially grown zooids (see section C, 1). 2. Under the influence of light the path taken by the spherical cells along the cupula of the bud is the arc of the phototropic inclination. The length of the path is proportional to the illumination time and a function of the light intensity (see section D, 6, 7). 3. The phototropic bending at first increases with the logarithm of the intensity; at 100 lux it drops to 1/3 of the former maximum and continues to drop with higher intensities (see section C, 2). 4. The threshold intensity (with 15 min illumination) where there is no longer a phototropic reaction is in the order of 10−12 watts/mm2 at 506 mμ. Each spherical cell receives approximately 400 quanta per second (see section D, 9). 5. The action spectrum of the phototropic reaction has its maximum at approximately 500 mμ, a minimum at 400 mμ, and rises again with shorter wavelengths. At 686 mμ the curve's amplitude is very low. The shape of the spectral efficiency curve is similar to curves of retinin-opsin compounds (see section C, 4 and D, 3). 6. Absorption measurements of whole, living zooids show a gradual rise towards shorter wavelengths (see section C. 5). 7. Superimposed on the phototropic bendings are morphogenetically fixed bendings which also occur in darkness. These, as well as irregular, light-independent bendings cause the great variance in the data (see section C 6, 7 and D, 4). 8. The extent of the morphogenetically fixed bendings is dependent on the wavelength. This dependence differs from the action spectrum of the phototropic bendings (see section C 6, 7 and D, 4). 9. The light-directed movement of the spherical cells begins between 5 and 30 min after the onset of the light stimulus. Similar reaction times are observed when the incidence of light is changed 180°. Latency accounts for the main part of the reaction time. Ten to 30 min after the end of a longer light stimulus, the cells begin to deviate from the former direction of movement (see section C, 8 and D, 5). 10. A 180°-change in the direction of movement takes between 9 and 18 min, both in the dark as well as after a directional light stimulus (see section C, 8 and D, 5). 11. The cells may move up to two hours with approximately constant speed (2–3 μ/10 min) under the influence of light (see section C, 8 and D 6, 7). 12. Sometimes spherical cells rhythmically separate and close together. No influence of the light stimulus on this “pulsation” was observed (see section C, 9 and D, 8). 13. If we assume that the spherical cells secrete wall material, they are bound to make movements relative to the cuticle, because the wall material flows out of range of the cell plate. These relative movements are discussed in connection with the pulsations and the phototropic movements of the cells (see section 0, 10 and D, 8). 14. Some observations indicate that the single spherical cell is capable of light directed movement. However, the following considerations are also valid in principle, even if only the cell plate react phototropically as a whole (see section D, 2). 15. The spherical cells have a higher refractive index than the surrounding medium and they focus the light. This effect probably serves to produce the intracellular intensity gradient necessary for orientation (see section D, 2). 16. It is necessary to postulate the presence of intracellular receptive units which are able to transform the intensity pattern of the cell's interior into a corresponding excitation pattern by translating local intensities independently of each other into physiological values (local excitations) (see section D 1, 2). 17. Directed reaction is the result of a comparison of local responses or of processes dependent on them. This comparison could be understood as a vectorial sum formed by the difference in the values of opposing vectors (see section D, 2). 18. The measured reaction itself could be the result of a mathematical difference between partial reactions. Under two other very probable assumptions the partial reactions would have a sigmoid dependence on light intensity. This dependence could be calculated through integration of the measured reaction curve In this case the drop in the phototropic reaction at high intensities could be explained by an increased saturation of the partial reactions (see section C, 2 and D, 2). 19. The main possible ways of detecting the directions of the light source are enumerated (see section D, 1).

Notes: Zusammenfassung 1. Extrazelluläre Impulse einzelner olfaktorischer Sinnesnervenzellen lassen sich mit Wolfram-Mikroelektroden von der Antenne des männlichen Seidenspinners Antheraea pernyi ableiten. 2. Die 2 oder 3 Rezeptorzellen der Sensilla trichodea et basiconica beantworten Duftreize entweder durch Zunahme (+) oder Hemmung (-) der im reizlosen Zustand auftretenden Impulse. Ein Reiz kann auch von einer Zelle unbeantwortet (0) bleiben, obgleich er bei anderen Zellen wirksam ist. 3. Eine der Rezeptorzellen der S. trichodea reagiert mit einer phasischen Erregung auf den Sexuallockstoff des Weibchens der eigenen Art. Fruchtig-blumige, aromatische Düfte wirken vorwiegend hemmend auf diese Zelle, jedoch unterdrücken sie bei Mischreizungen die Lockstoff-reaktion nicht völlig (Tabelle 1). 4. Die andere oder die beiden anderen Rezeptorzellen der S. trichodea antworten nicht auf den Sexuallockstoff, sondern nur auf andere Düfte mit phasischer Erregung oder Hemmung (Tabelle 1). 5. Alle 2 oder 3 Zellen der S. basiconica antworten wie die unter 4. genannten Zellen, allerdings phasisch-tonisch, auf verschiedene Düfte, nicht aber auf den Sexuallockstoff. Unter mehr als 50 Zellen fanden sich keine mit identischen Reaktionsspektren. Die Spektren der einzelnen Zellen überlappen sich (Tabelle 2). 6. Der Umfang der Selektivität der verschiedenen Rezeptorzellen für die verwendeten Duftstoffe zeigt eine statistisch gesicherte Korrelation zur Länge der Sensillen. Mit zunehmender Haarlänge sinkt die Anzahl der von einem Rezeptor mit Erregung beantworteten Stoffe; dagegen steigt die Anzahl der mit Hemmung beantworteten Stoffe. 7. Ähnlich stark wie die Reaktionsspektren der Rezeptorzellen variieren die Wirkungsspektren der Duftstoffe. Dabei finden sich auch alle Übergänge von vorwiegend erregenden zu vorwiegend hemmenden Duftstoffen. 8. Die Cuticula der S. trichodea wird von Tubuli durchbrochen. Mehrere Tubuli, die wahrscheinlich die letzten Verzweigungen der Dendriten der Sinnesnervenzellen darstellen, enden nebeneinander in einer Grube, die sich in einem Porus nach außen öffnet.

Notes: Summary Electrophysiologically, we could identify two types of olfactory receptor cells, which respond to pheromones of the honeybee. These cells are associated with the poreplates on the antennae of all three castes of Apis mellifica. One of the cell types is specialized for the queen substance (9-oxo-trans-2-decenoic acid) while the other responds to the scent of the Nasanov gland.

Notes: Zusammenfassung Riechzellen des SeidenspinnersBombyx mori reagieren auf ein einzelnes Lockstoffmolekül mit einem einzelnen Nervenimpuls. Die mittlere Reaktionszeit beträgt etwa 1/2 sec. Bei schwachen Reizen deckt sich die Häufigkeitsverteilung der Impulse mit der Zufallsverteilung der Molekültreffer. Dabei werden nahezu alle auf die Oberfläche der Riechhaare treffenden Moleküle zu den Wirkorten geleitet. Im Verhaltenstest reagiert ein signifikanter Prozentsatz von Tieren, wenn etwa 1% der Lockstoffrezeptoren der Antenne durch den Duftreiz errget ist. Das Signal-Rauschverhältnis der gesamten Rezeptoren hat dann das theoretische Minimum gerade überschritten. Die Impulsmeldungen können offenbar über mehr als eine Sekunde zentral integriert werden.