Weitere biologische Literatur (eingeschränkter Zugriff)
Refine
Year of publication
Document Type
- Book (32) (remove)
Has Fulltext
- yes (32)
Is part of the Bibliography
- no (32)
Keywords
- Boden (1)
- Bombay duck (fish) (1)
- Bundesgartenschau (1)
- Feathers (1)
- Franken (1)
- Frankfurt (1)
- Fruchtfliegen (1)
- Geoökologie (1)
- Harpadon nehereus (1)
- India (1)
Institute
- Extern (4)
Die Chilopoden, über welche ich im folgenden berichte, stammen von einer Forschungsreise durch Kärnten, welche ich irn Herbst 1938, und zwar vom 20. September bis 18. Oktober, unternommen habe. Der Preußischen Akademie der Wissenschaften, welche mich durch ein Stipendium unterstützte, spreche ich meinen herzlichsten Dank aus. Verwiesen sei hier auf meine "Diplopodenfauna Kärntens in ihren Beziehungen zu den Nachbarländern und in ihrer Abhängigkeit von den Vorzeiten", Zool. Jahrb. (Syst.), Bd. 73, 1939, S. 63 bis 110, sowie meine Arbeit über die Isopoda terrestria Kirntens in den Abhandl. d. Preuß. Akad. d. Wiss., math.-naturw. Klasse, 1939, Nr. 15. Im ersteren Aufsatz, und zwar im 8. Kapitel S. go, bin ich bereits auf das quantitative Auftreten der karntnerischen Chilopoden im Vergleich mit Diplopoden und Isopoden eingegangen und will nur wiederholen, daß neben 1048 Stück Diplopoden und 352 Stück Isopoden von Chilopoden 112 Stück untersucht wurden. Von letzteren soll also im folgenden die Rede sein. Ich will auch betonen, daß diese quantitativen Verhältnisse der drei Tiergruppen keine zufälligen sind, sondern sich in den meisten Alpenländern in ähnlicher Weise wiederholen. Die geringere Zahl der Chilopoden beruht auf ihrer räuberischen Natur gegenüber der überwiegend vegetabilischen der beiden anderen Gruppen. Da sich unter den 23 Chilopoden-Formen, welche ich im Herbst 1939 in Kärnten beobachtet habe, einige Nova befinden, müssen diese zunächst klargestellt werden....
The present work deals with the problem of the essential factor regulating the wing-stroke frequency in some insects in wing mutilation and loading experiments and in subatmospheric air pressure experiments. The diverse opinions concerning this factor, appearing in the literature, are reviewed. As appears in this review, one of two factors, the inertia of the wings or the resistance of the gas medium, is claimed to be the main regulator of the wingstroke frequency. Therefore two series of experiments have been performed. In the first series the correlation between the moment oi inertia of the wings and the wing-stroke frequency is examined. The wings are mutilated by cutting them transversely, longitudinally or obliquely or loaded with a drop of collodion. It is found that (1) the wing-stroke frequency is proportional to the -0.35th power of the moment of inertia of the wings, that (2) this applies to both mutilation and loading experiments, that (3) it makes no difference whether the procedures are equal or unequal on both sides or only one-sided, and that (4) the frequency tends not to rise above a certain lirnit in mutilation experiments. In the second series of experiments the correlation between the pressure of the gas medium and the wing-stroke frequency is examined. It is found that the effect of pressure varies greatly in different insects and may even be totally absent. The wing-stroke frequency is proportional to (pressure) exp 0 to (pressure) exp -0.25. The degree of the effect is found to depend on the size and the wing-stroke frequency of the insect; the effect is absent in big insects with a medium or high frequency, and more or less present in insects with a small size or with a low frequency. The results are discussed. A theory is constructed using well established physical concepts by considering the wings as acting simultaneously as bodies performing simple harmonic rotary motion and as paddles working against the air. It is assumed that the kinetic energy is destroyed after each single stroke. By making this assumption, the frequency in the energy equation is found to be, within a constant rate of energy output, proportional to the -0.33rd power of the moment of inertia of the wings, and thus agrees very well with the correlation between these factors found experimentally. Further it is found that the aerodynamic work of the wings is in most cases very much smaller than the work done in overcoming the effect of the inertia of the wings. It is negligible in big insects with, a medium or high frequency, but more or less significant in insects with a small size or a low frequency. The magnitude of this effect thus depends, in theory, on the size and the wing-stroke frequency, which entirely agrees with the effect of atmospheric pressure found experirnentally. The inferences drawn from this theory show that (1) the energy economy in a big insect is very wasteful, that (2) the rate of energy output is not greatly varied, that (3) it is profitable for the insect to vary the aerodynamic work of the wings by altering the amplitude rather than the frequency of the stroke, that (4) the distribution of energy in flight is delicately balanced, and that (5) the frequency must be low and the amplitude large in insects of great size and weight, and that a very high frequency and a small amplitude can be afforded only by small insects. Many such observations as have been made in nature agree with these inferences. Furthermore, (6) attempts are made to calculate the muscle efficiency in some insects on the basis of the theory. In Appendix I, the technique used to check and eliminate some sources of error in the methods is described, in Appendix II, an application of tlie theory to derive a law between the wing-stroke frequency and the morphological properties of insects is attempted, and in Appendix III, some laws relating different morphological properties of the wings of insects are described.
Flora des tropischen Arabien
(1939)
Contents: Foreword I. Prolonged Diving Previous Investigations Present Investigations Diving Experiments with Seals Diving Experiments with a Beaver Investigations on Whales Diving Experiments with Penguins and Domestic Ducks II. Deep Diving Previous Investigations and Views Present Investigations Methods References Appendix (Tables)