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On the Respiratory Mechanism of Melophagus ovinus L. (Dipt.)
Author(s) -
Webb J. E.
Publication year - 1945
Publication title -
proceedings of the zoological society of london
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.915
H-Index - 96
eISSN - 1469-7998
pISSN - 0370-2774
DOI - 10.1111/j.1096-3642.1945.tb00859.x
Subject(s) - respiratory system , respiration , anatomy , respiratory rate , biology , abdomen , ventilation (architecture) , anesthesia , medicine , meteorology , physics , heart rate , blood pressure , endocrinology
SUMMARY.1 An account is given of the morphology of the respiratory system of Melophagus ovinus . 2 The respiratory movements of the abdomen in the male and the female are described. 3 The function of the respiratory system is discussed and the probable respiratory mechanism is deduced from the morphological data. 4 Experiments in which the rate of entry of ground derris root into the tracheal system is used as a measure of the rate of breathing show that mechanical ventilation of the tracheal system normally takes place in the ked. Respiratory movements of the abdomen produce a directed flow of air passing in through the abdominal spiracles, over the intra‐tracheal valves in the anterior region of the dorsal longitudinal tracheæ, and out through the thoracic spiracles. 5 Experiments comparing the rates of respiration of male and female keds are described. It is found that the sexual modifications of the respiratory system which have arisen in the female do not increase the volume of air respired, although they may induce a more perfectly directed flow of air than in the male. It is thought that they ensure a plentiful supply of oxygen and adequate growing space for the larva which remains relatively undisturbed by the pumping movements of the abdomen. 6 The spiracular rhythm of the prothoracic spiracle is correlated with the respiratory movements of the abdomen. The effect of carbon dioxide and oxygen on the spiracular rhythm is demonstrated. 7 Experiments with both derris and inert dusts show that at high rates of respiration the amount of dust entering the tracheal system is governed by the structure of the spiracle, the particle size of the dust, and the volume of air inspired in a given time. At low rates of respiration the number of spiracles operating is of importance. 8 It is shown that the abdominal spiracles afford greater protection against the entry of dust into the tracheal system than the thoracic spiracles.