The Respiration of Insects Through the Skin

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Abstract
1. When blowfly larvae are paralysed by ligaturing behind the ganglion the resultant respiration of the hind parts represents the basal metabolism of the animal. 2. When the hind spiracles are also ligatured off, all respiration takes place by diffusion through the skin and is about one-quarter of the basal value. The R.Q. of the twice-ligatured larvae is 1.34. This indicates that part of the metabolic processes are maintained by anaerobic respiration. 3. The O2 tension inside the larvae has been measured and is about 15% inside the normal larvae and 2.4% inside the double-ligatured larvae. 4. Therefore a much larger amount of oxygen diffuses through the skin in the double-ligatured than in the normal larvae, and it has been found by calculation for the normal larva to be one-tenth of the basal value. 5. When insects are submerged in water their spiracles are not able to function and all respiration takes place by diffusion through the skin. 6. In the normal blowfly respiration is independent of the O2 tension from 100% O2 down to about 7.5%, whereas in the double-ligatured larvae it is entirely dependent on the oxygen tension. 7. Experiments with other insects, Chaerocampa elpenor larvae (spiracles blocked with grease), Tenebrio molitor larvae and Culex sp. larvae (submerged in water), gave results similar to those obtained with the blowfly larvae.