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FIGURE 15.8. Examples of gas stores. (A) Hair pile on abdominal sternum of Aphelocheirus (Hemiptera); (B) spiracular gill of pupa of Psephenoides gahani (Coleoptera) comprising about 40 hollow branches; and (C) part of wall of spiracular gill branch of P. gahani showing cuticular struts that support the plastron. [A, after W. H. Thorpe and D. J. Crisp, 1947, Studies on plastron respiration. I. J. Exp. Biol. 24:227-269. By permission of Cambridge University Press. B, C, after H. E. Hinton, 1968, Spiracular gills, Adv. Insect Physiol. 5:65-162. By permission of Academic Press Ltd.]

FIGURE 15.8. Examples of gas stores. (A) Hair pile on abdominal sternum of Aphelocheirus (Hemiptera); (B) spiracular gill of pupa of Psephenoides gahani (Coleoptera) comprising about 40 hollow branches; and (C) part of wall of spiracular gill branch of P. gahani showing cuticular struts that support the plastron. [A, after W. H. Thorpe and D. J. Crisp, 1947, Studies on plastron respiration. I. J. Exp. Biol. 24:227-269. By permission of Cambridge University Press. B, C, after H. E. Hinton, 1968, Spiracular gills, Adv. Insect Physiol. 5:65-162. By permission of Academic Press Ltd.]

of gas over certain parts of the body, held in place by a mat of hydrofuge hairs (Figure 15.8A). A third arrangement is for the gas to be held as a layer adjacent to the body by cuticular extensions of the body wall adjacent to the spiracles, known as spiracular gills (Figure 15.8B,C).

The degree of independence from atmospheric air (measured as the length of time that an insect is able to remain submerged between visits to the surface) depends on a number of factors. These include (1) the metabolic rate of the insect, which itself is temperature-dependent; (2) the volume, shape, and location of the gas store, which determine the surface area of the store in contact with the water; and (3) the oxygen content of the water. Factors (2) and (3) relate particularly to use of the gas store as a physical (gas) gill, that is, a structure that can take up oxygen from the surrounding water. When the oxygen used by an insect can be only partially replaced by diffusion into the gas store of oxygen from the water, the volume of the gas store will decrease and, eventually, the insect must return to the surface to renew the gas store. This is known as a temporary (compressible) gas gill. When an insect's oxygen requirements can be fully satisfied by diffusion of oxygen into the gill, whose volume will therefore remain constant, the gill is described as a permanent (incompressible) gas gill or plastron.

Beekeeping for Beginners

Beekeeping for Beginners

The information in this book is useful to anyone wanting to start beekeeping as a hobby or a business. It was written for beginners. Those who have never looked into beekeeping, may not understand the meaning of the terminology used by people in the industry. We have tried to overcome the problem by giving explanations. We want you to be able to use this book as a guide in to beekeeping.

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