Chapter

440 connected to the myosin filaments by a means of cross bridges present at each end of the myosin. Periodically, the plasma membrane (sarcolemma) of the muscle fiber is deeply invaginated and forms the so-called T system (transverse system). In most insect muscles the T system occurs midway between the Z line and H band; in fibrillar muscles, however, there is no regular pattern for the position of the invaginations.

Though the above description is applicable to all insect muscles, different types of muscles can be distinguished, primarily on the basis of the arrangement of myofibrils, mitochondria, and nuclei; the degree of separation of the myofibrils; the degree of development of the sarcoplasmic reticulum; and the number of actins surrounding each myosin (Figure 14.3). These include tubular (lamellar), close-packed, and fibrillar muscles, all of which are skeletal, and visceral muscles.

Leg and segmental muscles of many adult insects and the flight muscles of primitive fliers, such as Odonata and Dictyoptera, are of the tubular type, in which the flattened (lamellate) myofibrils are arranged radially around the central sarcoplasm. The nuclei are distributed within the core of sarcoplasm and the slablike mitochondria are interspersed

FIGURE 14.3. Transverse sections of insect skeletal muscles. (A) Tubular leg muscle of Vespa (Hymenoptera); (B) tubular flight muscle of Enallagma (Odonata); (C) close-packed flight muscle of a butterfly; and (D) fibrillar flight muscle of Tenebrio (Coleoptera). (Not to same scale.) [A, after H. E. Jordan, 1920, Studies on striped muscle structure. VI, Am. J. Anat. 27:1-66. By permission of Wistar Press. B, C, redrawn from electron micrographs in D. S. Smith, 1965, The flight muscles of insects, Scientific American, June 1965, W. H. Freeman and Co. By permission of the author. D, redrawn from an electron micrograph in D. S. Smith, 1961, The structure of insect fibrillar muscles. A study made with special reference to the membrane systems of the fiber, J. Biophys. Biochem. Cytol. 10:123-158. By permission of the Rockefeller Institute Press and the author.]

FIGURE 14.3. Transverse sections of insect skeletal muscles. (A) Tubular leg muscle of Vespa (Hymenoptera); (B) tubular flight muscle of Enallagma (Odonata); (C) close-packed flight muscle of a butterfly; and (D) fibrillar flight muscle of Tenebrio (Coleoptera). (Not to same scale.) [A, after H. E. Jordan, 1920, Studies on striped muscle structure. VI, Am. J. Anat. 27:1-66. By permission of Wistar Press. B, C, redrawn from electron micrographs in D. S. Smith, 1965, The flight muscles of insects, Scientific American, June 1965, W. H. Freeman and Co. By permission of the author. D, redrawn from an electron micrograph in D. S. Smith, 1961, The structure of insect fibrillar muscles. A study made with special reference to the membrane systems of the fiber, J. Biophys. Biochem. Cytol. 10:123-158. By permission of the Rockefeller Institute Press and the author.]

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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