Structure

Insect muscles can be arranged in two categories: (1) skeletal muscles whose function is to move one part of the skeleton in relation to another, the two parts being separated by a joint of some kind, and (2) visceral muscles, which form layers of tissue enveloping internal organs such as the heart, gut, and reproductive tract.

Attachment of a muscle to the integument must take into account the fact that periodically the remains of the old cuticle are shed; therefore, an insertion must be able to break and re-form easily. As Figure 14.1 indicates, a muscle terminates at the basal lamina lying beneath the epidermis. The muscle cells and epidermal cells interdigitate, increasing the surface area for attachment by about 10 times, and desmosomes occur at intervals, replacing the basal lamina. Attachment of a muscle cell to the rigid cuticle is achieved through large numbers of parallel microtubules (called "tonofibrillae" by earlier authors). Distally, the epidermal cell membrane is invaginated, forming numbers of conical hemidesmosomes on which the microtubules terminate. Running distad from each hemidesmosome is one, rarely two, muscle attachment fibers (= tonofibrils). Each fiber passes along a pore canal

FIGURE 14.1. Muscle insertion. [After A. C. Neville, 1975, Biology of the Arthropod Cuticle. By permission of Springer-Verlag, New York.]
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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