Storage Excretion

An alternative strategy to the removal of wastes through the Malpighian tubule-rectum system used by some insects is storage excretion, the retention of the wastes in "out of the way places" within the body. In Dysdercus, for example, uric acid is deposited permanently in the epidermal cells of the abdomen, forming distinct, white transverse bands (Berridge, 1965). Adult Lepidoptera convert much of their waste nitrogen into pteridines that are stored in the integument, eyes, or wing scales, giving the insects their characteristic color patterns (Chapter 11, Section 4.3).

At other times storage of urate occurs even when the tubules are working normally and may be regarded as a supplementary excretory mechanism for occasions when the tubules cannot cope with all the waste that is being produced. In the larval stages of many species uric acid crystallizes out in ordinary fat body cells and epidermis, even though the Malpighian tubules are functional. It appears that this is caused by the metabolic activity of the cells themselves (i.e., they are not accumulating uric acid from the hemolymph), and crystallization occurs by virtue of the particular conditions (pH, ionic content, etc.) existing in the cells. During the later stages of pupation the crystals disappear, the uric acid apparently having been transferred to the meconium (the collective wastes of pupal metabolism, released at eclosion) via the excretory system. It is worth noting that in many species the Malpighian tubules are entirely reconstituted during the pupal stage. Thus, storage of uric acid in fat body and epidermal cells is of great importance at this time. Yet other insects, notably termites and cockroaches, retain large quantities of uric acid in special cells (urocytes) within the fat body. However, as Cochran (1985) pointed out, this is not a

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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