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FIGURE 21.8. Pupal types. (A) Decticous (Chrysopa sp., Neuroptera); (B) exarate adecticous (Brachyrhinus sulcatus, Coleoptera); and (C) obtect adecticous (Heliothis armigera, Lepidoptera). [From A. Peterson, 1951, Larvae of Insects. By permission of Mrs. Helen Peterson.]

Pupae are categorized according to whether or not the mandibles are functional and whether or not the remaining appendages are sealed closely against the body (Figure 21.8). Decticous pupae, found in more primitive endopterygotes [Neuroptera, Mecoptera, Trichoptera, and Lepidoptera (Zeugloptera and Dacnonypha)], have well-developed, articulated mandibles (moved by the pharate adult's muscles) with which an insect can cut its way out of the cocoon or cell. Decticous pupae are always exarate; that is, the appendages are not sealed against the body so that they may be used in locomotion. Some neuropteran pupae, for example, can crawl and some pupae of Trichoptera swim to the water surface prior to eclosion. Adecticous pupae, whose mandibles are non-functional and often reduced, may be either exarate or obtect. In the latter condition the appendages are firmly sealed against the body and are usually well sclerotized. Adecticous exarate pupae are characteristic of Siphonaptera, brachycerous Diptera, most Coleoptera and Hymenoptera, and Strepsiptera. In nematocerous Diptera, Lepidoptera (Heteroneura), and in a few Coleoptera and Hymenoptera, pupae are of the adecticous obtect type.

In muscomorph Diptera at the end of the final larval stadium the cuticle becomes thickened and tanned. The tanned cuticle is not shed but remains as a rigid coat (puparium) around the insect. A few hours after pupariation the larval epidermis apolyses so that a pharate pupal instar is formed within the puparium, serving as in other endopterygotes as the mold for adult tissues.

An immobile pupa is vulnerable to attack by predators or parasites and to severe changes in climatic conditions, particularly as the pupal stadium may last for a considerable time. To obtain protection against such adversities the pupa typically has a thick, tanned cuticle. Also, in many species it is enclosed within a cocoon or subterranean cell constructed by the previous larval instar. The cocoon may comprise various kinds of extraneous material, for example, soil particles, small stones, leaves or other vegetation, or may be made solely of silk. In some endopterygotes the pupa is exposed (not surrounded by a protective cocoon) but obtains additional protection by taking on the color of its surroundings. Many parasitic species remain within, and are thus protected by, the host's body in the pupal stage.

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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