Life History and Habits

Although they are found in large numbers in most major habitats, beetles are among the least frequently observed insects by virtue of their secretive habits. The vast majority (ca. 98%) of the world's species are terrestrial, approximately 5000 species live in fresh water, and a few species have managed to invade the littoral zone of the shore where they are submerged twice daily in seawater. Terrestrial species are most common in soil and rotting plant and animal remains, though many live on or in all parts of living plants and fungi, in dung, in nests of vertebrates and other insects, and in caves. Many species are associated with humans and live in clothes, carpets, furniture, and food. Some groups are very well adapted for survival in extremely dry situations. A wide range of adaptation for an aquatic existence is found. In some species only the larvae are aquatic, though the adults live in the vicinity of water and may be able to survive short periods of submersion. Other species are aquatic both as larvae and as adults, the latter having various devices for retaining air in a layer around their body, as their spiracles are still functional (see Chapter 15, Section 4.2). Perhaps surprisingly, there are very few truly aquatic pupae; larvae almost always leave the water to pupate or construct a submerged but air-filled cocoon. The only exception to this is in a few species of Psephenidae (Dryopoidea), where pupae respire by means of spiracular gills.

About 75% of beetle species are phytophagous in both the larval and adult stages, living in or on plants, wood, fungi, and a variety of stored products, including cereals, tobacco, and dried fruits. However, almost all Adephaga and some Polyphaga are carnivores, capturing almost anything of suitable size. Others feed on dead animal materials such as wool and leather. Species representing many families have evolved symbiotic relationships with social insects, living as inquilines in the nests of their hosts that either serve as prey or are persuaded to feed their guests. Only a few Coleoptera are parasitic. It is obvious from the above examples that many beetles will be of economic importance to humans. The majority of these are pests, though many are beneficial through their feeding on weeds or other insects such as aphids.

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.

Get My Free Ebook


Post a comment