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Beetles Harde

Beetles Harde

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The bee ties of central Europe - . . . . . 6
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Ecology *6
Physiology    20
Reproduction 22
Parental care    24
Disguise and defence 33
Production of sounds and light    35
Beetles and man    36
Indoor pests ...      37
Garden pests . 45
Pests of agriculture    47
Woodland and forest pests    50
Beneficial species     56
How to collect beetles 57
How to kill and prepare beetles    59
How to start a collection - 66
A code for insect collecting : 62
Classification and scientific names ' 66
Guide to families 69
Guide to species    79
References   320
index   321
By any account beetles are a particularly sufic%&sfirf. group of organisms, TlieppproKtmately 370,000 species described to date outoumber.all flip ku#wn species of vaseuf|r pittate; there are six or seven described beetle species for every one of yertehrates! Even «pj beetle species already named represent only the tip of an iceberg, M»stiiient ol the Coleoptera uoubts that at least an equal number of beetle species remains to be described, blit even a vdgy approximate estimate of total numbers is difficult to m»k#. Study of the immensely rie» insect faunas of tropical rain forests is in its infancy, but recent investigation of «elected tropical «teas ha*- tec some entomologists to predict that as many as 5 million beetle specie*-, still await discovers.
Beetles belong to the group of insects known as the Endopterygota, those having a ‘complete' metamorphosis, with a distinct pupal stage -kì^rvesÉag between life as a larva and as a sexually mature adult. As in other endopterygotes the larvae of beetles represent the principal feeding stage. As well as having a very different structure, adult beetles tend to beve quite different habits. This division of an individual’s life into two completely separate phases seems to provide a recipe for success. Several other characteristics»© likely to have t»een particularly advantageous to beetles in the course of their evolution and diversification. Among these are the features by which, as adults, they ape generally most readily re«piise<l. Most beetles have an extremely robust and hard external skeleton and possess a pair of horny wing-cases (elytra). The tough carapace not only helps in protecting them from potential predators, but also from a variety of other environmental hazards, sudi as excessive heat or, aridity. It may be noted that adult beetles are especially numerous in habitats where an ability to push or burrow through densely packed substrates is at a premium, In such circumstances they are less likely to be crushed or damaged than a softer bodied insect. Adults of the majority of beetle species have membranous flight wings and are able to fly. Their wings often escape notice because, when not in use, they are folded atpty lÉpeath the elytra, often ш a complex manner. The protection afforded by the elytra is-important as it enables adult beetles to have the best of both worlds. They are able to fly and so dispose themselves widely to occupy new habitats and, at the same time, they are able to crawl or burrow into cracks «fid crevices, into soil or wood, without risk of damage to their delicate organs of flight. ;
Beetles are to be found in virtually every terrestrial ecosystem, and there isMery little in the way of potential nourishment which is not consumed by one species or another. However, their major impact on the world about us is through three types of activity; dìrea feeding on plants (including fungi), breaking down animal and plant debris, and preying on other invertebrates. À fairly large number of beetle species may be classified as pests. However. the;r depredations are frequently on a relatively minor scale, and they tend, as a group, to receive less attention 441m agriculturalists and applied entomologists than do certain other insect groups, insect* with sucking mouthparts, such as aphids or biting flies, are often important vectors of animal or plant diseases. This seems to be less frequently the case with beetles, although hark beetles *ed certain groups of weevils provide notable exceptions.
Apart from their directly economic aad-:gieef«i.eQ^igica] significance beetles claim the attention of scientists because of their enormous diversity of life-style and r>ciiavinu<. /V» excellent account of this diversity — very much a summary', although the book runs 8»K pages — is to be found in The Biology of Coleoptera (R. A. Crowson, 1981) le this work Dr Crowson notes that the Coleoptera ‘provide excellent illustrations and test cases for almost every general evolutionary principle, and future study of the group may well lead to the formulation of new generalisations’. This may not be a vain hope. After all. the evolutionary studies of such great biologists of the past as Charles Papsvin and Alfred Musei Wallace began with an interest in the diversity of beetles!
Beetles are, of course, not without their aesthetic appeal. A number are of relatively large size, have striking forms and bright, often metallic, colours. Add to this the fact that they are easy to collect and preserve, and it is not difficult to see why they have become populat with amateur students of entomology. In this respect, at least in Europe, they rank second only to the Lepidoptera. Compared with many other insect groups the beetles of northern and central Europe are relatively well-known. Reasonably up-to-date identification works are avail*;1'1“ for the beetles of many European countries. However, because of the large number of sp-c e«