The Economic Importance of Insects

399 Pages·1997·18.47 MB·English

by  Dennis S. Hill (auth.)

THE E C O N O M IC
IMPORTANCE OF
INSECTS
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THE INSTITUTE OF BIOLOGY AND CHAPMAN & HALL
Biology is a disparate science, embracing a spectrum of study from the molecular
level to groups of whole organisms. It is increasingly difficult for both
professional biologists and students to keep abreast of developments. To help
address this problem the Institute of Biology is complementing its own in-house
publications with those produced by professional publishing houses. The
Institute is pleased to be publishing The Economic Importance of Insects with
Chapman & Hall. The Institute's Books Committee welcomes proposals ftr
other advanced-level texts.
THE INSTITUTE OF BIOLOGY
The Institute of Biology is the professional body for UK biologists. It is a
charitable organization, charged by Royal Charter, to represent UK biology and
biologists. Many of its 15 000 members are Chartered Biologists (CBiol),
a qualification conferred by the Institute on professional biologists and
which is recognized throughout the European Communities under Directive
89/48/EEC.
The Institute's activities include providing evidence on biological matters to
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For further details please write to:
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TH E E C O N O M I C
IMPORTANC E OF
INSECTS
Dennis S. Hill
Animal Resource sProgram
Faculty of Resourc eScienc eand Technology
Universiti Malaysia Sarawak
East Malaysia
The Institut eof Biology
im
Incorporate bdy Roya lCharter
SPRINGER-SCIENCE+BUSSI NMEESDIA, B.V.
First edition 1997
© 1997 Dennis S. Hill
Originally published by Chapman & Hall in 1997
Softcover reprint of the hardcover 1st edition 1997
Typeset in 10/12pt Palatino by Keyset Composition, Colchester
ISBN 978-94-010-6248-0 ISBN 978-94-011-5348-5 (eBook)
DOI 10.1007/978-94-011-5348-5
Apart from any fair dealing for the purposes of research or private
study, or criticism or review, as permitted under the UK Copyright
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or in accordance with the terms of licences issued by the appropriate
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concerning reproduction outside the terms stated here should be sent
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The publisher makes no representation, express or implied, with
regard to the accuracy of the information contained in this book and
cannot accept any legal responsibility or liability for any errors or
omissions that may be made.
A catalogue record for this book is available from the British Library
Library of Congress Catalog Card Number: 96-84902
(po) Printed on permanent acid-free text paper, manufactured in
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Z39.48-1984 (Permanence of Paper).
To Ellie, with love
CONTENTS
Preface ix
1 Introduction 1
2 Beneficial insects 7
2.1 Pollination 7
2.2 Apiculture 14
2.3 Sericulture 21
2.4 Insect farming 23
2.5 Natural control of pests 29
2.6 Biological control of pests 33
2.7 Insects in natural food webs 42
2.8 Insects as human food 45
2.9 Miscellaneous 47
3 Pest definitions 51
3.1 Definitions 51
3.2 Development of pest status 54
4 Damage caused by Insecta and Acarina 65
4.1 Indirect damage 65
4.2 Direct damage 68
4.3 Host vulnerability 69
4.4 Damage assessment 73
5 Harmful insects 77
5.1 Medical pests 77
5.2 Veterinary pests 93
5.3 Household and stored products pests 106
5.4 Agricultural pests 142
5.5 Forestry pests 244
6 Insect pest control 333
6.1 Legislation 334
6.2 Physical methods 337
6.3 Cultural control 340
6.4 Breeding/genetic methods 344
6.5 Biological control (biocontrol) 346
viii Con ten ts
6.6 Chemical control 349
6.7 IPM 355
6.8 Pest eradication 356
Glossary 359
References and further reading 379
Index :185
PREFACE
In the last few decades there has been an ever-increasing component in most
BSc Zoology degree courses of cell biology, physiology and genetics, for
spectacular developments have taken place in these fields. Some aspects of
biotechnology are now also being included. In order to accommodate the new
material, the old zoology courses were altered and the traditional two-year basis
of systematics of the animal kingdom, comparative anatomy (and physiology)
and evolution, was either severely trimmed or reduced and presented in an
abridged form under another title. Soon after these course alterations came the
swing to modular teaching in the form of a series of shorter, separate courses,
some of which were optional. The entire BSc degree course took on a different
appearance and several different basic themes became possible. One major
result was that in the great majority of cases taxonomy and systematics were
no longer taught and biology students graduated without this basic training.
We field biologists did appreciate the rising interest in ecology and environ
mental studies, but at the same time lamented the shortage of taxonomic skills,
so that often field work was based on incorrect identifications. For years many
of us with taxonomic inclinations have been bedevilled by the problem of
teaching systematics to undergraduates. At a guess, maybe only 5% of students
find systematics interesting. It is, however, the very basis of all studies in biology
- the correct identification of the organism concerned and its relationships to
others in the community.
The present situation is that the British university system offers many aspects
of environmental biology in a wide range of programmes and a few pest
management courses where a broad integrated approach is taken. Very recently
it has been encouraging to note that taxonomy and systematics have returned
as topics of scientific importance under the guise of 'biodiversity'. However, in
schools and most universities the emphasis in biology teaching has been placed
more and more on laboratory work, and computers are assuming an ever
increasing importance. Field studies are being minimized and even abandoned,
and now many 'biologists' graduate with a BSc but have never spent any time
in the field and cannot tell a meadow pipit from an osprey or a mealybug from
a moth. Much environmental study has become theoretical.
There has been professional lamentation about a general decline in student
interest in (field) biology, and more specifically the lack of interest in
entomology. This is in part rather strange, for there is now a proliferation of
books on natural history, birds, mammals and insects, and many are extensively
illustrated. I feel that part of the problem may lie with the teachers, many of
whom are not naturalists or field-oriented, and sad to say some biology teachers
are not interested in biology at all.
x Preface
Many of we practising applied entomologists are aspmng to encourage
student interest in insects and also in field biology generally, and it is to be
hoped that mid-level university texts such as these will be used by both BSc
undergraduates and also practising biology teachers in secondary schools. After
all, the importance of the Insecta, both beneficially and as pests of humanity,
cannot be over-emphasized, and the interrelationships between insects and their
host plants and other animals are a fascinating source of study.
The illustrations and most of the data used in this book have come from a
recently published text, Agricultural Entomology (Hill, 1994). That book was based
on 40 years of field work and photography in many parts of the world but mainly
in the Far East, East Africa and eastern England. It is very striking how similar
are the insect faunas of Europe, East Asia and North America, but there are
equally interesting differences. Similarly, East Africa and tropical South Ea,t
Asia have both similarities and differences of importance to humans and
agriculture. The bulk of the 1994 book was a systematic review of the class
Insecta at family level with reference to the important species that are either
beneficial to humans or pests in all parts of the world.
Over the years, I have received much help from colleagues and friends, ani
these were thanked in the Preface of Agricultural Entomology. The insect pe~;t
drawings were made by several different artists who were likewise acknow;
edged. The photographs were taken by me.
An alternative title for this book could be An Introductiion to Appliei
Entomology.
Dennis S. Hill
1
INTRODUCTION
The human animal clearly dominates the insects. To put the figures into better perspec
world in terms of its impact on the environ tive, there is a total of about 10 000 species of
ment and its general effect upon the Earth. Vertebrata (mammals, birds, reptiles, am
Biologically, however, the class Insecta can phibians and fish). Thus 80% of known animal
claim to be the more important. Insects are species in the world are insects. Recent survey
humanity's greatest rival for the world's food work in parts of the tropical rain forests (South
resources, both directly by eating the plants East Asia and South America) has disclosed
cultivated for food, and indirectly as vectors many hitherto unknown species of insect that
of disease-causing organisms. In terms of are as yet unnamed. This has led to some
evolution, insect pests kept humanity at a discussion in the scientific press as to just how
subsistence level for thousands of years. But many undescribed insect species remain to be
as we evolved, we developed skills in agricul found in the tropical rain forests of the world.
ture, chemistry and medicine, and now we Some proponents suggest that there could be
have many weapons with which to attack the a grand total of up to 4-5 million different
insect hordes and the parasites they trans species of insect inhabiting the world; some
mit. However, human progress in the battle believe the figure to be even higher It would
against the insects is somewhat like climbing seem that some of these estimates are rather
a steep sand dune - for every metre climbed, fanciful, but an overall figure of up to 2 million
one slips back half a metre; at any point a species - that is, double the existing figure - is
quick landslide can precipitate one down to not unreasonable to assume. Thus out of a
the base again, and each step requires a total of maybe 2 200 000 species of animals in
major effort. A constant striving, and a vast the world, some 90'X, are insects.
financial expenditure on a day-to-day basis, Consider the numbers of individuals
does keep the insect pests at bay - just! present: in 1994 the estimate of the human
The dominance of the Insecta in the world population of the world was in the region of
fauna and their general biological success can 3000 million (or 3 x 1(9); an estimate of the
be shown in several different ways. The number of insects alive at anv one time in the
three usual ways are to consider the number world was recently published as being 1018.
of species concerned, the numbers of in If this estimate is accurate, then there would
dividuals, and the range of habitats colonized be 300 million insects for every human being
and niches occupied. The number of animal in the world at the present time; a daunting
species named, and thus validated, is about 1 thought! Social insects often live in large
million in total. Of these, some 800 000 are communities. Some ant and termite nests