The Principles of Insect Physiology

833 Pages·1972·54.33 MB·English

by  V. B. Wigglesworth C.B.E.

THE PRINCIPLES OF
INSECT PHYSIOLOGY
THE PRINCIPLES OF
INSECT PHYSIOLOGY
by
V. B. WIGGLESWORTH
C.B.E., M.D., F.R.S.
EMERITUS PROFESSOR OF BIOLOGY IN THE UNIVERSITY OF CAMBRIDGE;
FORMERL Y DIRECTOR, AGRICULTURAL RESEARCH COUNCIL UNIT
OF INSECT PHYSIOLOGY
Seventh Edition
With illustrations
412
LONDON NEW YORK
CHAPMAN AND HALL
First published in 1939 by Methuen and Co. Ltd
Second edition 1944
Third edition 1947
Fourth edition, revised, 1951
Fifth edition, with addenda, 1953
Sixth edition, revised, 1965
Reprinted once
Seventh edition 1972 published by Chapman and Hall Ltd
11 New Fetter Lane London EC4P 4EE
First published as a Science Paperback 1!]82
Published in the USA by Chapman and Hall
733 Third Avenue New rork Nr 10017
© 1972 V. B. Wigglesworth
ISBN-13: 978-0-412-24660-9 e-ISBN-13: 978-94-009-5973-6
DOl: 10.1007/978-94-009-5973-6
This paperback edition is sold subject to the condition that
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PREFACE
INSECTS PROVIDE an ideal medium in which to study all the problems of
physiology. But if this medium is to be used to the best advantage, the principles
and peculiarities of the insect's organization must be first appreciated. It is the
purpose of this book to set forth these principles so far as they are understood at
the present day. There exist already many excellent text-books of general ento
mology; notably those of Imms, Weber, and Snodgrass, to mention only the more
recent. But these authors have necessarily been preoccupied chiefly with
describing the diversity of form among insects; discussions on function being
correspondingly condensed. In the present work the emphasis is reversed. Struc
ture is described only to an extent sufficient to make the physiological argument
intelligible. Every anatomical peculiarity, every ecological specialization, has
indeed its physiological counterpart. In that sense, anatomy, physiology and
ecology are not separable. But regarded from the standpoint from which the
present work is written, the endless modifications that are met with among
insects are but illustrations of the general principles of their physiology, which it
is the aim of this book to set forth. Completeness in such a work is not possible,
or desirable; but an endeavour has been made to illustrate each physiological
characteristic by a few concrete examples, and to include sufficient references to
guide the student to the more important sources.
The physiology of insects is to some the handmaid of Economic Entomology.
For although it is not the purpose of physiology to furnish directly the means of
controlling insect pests, yet the rational application of measures of control
whether these be insecticides of one sort or another, or artificial interferences
with the insect's environment-is often dependent on a knowledge of the
physiology of the insect in question. Physiology may thus serve to rationalize
existing procedures, or to discover the weak spots in the ecological armour of
a species. A knowledge of the ecology of a species is always necessary to its
effective control; its ecology can be properly understood only when its physiology
is known.
1939
PREFACE TO FOURTH EDITION
DESPITE THE turmoil of the intervening years there have been substantial
advances in our knowledge of insect physiology since this book was published in
1939. Some of these represent new principles; others illUIninate established
notions. In this revised edition an attempt has been made to incorporate this new
material into the old framework. It is the aim of such a book as this to provide a
framework sufficiently well founded to support the new knowledge but not so
rigid as to impede its progress.
v
PREFACE TO THE FIFTH EDITION
IN THIS edition a few corrections and alterations have been made in the main
text. At the end of each chapter will be found a number of Addenda, which
include the most recent advances with cross-references to the pages which they
supplement.
1953
PREFACE TO THE SIXTH EDITION
DURING THE twelve years that have elapsed since the last revision of this book
the study of insect physiology has been transformed. New techniques in electron
microscopy, neurophysiology, and many sides of biochemistry have led to spec
tacular advances. The rate at which new material is being published is rising
steeply.
A complete revision of the text with the incorporation of this new knowledge
has been undertaken, and some fifty new illustrations have been introduced. As
in earlier editions the bibliography has been restricted-so far as is compatible
with providing authority for each statement. That has entailed the addition of
more than two thousand new references.
It goes without saying, however, that to master the advances that are being
made on so many fronts, and to sift the essential discoveries from the non
essential, is becoming beyond the range of a single author. It is only the convic
tion that the physiology of any group of animals must be treated as a unity that
has encouraged the present writer to make the attempt.
PREFACE TO THE SEVENTH EDITION
THIS EDITION is a reprint of the sixth edition supplemented by inclusions,
amounting to some ten per cent. of the whole text, in which the major advances
of the past seven years have been incorporated, together with a few new illus
trations. In order to hold down the cost of reprinting, page references to the
new material are given in square brackets at the end of the relevant paragraphs;
but all the new entries are printed together, under appropriate captions, in an
addenda section at the end of each chapter, where the many new references
to the literature will be found.
vi
CONTENTS
CHAP. PAGB
PREFACE V
DEVELOPMENT IN THE EGG
References
II THE INTEGUMENT 27
Properties of the cuticle. Formation and shedding of the cuticle.
References
III GROWTH 61
Moulting. Metamorphosis. Determination of characters during post
embryonic development. Regeneration. Diapause. References
IV MUSCULAR SYSTEM AND LOCOMOTION
Anatomy and histology. Physiological properties of insect muscles.
Locomotion. References
V NERVOUS AND ENDOCRINE SYSTEMS
Nervous system. Visceral nervous system. Endocrine system.
References
VI SENSE ORGANS: VISION 215
Compound eye. Simple eyes. References
VII SENSE ORGANS: MECHANICAL AND CHEMICAL SENSES
Mechanical senses. Hearing. Chemical senses. Temperature and
humidity. References
VIII BEHAVIOUR 310
Kinesis and related phenomena. Orientation. Co-ordinated behaviour.
References
IX RESPIRATION 357
Tracheal system. Development of the tracheal system. Transport of
oxygen to the tracheal endings. Elimination of carbon dioxide. Respir
ation of aquatic insects. Respiration of endoparasitic insects. Respir
atory function of the blood. Regulation of respiratory movements.
References
X THE CIRCULATORY SYSTEM AND ASSOCIATED TISSUES
Circulatory system. Haemolymph. Haemocytes. Pericardial cells and
so-called 'nephrocytes'. Fat body. Oenocytes. Light-producing organs.
References
XI DIGESTION AND NUTRITION
Fore-gut. Peritrophic membrane. Mid-gut. Hind-gut. Secretions of
the alimentary canal. Digestion of some skeletal and other substances
of plants and animals. The role of lower organisms in digestion. Nutri
tion. References
XII EXCRETION 553
Urine. Intermediary nitrogen metabolism. Malpighian tubes. Histo
physiology of the Malpighian tubes. Accessory functions of Malpighian
tubes. Malpighian tubes during moulting and metamorphosis. Cephalic
excretory organs and intestinal excretion. Storage excretion. References
vii
Vlll THE PRINCIPLES OF INSECT PHYSIOLOGY
CHAP. PAGE
XIII METABOLISM 593
Chemical transformations. Some chemical products of insects. Pig
ment metabolism. Respiratory metabolism. References
XIV WATER AND TEMPERATURE
Water relations. Temperature relations. References
XV REPRODUCTIVE SYSTEM 700
Female reproductive system. Male reproductive system. Mating, im
pregnation and fertilization. Some factors controlling fertility and
fecundity. Special modes of reproduction. Sex determination. Trans
mission of symbiotic micro-organisms. References
INDEX OF AUTHORS
GENERAL INDEX
Chapter I
Development in the Egg
Cuticular membranes of the egg: the chorion-Most insects begin
their independent life within an egg. When the egg is laid it is enclosed by two
envelopes, the chorion and the vitelline membrane. The egg-shell or chorion is
the product of the follicular cells in the ovary of the mother (p. 704). It has been
studied in great detail in Rhodnius6 where it consists of some seven layers of pro
teinaceous material modified in various ways by tanning (p. 34), by association
with lipids, and perhaps by the formation of sulphur linkages (Fig. I). Two
layers compose the outer part or 'exochorion', the substance of which, termed
'chorionin'79 resembles the 'cuticulin' of the epicuticle (p. 35). The inner part
or 'endochorion' is composed of five layers, the innermost (like the outermost
layer of the cuticle) being rich in polyphenols.
The egg is covered with a layer of cement secreted by the collet erial glands
of the female. This secretion secures the eggs to the surface on which they are
laid; or it may serve to bind them
together into a compact capsule or
ootheca, as in Blattidae and Mantidae
(p. 706). In the familiar egg rafts of
Culex, on the other hand, the eggs are
held together not by any cement, but
only by the surface tension of the water
on which they rest.lS The chorion may
be thin and flexible, as in the eggs of
such insects as Tenebrio, which are
laid in protected situations; usually it FIG. I.-Section of chorion in egg of Rhodnius
is more or less rigid, as in the exposed (schematic) (after BEAMENT)
eggs of Lepidoptera, Hemiptera, &c. a, resistant exochorion; b, soft exochorion (both
of the lipoprotein 'chorionin'); c, soft endochorion;
In Phasmidae, and likely enough in
d, amber layer of lipidized tanned protein; e, outer
other groups, it is strengthened by polyphenol layer: f. resistant layer of tanned pro
tein; g. inner polyphenol layer; h, primary wax
the incorporation of lime in its
layer.
substance. 50, 48
The coverings of the egg must protect it also from the loss of water by
evaporation. The copious colleterial secretion or 'spumaline' over the eggs of
Malacosoma (Lep.) is hygroscopic and probably helps to conserve moisture.
33
The chorion itself may assist in the retention of water, particularly if its sub
stance is kept dry,20 but it is not usually responsible for the protection of those
eggs which are highly resistant to desiccation. In the egg of Rhodnius, for example,
all the layers of the chorion are freely permeable to water. Waterproofing is due
to a layer of wax, perhaps o'5 fl thick, which is laid down by the developing oocyte
before ovulation and is firmly attached to the inside of the chorion. The egg
2 THE PRINCIPLES OF INSECT PHYSIOLOGY
is therefore waterproofed before laying, the process being independent of
fertilization. 6 This wax resembles in its properties the waterproofing waxes of the
cuticle (p. 35). Likewise in the egg of Bombyx, a wax layer below the endochorion
is the chief barrier to transpiration.13O In the Culex egg an oily layer seems to
exist between the exochorion and the endochorion;18 in Lucilia the waterproofing
lipoid is laid down by the oocyte between the chorion and the chorionic vitelline
membrane,2o and the same applies to Aedes hexodontus.95 In the grasshopper
Melanoplus a hard white wax in a layer about 0' Ifl, thick is deposited, as in Rhod
nius, beneath the chorion,71 and a secondary wax layer on the surface of the
serosal cuticle (p. 4).45, 125 The egg is not, of course, completely impermeable to
water, for insect eggs kept under too dry conditions may fail to hatch, in some
cases because the embryo within is desiccated, in others because the chorion itself
becomes too hard for the young insect to compass its escape. a, 19
Respiratory mechanisms-Respiration takes place through the general
surface of the chorion when this is thin; but some eggs show structural adapta-
c
A O'5mm, .
FIG. 2.-Respiratory system in the egg of Blattella (after WIGGLESWORTH and BEAMENT)
A, dorsal view of single egg showing the curved respiratory process at the anterior pole. B, crest
of the ootheca seen from above; overlying the respiratory process on each egg is a small T -shaped
chamber filled with air. C, crest of the ootheca seen from the side; the air chamber has been
injected and the black contents extend along a curved duct to the respiratory process. 0, transverse
section of the crest of the ootheca after injection showing how the air (replaced by the black
injection material) extends from the exterior to the respiratory process and so to the thin chorion
below.
tions which combine rigidity with the needs of respiration. It was shown by
Leuckart (1855) that in many eggs the shell is lined by a porous air-filled layer
which communicates with the environment so that diffusion of the respiratory
gases can proceed in a gaseous phase to all parts of the egg surface. The filaments
at the anterior pole of the eggs of Nepa and Ranatra are the openings of this
respiratory system. Around the rim of the cap on the egg of Rhodnius are
numerous 'pseudo-micropyles' which serve the same purpose;6, 87 if these are
blocked the egg is asphyxiated.so The 'sperm cups' of the Lygaeid Oncopeltus
have a central canal which serves as a micropyle (p. 705) and spongy air-filled
walls which serve for respiration.81 Elaborate arrangements of the same general