Insect Aging: Strategies and Mechanisms

248 Pages·1986·9.866 MB·English

by  K.-G. Collatz (auth.), Prof. Dr. Klaus-Günter Collatz, Prof. Dr. Rajindar S. Sohal (eds.)

Insect Aging
Strategies and Mechanisms
Edited by
K.-G. Collatz and R. S. Sohal
With 79 Figures
Springer-Verlag
Berlin Heidelberg New York Tokyo
Prof. Dr. KLAUS-GUNTER COLLATZ
Institut fUr Biologie I (Zoologie)
UniversWit Freiburg
AlbertstraBe 21 a
D-7800 Freiburg, FRG
Prof. Dr. RAJINDAR S. SOHAL
Department of Biology
Southern Methodist University
Dallas, TX 75275, USA
Cover illustration: Aging of insects is not only characterized by a
senescent deterioration but also in a programmed manner by a sudden
drop of physical performance. (See chapter "Aging of Flight Mecha
nism", p. 55).
ISBN-13: 978-3-642-70855-8 e-ISBN-13: 978-3-642-70853-4
DOl: 10.1007/978-3-642-70853-4
Library of Congress Cataloging in Publication Data. Main entry under title: Insect aging.
Bibliography: p. Includes index. 1. Insects-Age. 2. Insects-Development. I. Collatz,
K.-G. (Klaus-Giinter), 1942- . II. Sohal, R. S. QL495.5.156 1986 595.7'0372 85·27818.
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© by Springer-Verlag Berlin Heidelberg 1986
Softcover reprint of the hardcover 1s t edition 1986
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Preface
"Leben ist die schonste Erfindung der Natur
und der Tod ist ihr Kunstgriff, viel Leben zu
haben" . J. W. v. Goethe
Life is the most beautiful invention of nature,
and death is her device to exhibit most life.
The eminent British biologist Sir Vincent B. Wigglesworth noted in 1939 that
insects are an ideal medium in which to study all problems of physiology. Many
fundamental discoveries in biology, particularly genetics and development, have
been made on the basis of studies conducted in insects. Because of their ex
treme adaptability and diversity, an appropriate insect model is available for the
study of virtually any biological problems. The applicability to other groups,
including mammals, of basic studies conducted on insects has helped in the
gradual acceptance of the fundamental unity of biochemical principles as a
dogma among biologists, as well as among enlightened medical scientists.
With the recent upsurge of interest in the study of the aging process, in
sects have been increasingly employed not only for the investigation of basic
mechanisms of aging, but also to gain insight into the evolution of aging and
senescence. If only one aging mechanism exists, it is foreseeable that some in
sects, especially Drosophila, will help to unravel its molecular basis. Because
of their diversity, existing studies in the gerontology of insects are widely scat
tered in various specialized journals. This wealth of existing information has
not, as yet, been brought together in a synthesized and comprehensive form.
This volume was conceived during the symposium on insect gerontology
at the XVII International Congress of Entomology held in August, 1984, in
Hamburg. The original scope of the symposium was broadened to provide, for
the first time, a compendium of the significant existing information on the aging
process in insects. Aging occurring at different levels of biological organization
has been addressed in separate chapters; efforts have been made to demonstrate
relevance of insect studies to other living systems. It should not be overlooked
that the reader will find variety in the descriptions of what is meant by aging
and senescence in insects; this in fact represent the state of the art in this field
of research. This book will be useful to advanced students and practitioners of
gerontology and entomology, as well as to other biologists wishing to broaden
their knowledge of the post-reproductive phase of life. It is hoped that this vol
ume will help promote interest in the study of aging using insect model system.
In our task of bringing this book to fruitition, we gratefully acknowledge
the support and enthusiasm of Dr. Czeschlik and the staff of the Springer
Verlag. The editors are also indebted to Ms. Karen J. Farmer and Mr. Ludwig
Mehler for editorial assistance.
January 1986 K.-G. COLLATZ
R.S. SOHAL
Contents
Towards a Comparative Biology of Aging
K.-G. COLLATZ ......... ...... ........ ............. ................... 1
Critical Points in Time and Their Influence on Life Cycle,
Life Span and Aging
K.P. SAUER, C. GRUNER, and K.-G. COLLATZ (With 5 Figures) 9
The Rate of Living Theory: A Contemporary Interpretation
R. S. SOHAL (With 10 Figures) ........................................ 23
Sexual Activity and Life Span
L. PARTRIDGE (With 2 Figures) ....................................... 45
Aging of Flight Mechanism
K.-G. COLLATZ and H. WILPS (With 9 Figures) ..................... 55
Radiation and Longevity Enhancement in Tribolium
H. S. DUCOFF (With 4 Figures) ........................................ 73
Brain Aging in Insects
M.J. KERN (With 9 Figures) .......................................... 90
Programmed Cell Death and Aging
R. A. LOCKSHIN and A. G. W ADEWITZ
(With 4 Figures) ........................................................ 106
Structural Correlates of Aging in Drosophila:
Relevance to the Cell Differentiation, Rate-of-Living and
Free Radical Theories of Aging
J. MIQUEL and D.E. PHILPOTT (With 8 Figures) ..................... 117
Role of Mitochondria in Drosophila Aging
J .E. FLEMING (With 6 Figures) ....................................... 130
VIII
Metal Ions, Mitochondrial DNA and Aging
H.R. MASSIE (With 1 Figure) ......................................... 142
Age-related Changes in Cell Nuclei
J.P. PANNO and K.K. NAIR (With 1 Figure) ......................... 155
Role of Glutathione in the Aging and Development of Insects
R.G. ALLEN and R.S. SOHAL (With 4 Figures) ...................... 168
Role of Steroids in Aging
D.M. NORRIS, K.D.P. RAO, and H.M.CHU (With 12 Figures) ........ 182
Protein Synthesis in Relation to Insect Aging: An Overview
L. LEVENBOOK ........................................................ 200
Effect of Aging on the Components of the Protein Synthesis System
G. C. WEBSTER ............................•.......................... 207
Genetics of Aging: Effective Selection for Increased Longevity in
Drosophila
R. ARKING and M. CLARE (With 4 Figures) .......................... 217
Subject Index ........................................................... 237
Contributors
You will find the addresses at the beginning of the respective contribution
Allen, R.G. 168 Miquel, J. 117
Arking, R. 217 Nair, K.K. 155
Chu, H.M. 182 Norris, D.M. 182
Clare, M. 217 Panno, J.P. 155
Collatz, K.-G. 1, 9, 55 Partridge, 1. 45
Ducoff, H.S. 73 Philpott, D.E. 117
Fleming, J.E. 130 Rao, K.D.P. 182
Griiner, C. 9 Sauer, K.P. 9
Kern, M.J. 90 Sohal, R.S. 23, 168
Levenbook, 1. 200 Wadewitz, A.G. 106
Lockshin, R.A. 106 Webster, G.C. 207
Massie, H.R. 142 Wilps, H. 55
Towards a Comparative Biology of Aging
K.-G. COLLATZI
CONTENTS
1. Introduction
2. A Problem of Terminology: Aging, Senescence, Development,
Programmed Aging, Programmed Death, Programmed Senescence
3. Are Aging and Senescence Evolutionarily Adaptive?
3.1 Ultimate Factors
3.2 Proximate Factors
4. Aging Strategies as Correlates of r- and K-Selection
5. Insects as Model Systems for the Study of Aging?
6. Conclusion
References
1. Introduction
Because not all scientists mean the same thing when they speak of aging, some
introductory remarks on this theme and its comparative aspects are appropri
ate.
Everyone who is engaged in gerontological research is at first faced with the
problem of distinguishing and separating such terms as: development, aging,
senescence, longevity, vitality, death; all of which variously touch on the same
fact. A short examination of the terminology appears to be necessary. This
is more than "linguistic housecleaning" , as Reiner (1983) called such semantic
attempts. It may be fruitful in providing a framework to clarify our observations
on life history events and especially when comparing similar events among
various forms of life.
2. A Problem of Terminology:
Aging, Senescence, Development, Programmed Aging,
Programmed Death, Programmed Senescence
First I will propose some practicable definitions for the terms - a task which is
certainly not new but nevertheless is inevitable. Comfort's "Biology of Senes-
1 Institut fiir Biologie I (Zoologie), Universitiit Freiburg, Albertstra6e 21a,
D-7800 Freiburg i.Br., FRG
Insect Aging
Ed. by K.-G. Collatz and R.S. Sohal
©
Springer-Verlag Berlin Heidelberg 1986
2
cence" (1979) and Lamb's "Biology of Aging" (1977), for instance, both de
scribe the same field; while the book "Principles of Mammalian Aging" by
Kohn (1978) strictly avoids the term "senescence". The comparative biologist
should prefer the broadest applicable definition for aging. In this case, aging
can then be simply defined as the unidirectional and irreversible course of in
trinsic events which leads the metazoan organism from the beginning to the
end of its life. A consequence of this is that as the force of mortality rises (either
earlier or later and rapidly or stepwise) that of vitality decreases. This, in turn,
results in a reduced adaptation to the environment. A particular process of
aging is common to all members of a species population and is thereby distin
guishable from "disease". It should be noted that we use the term "population"
not "species" because it is reasonable to suppose that different populations of a
species living under various conditions exhibit differently evolved aging strate
gies. This aspect will be discussed later. We also feel it better to exclude the
protozoans from our considerations because it is generally difficult to define ag
ing, senescence and longevity for this group except the ciliates. In addition, in
protozoans the switch from an almost indefinite lifespan to senescence processes
seems to be strongly dependent on extrinsic factors (Smith-Sonneborn 1983).
Lamb (1977) pointed out that using "aging" in this general way contrasts with
the common language usage which attributes aging to the post-reproductive
phase and pays special attention to the deleterious effects. Different meanings
of terms in common language and science, however, are not uncommon; the
term "information" is another well known example. But in contrast to "aging" ,
"information" is strictly defined for scientific use (in the sense of Shannon or
genetic information). Going back to the term "aging", the proposed broader
definition gives us the possibility to distinguish "aging" from "senescence". To
do this may be unimportant for those who are concerned with mammalian ag
ing, because in mammals senescence inevitably attends old age. Indeed both
terms are used in the same manner, especially by authors of this profession.
However, for the biologist studying insect aging, for instance, this distinction
gains importance. It can be hardly said that the termination of life of many
lepidopteran or ephemeropteran species has anything to do with senescence,
but it is, of course, the end of an aging process. "Senescence" should therefore
be used only when the process of a gradual and slow accumulation of deleteri
ous effects has to be described. Aging can be accompanied by senescence but
certainly many life forms age without senescence and others show senescence
only under laboratory, cage or domesticated conditions. Furthermore, even in
vertebrates it is an arbitrary distinction to assign the onset of senescence after
reproduction has ceased. Also in many invertebrates the symptoms of senes
cence can already be detected long before the reproductive activity comes to
an end. Daphnia and the scorpion fly, Panorpa may serve as good examples.
According to Schulze-Robbecke (cited in Comfort 1979), even the eldest spec
imens of Daphnia still show considerable ovarian activity and continue to lay
eggs up to the time of death. Our own observations reveal that the final ac
tivities of dying Panorpa females include, at least in the laboratory, egg-laying
(Collatz, unpubl.). Both species show true senescence even under free living
conditions.
3
Another aging connected term to be considered is "development". Kohn
(1978) among others claimed in his "Principles of Mammalian Aging", that
"development" can be considered as a form of aging, or aging can be thought
of as a continuation of "development" , the borderline between development and
aging being frequently indistinct. I believe this is truly the case; in the broad
sense mentioned above, "aging" and "development" are descriptions of the same
process. For practical purpose and for comparative studies the use of the term
"development" should exclude embryonic development and larval development.
The embryonic development of a vertebrate, the development of hemimetabolic
insects and the total metamorphosis of frogs or holometabolic insects certainly
have very different influences on the longevity of the adults. To my knowledge,
there are unfortunately relatively few studies on this topic. The results of sev
eral authors on the effect of preimaginal conditions in Drosophila on life span
of the adults show the complexity of such interrelationships (Lints and Lints
1969, 1971a,b, Economos and Lints 1984a-c, Mayer and Baker 1984). Some
confusion exists as to what is meant by "programmed aging" and "programmed
death". In consensus with our aging definition, speaking of programmed aging
simply means to describe the genetically specified development after birth or
in animals with metamorphosis after reaching the imaginal phase. It is another
question whether "programmed senescence" exists or not. From all that we
know about this complex syndrome of single effects affecting different parts
of the organism later in life it is unlikely to be programmed. This does not
exclude, however, the possibility that senescence is selectively advantageous.
Finally, we have to distinguish programmed death from programmed aging
and senescence. "Programmed death" means that special physiological events
act in such a way that the death of the organism inevitably follows shortly
after the onset of such events. Undoubtedly, programmed death is strictly a
mechanism to separate the generations. Intraspecific competition appears to
be the selective force through which such a mechanism evolves. In my view
intraspecific competition bears a strong selective force on the determination of
the duration of life in many if not most species. We shall later refer to this in
more detail.
As Korschelt (1924) has already pointed out, programmed death is directly
or indirectly associated with reproduction. He therefore called it "Fortpflan
zungstod" (reproductive death). Reproductive death appears to be more widely
distributed in insects than first thought. The obvious mechanisms underlying
this aging strategy are primarily hormonal in nature. Two rather new examples
of "reproductive death" are known from Octopus (Wodinsky 1977) and an
Australian hopping mouse. In the latter, the level of epinephrine is said to be
so high in males shortly after copulation that they die of stroke. Other long
known examples include lampreys and salmon. Clearly this mechanism must
serve as regulator of population density.