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Reproductive success: Studies of individual variation in contrasting breeding systems
TREE vol. 4, no. 7, July
suggests that crustaceans possess two forms of carbonic anhydrase on gill epithelial cellss, which may effectively replace that provided in the vertebrate red blood cell, but protein buffering capacity is limited by colloid osmotic pressure because haemocyanin is in colloidal suspension in the haemolymphlO. It may be this factor that ultimately sets the physiological limit on the activity and even survival of land crabs in air. The editors of this book and their authors have provided us with a well written, well researched account of our contemporary knowledge of land crab biology. In addition to various aspects of physiology, the book covers evolution, systematics and
biogeography, ecology, behaviour, reproduction and development, and growth and moulting. Each chapter gives its own fascinating insight into an area of the subject, and the editors have clearly worked hard to relate each chapter to the others in the book. What emerges cannot fail to raise the enthusiasm of animal biologists interested in comparative environmental physiology and evolution by natural selection, and will encourage further exciting discoveries
E.W. Taylor School of BiologicalSciences, University of Birmingham, PO Box 363, Birmingham 815 2lT, UK
1989
References 1 Cameron, J.N. (1981) J. Exp. Zoo/. 218, l-5 2 Starch, V. and Welsch, U. (1975) Mar. Biol. 29,363-371 3 Wood,C.M. and Randall, D.J. (1981) J. Exp. Zool. 218,7-22 4 Truchot, J-P. (1975) Respir. Physiol. 23, 351-360 5 Morris, S., Tyler-Jones, R. and Taylor, E.W. (1986) J. Exp. Bid. 121.315-326 6 Taylor, E.W. and Innes, A.J. (1988) Biol. J. Linn. Sot. 34229-247 7 Rahn, H. (1966) Respir. Physiol.
1, l-l
2
8 Innes, A.J., Taylor, E.W. and El Haj, A. (1987) Camp. Biochem. Physiol. 87A. 1-8 9 Henry, R.P. (1987)Am.J. R966-R971
Physiol. 252,
10 Mangum, C.P. and Johansen, J. Exp. Biol. 63,661-671
K. (1975)
Breeding Biology Reproductive Success:Studies of Individual Variation in Contrasting Breeding Systems
edited
by T.H. Clutton-Brock,
sity of Chicago f59.95 hbk, (ix+538 pages)
Univer-
Press, 1986. $86.25/ $34.5O/f23.95 pbk IS&V 0 226 11059 1
Botanists have long realized that it is essential to study individual differences in fecundity and survival in order to understand population dynamics and evolutionary biology. Zoologists have also started to consider the importance of individual differences in performance. The recent explosion of interest in evolutionary theory and the theoretical background provided by game theory has encouraged researchers to study individual variation in the behaviour of animals in the field. This allows researchers to consider why such variation occurs and what its consequences are. Many of the previous studies on individual differences in reproductive success used data collected over a short time span. The worry here is that a short-term measure may bear little relation to the performance over a life span. Some of the studies in this book concern species, such as insects, whose life span easily fits within a PhD programme, but many other studies, and especially those of birds and mammals, require longer-term research. I wonder how many long-term studies are being started now. The core of this book is 25 chapters describing detailed studies of specific species. The animals chosen for research reflect the preferences of behavioural ecologists: there are five studies of insects, one of amphibians, 13 of birds, and six of mammals (including man). The 218
species differ markedly in social organization - from the monogamous fulmar to the harem-forming elephant seal. These chapters are filled with solid behavioural ecological research and make very good reading. Each contributor was asked four questions about the study species. How widely does breeding success vary between individuals of each sex? How much of the variation in success is contributed by the different components of breeding success? To what extent does reproductive success change with age? What environmental, phenotypic, developmental or genetic factors affect breeding success in each sex? As well as tackling these major questions, each chapter considers a range of subsidiary questions which shed light on subjects as diverse as lekking, senescence and bride wealth. A further two chapters provide a review of the theoretical means of analysing lifetime reproductive success, and a consideration of the advantages and disadvantages of measuring it. Brown considers the statistical problems associated with each method of partitioning variance; Grafen discusses some of the limitations of measuring lifetime reproductive success and stresses the importance of experimental manipulations for the study of adaptations. In the final chapter, Clutton-Brock draws the studies together and provides general principles that are the most original part of the book. By summarizing all the studies, he shows that there are considerable differences between males in their genetic contribution to zygotes, whilst the variation between females tends to be less. This sex difference in variance in reproductive success is
reduced when, instead of considering the number of zygotes, the analysis considers the number of surviving young. A few studies succeeded in measuring the number of recruits; in these studies the sex difference disappears completely. The reason for this phenomenon is that individual differences between females in the survival of their offspring is a major source of variation in the number of surviving offspring. Of course, this analysis does not show that sexual selection operates equally on the two sexes, but may indicate how selection may differ between the sexes. Another general conclusion is that most studies showed a positive correlation between fecundity and longevity, which suggests that the variation between individuals cannot be attributed to pleiotropy or tradeoffs. As has been realized for studies of clutch size, these differences in phenotypic quality may hide the costs of various life history phenomena; experimental manipulations are clearly necessary to understand the relevant evolutionary relationships. A major recurrent problem in determining lifetime reproductive success is that it is difficult to determine the contribution of individual males. The authors attempt to overcome the problem by various unsatisfactory methods of assigning paternity. The revolution brought about by DNA fingerprinting should rapidly change this. This book is well worth buying for its detailed summaries of the 25 studies, many of which are classic long-term projects, and for its insights into the factors determing reproductive success.
William J. Sutherland School of Biological Sciences, University of East Anglia, Norwich NR47TJ, UK
suggests that crustaceans possess two forms of carbonic anhydrase on gill epithelial cellss, which may effectively replace that provided in the vertebrate red blood cell, but protein buffering capacity is limited by colloid osmotic pressure because haemocyanin is in colloidal suspension in the haemolymphlO. It may be this factor that ultimately sets the physiological limit on the activity and even survival of land crabs in air. The editors of this book and their authors have provided us with a well written, well researched account of our contemporary knowledge of land crab biology. In addition to various aspects of physiology, the book covers evolution, systematics and
biogeography, ecology, behaviour, reproduction and development, and growth and moulting. Each chapter gives its own fascinating insight into an area of the subject, and the editors have clearly worked hard to relate each chapter to the others in the book. What emerges cannot fail to raise the enthusiasm of animal biologists interested in comparative environmental physiology and evolution by natural selection, and will encourage further exciting discoveries
E.W. Taylor School of BiologicalSciences, University of Birmingham, PO Box 363, Birmingham 815 2lT, UK
1989
References 1 Cameron, J.N. (1981) J. Exp. Zoo/. 218, l-5 2 Starch, V. and Welsch, U. (1975) Mar. Biol. 29,363-371 3 Wood,C.M. and Randall, D.J. (1981) J. Exp. Zool. 218,7-22 4 Truchot, J-P. (1975) Respir. Physiol. 23, 351-360 5 Morris, S., Tyler-Jones, R. and Taylor, E.W. (1986) J. Exp. Bid. 121.315-326 6 Taylor, E.W. and Innes, A.J. (1988) Biol. J. Linn. Sot. 34229-247 7 Rahn, H. (1966) Respir. Physiol.
1, l-l
2
8 Innes, A.J., Taylor, E.W. and El Haj, A. (1987) Camp. Biochem. Physiol. 87A. 1-8 9 Henry, R.P. (1987)Am.J. R966-R971
Physiol. 252,
10 Mangum, C.P. and Johansen, J. Exp. Biol. 63,661-671
K. (1975)
Breeding Biology Reproductive Success:Studies of Individual Variation in Contrasting Breeding Systems
edited
by T.H. Clutton-Brock,
sity of Chicago f59.95 hbk, (ix+538 pages)
Univer-
Press, 1986. $86.25/ $34.5O/f23.95 pbk IS&V 0 226 11059 1
Botanists have long realized that it is essential to study individual differences in fecundity and survival in order to understand population dynamics and evolutionary biology. Zoologists have also started to consider the importance of individual differences in performance. The recent explosion of interest in evolutionary theory and the theoretical background provided by game theory has encouraged researchers to study individual variation in the behaviour of animals in the field. This allows researchers to consider why such variation occurs and what its consequences are. Many of the previous studies on individual differences in reproductive success used data collected over a short time span. The worry here is that a short-term measure may bear little relation to the performance over a life span. Some of the studies in this book concern species, such as insects, whose life span easily fits within a PhD programme, but many other studies, and especially those of birds and mammals, require longer-term research. I wonder how many long-term studies are being started now. The core of this book is 25 chapters describing detailed studies of specific species. The animals chosen for research reflect the preferences of behavioural ecologists: there are five studies of insects, one of amphibians, 13 of birds, and six of mammals (including man). The 218
species differ markedly in social organization - from the monogamous fulmar to the harem-forming elephant seal. These chapters are filled with solid behavioural ecological research and make very good reading. Each contributor was asked four questions about the study species. How widely does breeding success vary between individuals of each sex? How much of the variation in success is contributed by the different components of breeding success? To what extent does reproductive success change with age? What environmental, phenotypic, developmental or genetic factors affect breeding success in each sex? As well as tackling these major questions, each chapter considers a range of subsidiary questions which shed light on subjects as diverse as lekking, senescence and bride wealth. A further two chapters provide a review of the theoretical means of analysing lifetime reproductive success, and a consideration of the advantages and disadvantages of measuring it. Brown considers the statistical problems associated with each method of partitioning variance; Grafen discusses some of the limitations of measuring lifetime reproductive success and stresses the importance of experimental manipulations for the study of adaptations. In the final chapter, Clutton-Brock draws the studies together and provides general principles that are the most original part of the book. By summarizing all the studies, he shows that there are considerable differences between males in their genetic contribution to zygotes, whilst the variation between females tends to be less. This sex difference in variance in reproductive success is
reduced when, instead of considering the number of zygotes, the analysis considers the number of surviving young. A few studies succeeded in measuring the number of recruits; in these studies the sex difference disappears completely. The reason for this phenomenon is that individual differences between females in the survival of their offspring is a major source of variation in the number of surviving offspring. Of course, this analysis does not show that sexual selection operates equally on the two sexes, but may indicate how selection may differ between the sexes. Another general conclusion is that most studies showed a positive correlation between fecundity and longevity, which suggests that the variation between individuals cannot be attributed to pleiotropy or tradeoffs. As has been realized for studies of clutch size, these differences in phenotypic quality may hide the costs of various life history phenomena; experimental manipulations are clearly necessary to understand the relevant evolutionary relationships. A major recurrent problem in determining lifetime reproductive success is that it is difficult to determine the contribution of individual males. The authors attempt to overcome the problem by various unsatisfactory methods of assigning paternity. The revolution brought about by DNA fingerprinting should rapidly change this. This book is well worth buying for its detailed summaries of the 25 studies, many of which are classic long-term projects, and for its insights into the factors determing reproductive success.
William J. Sutherland School of Biological Sciences, University of East Anglia, Norwich NR47TJ, UK