theoretical research, especially when using dynamic modelling as the tool. They go on to discuss theapplication of the methods learned. Clark & Mangel, also loyal to the tradition of their nation, gostraight to the business of explaining how stochastic dynamic state variable models are constructed(®rst program listing on p. 10; this is a corrected version of the program listing in their earlier book).Only afterwards do Clark &Mangel give advice on how dynamic modelling should be done in practice.The rest of the two books are structured around examples taken either from the authors' own researchor modelling done by others, more so in Clark & Mangel. In di�erent chapters they cover topics likeoviposition behaviour of parasitoids, over-wintering and food hoarding in tits, bird migration, andideal free distribution. A nice surprise is that Clark & Mangel also discuss issues of conservationbiology and ®sheries ecology, agroecology and population management.

To a more advanced student the book by Houston & McNamara perhaps provides a bit moreinformation, which is merely due to di�erences in how the two books are set up. Throughout the bookthese authors discuss conceptual issues involved in theoretical research (or evolutionary ecologicalresearch in general). While reading the book I got the impression that modelling adaptive behaviour byusing state variable models served as a vehicle for Houston & McNamara to express the(ir) philosophyof theoretical ecology. Also, these authors keep on commenting upon technical issues and advising thereader of potential pitfalls often encountered in (dynamic) modelling.

Interestingly enough, the dynamic modelling in both texts is motivated by using diet and patchchoice models of foraging theory. Much coverage is given in both books to the stickleback foragingstudies done by Dr Paul Hart and his team at Leicester, UK. No wonder, as these studies are anexcellent example of what one can achieve by using stochastic dynamic modelling in solving problemsin foraging behaviour. This is especially true as the classical diet theory could not account for thepartial preference for smaller prey items by sticklebacks, while a model built around a changing statevariable (hunger level) mastered this task successfully.

The two books, despite the substantial overlap in topics and examples treated, are not similar.Houston & McNamara is more strict in (mathematical) presentation, while Clark & Mangel providemore hands-on advice on how to program dynamic models. Houston & McNamara go direct to thescience of adaptive behaviour and how to solve problems in this ®eld with the help of dynamicmodelling. Both books are written in a lucid style. Houston & McNamara tend to correct mistakesmade by others in modelling dynamic behaviour, while Clark & Mangel are somewhat apologetic intheir style of presenting the advantages of stochastic dynamic modelling.

The ultimate question is which of the two books one should buy? There is no easy answer. The twobooks cover the same ®eld, use the same examples and introduce stochastic dynamic modellingtechnique in all its detail. By following the instructions provided in either of the books, and by havingbasic knowledge of some programming language, one can start writing one's own applications of amodel on adaptive behaviour. Both authors emphasize the role of stopping to think about the modelstructure before implementing it on any programming language: wise advice.

So, which of the two books to buy? Both, if your budget allows.

van Schaik, C. P. & Janson, C. H. 2000: Infanticide by Males and its Implications.Cambridge University Press, Cambridge. 569 pp., Hb US$ 130.00, £80.00,ISBN 0-521-77295-8; Pb US$ 47.00, £29.95, ISBN 0-521-77498-5.

Reviewed by Joseph Soltis, Laboratory of Comparative Ethology, NationalInstitutes of Health. E-mail: soltisj@mail.nih.govSince Yukimaru Sugiyama ®rst observed male infanticide in primates over three decades ago,

controversy has ensued as to its adaptive value, and more recently, its potential e�ects on femalebehavior and social organization. This edited volume represents our current knowledge regarding thesetwo broad themes, mainly for the Order Primates. Readers will be convinced early on that most maleinfanticide in primates is indeed sexually selected. The heart of the book, however, moves beyond thisparticular debate and examines the in¯uence of male infanticide on such variables as female matingbehavior, female transfer, male±female relationships, group size and social organization. Herein lies thebook's value and its contribution beyond previous works on the topic. For those hoping to ®ndconclusive evidence for many di�erent e�ects of male infanticide on aspects of female behavior and onsocial organization, however, the book may not be wholly satisfying. As one progresses it becomesincreasingly clear that there is often great uncertainty with regard to the implications of male infanticide,as opposed to the phenomenon of male infanticide itself. Nevertheless, the book o�ers a timely survey ofwhat we do and do not know, and thus points in the direction where future work should be done.

669Book Reviews

The ®rst section of the book opens with Volker Sommer's fair (to my mind) and concise review ofthe history of the `infanticide controversy' as it played out in anthropological circles and more widelyas part of the `culture wars' between, crudely put, science and postmodernism. I could have enjoyed amuch longer piece on this topic, but appropriate literature is cited for those interested in pursuing thevarious historical and philosophical issues.

Carel van Schaik supplies the principal chapter of this section, in which overwhelming evidenceessentially clinches the argument that most infanticide in primates is a male reproductive strategy. Hisreview is an update of Stuhsaker and Leland's review in a previous volume on primate biology(Primate Societies, 1987, University of Chicago Press), and is evidenced with many more cases. Itfocuses on directly observed infanticide in wild populations. Infanticidal males are almost alwaysunrelated to their victims, and they usually have increased probability of mating with the mothers ofvictims. The third element in the argument for such adaptive infanticide is a reduction in the interbirthinterval (IBI) following infant death. My only quibble with this important chapter is that this thirdelement was supported only by anecdotes. The best and commonly used means of demonstrating thebene®t of male infanticide is to show that the loss of an infant (due to any cause) results in reduced IBI.Nevertheless, the preponderance of the evidence is convincing, alternative explanations are considered,and proper emphasis is given to speci®c cases, such as infanticide in chimpanzees and the work ofCarola Borries on Hanuman langurs, which to my mind constitutes the best evidence of sexuallyselected infanticide in any primate species.

The introductory section is followed by several case studies of primate species in which infanticideoccurs. These are signi®cant, in part, because they go beyond the classic demonstration of sexuallyselected infanticide in species forming one-male groups. Contrary to earlier predictions, for example,sexually selected infanticide is increasingly found in seasonally breeding species forming multimale,multifemale groups, and there is evidence showing how female group size in¯uences the probability ofinfanticidal attack.

The book is not limited to male infanticide in primates. There are chapters reviewing infanticide inrodents and birds, for example. In addition, there are two chapters on female infanticide, including oneparticularly fascinating study of demographic data on humans, which suggests that women caused thedeath of their own infants when this may have bene®ted them in terms of future mate choiceopportunity.

The main section of the book concerns the in¯uence of male infanticide on female behavior andoverall social organization, however. As stated at the outset, there is great variability among the chapterswith regard to the certainty of conclusions. They range from rather speculative ruminations, where thereare next to no data, to thoroughly satisfying reviews where more data are available. Examples of thelatter include Ryne Palombit's excellent chapter on infanticide's role in establishing male±femalerelationships. He covers a wide variety of taxa and recognizes where evidence warrants the conclusionthat male±female associations are linked to protection from infanticide and, importantly, where theevidence does not warrant such a conclusion. In a related vein, Andreas Paul and others provide a goodoverview of the growing body of evidence that male protectors do play a role in defending victims fromother, potentially infanticidal males. Even in chapters where the lack of data leaves one with a somewhatempty feeling, however, this may serve the useful purpose of inspiring new research agendas.

In several chapters, authors use comparative analyses to link the risk of male infanticide withsocial organization and female behavior. Overwhelming evidence in favor of ®rm conclusions is notcommon, however. For example, Charles Nunn and Carel van Schaik compare the e�ects of predationand risk of male infanticide on primate social organization. While the e�ect of predation on group sizeis well demonstrated, infanticide risk could not be shown to a�ect female group size or patterns offemale transfer. In another chapter, Maria van Noordwijk and Carel van Schaik explore the possibilitythat females mate with multiple males in order to confuse paternity and inhibit infanticide. They reportan intriguing positive relationship across species between female multiple mating and infanticide risk inprimates and carnivores, but oddly in this instance phylogenetic tests are not performed, as they are inmost other such analyses. Additionally, I found one general problem with the analyses involvinginfanticide risk. One measure of risk often used in the book is the ratio of lactation length to gestationlength. It is argued that a longer lactation period relative to the gestation period results in an increasedrisk of infanticide. I was not completely convinced of this, however. Even when lactation is shorterthan gestation, as long as infant death reduces IBI then infanticide should still be adaptive for males(i.e. there is a risk of infanticide). Nevertheless, it is pleasing to see increasing evidence that infanticideis a selective force in and of itself, which can in¯uence the evolution of behavioral responses andultimately social organization. This approach adds richness to the simplistic model in which ecologyuni-directionally yields social behavior and organization.

670 Book Reviews

Arriving over three decades after infanticide was ®rst observed in primates, this volume sets thestage for future research on the potentially widespread implications of infanticide for the behavior andsocial organization of animals. It will be useful to anyone whose research concerns involve infanticide,especially infanticide by primate males.

Espmark, Y., Amundsen, T. & Rosenqvist, G. (eds) 2000: Animal Signals:Signalling and Signal Design in Animal Communication. Tapir AcademicPress, Trondheim, Norway. 496 pp., 107 ®gs, 20 tables, US$ 60.00, £41.00,plus postage from publisher (Tapir Academic Press, N-7005 Trondheim,Norway). ISBN 82-519-1545-7.

Reviewed by Scott A. MacDougall-Shackleton, Department of Psychology, Uni-versity of Toronto at Mississauga. E-mail: smacdoug@credit.erin.utoronto.caAnimal Signals is based on the proceedings of an international symposium on the `Adaptive

Signi®cance of Signalling and Signal Design in Animal Communication' held at Kongsvoll, Norway inSeptember 1998. As such it represents a good survey of topics in signal evolution that are current at theturn of the century. The editors have compiled a survey of recent theory and research in this area thatre¯ects how far this ®eld has come in the last few decades. Many of the chapters are truly integrative,combining current evolutionary theory with proximate mechanisms of signal production andperceptual psychology of receivers. In addition, the perception and production of courtship signalsby females is given its due in this collection, rather than being ignored as in the past. This stimulatingbook will provide a useful historical milestone in the development of this ®eld, illustrating both how farwe've come and where we still need to go.

Animal Signals displays all of the costs and bene®ts associated with publishing symposiumproceedings in a hard-bound volume. The bene®ts include having a relatively thorough survey of recenttheory and ± to a somewhat lesser extent ± data summarized in a single volume, including useful subjectand taxonomic indexes. The costs include the delay in publication and the inevitable high interchaptervariance in quality, length and format. In this case, the editors have succeeded in minimizing the formercosts much more than the latter. The chapters in this book are truly current, and only the most veryrecent publications have been excluded or cited as unpublished. On the other hand, the heterogeneityamong the 25 chapters is rather conspicuous. An example of this high variation lies in the two chaptersexploring the connections among genes in the major histocompatibility complex (MHC), immunefunction, and sexually selected signals. Mats Grahn provides a relatively detailed review of the linkbetween variation in the MHC and immune function, and outlines a useful framework with which tothink about immunocompetence and condition-dependent ornaments. Wedekind and others, on theother hand, provide the briefest of reviews of previously published work on MHC-correlated sexualselection in humans and mice without adding anything new. Although perhaps most extreme here, thishigh variation among chapters on related topics occurs elsewhere in the book as well.

Thorough coverage of each chapter is beyond the scope of this review; however, highlighting a fewof the numerous topics should reveal this volume's scope. One repeated theme is the use of colorationin signals. Andersson argues that signals must have both e�cacy (in terms of transmission) andinformation content and provides the UV/blue re¯ectance of bluethroat (Lusciana svecica) plumage asan example of a signal selected for e�cacy, whereas more costly colors such as red carotenoids areargued to be designed by considerations of content (honest advertising). Cuthill, Partridge and Bennettreview the mechanisms of avian color vision as well as the growing number of studies indicating thatUV routinely plays a role in color signals of birds. Marshall provides a mammoth review of there¯ectance of over 200 species of coral reef ®sh and discusses the distribution of ®sh colors in termsof their visual ecology. These chapters highlight that understanding signal design requires anunderstanding of properties related to production, transmission and reception, a theme continuedthroughout the book.

A second theme I am delighted to note is a consideration of the production of secondary sexualdisplays by females. Amundsen reviews the historical neglect of female ornaments and argues thatfemale plumage ornaments are not merely a result of genetic correlation with a selected male trait. Asan example, data on bluethroats suggest that males prefer more colorful and symmetric females asmates. Langmore continues this theme in a review of song production by female songbirds. Femalesong appears to result from sexual selection, just as in males; however, the causes of competition maydi�er between males and females. Females sing to defend territories when competition for territories is

671Book Reviews