Morals, menarche and motherhood

BOOK REVIEWS

A compass for biological control Theoretical Approaches to Biological Control edited by B.A. Hawkins and H.V. Cornell Cambridge University Press, 1999. £65.00 hbk (xii 1 412 pages) ISBN 0 521 57283 5

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iological control of agricultural pests has a history of more than one thousand years. The method achieved recognition in 1889, when the cottony-cushion scale basin (Icerya purchasi) in California’s orange orchards was successfully controlled by an introduced predator, the Vedalia ladybeetle (Rodolia cardinalis). After the success of the Vedalia ladybeetle, numerous attempts to introduce natural enemies into new areas were carried out throughout the world. Although some of the introduction attempts resulted in spectacular success, most of them failed. Thus, biological control has not yet become a major pest-controlling method in agriculture. Traditionally, most attempts at biological control have used the introduction of natural enemies against exotic pests, but additional methods have been developed. These include periodic release of massproduced agents (e.g. Encarsia formosa and Phyoseiulus persimilis) and augmentation of their effectiveness. Thus, biological control of greenhouse pests, such as the greenhouse whitefly (Trialeurodes vaporariorum) and the two-spotted spider mite (Tetranychys urticae), are applied in European countries; however, many greenhouse farmers in non-European countries, such as those in Japan, still rely on chemical pesticides. Many problems, such as environmental pollution, new pest resurgence and damage to human health, have arisen from the overuse of chemicals on farmland. This has led to social demands for the reduction of chemical pesticide applications in agriculture. Biological control is believed to be a potentially powerful form of pest control with few environmental disadvantages. Why, therefore, is biological control not as popular as chemical pesticides? Chemical control does not require as much information about the biology and the ecology of pests. Pest suppression is easily achieved, temporarily, by killing as many individuals of the pest population as possible. Biological control is not so simple, because it affects the interspecific relationships of organisms in the field. Processes and mechanisms of biological TREE vol. 15, no. 1 January 2000

control are consequently complicated and its effectiveness is sensitive to environmental factors that are variable to field conditions. To increase the efficiency and the reliability of biological control, more science-based technology should be used. Intensive ecological research on the biology and ecology of both pests and natural enemies is required. But, what type of ecological research is needed? There are several good textbooks on biological control1–3. DeBach’s Biological Control is the first standard textbook; Huffaker and Messenger’s Theory and Practice in Biological Control is another encyclopedic textbook; and, recently, Driesche and Bellows released their version of Biological Control, and Bellows and Fisher4 released the edited Handbook of Biological Control. Although these textbooks have some chapters on the theoretical bases of biological control, they do not provide any critical appraisal of the current methods. About a decade ago, Mackauer et al.5 released Critical Issues in Biological Control which emphasized the importance of the scientific basis of biological control and contained numerous ideas for future research. Recently, theoretical and empirical research into biological control, which includes theoretical studies of host–parasitoid or prey–predator population dynamics, has made considerable progress (i.e. stage-structured, spatially structured, individually based and tri-trophic population models). Considerable progress has also been made in the behavioral ecology of parasitoids, such as host-feeding, host selection and sex allocation. The discovery of microorganisms that induce thelytoky (i.e. parthenogenesis in which females give rise only to female offspring; for example, uniparental reproduction of Trichogramma spp. and other parasitoids infected by Wolbachia) of parasitoids is another step forward for sex ratio modification technology in natural enemies. Application of population models to improve microbial control is also a hot field, although epidemiology itself is not new. We had been looking forward to a new critical book on biological control for the next decade. Therefore, Theoretical Approaches to Biological Control is a timely volume, which covers all the recent debates related to biological control. I am not satisfied with the present status of the scientific basis of biological control6 and hope that this new book will direct future study.

Masami Takagi Institute of Biological Control, Faculty of Agriculture, Kyushu University, Fukuoka 812-8581, Japan ([email protected])

References 1 DeBach, P., ed. (1974) Biological Control of Insect Pests and Weeds, Reinhold 2 Huffaker, C.B. and Messenger, P.S., eds (1976) Theory and Practice in Biological Control, Academic Press 3 Van Driesche, R.G. and Bellows, T.S., Jr (1996) Biological Control, Chapman and Hall 4 Bellows, T.S. and Fisher, T.W. (1999) Handbook of Biological Control, Academic Press 5 Mackauer, M. et al. (1990) Critical Issues in Biological Control, Intercept 6 Takagi, M. (1999) Perspective of practical biological control and population theories. Res. Popul. Ecol. 41, 121–126

Morals, menarche and motherhood Death, Hope and Sex: Steps to an Evolutionary Ecology of Mind and Morality by James S. Chisholm Cambridge University Press, 1999. £47.50 hbk, £17.95 pbk (xiv 1 296 pages) ISBN 0 521 59281 X/0 521 59708 0

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hen first asked to teach a course in Human Sociobiology a few years ago, I was rather nervous: this topic is the notorious graveyard of many a promising career in anthropology. When outlining the basic principles in my first lecture, I explained to my students G.E. Moore’s naturalistic fallacy1, which states that it is wrong to argue from facts to values. I thought that the fig leaf of our philosophical ancestors would protect me from any hostility that the subject matter might evoke. But, even as I was explaining that ‘is’ does not make ‘ought’, it did not seem altogether correct to me. The subject matter did not in fact evoke any hostility in my students: adaptive interpretations of abortion, infanticide and cultural differences in the most personal aspects of life were digested with interest. Only once did I incur the wrath of my students. When outlining the circumstances in which altruism is expected to evolve, I pointed out that this explained why they did not give money to the Big Issue sellers who sit dejectedly on the pavements around the perimeters of the college. My students stated that they did give them money; however, I pointed out that they did not give them much, and that they were more likely to do so either if the recipient was of the opposite sex, or if they were accompanied by a friend of the opposite sex who could observe their generosity2. They insisted that there is some genuine

0169-5347/00/$ – see front matter © 2000 Elsevier Science Ltd. All rights reserved.

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BOOK REVIEWS altruism on this earth, and I hope that they are right. But, not withstanding this episode, I now teach that G.E. Moore was wrong. Chisholm devotes the first chapter of this book to how attitudes have been shifting, thanks to many authors on whose work he draws, towards his own view that evolutionary ecology does actually help us to understand precisely where our value systems come from. Our value systems are a product of evolution favouring attitudes that enhance our reproductive success. For example, courts are far more likely to be lenient to a mother who murders her newborn infant than to one who murders her teenage daughter. The National Health Service in Britain does not call women over sixty for breast cancer screening, in spite of the fact that their risk of the disease is high and increases steadily with age. The reproductive value of individuals suffering these risks is not explicitly alluded to in the justification of these decisions, but it is certainly convincing to argue that this is what influences such attitudes. Even cultural relativism, which is alive and well in many anthropology departments, but the bane of those arguing for universal human rights, can find some comfort in evolutionary ecology. When working as a field anthropologist, I lived in a society where the external genitalia of all four-yearold girls were removed without anaesthetic. This can only be described as a gross act of child abuse, the origins of which lie within asymmetries in the power of men and of women in that culture. But, the fact that mothers were arranging this mutilation in the best reproductive interests of their daughters, within the constraints of that society, at least enabled me to live with this tradition – even if somewhat uneasily. We do not expect people to do things that would seriously jeopardize their prospects of reproducing. This book does not restrict itself to arguing about morality – that must have been the Hope bit. The Death and Sex parts of the book draw more on psychology and on life history theory. One central theme is that we assess our own reproductive value in childhood based on how our parents treat us. Chisholm argues that if we assess our reproductive prospects and our life expectancy to be low, then this will influence our reproductive scheduling. In particular, he associates both early menarche and teenage motherhood with stressful childhood, and draws on a range of studies, mainly of Westerners, that support this view. Nobody from a population that does not use contraception would describe teenage motherhood as a syndrome in need of an explanation, and I suspect that it is the ponderous pace of reproduction in the rest of us that needs to be explained. Nonetheless, Chisholm’s thought experi-

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ment is logical and coherent. From evolutionary ecology, he has taken the notion that many phenotypes can arise from the same genotype, and that such variation can itself be understood in adaptive terms. This is a welcome departure from much of the evolutionary psychology found in increasingly large piles at your local bookshop. But, the other part of evolutionary ecology is the strong, formal, theoretical tradition combined with empirical tests. It is these other traditions that make evolutionary ecology so powerful and enable us to judge whether an idea is important. Life history models have a frustrating habit of predicting large differences in outcomes based on rather small changes to the assumptions and the parameters in a model. Similarly, empirical studies provide us with a range of different outcomes in closely related (or even the same) species, suggesting that the chaotic behaviour of the models might be an accurate reflection of the evolutionary process. Formal modelling would help us to assess whether changes in the expected lifespan of an individual really would be predicted to have an effect on the reproductive rate of the magnitude observed. Empirical studies of human life history are hampered by our longevity, but assisted by our habit of documenting our past. Thus, there is no reason, in principle, why these interesting ideas could not be explored further. References 1 Moore, G.E. (1903) Principia Ethica, Cambridge University Press 2 Goldberg, T.L. (1995) Altruism towards panhandlers: who gives? Hum. Nat. 6, 79–89

Ruth Mace Reader in Biological Anthropology, UCL, Gower Street, London, UK WC1E 6BT ([email protected])

A fish out of water Intertidal Fishes. Life in Two Worlds edited by M.H. Horn, K.L.M. Martin and M.A. Chotkowski Academic Press, 1999. $69.95 hbk (xiv 1 399) ISBN 0 12 356 040 3

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he fishes inhabiting the intertidal zone that fringes the world ocean are a fascinating and largely under-appreciated group. Many of these species tend to be overlooked because they are usually small and hidden from casual view. The assemblage

0169-5347/00/$ – see front matter © 2000 Elsevier Science Ltd. All rights reserved.

of fishes using the intertidal zone consists of both resident and transient species, but, because of nearshore sampling limitations during tidal immersion, resident species remaining in the intertidal zone during emersion are better characterized. Intertidal fishes are most abundant and most diverse on rocky shores where these cryptic, short-lived forms show adaptations for persistence in a periodically turbulent habitat (e.g. vision is the most important sense); they are distributed in characteristic vertical zonation patterns. Resident intertidal fish species belong to relatively few families and probably originated from subtidal ancestors. Although several traits suggest convergent evolution across families and genera (e.g. body plan, tolerance to desiccation, airbreathing ability and extended duration of parental care), at least some might be subtidal exaptations (pre-adaptations). Adapted as they are to ‘life in two worlds’ – alternately immersed in sea water and exposed to air – the resident intertidal fish species might hold clues to early tetrapod evolution. The varying degree to which intertidal fishes meet the challenge of this semi-terrestrial lifestyle offers intriguing research possibilities to physiologists,ecologists and systematists. Reflecting diverse research interests, Intertidal Fishes brings together 21 authors in 17 chapters; the book includes sections on physiological specializations, behavior and sensory systems, reproduction and recruitment, trophic relationships and community structure, and systematics, biogeography and evolution of these species. Some of today’s leading authorities in fish biology, ecology and phylogeny are among the authors: this is obvious in the overall high quality of the content and the writing. The editors are to be congratulated for assembling consistently well written chapters, which can sometimes be a problem in edited volumes. One of the salient features of almost every chapter is the discussion of promising research topics, particularly of interest to experienced and prospective professionals alike. For example, D.H. Evans et al. conclude with a list of eco-physiological questions regarding osmoregulation, maintenance of blood pH and nitrogen excretion in intertidal fishes that could stimulate a wealth of interesting research, including graduate theses. Several authors point out the need for improved phylogenies of intertidal fishes (e.g. R.N. Gibson and R.M. Yoshiyama, M.A. Chotkowski et al., and M.H. Horn). To date, relatively little is known of their molecular systematics1,2: although not prominently discussed in this book, molecular systematics could help determine the age and the origin of intertidal species, and the relationships of the intertidal and the subtidal fish taxa, thus resolving questions of adaptive radiation, TREE vol. 15, no. 1 January 2000