Searching behaviour: The behavioural ecology of finding resources

TREE vol. 6, no. 17, November

7997

References I Ginzburg, L.R. t 19861/. Theor. Biol. 122, 385-399 2 Michod, R.E. t 1981) Br. /. Phi/OS. Sci. 32, l-36 3 Eigen. M. f 1971 I Natorwissenschaften 58. 465523 4 Eigen. M. and Schuster, P. f 19791 The Hypercycle. Springer-Verlag 5 Von Kiedrowski, G. f 19861 Angew. Chem. 98,932-934 6 Zielinski, W.S. and Orgel, L.E. f 19871 Nature 327. 346347 7 Szathmary, E. (1989) in Oxford Surveys in Evolutionary Biology (Vol. 61 (Harvey, P.H. and Partridge, L.. eds). pp. 169-205, Oxford University Press 8 Szathmary, E. and Gladkih, 1. f 19891 1. Theor. Biol. 138, 55-58 9 DeAngelis, D.L.. Goldstein, R.A. and O’Neifl. R.V. f 19751 Ecology 56. 881-982 IO Szathmary. E. II9891 Trends Ecol. Eva/. 4, 200-204 II Hopf. F.A. and Hopf, F.W. 11985) Theor. Popol. Biol. 27, 27-50 12 Michod, R. f 1984) in A New Ecology (Price, P.W.. Slobodchikoff. C.N. and Gaud, W.S.. edsl. pp. 253-278, Wiley 13 Volterra. V. f 19381 Hum. Bio/. IO, l-l I 14 Philip, 1.R. (1957) Ecology 38, 107-I I I

I5 Eigen, M. and Winkler. R. f 1975) Das Spiel: Naturgesetze steuern den Zufa//, R. Piper Verlag I6 Fowler. R.C. f 19871 /. Sci. Explor. I, I l-20 I7 Szathmary, E. f 1986) Bioldgia 34, ‘3-37 I8 Hallam, T.G. ( 19861 in Mathematical Ecology: An introduction (Halfam. T.G. and Levin. S.A., edsl, pp. 241-285, SpringerVerlag 19 MacArthur, R.H. (19721 Geographical Ecology: Patterns in the Distributions of Species, Harper & Row 20 May, R.M. ( I973 1 Stability and Complexity in Mode/ Ecosystems, Princeton University Press 21 Roughgarden. I. II9791 Theory of Population Genetics and Evolutionary Ecology: An Introduction, Macmillan 22 Hutchinson, C.E. ( I9781 An /ntroduction to Population Ecology, Yale University Press 23 Menegozzi, L.N. and Lamb, W.E., fr i 1978) Phys. Rev. A 17, 701-732 24 Darwin, C. ( 1859) The Origin of Species by Means of Natural Selection. fohn IMurray 25 Bernstein, H., Byerly. H.C., Hopf. F.A. and Michod. R.E. i 19851/. Theor. Biol. I I7,665-690 26 Maynard Smith, I. (I9781 The Evo/ution of Sex, Cambridge University Press 27 Hopf. F.A. I I9901 in Organizationa/

Constraints on the Dynamics of Evolution (Maynard Smith, I. and Vida. G., edsf, pp. 357-372, Manchester University Press 28 Arthur, B.W. t 19891 Econ. 1. 99 (3941, I l&I31 29 Cause, C.F. ( 19341 The Struggle for Existence, Hafner 30 Szathmary. E.. Kotsis. M. and Scheuring, I. (19881 in Mathematical Ecology IHallam, T.C.. Gross, L.I. and Levin. S.A., edsl, pp. 46-68. World Scientific 31 Szathmary. E.. Scheuring, I., Kotsis, M. and Gladkih. I. II9901 in Organizational Constraints on the Dynamics of Evolution (Maynard Smith, f. and Vida, G., eds), pp. 279-289, Manchester University Press 32 King, G.A.M. f 1981 I BioSystems 13, 225-234 33 Kostitzin, V.H. (19401 Acta Biotheor. 5, 155-159 34 Vandermeer, f.H. and Boucher, D.H. ( I9781 /. Theor. Biol. 74, 549-558 35 Britton, N.F. (I9891 1. Theor. Biol. 136. 57-66 36 Michod, R. in 1990 Lectures in Complex Systems (Santa Fe Institute Studies in the Sciences of Complexity. Vol. Ill) f Nadel, L. and Stein, D.. edsf, Addison-Wesley iin press)

cesses1,2. However, the various fields have evolved somewhat in isolation of one another, although there are good examples of fruitful interactions, as with the study of aspects of spatial memory that has attracted researchers with backgrounds from psychology as well as those from ecology and behaviour3p4. On the functional side, the accumulated evidence shows that animals are quite efficient in the way they locate and utilize resources, and, as a corollary, that it is therefore possible to study such problems by using economic principles that take into account costs and benefits of behavioural actions in terms of fitnessrelevant criteria. Such analyses can become quite sophisticated and are no longer restricted to simple tasks, but can address stage-dependent behavioural policies over time5 or decisions in stochastic environment@. Furthermore, many of the problems that one would typically associate with searching behaviour, such as allocation of search effort in space, are notoriously difficult to solve. A classic is the travelling-salesman problem, where unconventional methods for numerical solutions7 could pave the way for a new look at the spatial behaviour of animals. On the other

hand, in the instances where the mechanics of problem solving by animals was analysed, despite all of the computational and conceptual complexity of the problem, often the actual decision rules or estimation procedures may actually be quite simple8. What is a characteristic of the topic of ‘searching behaviour’, therefore, is its relevance to a number of different disciplines and thevariety of methodological approaches and concepts used. The publication of Bell’s new treatise on the subject, specifying in its subtitle ‘the behavioural ecology of finding resources’, should thus be a timely addition. The subjects covered by this book explicitly not only include searching per se, but also the utilization of resources after they have been discovered. The book contains an ample collection of examples that in some sense or another relate to these issues. One should therefore applaud the intention of the author to bring together the various aspects in a single volume and make it understandable for a broad audience. In part, this aim has been achieved. It is, for example, useful that each section of the book is summarized, allowing specialists in particular

Book Reviews Behavioural Ecology Searching Behaviour: The Behavioural Ecology of Finding Resources by W.J. Bell, Chapman & Hall, f35.00 hbk (xii + 358 paged 0472292706

7997. lSBN

Almost by definition, one of the most important tasksfor mobileorganisms is to search for the resources they need to survive and reproduce. That includes things such as looking for food, mates or a safe place to evade predators. Animals show a bewildering variety of behaviours associated with this task, and it is likely that the strategies of plants, albeit expressed in different ways and on different time scales, will demonstrate an equally intricate fabric towards the same ends. Traditionally, the more functional questions about searching behaviour have been the domain of behavioural ecology (mostly), while the more proximate questions have been of interest to physiology, ethology or psychology. Moreover, since exploitation of resources, notably of food, has repercussions for populations and species assemblages, this question has always been of concern for ecologists trying to understand the mechanics of ecological pro370

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topics to skip those of secondary interest. The chosen studies are explained in some detail, so that they could be understood by people not particularly familiar with a given beast. The illustrations are generally useful, and the section on methodology makes a good start. However, I am afraid that I was left somewhat insecure as to what the book was really about, and felt that it comes as a rather mixed bag. In some ways, because the book strives for a very broad coverage, with remorseless consequence it falls short of much. In addition, despite the aim of concentrating on mechanisms, the treatment of functional questions is very prominent throughout the text, particularly with respect to foraging for food. One does not have to be an addict of foraging theory to conclude that Bell’s treatment of this subject is not very helpful and is likely to create some confusion about the intricacies of giving-up times, threshold rates or central-place foraging systems. Given the broad scope of the book, some issues have of course to be neglected. But all too often, as for example in the coverage of learning theory and the implications of operant psychology (e.g. the matching law) for searching behaviour, the text does not do justice to many of the more relevant studies (e.g. by people such as Staddong and many otherslo). Often the author jumps to generalities that are not substantiated by the text. For example, we learn that conditioning is the most common type of learning in searching behaviour (actually the section on exploratory behaviour is rather short), that the most common conditioning of perception is search-image formation (after this has been questioned a few pages before), that most animals that show central-place foraging are social species and so forth. This may or may not be true, butthe reader is left wondering why this generality is proposed. Similar remarks would apply to the citation of the formulae, most of which stand without use, whereas in the methodological section some more would have been appreciated. Searching behaviour is indeed a multidisciplinary topic. So by synthesizing the various aspects, this book could have filled an important gap and perhaps will help to galvanize a common perception of the problems. For the time being, however, it will mostly be useful for those shopping for examples about the functions and mechanisms involved in searching behaviour. Yet, be advised that this book is not for the unwary, but rather requires that you

carefully read and place things in order. I would therefore not trust it to the hands of unprepared students, for whereas they can gain access to many different aspects of the problem, much confusion about the various subjects could result too.

Paul Schmid-Hempel Zoologisches

lnstitut der Universitdt, Rheinsprung 9, CH-4051 Easel, Switzerland

References 1 MacArthur, R.M. (1972) Geographical Ecology, Princeton University Press 2 Werner, E.E., Gilliam, J.F., Hall, D.J. and Mittelbach, C.G. (1983) Ecology64,

1540-I 550 3 Sherry, D.F. (1985) Adv. Stud. Behav. 15,338348 4 Smith, C.C. and Reichmann, O.J. (1984) Annu. Rev. Ecol. Syst. 15,329-352 5 Mangel, M. and Clark, C. (1988) Dynamic Programming in Behavioural Ecology, Princeton University Press 6 Stephens, D.W. (1988) Am. Nat. 134, 128-140 7 Brady, R.M. (1985) Nature 317, 804-806 8 Seeley, T.D. (1977) Behav. Ecol. Sociobiol. 2, 201-227 9 Staddon, J.E.R. (1980) in Limits to Action: the Allocation of Individual Behavior (Staddon, J.E.R., ed.), pp. 101-141, Academic Press 10 Gibbon, J., Church, R.M., Fairhurst, S. and Kacelnik, A. (1988) Psycho/. Rev. 95, 102-I 14

Aquatic Ecology Fundamentals of Aquatic Ecology edited Mann, cations, (vii f

by

R.S.K.

Barnes

and

K.H.

Blackwell Scientific Publi1991. f39.50 hbk, f 18.50 pbk 264 pages) ISBN 0 632 02983 8

It is a bone of contention amongst aquatic ecologists that their discipline has largely lived in the shadow of terrestrial ecology. This is surprising, given that aquatic habitats cover over 70% of the surface of the globe, but also understandable. There have been problems in larval systematics, difficulties in quantitatively sampling complex, patchy and multidimensional habitats (the extensive vertical dimension of many aquatic habitats is virtually absent in terrestrial systems), and almost no exchange of ideas between marine and freshwater ecologists. The two aquatic areas have historically been separate disciplines, each with its own independent societies, institutes, journals, undergraduate courses and textbooks. So it was not until fairly recently that aquatic ecologists overcame their prejudices and started to seek a mutually beneficial common thread, a similarity in pattern or process, that might underpin both freshwater and marine ecology. The first edition of Barnes and Mann’s book (Fundamentals tems) was

of

Aquatic

Ecosys-

amongst the first to try. The second edition takes things a bit further, with a new title, new topics and new contributors, but the same goal of seeking some fundamental unity between the structure and functioning of aquatic habitats. The new book is divided into five parts. An introduction is followed by a section mainly restricted to open: water and deep-sea ecosystems, exploring processes (largely physical,

involving nutrients and gases, and planktonic productivity) and interactions with biogeochemical cycles and climate on a larger scale. Part 3 (concentrating on invertebrates) covers community organization, reproduction and life histories, speciation and biogeography, and specialist feeding mechanisms. Part 4 covers the basic ecology of two habitats peculiar to aquatic systems (reefs and streams and rivers) and the book concludes with an overview of the impact of human activities. The contributors are well known, and the book is full of interest for specialist and generalist alike. Some readers will relish the restricted number of references (a deliberate editorial policy), as it improves the flow of the text, although frankly I found it frustrating. Repetition arises from insufficient integration between chapters, which sometimes appear as rather isolated entities. Editorial sections linking the various chapters are sorely missed. These niggles notwithstanding, the book is very well worth reading and should find itself on every aquatic ecologist’s bookshelf. But what does it tell us? How far have we got on the road to unity? There are some obvious similarities, such as in the outcome of competition, predation and disturbance within freshwater and marine habitats, and in specialist feeding mechanisms (suspension feeding and symbiosis with internal autotrophs). But, there is also a clear d,ivide between the ‘three-dimensional’ lakes and oceans and the ‘two-dimensional’ streams, rivers and intertidal areas. Lakes and oceans are clearly the most similar; the book stresses the interplay of physical, chemical and

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