Ecology and natural history of tropical bees

TREE vol. 5, no. IO, October

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Mammal Phylogeny

The Evolution of Perissodactyls extinction events on perissodactyl diversity are also presented. edited by Donald R. Prothero and The book gives a good feeling for Robert M. Schoch, Oxford University the conclusions reached by the parPress (Oxford Monographs on Geolticipants in a workshop held in 1985, I:lgy and Geophysics, 15), 1989. f55.00 upon which the book is based. How,Llbk Ix + 537pages) ISBN 0 195060393 ever, the balance and content of the chapters isveryvariable. Mammalian ‘:-he pattern of mammalian evolution systematists will read the contriis of great interest at present1r2, not butions by Fischer (evidence that only because a clear-cut model of phyhyracoids are the sister group of 13geny is an essential prerequisite perissodactyls), Hooker (the place of ior many evolutionary and ecologiHyracotherium in horse evolution), cal studies, but also because such Evander (cladogram of horses), rnodels are proving very hard to work Lucas and Sobus (the giant inout. There are two major approaches dricotheres) and Mader (brontothere .-. cladistic analysis of morphological phylogeny) with particular interest; r:haracters, and molecular sequencmany of the others are based, to ‘ng - and each has advantages, but some extent at least, on work already ~leither is yielding quite the un- published elsewhere. equivocal results that were expected. The book succeeds better than Prothero and Schoch’s book conmany of its type in being comprehenI::erns only one of the 20 or so orders sive - every perissodactyl taxon is Iof placental mammals: the perissodealt with somewhere, whether in dedactyls (horses, tapirs, rhinoceroses tail or only briefly. The volume also Elnd extinct relatives). Today, the succeeds in extracting a consensus i;lroup is relatively small, containing view on a number of radical phyloonly six genera (or nine if hyraxes are genetic proposals. The consensus !ncluded), but extinct representatives may be genuine, although others taring the total up to about 250 genera might argue that it was achieved distributed in 20 or so families. The by the choice of contributors! For book contains two introductory chapexample, Novacek and co-workers3r4 ters, and 27 contributions by various strongly dispute the close pairing of ::ombinations of 28 authors from all hyraxes and perissodactyls. Further, parts of the world. Most of the chapthe molecular data are not tackled ters cover the phylogeny of major directly, although Fischer refers groups within the Perissodactyla, alihough several focus on individual laxa. The editors provide an excellent :;ynthesis of the views presented in Ihe volume, but there may not be Ecology and Natural History of Tropical Bees quite such agreement as they imply c)n some of the ‘consensus’ views by David W. Roubik, Cambridge Unilhey enumerate. The findings of the versity Press (Cambridge Tropical Bi\larious contributors give the folology Series), 1989. f50.00/$69.50 hbk lowing picture of perissodactyl evol(x + 514 pages) ISBN 0 527 26236 4 ution. The group arose in Asia or Africa in the Late Palaeocene, 60 million Tropical bee communities may not be l/ears ago, from a common ancestor notable for numbers of species, but in shared with the tethytheres (probdiversity of habit and lifestyle they far oscideans, sirenians, desmostylians) exceed those of temperate regions. (and arsinoitheres. Hyraxes, otherThey are special partly because they Iwise associated with the tethytheres, include so many eusocial species are here regarded as true perissodacwith large perennial colonies. Like lyls. The hyraxes diverged first and hummingbirds, perennial colonies of :.adiated in Africa, and later spread to highly eusocial bees are largely conEurasia. The remaining perissodacfined to climates where flowers are ‘yls then split into three main groups available all year round. In the Early Eocene: the titanotheres For a temperate-zone ecologist, (found in Asia and North America in perhaps the most novel and characteristic elements in a tropical bee Ihe Late Eocene to Oligocene), the community are the stingless bees hippomorphs (horses, palaeotheres) ,jnd the moropomorphs (tapirs, (Meliponinae) which are particularly abundant, ubiquitous and diverse in I-hinos, chalicotheres), the last two ibeing important in the northern neotropical forests. A single tree may house more than 20 nests of several iiemisphere from the Eocene onwards. Radical new models of the species. Some inhabit the nests old stories about the early history of of termites, and one occupies caviexcavated by pangolins in the horses, and about the effects of ties

to results that have a bearing on the hyrax-perissodactyl question. The small numbers of living, compared to extinct, taxa will reduce the value of molecular approaches to reconstructing the phylogeny of the perissodactyls. This book is a tribute to the industry of the editors, who also contribute or co-contribute nine of the 29 articles, and who helped to keep the price below what it might have been by retyping everything on a desk-top publishing system before sending it to their publisher. This has not caused any serious fall-off in quality. This massive database will supply the needs of many palaeontologists, mammalian systematists and evolutionists.

Michael J. Benton Deptof Geology,Universityof Bristol,Bristol BS8lRJ, UK References 1 Benton, M.J. (1988) Trends Ecol. Evol. 3,40-45 2 Janis, CM. (1988) Trends Ecol. Evol. 3, 291-297 3 Novacek, M.J. and Wyss, AR (1986) Cladistics 2, 257-287 4 Novacek, M.J., Wyss, A.R. and McKenna, M.C. (1988) Syst. Assoc. Spec. Vol. 35B, 31-71

Tropical Entomology Crematogaster ant nests. Most collect nectar and pollen from flowers; when they forage on flowers evidently adapted for pollination by other agents such as wind, bats or birds it is not clear whether they operate as thieves or as pollinators. Some raid the nests of other bees for provisions and nesting materials. For Lestrimelitta limao, this prudent robbery is a way of life. Raids, mediated by chemical weapons, result in many deaths, but often leave enough survivors to allow the violated colony to persist and accumulate further provisions, only to be robbed again later by the same colony of L. limao. Other stingless bees eat meat. A band of worker bees can quickly demolish a dead lizard or frog, spitting enzymes into the carcase and then sucking the partially digested flesh into the crop to carry it to the nest where it is stored and fed to the brood. The provisioned nest of a stingless bee colony is a commodity valuable to a range of organisms from microorganisms to humans. It may be exploited by larger animals (notably 347

TREE vol. 5, no. 10, October

humans and honey badgers working in collaboration with birds, the honeyguides) and will house an assemblage of smaller associates, in which bacteria, yeasts, mites, beetles and flies interact in ways that may or may not ultimately benefit the bees. As well as stingless bees, other social and solitary bees are considered in comparable detail. Roubik bringstogetherthefragmentarywork on the biology of the exotic and ornamental euglossine orchid bees of the neotropics, pointing out that we still do not know why male orchid bees collect orchid fragrances and other compounds, including DDT. In the context of the wider treatment of tropical bee ecology, he provides an authoritative synthesis of the ecology of Africanized honeybees in the neotropical regions, where their spread is causing so much interest and concern.

1990

One way to begin to understand the ecology of a complex community is to focus on a single group. Bees are particularly appropriate, because of their interactions with plantsand with so many other organisms. In this sense, the book offers a picture of an important part of the tropical world. But inevitably the picture is still patchy. Like palaeontologists faced with an incomplete fossil record, tropical ecologists must try to complete the picture by setting fragments of evidence in a matrix of speculation. The fragments are sometimes very small and far apart, because (with notable exceptions, such as Roubik’s own work) so many tropical studies are short-term and opportunistic, lacking the continuity and context of known natural history that is our unacknowledged endowment in Europe. If we start to build the picture too soon, the speculative matrix will

be extensive, and may solidify into gospel before it can be tested. Roubik acknowledges that risk but argues persuasively that over-long delay would be even more dangerous. Many of the perennial eusocial species that dominate tropical bee communities are denizens of undisturbed rain forest, nesting in mature, living trees. As forests are destroyed, bee communities will be lost. As a stimulus for further research, this book is needed now. It will be valued for its substantial and wideranging bibliography, as well as for the text, which is a carefully organized mosaic of sparkling fragments giving tempting glimpses of a relatively unexplored world.

into the early 198Os, literature of the last 20 years has not been used in the text to any great extent. There are fields of botanical research that have had a large impact on our understanding of floral structure in the’last 20 years. Since the 1970s a new wave of ontogenetic studies, made possible by the availabilityofthescanningelectron microscope, led to an expansion of our knowledge of patterns and plasticity of floral ontogeny2. In the 198Os, unprecedented paleobotanical finds of Cretaceous flowers modified our view on early floral evolution*5. Extensive studies (e.g. Ref. 6) of reproductive biology brought to light an immense amount of plasticity in floral behaviour. Systematic studies have influenced our knowledge of evolutionary trends in flowers. These developments have not been sufficiently incorporated into this book. The three main sections of the book are: ‘Morphology of flowers’, ‘Morphology of the inflorescence’ and ‘The flower as a formal and functional entity - aspects of the biology of pollination and dispersal’. Emphasis is laid on basic morphological categories, such as ‘leaf’ and ‘axis’ in the flower, and on subcategories like sepals, petals, stamens and carpels. In contrast, although fusions of floral organs are well treated, synorganization is not extensively discussed. Many floral parts, which appear as mere curiosities if discussed in isolation, make more sense in the light of floral synorganization. The emphasis throughout is on temperate plant groups.

All the sections contain a large number of perhaps unfamiliar technical terms. These may have proved useful to many morphologists, but they may also hide a dangerous side: if we try to understand the evolution of a particular group of plants we have to approach it in a manner as flexible as possible rather than be diverted by a too strict and closemeshed terminology. Many of the phenomena discussed in the work are excellently illustrated with elaborate line drawings and (especially for the inflorescences) beautiful photographs. The book, in its rich content, is certainly a treasure for every botanist who is interested in floral structure. But it also shows how much we now need more modern syntheses on flower structure, function and evolution.

Sarah A. Corbet University, Downing Deptof Zoology,Cambridge Street,Cambridge CB23EJ,UK

Floral Structure Morphology of Flowers and lnflorescences by F. Weberling, Cambridge University Press, 1989. f55.00/$110.00 hbk (xx + 405 pages) ISBN 0 52125134 6 How can we understand flowers? One of the most profitable apmorproaches is comparative phology. It is important to update morphological surveys of all groups of organisms for the further advancement of evolutionary biology, especially since - as Riedl’ puts it: ‘there have been, say 200 years of scientific biology, and for 150 of those years morphology was its backbone. But after scarcely 50 years of experimental study we are on the point of losing this backbone entirely. This would mean losing the method which gave scientific proof of relationship, descent, and phylogeny in general’. In this light, the translation of Weberling’s work is of great significance and must be warmly welcomed. The first publication of Morphology of Flowers and Infiorescences, in 1981, was in German. Except for the addition of a glossary and some new references there are no changes in this edition. The translation by R.J. Pankhurst is very careful and keeps the personal style of the author. The book is based on what has been studied by German and other European morphologists up to the early 1970s. Therefore, the statement on the cover that the book gives a ‘summary of current understanding of flower and inflorescence morphology’ is misleading. Although there is a reference list that extends 348

Peter K. Endress Instituteof Systematic Botany,Universityof Zurich, Zollikerstrasse 107,EOOEZurich, Switzerland References 1 Riedl, R. (1978) Order in Living Organisms, Wiley 2 Endress, P.K. (1990) Biol. J. Linn. Sot. 39,153-175 3 Dilcher, D.L. (1979) Rev. Palaeobot. Palynol. 27, 291-328 4 Friis. E.M.. Chaloner. W.G. and Crane, P.R., eds (1987) The Origins of Angiosperms and Their Biological Consequences, Cambridge University Press 5 Crane, P.R. and Blackmore, S., eds (1989) Evolution, Systematics, and Fossil History of the Hammelidae (Vol. I), Clarendon Press 6 Richards, A.J. (1986) P/ant Breeding Systems, Allen & Unwin