Advances in ECOLOGICAL RESEARCH VOLUME 23 This Page Intentionally Left Blank Advances in ECOLOGICAL RESEARCH Edited by M. BEGON Department of Zoology, University of Liverpool, Liverpool, L69 3BX, UK A. H. FITTER Department of Biology, University of York, York, YO1 SDD, UK VOLUME 23 ACADEMIC PRESS Harcourt Brace Jovanovich, Publishers London San Diego New York Boston Sydney Tokyo Toronto ACADEMIC PRESS LTD 24/28 Oval Road London NWI 7DX United States Edition published by ACADEMIC PRESS INC. San Diego, CA 92101 Copyright 0 1992 by ACADEMIC PRESS LIMITED AN Rights Reserved No part of this book may be reproduced in any form by photostat, microfilm, or any other means, without written permission from the publishers British Library Cataloguing in Publication Data Advances in ecological research. Vol. 23 I . Ecology 1. Begon, Michael 574.5 ISBN&l2413923-5 This book is printed on acid-free paper Typeset by Latimer Trend & Company Ltd, Plymouth Printed in Great Britain by T. J. Press (Padstow) Ltd, Padstow, Cornwall. Contributors to Volume 23 A. D. Q. AGNEW, Department of Biological Sciences, University College of Wales, Aherystwyth SY23 3DA, UK. J. BASTOW WILSON, Botany Department. University of Otago, PO Box 56, Dunedin, New Zealand. M . L. CIPOLLINI, Department of Biological Sciences, Rutgers University, New Brunswick, NJ 08855-1059, USA. R. M . M. CRAWFORD, Department of Biology and Preclinical Medicine, Sir Harold Mitchell Building, The University, St Andrews. Fife KY16 9AL, UK. H. LAMBERS, Department of Plant Ecology and Evolutionary Biology, PO Box 800.84, NL-3508 T B Utrecht. The Netherlands. J . LUSSENHOP, Department of Biological Sciences, University of Illinois at Chicago, Box 4348, Chicago, I L 60680, USA. H. POORTER, Department of Plant Ecology and Evolutionary Biology, PO Box 800.84, NL-3508 T B Utrecht, The Netherlands. E. W. STILES, Department of Biological Sciences, Rutgers University, New Brunswick, N J 08855-1059. USA. This Page Intentionally Left Blank Preface The contributions to this volume are linked by their concern with topics or questions that have suffered a degree of neglect. Nobody can now seriously doubt the crucial importance of biotic interactions, hidden from the sight of most ecologists, within the soil, nor of the increasing necessity of conscious management of the soil biota, within agricultural and forest soils at least. Interactions between micro-organisms and micro-arthropods are central to many, if not most, soil processes. Lussenhop reviews what is known of the mechanisms through which these interactions occur, focusing separately on saprophytic systems and the rhizosphere, and ranging from simple grazing and dispersal, through the stimulation of microbial activity, to the potential regulation of pathogens. The conclusion, as so often, seems to be that the steps from description to useful quantification have yet to be taken. The co-evolutionary pressures connecting plants and their potential consumers are rarely if ever straightforward. Certainly, those addressed by Cipollini and Stiles, between fleshy fruits, their vertebrate dispersers and fruit-rot fungi are complex and subtle. In the past, studies of the secondary chemicals of fleshy fruits have concentrated on the almost certainly atypical, highly-selected cultivated species. By contrast, these authors evaluate selection pressures in a more general and natural context, generate a number of broad hypotheses, and then, using their own work with Ericaceous species as a springboard, show how these predictions may be given added specificity.