Advances in ECOLOGICAL RESEARCH Edited by J. B. CRAGG The Nature Conservancy, Merlewood Research Station, Grange-over-Sands, Lancashire, England VOLUME 2 1964 ACADEMIC PRESS London and New York ACADEMIC PRESS INC. (LONDON) LTD. BERKELEY SQUARE HOUSE LONDON,W.1 U.S. Edition published by ACADEMIC PRESS INC. 111 FreTH A v E ~ NEW , YORK10003, NEWYORX Copyright @ 1964 by Academic Press Inc. (London) Ltd. Second Printing 1968 All rights reserved N O PART O W THIS BOOK MAY BE REPRODUCED IN ANY FORM BY PHOTOSTAT, MICROFILM OR ANY OTHER MEANS, WITHOUT WRITTEN PERMISSION FROM THE PUBLISHERS Library of Congress Catalog Card Number: 62-21479 Contributors to Volume 2 J. R. BRAY,Botany Division, D.S.I.R. Zealund. Palmerston North, New M. B.DALE,Botany Department, University of Southampton, England. E. GORHAM, Botany Department, University of Minnesota, Minneapolis, Minnesota, U.S.A. J. HESLOP-HARRISON, Department of Botany, University of Birmingham, England. J. M. LAMBERT, Botany Department, University of Southampton, England. M. E. SOLOMON, Agricultural Research Council, Pest Infestation Laboratory, Slough, England. Preface The main aim of Advances in Ecological Research, as was pointed out in the preface to Volume 1,is “. . .to present comprehensive accounts of selected topics of ecological research in such a way that biologists with a general interest in ecology as well as specialists in ecology, can obtain a balanced picture of what is taking place”. Mr. M. E. Solomon’s review of processes involved in the natural control of insects will certainly not be the last word in,this very controversial field of study. In taking the insects as his basic material and utilizing information from other groups of animals, he has presented a personal viewpoint of this branch of population dynamics. This should help the general ecologist who cannot hope to keep up with the vast literature and provide workers in population dynamics with many points for discussion and development. I n the first number of Advances, Professor M. E. D. Poore gave an account of his approach to the analysis and description of plant communities. His discussion of classification was of value to animal as well as to plant ecologists. I n this number Dr. Joyce Lambert and Mr. M. B. Dale have looked at the classification of plant communities in a different way and they challenge some of the views expressed by Professor Poore. Their paper, in discussing methods of analysing phytosociological data, gives readers a chance of assessing the value of computers in this branch of ecology. Now that the International Biological Programme is taking shape, the information and discussion in Dr. Gorham’s and Dr. Bray’s paper will provide a valuable starting point for those who will soon be engaged in studying the production of terrestrial communities as part of an international effort. Finally Professor J. Heslop-Harrison’s extensive review of genecology provides the ecologist not familiar with the extensive links between genetics and plant ecology, with a broad perspective of the subject and presents a challenge to the animal ecologist. It was originally planned that Advances in Ecological Research should appear every two years. However, sufficient contributions of high quality are coming forward to justify annual volumes. J. B.CRAUU September, 1964 vii Analysis of Processes Involved in the Natural Control of Insects . . M E SOLOMON Agricultural Research Council. Pest Infestation Laboratory. Slough. England I . Introduction .......................................................... I1. ConceptsandTerms ................................................... I11 Three Types of Processes influencing Abundance...............