PHYTOPHAGOUS COLEOPTERA ASSOCIATED WITH HABITATS OF DIFFERENT SUCCESSIONAL AGE PAUL SPENCER HYMAN, B.Sc. (C.N.A.A.). A thesis submitted for the degree of Doctor of Philosophy of the University of London and for the Diploma of Imperial College. Department of Pure and Applied Biology, Imperial College, Si1wood Park, Ascot, Berkshire. May 1983. - %i - the memory of my father Gerry To my mother Mavis, and Alan and to my Uncle Joe - -iti - ABSTRACT Phytophagous Coleoptera from the superfamilies Curculionoidea and Chrysomeloidea are described and compared in relation to plant assemblages along a successional gradient. Experimental sites at Silwood Park, Berkshire represented areas of different successional age. A series of sites, established between 1977-1981 from harrowed land comprised, an early succession 0-5 years old, an area of per- manent grassland a mid successional site, 10-11 years old, and a pre- dominantly birch woodland a late successional site, in excess of 60 years old. Insect material was collected from ground vegetation using a D-vac. suction sampler, whilst material from the birch canopy was collected using a beating bag. All ground vegetation was monitored using pin quadrats. Canopy foliage was not recorded. All beetles and plants were identified to species. Ecological trends in diversity (a and 6), dominance and equita- bility for beetles and plants are described and compared along the successional gradient and discussed in terms of current ecological theory. Insect/plant interactions are analysed and discussed in terms of previously described ecological trends, degree of specialism (feeding specificity) of beetles, niche (diet) breadth, plant apparency and plant life-form (life-history strategy). Changes in community organ- ization of beetles and plants are investigated using an ordination method, Reciprocal Averaging. - iv ~ ACKNOWLEDGEMENTS I wish to thank the following people who have either given advice or who have helped with fieldwork during this project:- Firstly my supervisor, Dr. V.K. Brown, for her patience, encour- agement and advice throughout the course of this project. Prof. M.J. Way for allowing me to use facilities at Silwood Park. Dr. C.A. Stinson for help with D-vac. sampling in 1980, for D-vac. sam- pling site 1-81 in 1981 and for plant recording in sites 1-80 (in 1980) and 1-81 (in 1981). Ms. S.A. Wintcai for help with D-vac. sam- pling in 1981. Dr. M. Cox (C.I.E., at the British Museum, Natural History) for the identification of all Attica and Longitarsus specimens, all leaf-beetles for years 1977-79, and the confirmation of identi- fication of all leaf-beetles other than the genera Attica and Longitarsus for 1980 samples. Dr. A. Morton for all matters pertaining to the use of Reciprocal Averaging. Prof. R.G. Davies for all matters concerning Canonical Correlation. Dr. A.R. Ludlow for statistical advice. Dr. M.J. Crawley for statistical advice and the confirmation of identification of some plants. Finally, I wish to thank Miss R. Morrison for typing this thesis. - mmdcxxxiii - CONTENTS PAGE ABSTRACT m ACKNOWLEDGEMENTS ^ TABLE OF CONTENTS v LIST OF TABLES vm LIST OF FIGURES ^ LIST OF APPENDICES ^ 1. INTRODUCTION x 2. MATERIALS AND METHODS 9 2.1 Description of Sites 9 2.1.1 Site names and symbols 10 2.2 1977-1979 Samples 10 2.3 Sampling Methods 12 2.3.1 Insect sampling methods 12 2.3.1.1 Grassland sampling 12 2.3.1.2 Canopy sampling 14 2.3.2 Plant recording techniques 14 2.3.3 Time of sampling lg 2.4 Data Recorded Using Pin Quadrats lg 2.5 Identification and Sorting 17 2.5.1 Plant identification 17 2.5.2 Insect sorting ... ig 2.5.3 Insect identification 18 2.6 Indices Used in this Study Ig 3. ECOLOGICAL TRENDS IN PLANTS DURING SUCCESSION 22 3.1 Cover and Species Richness 22 - vi ~ PAGE 3.2 Diversity, Equitability and Dominance 35 3.3 Life-Form 51 3.4 3- Diversity 56 3.5 Discussion 59 4. ECOLOGICAL TRENDS IN INSECTS DURING SUCCESSION 67 4.1 Abundance and Species Richness 67 4.2 Diversity, Equitability and Dominance 77 4.3 3- Diversity 102 4.4 Discussion 102 5. INSECT-PLANT RELATIONSHIPS DURING SUCCESSION 112 5.1 Taxonomic Diversity, Colonisation and Dominance 112 5.1.1 Taxonomic diversity 112 5.1.2 Colonisation 117 5.1.3 Dominance 122 5.2 3- Diversity 122 5.3 Degree of Specialism and Niche Breadth 127 5.3.1 Niche (diet) breadth 143 5.3.2 Canonical Correlation Analysis 148 5.4 Degree of Specialism and Plant Apparency 150 5.5 Summary 152 6. ORDINATION 157 6.1 Introduction 157 6.2 Reciprocal Averaging (R.A.) 161 6.3 Ordination of Sites 162 6.4 Ordination of Species 180 - vii - PAGE 7. DISCUSSION 184 REFERENCES 198 APPENDICES 1) Species Lists a) Plants 214 b) Weevils 220 c) Leaf-beetles 232 2) Primary Data Sheets a) Plants 236 b) Weevils 265 c) Leaf-beetles 288 3) Reciprocal Averaging Scores a) Herbs 300 b) Weevils 304 c) Leaf-beetles 307 d) Herbs and Weevils (sites, 1977-1981) 309 - viii ~ LIST OF TABLES PAGE TABLE 2.1 Summary of Symbols and Terminology for .successional sites sampled in 1980 and 1981. 11 TABLE 3.1 Dominance values for Herbs and Grasses (treated separately) , using the Dominance Index (ni/N) 45 TABLE 4.1 Abundance (N) and Species Richness (S) of phytophagous Coleoptera during succession. 68 TABLE 4.2 Abundance (N) and Species Richness of Leaf-Beetles during succession. 74 TABLE 4.3 Equitability (J1 ) for Weevils and Leaf-Beetles during succession. 92 TABLE 4.4 Dominance values for Weevils and Leaf-Beetles (treated separately) using the Dominance Index (ni/N) . a A - ix - PAGE TABLE 5.1 Correlation coefficients between 8 - diversity (Indices of Similarity, I and J^ for Herbs, Weevils and Leaf-Beetles from early and mid successional stages. 126 TABLE 5.2 Correlation matrices between Feeding Specificity of Weevils and Leaf-Beetles and the Life-Form of Herbs, using Abundance and Species Composition 142 TABLE 5.3 Correlation coefficients between potential Host- Plants and associated Weevils in early and mid succession using Abundance and Species Composition. 144 TABLE 5.4 Diet Breadth for Weevils during succession. 149 TABLE 5.5 Coevolution between Plants and Herbivores reproduced from Rhoades (1979, Fig. 1A p. 29), superimposed with pathways indicated (broken line) for Weevils 153 - mmdcxxxviii - PAGE TABLE 6.1 Correlates between successional age and axis 1 (using R.A. ordination) for Herbs, Weevils, and Leaf-Beetles (1980-81). 163 TABLE 6.2 Correlates between secondary gradients (Life-Form and Feeding Specificity) and axes 1 and 2 (R.A.) for Herbs, Weevils and Leaf-Beetles. 173 TABLE 6.3 Correlates between Herb attributes (Life-Form) and axes 1 and 2 (R.A.) for Weevils and Leaf-Beetles. 174 TABLE 6.4 Comparison between literature Host-Plant records (in order of number of records per weevil) and R.A. predictions for Tri,folium species and associated Weevils (listed in order of successional position) 183 - xi - LIST OF FIGURES PAGE FIG. 3.1 Vegetation Cover (%) during succession. 24 FIG. 3.2 Plant Species Richness (S) during succession. Data for 1980 field season. 26 FIG. 3.3 Herb and Grass Cover (%) during succession 29 FIG. 3.4 Herb and Grass Species Richness (S) during succession. 33 FIG. 3.5 Herb and Grass Diversity (a) during succession 37 FIG. 3.6 Herb and Grass Diversity (H ) during succession 39 FIG. 3.7 Log. abundance curves for Herbs in relation to successional age. For samples taken in August. 41 FIG. 3.8 Herb and Grass Equitability (J ) during succession 44 FIG. 3.9 Percentage contribution of Annuals, Biennials, Perennials and Seedling Trees/Shrubs during succession, based on Cover and Species Composition 53 FIG. 3.10 Diversity (3) for Herbs during succession 58 - xii - PAGE FIG. 4.1 Abundance (N) of Weevils during succession y^ FIG. 4.2 Species Richness (S) of Weevils during succession yg FIG. 4.3 Diversity (a) of Weevils during succession g2 FIG. 4.4 Diversity (a) of Leaf-Beetles during succession g4 t FIG. 4.5 Diversity (H ) of Weevils during succession gg » FIG. 4.6 Diversity (H ) of Leaf-Beetles during succession gg FIG. 4.7 Log. abundance curves for Weevils in relation to successional age. For samples taken in August. 91 FIG. 4.8 Diversity (6) for Weevils during succession 104 FIG. 4.9 Diversity (3) for Leaf-Beetles during succession iQg FIG. 4.10 Species Richness (S) and Diversity (a) for Weevils along a successional gradient. Data for 1977-81 samples. 109 FIG. 5.1 Comparative Diversities (a) of Plants, Insects (total Heteroptera and Coleoptera) and Weevils in relation to log. successional age of the habitat. Data for 1977-78. 114 - xiii - PAGE FIG. 5.2 Comparative Diversities (a) of Herbs, Weevils and Leaf-Beetles in relation to log. successional age of the habitat. Data for 1980-81. 116 FIG. 5.3 Species gain of Herbs, Annuals (= Annuals + Biennials) and Perennials (= Perennials + Trees/Shrubs) during succession. Data based on 1980 field season. 119 FIG. 5.4 Species gain of Weevils, Generalists (= Sill + G) and Specialists (= SI + Sll) during succession. Data based on 1980 field season. 121 FIG. 5.5 Comparative indices of Dominance of Herbs, Weevils and Leaf-Beetles in relation to log. successional age of the habitat. Data for 1980 - 81. 124 FIG. 5.6 Percentage contribution of Specialist I, Sll and Sill and Generalist feeding categories for Weevils during succession based on Abundance and Species Composition. 130 FIG. 5.7 Percentage contribution of Specialist I, Sll, Sill and Generalist feeding categories for Leaf- Beetles during succession, based on Abundance and Species Composition.