THE IMPACTS OF HABITAT MANAGEMENT ON BENEFICIAL INSECTS IN LOWBUSH BLUEBERRY AGROECOSYSTEMS by Robyn S. McCallum Submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Dalhousie University Halifax, Nova Scotia August 2017 © Copyright by Robyn S. McCallum, 2017 TABLE OF CONTENTS LIST OF TABLES .................................................................................................. v LIST OF FIGURES .............................................................................................. vii ABSTRACT .......................................................................................................... ix LIST OF ABBREVIATIONS AND SYMBOLS USED ............................................. x ACKNOWLEDGEMENTS ................................................................................... xiii CHAPTER 1: INTRODUCTION ............................................................................ 1 1.1 BENEFICIAL INSECTS IN AGROECOSYSTEMS ................................................. 1 1.2 LOWBUSH BLUEBERRY AGROECOSYSTEMS................................................... 3 1.3 HABITAT MANAGEMENT FOR BENEFICIAL INSECTS ....................................... 4 1.4 WILD POLLINATORS IN LOWBUSH BLUEBERRY .............................................. 8 1.5 NATURAL ENEMIES IN LOWBUSH BLUEBERRY .............................................. 14 1.6 THE CONSERVATION CONUNDRUM ................................................................ 18 1.7 OBJECTIVES ....................................................................................................... 18 CHAPTER 2: AN ASSESSMENT OF ARTIFICIAL NESTS FOR CAVITY- NESTING BEES IN LOWBUSH BLUEBERRY ................................................... 21 2.1 ABSTRACT .......................................................................................................... 21 2.2 INTRODUCTION.................................................................................................. 22 2.3 MATERIALS AND METHODS .............................................................................. 24 2.3.1 ARTIFICIAL NEST DESIGNS ........................................................................... 24 2.3.2 2014 NEST STUDY .......................................................................................... 27 2.3.3 2015 MILK CARTON STUDY ............................................................................ 28 2.3.4 2015 CLAY LID STUDY .................................................................................... 29 2.3.5 INSECT IDENTIFICATION ................................................................................ 29 2.4 RESULTS ............................................................................................................ 30 2.4.1 2014 NEST STUDY .......................................................................................... 30 2.4.2 2015 MILK CARTON STUDY ............................................................................ 32 2.4.3 2015 CLAY LID STUDY .................................................................................... 37 2.5 DISCUSSION ....................................................................................................... 38 2.6 SUMMARY OF CHAPTER 2 AND TRANSITION TO CHAPTER 3....................... 42 ii 2.7 SUPPLEMENTARY INFORMATION .................................................................... 43 CHAPTER 3: ENHANCING LOWBUSH BLUEBERRY FIELD MARGINS FOR WILD BEES ........................................................................................................ 45 3.1 ABSTRACT .......................................................................................................... 45 3.2 INTRODUCTION.................................................................................................. 46 3.3 MATERIALS AND METHODS .............................................................................. 49 3.3.1 BUCKWHEAT AND CONTROL TRANSECT SAMPLING ................................. 49 3.3.2 STUDY SITES................................................................................................... 49 3.3.3 SAMPLING ....................................................................................................... 49 3.3.4 IDENTIFICATION .............................................................................................. 51 3.3.5 STATISTICAL ANALYSIS ................................................................................. 51 3.3.6 BLUEBERRY BLOOM SAMPLING ................................................................... 52 3.3.7 STUDY SITES................................................................................................... 52 3.3.8 SAMPLING ....................................................................................................... 52 3.3.9 STATISTICAL ANALYSIS ................................................................................. 53 3.4 RESULTS ............................................................................................................ 54 3.4.1 BUCKWHEAT AND CONTROL TRANSECTS EXPERIMENT .......................... 54 3.4.2 BLUEBERRY BLOOM EXPERIMENT ............................................................... 62 3.5 DISCUSSION ....................................................................................................... 67 3.6 SUMMARY OF CHAPTER 3 AND TRANSITION TO CHAPTER 4....................... 74 3.7 SUPPLEMENTARY INFORMATION .................................................................... 76 CHAPTER 4: ENHANCING LOWBUSH BLUEBERRY FIELD MARGINS FOR NATURAL ENEMIES .......................................................................................... 77 4.1 ABSTRACT .......................................................................................................... 77 4.2 INTRODUCTION.................................................................................................. 78 4.3 MATERIALS AND METHODS .............................................................................. 80 4.3.1 STUDY SITES................................................................................................... 80 4.3.2 SAMPLING ....................................................................................................... 80 4.3.3 IDENTIFICATION .............................................................................................. 82 4.3.4 STATISTICAL ANALYSIS ................................................................................. 82 4.4 RESULTS ............................................................................................................ 82 4.5 DISCUSSION ....................................................................................................... 88 4.6 SUMMARY OF CHAPTER 4 AND TRANSITION TO CHAPTER 5....................... 93 iii CHAPTER 5: DETERMINING THE INFLUENCE OF FORAGE CROP TYPE ON PLANT-POLLINATOR INTERACTIONS............................................................. 95 5.1 ABSTRACT .......................................................................................................... 95 5.2 INTRODUCTION.................................................................................................. 96 5.3 MATERIALS AND METHODS .............................................................................. 98 5.3.1 SITE ESTABLISHMENT ................................................................................. 100 5.3.2 POLLINATOR AND FLORAL SAMPLING ....................................................... 103 5.3.3 IDENTIFICATION ............................................................................................ 103 5.3.4 STATISTICAL ANALYSIS ............................................................................... 104 5.4 RESULTS .......................................................................................................... 106 5.4.1 FLORAL DENSITY AND BLOOM PERIOD ..................................................... 106 5.4.2 BEE ABUNDANCE ......................................................................................... 109 5.4.3 PLANT-POLLINATOR INTERACTIONS.......................................................... 113 5.4.4 BIPARTITE ANALYSIS ................................................................................... 113 5.5 DISCUSSION ..................................................................................................... 117 5.5.1 FLORAL DENSITY AND BLOOM PERIOD ..................................................... 117 5.5.2 BEE ABUNDANCE ......................................................................................... 118 5.5.3 PLANT-POLLINATOR INTERACTIONS AND BIPARTITE ANALYSIS ............ 119 5.6 SUMMARY OF CHAPTER 5 AND TRANSITION TO CONCLUSION ................. 121 5.7 SUPPLEMENTARY INFORMATION .................................................................. 122 CHAPTER 6: CONCLUSION ............................................................................ 123 6.1 INTRODUCTION................................................................................................ 123 6.2 SUMMARY ......................................................................................................... 124 6.3 DISCUSSION ..................................................................................................... 127 6.4 CHALLENGES OF HABITAT MANAGEMENT IN LOWBUSH BLUEBERRY ..... 128 6.5 CONCLUSION ..................................................................................................