UNIVERSITY OF CATANIA DEPARTMENT OF AGRI-FOOD AND ENVIRONMENTAL SYSTEMS MANAGEMENT INTERNATIONAL PhD PROGRAM IN PLANT HEALTH TECHNOLOGIES AND PROTECTION OF AGRO-ECOSYSTEMS CYCLE XXVI 2010-2013 DEVID GUASTELLA Title of the Thesis: Studies on Whiteflies Living on Herbaceous Plants and Their Parasitoids in Tropical and Sub-Tropical Environment through Combined Morphological, Molecular and Geostatistical Approaches PhD Coordinator: TUTOR Prof. Carmelo Rapisarda Prof. Carmelo Rapisarda CO-TUTOR: Dr. James P. Legg 1 CONTENTS ACKNOWLEDGEMENTS ..................................................................................................................... 7 ABSTRACT ............................................................................................................................................. 8 LIST OF FIGURES ............................................................................................................................... 12 LIST OF TABLES ................................................................................................................................ 15 CHAPTER 1: INTRODUCTION ....................................................................................................... 17 1.1 WHITEFLIES ............................................................................................................................ 17 1.1.1 GENERALITIES ............................................................................................................................................ 17 1.1.2 ECONOMIC IMPORTANCE .......................................................................................................................... 20 1.1.3 EVOLUTION OF WHITEFLIES: AN OVERVIEW ........................................................................................ 24 1.1.4 ZOOGEOGRAPHY ......................................................................................................................................... 26 1.1.5 SUBFAMILY ALEURODICINAE ................................................................................................................... 26 1.1.6 SUBFAMILY ALEYRODINAE ....................................................................................................................... 28 1.1.7 THE SPREAD OF WHITEFLIES AROUND THE WORLD ............................................................................ 32 1.2 PARASITOIDS .......................................................................................................................... 33 1.2.1 GENERAL NOTES ......................................................................................................................................... 33 1.2.2 ROLE OF PARASITOIDS IN BIOLOGICAL CONTROL OF WHITEFLIES .................................................... 37 1.3 MOLECULAR TAXONOMY .................................................................................................... 42 1.3.1 RIBOSOMIAL RNA ..................................................................................................................................... 43 1.3.2 MITOCHONDRIAL DNA ............................................................................................................................. 45 1.3.3 DNA BARCODING ...................................................................................................................................... 46 1.4 BIOINFORMATICS .................................................................................................................. 47 1.4.1 DATA MANAGEMENT ................................................................................................................................. 47 2 1.4.2 AVAILABLE “OPEN/FREE” TOOLS .......................................................................................................... 48 1.4.3 MODELS AND METHODS IN PHYLOGENETIC STUDY ............................................................................. 52 1.4.3.1 Summary of the activity on how to select the correct method ...................................... 58 1.5 GIS AND GEO-STATISTICS ................................................................................................... 61 1.5.1 INTRODUCTION ........................................................................................................................................... 61 1.5.2 WHITEFLIES AND GIS ............................................................................................................................... 62 1.5.3 SPATIAL ANALYSIS OF INSECT DIVERSITY AND DISTRIBUTION .......................................................... 64 1.5.4 ASSESSMENT OF A SPECIES COMPLEX ALONG AN ALTITUDINAL GRADIENT .................................... 65 1.5.5 MODELLING THE POTENTIAL INSECT DISTRIBUTION .......................................................................... 66 CHAPTER 2: AIM AND OUTLINE OF THIS THESIS .................................................................. 69 CHAPTER 3: MATHERIALS AND METHODS .............................................................................. 72 3.1 FIELD SURVEY: EXPLORATION FOR WHITEFLIES AND THEIR NATURAL ENEMIES .............................................................................................................................................. 72 3.1.1 SURVEY METHODOLOGY ........................................................................................................................... 72 3.1.2 STUDY AREAS ............................................................................................................................................. 74 3.1.2.1 Mediterranean environment (Sicily) ........................................................................................ 74 3.1.2.2 Tropical environment (Tanzania) .............................................................................................. 78 3.2 TAXONOMY: MORPHOLOGICAL IDENTIFICATION ...................................................... 85 3.2.1 ALEYRODIDAE ............................................................................................................................................. 85 3.2.2 APHELINIDAE .............................................................................................................................................. 87 3.3 MOLECULAR METHODS IN INSECT TAXONOMY ........................................................... 91 3.3.1 WHITEFLIES (THE BEMISIA TABACI SPECIES COMPLEX) .................................................................... 91 3.3.2 PARASITOIDS .............................................................................................................................................. 92 3.4 DATA MANAGEMENT ............................................................................................................ 95 3.5 GIS AND GEOSTATISTICS ..................................................................................................... 97 3 3.5.1.1 Additional Statistical Analysis ..................................................................................................... 99 CHAPTER 4: RESULTS ................................................................................................................... 100 4.1 WHITEFLIES AND THEIR PARASITOIDS ON HERBACEOUS PLANTS IN MEDITERRANEAN ENVIRONMENT ........................................................................................... 100 4.1.1 INTRODUCTORY NOTES .......................................................................................................................... 100 4.1.2 WHITEFLIES ............................................................................................................................................. 102 4.1.2.1 Identification of the collected material ................................................................................. 102 4.1.2.2 Species richness and abundance ............................................................................................. 106 4.1.3 MODELLING THE POTENTIAL DISTRIBUTION OF WHITEFLY PESTS ................................................ 110 4.1.4 PARASITOIDS ........................................................................................................................................... 112 4.1.4.1 Who was parasitizing whom? ................................................................................................... 112 4.1.4.2 Reserve selection of whitefly parasitoids ............................................................................ 113 4.1.5 DISCUSSION .............................................................................................................................................. 116 4.1.5.1 Whiteflies ........................................................................................................................................... 116 4.1.5.2 Parasitoids ......................................................................................................................................... 117 4.2 WHITEFLIES AND THEIR PARASITOIDS ON HERBACEOUS PLANTS IN TROPICAL ENVIRONMENT ................................................................................................................................ 120 4.2.1 INTRODUCTORY NOTES .......................................................................................................................... 120 4.2.2 WHITEFLIES ............................................................................................................................................