UNIVERSIDAD DE MURCIA ESCUELA INTERNACIONAL DE DOCTORADO Seasonal Biology and Reproductive Strategy of the Predatory Mirid Pilophorus gallicus (Hemiptera: Miridae) in the Pear Crop in the Mediterranean Area Biología Estacional y Estrategia Reproductiva del Mírido Depredador Pilophorus gallicus (Hemiptera: Miridae) en el Cultivo del Peral en el Área Mediterránea Dª Mª José Ramírez Soria 2018 UNIVERSIDAD DE MURCIA FACULTAD DE BIOLOGÍA Seasonal biology and reproductive strategy of the predatory mirid Pilophorus gallicus (Hemiptera: Miridae) in the pear crop in the Mediterranean area Biología estacional y estrategia reproductiva del mírido depredador Pilophorus gallicus (Hemiptera: Miridae) en el cultivo del peral en el área mediterránea TESIS DOCTORAL Dña. Mª José Ramírez Soria 2018 Directores: Tutor: Dr. Juan Antonio Sánchez Sánchez Dr. José Galián Albaladejo Dr. Felix Wäckers A mis padres y a mi abuelita Teresa, por todo y por todos “I have no special talent. I am only passionately curious.” Albert Einstein “Rien dans la vie n’est à craindre, tout doit être compris. C’est maintenant le moment de comprendre davantage, afin de craindre moins.” Marie Curie ÍNDICE AGRADECIMIENTOS………………………………………………………………..........i PRELIMINARES Y ESTRUCTURA DE LA TESIS DOCTORAL ……………………………iii INTRODUCCIÓN GENERAL Y OBJETIVOS ........................................................................ 1 1. ANTECEDENTES .................................................................................................... 1 1.1. El cultivo del peral en Jumilla .......................................................................... 1 1.2. El control de plagas en el cultivo del peral ..................................................... 3 1.3. Pilophorus gallicus: un potencial controlador biológico ............................... 6 2. LA BIOLOGÍA ESTACIONAL DE LOS INSECTOS ................................................... 7 2.1. Estrategias de adaptación en climas variables .............................................. 8 2.2. Factores ambientales reguladores de los ciclos de vida de los insectos ....... 10 2.2.1. La temperatura: un factor limitante para la vida de los insectos ......... 10 2.2.2. El fotoperiodo: un indicador fidedigno ................................................. 12 2.3. La biología estacional en el control biológico de plagas ............................... 13 3. OBJETIVOS .......................................................................................................... 15 REFERENCIAS .............................................................................................................. 17 CHAPTER 1: Thermal effects on the biological parameters of the predatory mirid Pilophorus gallicus (Hemiptera: Miridae) ....................................................................... 27 ABSTRACT ................................................................................................................... 27 1. INTRODUCTION ................................................................................................. 29 2. MATERIALS AND METHODS .............................................................................. 31 2.1. Insect rearing ................................................................................................. 31 2.2. Development of the pre-imaginal instars of P. gallicus at different temperatures ........................................................................................................... 31 2.3. Reproduction of P. gallicus at different temperatures ................................ 32 2.4. Statistical analyses ........................................................................................ 33 3. RESULTS ............................................................................................................. 34 3.1. Egg and nymphal development ................................................................... 34 3.2. Reproduction and demographic parameters ............................................... 37 4. DISCUSSION ....................................................................................................... 40 SUPPLEMENTARY MATERIAL ................................................................................... 45 REFERENCES .............................................................................................................. 47 CHAPTER 2: Population dynamics and seasonal variation in the embryonic dormancy of Pilophorus gallicus (Hemiptera: Miridae): "Don’t put all your eggs in one basket" .........................................................................................................................................53 ABSTRACT ...................................................................................................................53 1. INTRODUCTION ..................................................................................................55 2. MATERIALS AND METHODS ............................................................................. 58 2.1. Population dynamics of P. gallicus ............................................................... 58 2.1.1. Location and crop management........................................................... 58 2.1.2. Sampling of insects ............................................................................... 59 2.2. Study of the reproductive state of P. gallicus females and the condition of eggs ...................................................................................................................... 59 2.3. Statistical analyses ........................................................................................ 61 3. RESULTS .............................................................................................................. 61 3.1. Study of P. gallicus population dynamics ..................................................... 61 3.2. Study of the reproductive state of P. gallicus females and the conditions of eggs ...................................................................................................................... 63 4. DISCUSSION ....................................................................................................... 67 SUPPLEMENTARY MATERIAL .................................................................................... 73 REFERENCES ............................................................................................................... 75 CHAPTER 3: Induction and termination of embryonic diapause in the predatory mirid Pilophorus gallicus (Hemiptera: Miridae)...................................................................... 83 ABSTRACT .................................................................................................................. 83 1. INTRODUCTION ................................................................................................. 85 2. MATERIALS AND METHODS ............................................................................. 88 2.1. Completion of the diapause phase in P. gallicus .......................................... 88 2.2. Diapause induction in P. gallicus .................................................................. 89 2.2.1. Insect rearing ........................................................................................ 89 2.2.2. Experimental design, conditions and procedures ................................ 90 2.3. Statistical analyses ....................................................................................... 92 3. RESULTS ............................................................................................................. 93 3.1. Factors influencing the completion of diapausing eggs in P. gallicus ......... 93 3.2. Factors influencing the induction of diapause in P. gallicus eggs ................ 96 4. DISCUSSION ....................................................................................................... 99 SUPPLEMENTARY MATERIAL .................................................................................. 105 REFERENCES ............................................................................................................. 107 CHAPTER 4: Study of photoperiodism in diapause induction of the predatory mirid Pilophorus gallicus (Hemiptera: Miridae)...................................................................... 117 ABSTRACT .................................................................................................................. 117 1. INTRODUCTION ................................................................................................ 119 2. MATERIALS AND METHODS ............................................................................ 123 2.1. Insect rearing ............................................................................................... 123 2.2. Critical daylength assay ............................................................................... 123 2.3. Effect of the direction of change in daylength on P. gallicus embryonic diapause ................................................................................................................. 125 2.4. Reversibility of diapause induction in P. gallicus ........................................ 126 2.5. Statistical analyses ...................................................................................... 127 3. RESULTS ............................................................................................................ 128 3.1. Critical daylength assay ..............................................................................