[Digitare il testo] Dottorato di ricerca in “Scienze Agrarie e Forestali” “Gestione fitosanitaria eco-compatibile in ambienti agro-forestali ed urbani” Dipartimento Scienze Agrarie e Forestali Settore scientifico disciplinare AGR/11 Semiochemical exploitation by two egg parasitoids, Trissolcus basalis and Trissolcus brochymenae (Hymenoptera: Scelionidae) IL DOTTORE IL COORDINATORE TAKOUA SLIMANI PROF. VINCENZO BAGARELLO IL TUTOR EVENTUALE CO TUTOR PROF. STEFANO COLAZZA PROF. EZIO PERI DR. KYE CHUNG PARK CICLO XXIX 2017 Dedication To my beloved parents, thanks for your continuous care and for being always here for me. A special dedication to my great mother Sahbia whose gracious presence and boundless love have never ceased to give me the courage to face gaily the life. To my amazing husband Mouadh whose sacrificial care made it possible for me to complete this thesis. Thanks for supporting and encouraging me to believe in myself. To my very unique brother Bachar who taught me the power of hope Thanks for being my guardian angel and the happiness of my life. To the Soul of Fayouza my mother-in-law and to Ali you are more than a father- in-law you are another dad for me. To Dali and Mariouma who offered me unlimited encouragement and have been an enthusiastic sounding board. To my Little Taym thanks for being my thesis buddy and co-author before your birth. With all my best wishes Takoua Acknowledgment I would like to express my cordial thanks and great gratitude to my supervisor Prof. Stefano Colazza for his support, precious advices, constructive criticism and guidance for the achievement of this work. I am grateful for giving me the chance to be involved in the BUGSIE project and the opportunity to carry out a wonderful international experience. Thank you for giving me strength to persist and succeed. A Special appreciation to my co-supervisor Prof. Ezio Peri for his kindness, support and assistance. I would like to thank him for being so incredibly patient with me during the PhD thesis. There were few bumps along the road but he was always positive and incredibly helpful. My grateful thanks to Dr. Kye Chung Park and Dr. Michael Rostás for their hospitality, the efforts they had supplied and their assistance at the research institutions in New Zealand, Plant and food and Bioprotection center respectively. I want to say a great THANKS to all the staff in both institutions for their kindness, for being around, for welcoming me so warmly since the first day of my visit and making me feel like a part of their family. I would definitely love to return to New Zealand. I would like to express my deep sense of gratitude to Dr. Maria Cristina Foti, Dr. Rihem Moujahed and Dr. Antonino Cusumano for their support throughout this research and for his genuine and friendly approach. They showed me how to dissect the challenges into as many different ways as possible and to look at them from different angles. My appreciation extends my laboratory colleagues at Palermo University especially to my dear friends Dr. Salvatore Guarino, Dr. Paolo Lo Bue, Dr. Letizia Martorana and Dr. Milko Sinacori. I would like to convey my heartfelt gratitude and sincere appreciation to Professor Ibrahim Al-Jboory for his unlimited support that began from the first day I met him. I would also like to thank all of my friends who supported me in writing, and incented me to strive towards my goal especially to my great friends Ilhem, Emna, Fattoun and Amira for their love, positivity and inestimable moral support. On a different note, many people have been a part of my educational attainment and I am highly grateful to all of them. Content Chapter 1 Chemo-orientation in insect egg parasitoids mediated by semiochemicals .... 11 Abstract .................................................................................................................................... 11 1. Introduction ....................................................................................................................... 12 1.1. Morphological approach ............................................................................................... 15 1.1.1. Olfactory chemo-reception ................................................................................. 16 1.1.2. Contact chemo-reception .................................................................................... 19 1.2. Chemical approach ....................................................................................................... 21 1.3. Behavioral approach ..................................................................................................... 25 1.3.1. Random searching behavior pattern ................................................................... 26 1.3.2. Trail following behavior pattern ........................................................................ 28 2. Research objectives and outline of the thesis.................................................................... 30 2.1. Crops ............................................................................................................................. 31 2.2. Insects ........................................................................................................................... 32 2.3. Parasitoids ..................................................................................................................... 33 References ................................................................................................................................ 35 Chapter 2 Effect of previous experience on the response of an egg parasitoid to substrate-borne semiochemicals ........................................................................................... 53 Abstract .................................................................................................................................... 53 1. Introduction ....................................................................................................................... 54 2. Materials and methods ...................................................................................................... 57 2.2. Insect colonies ............................................................................................................ 57 2.2. General bioassay procedure ...................................................................................... 59 2.3. Experiment 1: unrewarded experience ....................................................................... 61 2.4. Experiment 2: rewarded experience ........................................................................... 61 2.5. Experiment 3: hierarchical value of host traces ........................................................... 62 2.6. Statistical analyses ....................................................................................................... 62 3. Results ............................................................................................................................... 63 3.3. Experiment 1: unrewarded experience ....................................................................... 63 3.4. Experiment 2: Rewarded experience ............................................................................ 65 3.5. Experiment 3: hierarchical value of host traces ........................................................... 66 4. Discussion ......................................................................................................................... 68 References ................................................................................................................................ 72 Chapter 3 Antennal olfactory responses of Trissolcus basalis (Hymenoptera: Scelionidae) to buckwheat plant volatile compounds ................................................. ……80 Abstract .................................................................................................................................... 80 1. Introduction ....................................................................................................................... 81 2. Materials and methods ...................................................................................................... 83 2.1. Insects ........................................................................................................................... 83 2.2. Test compounds and buckwheat extracts ..................................................................... 83 2.3. Gas chromatograph-linked electroantennographic detection ....................................... 86 2.4. Single sensillum recording ........................................................................................... 87 3. Results ............................................................................................................................... 88 3.1. Identification of EAD-active compounds ..................................................................... 88 3.2. Overall profiles of sensilla and ORNs .......................................................................... 89 4. Discussion ......................................................................................................................... 94 References ................................................................................................................................ 97 Chapter 4 Concluding remarks and future perspectives ................................................. 100 References .............................................................................................................................