Promoting Cotesia rubecula Marshall, 1885 (Hymenoptera: Braconidae) against the cabbage pest Pieris rapae Linnaeus, 1758 (Lepidoptera: Pieridae) through flowering plants Inauguraldissertation zur Erlangung der Würde eines Doktors der Philosophie vorgelegt der Philosophisch-Naturwissenschaftlichen Fakultät der Universität Basel von Shakira Erna Fataar aus Zürich (ZH) Basel, 2021 Originaldokument gespeichert auf dem Dokumentenserver der Universität Basel edoc.unibas.ch Genehmigt von der Philosophisch-Naturwissenschaftlichen Fakultät auf Antrag von Fakultätsverantwortlicher: Prof. Dr. Ansgar Kahmen, Universität Basel Dissertationsleiter: Dr. Henryk Luka, Forschungsinstitut für biologischen Landbau (FiBL), Frick Korreferent: Prof. em. Dr. Peter Nagel, Universität Basel Basel, den 26.03.2019 Prof. Dr. Martin Spiess, Dekan ii Table of Contents LIST OF FIGURES ................................................................................................................... VII LIST OF TABLES ....................................................................................................................... IX ACKNOWLEDGEMENTS ........................................................................................................ XI SUMMARY .................................................................................................................................... 1 GENERAL INTRODUCTION ..................................................................................................... 3 References ........................................................................................................................................ 9 CHAPTER 1 FUNDAMENTALS AND METHOD DEVELOPMENT ................................. 13 Abstract .......................................................................................................................................... 13 Introduction .................................................................................................................................... 14 Rearing of insects ........................................................................................................................... 15 Breeding of P. rapae food plants ........................................................................................... 15 Pieris rapae ............................................................................................................................ 16 Cotesia rubecula .................................................................................................................... 19 Lab-experiments ............................................................................................................................ 21 Pre-trials of longevity experiments with C. rubecula ............................................................ 21 Pre-trials of fecundity experiments with C. rubecula ............................................................ 24 Pre-trials olfactometer ............................................................................................................ 29 Pre-trials of longevity experiments with P. rapae ................................................................. 32 Pre-trials of fecundity experiments with P. rapae ................................................................. 36 Acknowledgements ........................................................................................................................ 37 References ...................................................................................................................................... 37 Appendix ........................................................................................................................................ 40 iii CHAPTER 2 INNATE AND LEARNED OLFACTORY ATTRACTION TO FLOWERING PLANTS BY THE PARASITOID COTESIA RUBECULA (MARSHALL, 1885) (HYMENOPTERA: BRACONIDAE): POTENTIAL IMPACTS ON CONSERVATION BIOLOGICAL CONTROL ............................... 41 Abstract .......................................................................................................................................... 42 Introduction .................................................................................................................................... 43 Material and Methods .................................................................................................................... 46 Flowering plants ..................................................................................................................... 46 Parasitoids .............................................................................................................................. 46 Y-tube olfactometer – Test procedure .................................................................................... 47 Absolute and relative olfactory attractiveness ....................................................................... 48 Associative learning potential of C. rubecula ........................................................................ 48 Statistics ................................................................................................................................. 49 Results ............................................................................................................................................ 49 Absolute and relative olfactory attractiveness ....................................................................... 50 Associative learning potential of C. rubecula ........................................................................ 51 Discussion ...................................................................................................................................... 52 Acknowledgements ........................................................................................................................ 56 References ...................................................................................................................................... 57 CHAPTER 3 HIGHER PROMOTION OF COTESIA RUBECULA (HYMENOPTERA: BRACONIDAE) THAN ITS HOST PIERIS RAPAE (LEPIDOPTERA: PIERIDAE) THROUGH FLOWERING PLANTS: PERSPECTIVES FOR CONSERVATION BIOLOGICAL CONTROL.......................................................... 62 Abstract .......................................................................................................................................... 63 Introduction .................................................................................................................................... 64 iv Material and Methods .................................................................................................................... 67 Plant and insect rearing .......................................................................................................... 67 Cotesia rubecula longevity assay........................................................................................... 67 Cotesia rubecula fecundity assay........................................................................................... 68 Pieris rapae longevity assay .................................................................................................. 68 Pieris rapae fecundity assay .................................................................................................. 69 Statistical analysis .................................................................................................................. 70 Results ............................................................................................................................................ 71 Cotesia rubecula longevity assay........................................................................................... 71 Cotesia rubecula fecundity assay........................................................................................... 73 Pieris rapae longevity assay .................................................................................................. 74 Pieris rapae fecundity assay .................................................................................................. 76 Discussion and Conclusions .......................................................................................................... 78 Cotesia rubecula longevity and fecundity ............................................................................. 79 Pieris rapae longevity and fecundity ..................................................................................... 80 Differentiated enhancement of the cabbage pest and its antagonist ....................................... 81 Acknowledgements ........................................................................................................................ 84 References ...................................................................................................................................... 84 CHAPTER 4 PEST DENSITY DEPENDENT SUCCESS OF CONSERVATION BIOLOGICAL CONTROL MEASURES: THE INCENTIVE TO PARASITIZE.. 90 Abstract .......................................................................................................................................... 91 Introduction .................................................................................................................................... 92 Material and Methods ...................................................................................................................