Chemical attraction and deception Intra- and interspecific communication in Hymenoptera Dissertation zur Erlangung des Doktorgrades der Naturwissenschaften (Dr. rer. nat.) der Naturwissenschaftlichen Fakultät III – Biologie und Vorklinische Medizin der Universität Regensburg vorgelegt von Johannes Kroiß aus Bad Neustadt/Saale Juni 2008 Promotionsgesuch eingereicht am: 24.06.2008 Die mündliche Prüfung (Kolloquium) wurde am 29.09.2008 abgelegt. Die Arbeit wurde angeleitet von: Prof. Dr. Erhard Strohm Prüfungsausschuss: Vorsitzender: Prof. Dr. Stephan Schneuwly 1. Prüfer: Prof. Dr. Erhard Strohm 2. Prüfer: Prof. Dr. Jürgen Heinze 3. Prüfer: Prof. Dr. Christoph Oberprieler “I cannot persuade myself that a beneficent and omnipotent God would have designedly created the Ichneumonidae with the express intention of their feeding within the living bodies of Caterpillars.” Charles Darwin, 22 May 1860, Letter to Asa Gray CONTENTS Contents............................................................................................................. 1 List of publications............................................................................................. 5 Chapter 1: General Introduction......................................................................... 7 1.1 Chemical communication.................................................................................................. 7 1.2 Semiochemicals.................................................................................................................8 1.3 Intraspecific chemical communication – Pheromones ....................................................9 1.4 Interspecific chemical communication........................................................................... 17 1.5 Structural colors in nature .............................................................................................. 21 1.6 Biology of the European Beewolf Philanthus triangulum .............................................24 1.7 Biology of the cuckoo wasp Hedychrum rutilans...........................................................32 1.8 Outline of the Thesis.......................................................................................................35 1.9 References.......................................................................................................................37 Chapter 2: A selfish function of a social gland? A postpharyngeal gland functions as a sex pheromone reservoir in males of the solitary wasp Philanthus triangulum....................................................................................................... 53 2.1 Summary.........................................................................................................................53 2.2 Introduction ...................................................................................................................54 2.2 Materials and Methods...................................................................................................55 2.3 Results ............................................................................................................................59 2.4 Discussion.......................................................................................................................64 2.5 Acknowledgements.........................................................................................................67 2.6 References ......................................................................................................................68 Chapter 3: Males of a solitary wasp possess a postpharyngeal gland. ................71 3.1 Summary......................................................................................................................... 71 3.2 Introduction....................................................................................................................72 3.3 Materials and methods...................................................................................................73 3.3 Results ............................................................................................................................ 77 3.4 Discussion.......................................................................................................................85 3.5 Acknowledgements........................................................................................................ 88 3.6 References ......................................................................................................................89 1 Chapter 4: The odor of origin: kinship and geographical distance are reflected in the marking pheromone of male beewolves (Philanthus triangulum f., Hymenoptera, Crabronidae). ........................................................................... 93 4.1 Summary ........................................................................................................................ 93 4.2 Background.................................................................................................................... 94 4.3 Results............................................................................................................................ 96 4.4 Discussion .....................................................................................................................102 4.5 Conclusions.................................................................................................................. 104 4.6 Materials and Methods .................................................................................................105 4.7 Acknowledgements .......................................................................................................110 4.8 References......................................................................................................................111 Chapter 5: Male territoriality and mating system in the European beewolf Philanthus triangulum (Hymenoptera, Crabronidae) – evidence for a “hotspot” lek polygyny. ................................................................................................... 115 5.1 Summary ....................................................................................................................... 115 5.2 Introduction .................................................................................................................. 115 5.3 Materials and methods.................................................................................................. 117 5.4 Results...........................................................................................................................120 5.5 Discussion .....................................................................................................................126 5.6 Acknowledgements .......................................................................................................130 5.7 References ..................................................................................................................... 131 Chapter 6: Do males of the cuckoo wasp Hedychrum rutilans (Hymenoptera, Chrysididae) have a sex pheromone? ..............................................................135 6.1 Summary .......................................................................................................................135 6.2 Introduction..................................................................................................................136 6.3 Materials and Methods .................................................................................................137 6.4 Results...........................................................................................................................139 6.5. Discussion ....................................................................................................................142 6.6. Acknowledgements ......................................................................................................144 6.7. References ....................................................................................................................145 Chapter 7: Hydrocarbons in the nest material of a solitary digger wasp represent a kairomone for a specialized cuckoo wasp. ....................................147 7.1 Summary........................................................................................................................147 7.2 Introduction ..................................................................................................................148 7.3 Materials and methods..................................................................................................149 7.4 Results...........................................................................................................................154 2 7.5 Discussion..................................................................................................................... 159 7.6 Acknowledgements....................................................................................................... 162 7.7 References..................................................................................................................... 163 Chapter 8: A cuckoo in wolves’ clothing? Chemical mimicry in a specialized cuckoo wasp of the European beewolf. ............................................................167 8.1 Summary......................................................................................................................