3 Evolution of the Pheromone Communication System in the European Beewolf Philanthus triangulum F. (Hymenoptera: Crabronidae) Dissertation zur Erlangung des naturwissenschaftlichen Doktorgrades der Bayerischen Julius-Maximilians-Universität Würzburg vorgelegt von Gudrun Herzner aus Nürnberg Würzburg 2004 4 Evolution of the Pheromone Communication System in the European Beewolf Philanthus triangulum F. (Hymenoptera: Crabronidae) Dissertation zur Erlangung des naturwissenschaftlichen Doktorgrades der Bayerischen Julius-Maximilians-Universität Würzburg vorgelegt von Gudrun Herzner aus Nürnberg Würzburg 2004 5 Eingereicht am………………………………………………………………………………….. Mitglieder der Promotionskommission: Vorsitzender: Prof. Dr. Ulrich Scheer Gutachter: Prof. Dr. K. Eduard Linsenmair Gutachter: PD Dr. Jürgen Gadau Tag des Promotionskolloquiums:……………………………………………………………….. Doktorurkunde ausgehändigt am:………………………………………………………………. 6 CONTENTS PUBLIKATIONSLISTE.................................................................................................................. 6 CHAPTER 1: General Introduction ......................................................................................... 7 1.1 The asymmetry of sexual selection .................................................................................. 7 1.2 The classical sexual selection models .............................................................................. 8 1.3 Choice for genetic compatibility...................................................................................... 9 1.4 Mate choice as a problem of communication................................................................. 10 1.5 Receiver bias models of sexual selection....................................................................... 11 1.6 Signal design and signal content .................................................................................... 12 1.7 Outline of the thesis........................................................................................................ 13 1.8 References ...................................................................................................................... 15 CHAPTER 2: The European Beewolf Philanthus triangulum (Hymenoptera: Crabronidae)........................................................................................................................... 20 2.1 Females........................................................................................................................... 20 2.2 Males .............................................................................................................................. 24 2.3 References ...................................................................................................................... 26 CHAPTER 3: Volatiles of foraging honeybees Apis mellifera L. (Hymenoptera: Apidae) and their possible role as semiochemicals and kairomones................................................ 27 3.1 Summary ........................................................................................................................ 27 3.2 Introduction .................................................................................................................... 28 3.3 Material and Methods..................................................................................................... 29 3.3.1 Composition of cuticular hydrocarbons of honeybees............................................ 29 3.3.2 Volatiles in the headspace of foraging honeybees .................................................. 30 3.4 Results ............................................................................................................................ 31 3.4.1 Composition of cuticular hydrocarbons of honeybees............................................ 31 3.4.2 Volatiles in the headspace of foraging honeybees .................................................. 31 3.5 Discussion ...................................................................................................................... 33 3.6 References ...................................................................................................................... 35 2 CHAPTER 4: Prey recognition by Female European Beewolves and its potential for a sensory trap............................................................................................................................. 38 4.1 Summary ........................................................................................................................ 38 4.2 Introduction .................................................................................................................... 39 4.3 Material and Methods..................................................................................................... 41 4.3.1 Beewolves ............................................................................................................... 41 4.3.2 Training ................................................................................................................... 41 4.3.3 Experimental blocks................................................................................................ 42 4.3.4 Procedure................................................................................................................. 44 4.3.5 Chemical analysis.................................................................................................... 44 4.3.6 Data Analysis .......................................................................................................... 45 4.4 Results ............................................................................................................................ 47 4.4.1 The role of olfaction................................................................................................ 46 4.4.2 The role of (Z)-11-eicosen-1-ol............................................................................... 46 4.5 Discussion ...................................................................................................................... 50 4.5.1 Prey recognition in female European Beewolves ................................................... 50 4.5.2 (Z)-11-eicosen-1-ol as reliable prey recognition cue .............................................. 51 4.5.3 (Z)-11-eicosen-1-ol and the sensory trap ................................................................ 52 4.6 References ...................................................................................................................... 53 CHAPTER 5: Flagellar sensilla in male and female European beewolves, Philanthus triangulum F. (Hymenoptera: crabronidae) ........................................................................ 58 5.1 Summary ........................................................................................................................ 58 5.2 Introduction .................................................................................................................... 58 5.3 Material and Methods..................................................................................................... 60 5.3.1 Specimens................................................................................................................ 60 5.3.2 Morphology............................................................................................................. 61 5.4 Results ............................................................................................................................ 62 5.4.1 General morphology of the antennae ...................................................................... 62 5.4.2 Sensilla and setae .................................................................................................... 62 5.5 Discussion ...................................................................................................................... 67 5.5.1 General morphology................................................................................................ 67 5.5.2 Sensilla types........................................................................................................... 67 5.6 References ...................................................................................................................... 73 3 CHAPTER 6: (S)-2,3-Dihydrofarnesoic acid, a new component in cephalic glands of male European Beewolves Philanthus triangulum........................................................................ 77 6.1 Summary ........................................................................................................................ 77 6.2 Introduction .................................................................................................................... 77 6.3 Material and Methods..................................................................................................... 78 6.3.1 Insects and sampling ............................................................................................... 78 6.3.2 Capillary Gas Chromatography – Mass Spectrometry (HRGC-MS)...................... 79 6.3.3 Capillary Gas Chromatography – Fourier Transform Infrared Analysis (HRGC- FTIR)................................................................................................................................ 79 6.3.4 Enantioselective Capillary Gas Chromatography (Enantio-HRGC)....................... 80 6.3.5 Chemicals...............................................................................................................