Université catholique de Louvain Earth and Life Institute Biodiversity Research Center Louvain-la-Neuve, Belgium Nectar resource limitation in agricultural landscapes: effects on behaviour and life-history traits in the meadow brown butterfly (Maniola jurtina) Author Julie Lebeau Supervisors Prof. Hans Van Dyck - Université catholique de Louvain, Earth & Life Institute, Louvain-la-Neuve (BE) Prof. Renate Wesselingh - Université catholique de Louvain, Earth & Life Institute, Louvain-la-Neuve (BE) Jury members Prof. Marie-Laurence De Keersmaecker (Chair) - Université catholique de Louvain, Earth & Life Institute, Louvain-la-Neuve (BE) Prof. Thierry Hance - Université catholique de Louvain, Earth & Life Institute, Louvain- la-Neuve (BE) Prof Nicolas Schtickzelle - Université catholique de Louvain, Earth & Life Institute, Louvain-la-Neuve (BE) Prof. John Dover - Staffordshire University, Science Centre (UK) Prof. Andreas Erhardt - Institut für Natur-, Landschafts- und Umweltschutz, Abteilung Biologie, Universität Basel (CH) Table of contents Summary .........................................................................................................V Résumé .......................................................................................................... IX Chapter 1 - General introduction ................................................................... 1 Food and energy requirements in animals ................................................. 1 Food and energy in butterflies ................................................................... 2 Intensively managed agricultural landscapes and the challenges they represent for flower-visiting insects ......................................................... 10 Chapter 2 - Thesis objectives and thesis outline ......................................... 17 Chapter 3 - Materials and methods ............................................................. 23 Study species ............................................................................................ 23 Study areas and collection sites ................................................................ 29 Field observations and experiments ..................................................... 31 Laboratory experiments and measurements ........................................... 39 Chapter 4 - Flower choice in the grassland butterfly Maniola jurtina: a generalist with a strong preference? .......................................................... 49 Abstract ..................................................................................................... 50 Introduction .............................................................................................. 51 Material and methods .............................................................................. 55 Study species......................................................................................... 55 Study sites ............................................................................................. 55 Behavioural tracking ............................................................................. 57 Nectar array experiment ....................................................................... 62 Statistics ................................................................................................ 66 Results ....................................................................................................... 67 Floral diversity and abundance ............................................................. 67 Butterfly foraging behaviour ................................................................. 70 Nectar array experiment ....................................................................... 78 Discussion ................................................................................................. 82 Chapter 5 - Floral resource limitation severely reduces butterfly survival, condition and flight activity in simplified agricultural landscapes ............. 89 I Abstract ..................................................................................................... 90 Introduction .............................................................................................. 91 Material and methods .............................................................................. 93 Meadow brown: study species ............................................................. 93 Nectar supply field experiment ............................................................ 93 Relative butterfly numbers ................................................................... 94 Experiment in outdoor flight cages ...................................................... 95 Lipid reserves ........................................................................................ 96 Statistical analyses ................................................................................ 97 Results ....................................................................................................... 98 Nectar deprivation in simplified agricultural landscapes ..................... 98 Adult survival under nectar-poor conditions ........................................ 98 Body mass and lipid content under nectar-poor conditions .............. 100 Decreased flight under nectar-poor conditions ................................. 100 Discussion ............................................................................................... 101 Chapter 6 - Landscape of origin affects the impact of quantitative and qualitative nectar limitation on life-history traits in a grassland butterfly ........................................................................................................... 105 Abstract ................................................................................................... 106 Introduction ............................................................................................ 107 Materials and methods ........................................................................... 111 Model species ..................................................................................... 111 Butterfly sampling ............................................................................... 111 Experimental setup ............................................................................. 112 Body mass, longevity and fecundity ................................................... 113 Statistical analyses .............................................................................. 114 Results ..................................................................................................... 117 Initial fresh mass ................................................................................. 117 Adult survival ...................................................................................... 117 Change in body mass .......................................................................... 117 Post-treatment longevity .................................................................... 120 Female fecundity ................................................................................ 122 Egg size and viability ........................................................................... 125 Discussion ............................................................................................... 127 Effect of nectar treatments ................................................................ 127 II Landscape of origin ............................................................................. 131 Males: nectar quantity matters for direct survival, whereas nectar quality for longevity ............................................................................ 132 Conclusion ........................................................................................... 133 Chapter 7 - Flight and metabolic ecology of butterflies in anthropogenic landscapes under strong resource limitation ............................................ 135 Abstract: .................................................................................................. 136 Introduction ............................................................................................ 137 Material and Methods ............................................................................ 141 Model species ..................................................................................... 141 Experimental setup ............................................................................. 141 Metabolism and flight capacities ........................................................ 142 Statistical analyses .............................................................................. 145 Results ..................................................................................................... 147 Flight distance and speed ................................................................... 148 Willingness to fly ................................................................................. 149 Efficiency of fuel consumption ........................................................... 150 FMR ..................................................................................................... 151 RMR ..................................................................................................... 153 Discussion ............................................................................................... 154 Chapter 8 - Butterfly density and behaviour