Faculty of Life Sciences Albrecht Daniel Thaer-Institute of Agricultural and Horticultural Sciences Food-dependent development of behavioural types in Heterandria formosa M.Sc. thesis in the study program: Fishery Science and Aquaculture submitted by: Theis, Sebastian 1st Examiner (Supervisor): Prof. Dr. Arlinghaus, Robert Division of or Institution: Human dimensions and bio-economics of recreational fisheries, inter- and transdisciplinary fisheries research, fish and fisher behavioural ecology. Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB) Humboldt-Universität zu Berlin (HU) 2nd Examiner: Dr. Schröder, Arne Division of or Institution: The ecological consequences of the joint individual variation in size-specific life histories and behavioural types. Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB) Humboldt-Universität zu Berlin (HU) Berlin, June 23, 2017 i Content List of Figures ..................................................................................................................................... iii List of Tables ....................................................................................................................................... iv List of Abbreviations ........................................................................................................................... vi List of Utilized software ...................................................................................................................... vi Abstract ............................................................................................................................................... 1 Acknowledgements ............................................................................................................................. 1 1 Animal behaviour ............................................................................................................................. 2 1.1 What is animal behaviour ......................................................................................................... 2 1.2 What is animal personality? – Behavioural types .................................................................... 4 1.2.1 Development of behavioural types ................................................................................... 6 1.2.2 Ecological and evolutionary consequences of behavioural differences ........................... 7 1.3 Hypotheses of the thesis ........................................................................................................... 9 2 Methods .......................................................................................................................................... 12 2.1 Study organism – Heterandria formosa .................................................................................. 12 2.2 Experimental fish and their housing ....................................................................................... 13 2.3 Rearing treatments .................................................................................................................. 15 2.4 Life history measurements ..................................................................................................... 15 2.5 The open field test and behavioural assessment ..................................................................... 16 2.5.1 What is measured? .......................................................................................................... 17 2.5.2 Arena setup and behavioural assays ............................................................................... 19 3 Analysis .......................................................................................................................................... 21 3.1 EthoVision XT ....................................................................................................................... 22 3.2 Analysis in R .......................................................................................................................... 22 3.2.1 Repeatability and behaviour analysis in R ..................................................................... 23 3.2.2 Linear mixed effect model in R and model simplification ............................................. 25 3.2.3 Specific growth rates ...................................................................................................... 25 3.2.4 Life history data analysis in R ........................................................................................ 26 4 Results ............................................................................................................................................ 26 4.1 Repeatability and variance components for swimming distance ............................................ 27 4.1.1 Stage, sex and food effects on mean swimming distance .............................................. 28 4.2 Repeatability and variance components for moving time ..................................................... 30 4.2.1 Analysis of variance and lsmeans comparison for time spent moving ........................... 31 4.3 Repeatability and variance components for actual velocity ................................................... 32 4.3.1 Analysis of variance and lsmeans comparison for actual velocity ................................. 33 ii 4.4 Repeatability and variance components for time spent in outer area ..................................... 35 4.4.1 Analysis of variance and lsmeans comparison for time spent in outer area ................... 36 4.5 Life history data ...................................................................................................................... 38 4.5.1 Growth rates ................................................................................................................... 38 4.5.2 Reproduction and offspring ............................................................................................ 40 5 Discussion ...................................................................................................................................... 42 5.1 Discussion of first hypothesis – life history effects of food ................................................... 42 5.2 Discussion of second hypothesis ............................................................................................ 43 5.2.1 Swimming distance .......................................................................................................... 44 5.2.2 Moving time .................................................................................................................... 47 5.2.3 Actual velocity ................................................................................................................. 49 5.2.4 Time spent in outer area .................................................................................................. 51 5.3 Discussion of third hypothesis................................................................................................ 53 5.4 Summary and implications of the thesis ................................................................................. 57 Appendix ........................................................................................................................................... 59 Experiment tables and calendars ....................................................................................................... 59 Feeding recipe ................................................................................................................................... 68 List of cited Literature ....................................................................................................................... 70 Images ............................................................................................................................................... 70 Literature ........................................................................................................................................... 71 iii List of Figures Figure 1. Tinbergen's four questions, divided by Proximate und Ultimate Causes. Figure 2. Between-individual and among-individual differences in behaviour across situations. Figure 3. Consequences for individual specimen due to different behavioural types. Figure 4. LESTER-model visualizing changes in energetic investment between growth and reproduction. Figure 5. Train of thought for the hypotheses and their linkage. Figure 6. Extant and extinct distribution of Heterandria formosa. Figure 7. Heterandria formosa and the expressed sexual dimorphism between the larger female and the smaller male specimen. Figure 8. Experimental housing setup of the individual test fish. Figure 9. Weekly length measurement of an individuum with a small petri dish. Figure 10. Plastic arena for behavioural assessments. Figure 11. The two stages of each behavioural trial phase. Figure 12. Repeatability as the variation proportion due to among-individual variation. Figure 13. Linear mixed effect model approach used for whole model repeatability calculations. Figure 14. Linear model used for single Age:Food:Sex combination calculation of repeatability. Figure 15. Formula for specific growth rate calculations. Figure 16. Repeatability, within and among-individual variance scores and confidence intervals for swimming distance and the factors sex, food and stage. Figure 17. Mean swimming distance with standard errors over all Stage:Sex:Food