Biologische Anstalt Helgoland Alfred-Wegener-Institut für Polar- und Meeresforschung Ph.D. thesis Ecological aspects on induced defenses in macroalgae by mesoherbivore attacks Dissertation zur Erlangung des Doktorgrades der Naturwissenschaften Vorgelegt dem Fachbereich Biologie/Chemie der Universität Bremen von Hee Young Yun January 2011 Hee Young Yun Section of Functional Ecology, Biologische Anstalt Helgoland, Alfred-Wegener-Institute for Polar and Marine Research, Kurpromenade 201, 27498 Helgoland, Germany Gutachter 1. Prof. Dr. Christian Wiencke Gutachter 2. Prof. Dr. Kai Bischof CONTENTS Summary………………………………………………………………………..........iii-vi Acknowledgment……………………………………………………………………….vii 1. INTRODUCTION………………………………………………………………..1-12 1.1. Macroalgae and their essential roles………………….………………………..1 1.2. Macroalgae and herbivory………………….…………………..……………1-2 1.2.1. Macroalgal strategies against herbivory ……………………………..2-3 1.2.2. Induced defenses in macroalgae to consumers.………………….…..3-5 1.3. Commonness of induced defensese in macroalgae…………………….…....5-6 1.4. Comparison of induced response in native to non-native species…………...6-8 1.5. Indirect species interactions via induced defenses…………..…………..…8-11 1.5.1. Macroalgal interactions mediated by induced defense……………..9-10 1.5.2. Herbivore interactions mediated by induced defense……..………10-11 1.6. Aims…………………………………………... …………………………11-12 2.