Contents
Acknowledgments V Contents VII
I. Introduction 13 A. Group living 15
1. Advantages & disadvantages 16 2. Group living & disturbances 19
3. Interests of the study of group living and disturbances 26 B. Consistent behavioural differences 29
C. Research aims & scope 30 D. Periplaneta americana 31 E. References 34
II. Information cascade ruling the fleeing behaviour of a gregarious insect 45 A. Introduction 47
B. Methods 50
1. Biological model 50 2. Experimental set-up 50
3. Experimental procedure 51 4. Measurements 53
C. Results 53
1. Qualitative behavioural description 53 2. Global behavioural description 54
3. Reaction times 55 4. Arrival times 59 5. Waiting times 60 6. Exit time 61 7. Simulations 61 D. Discussion 63
E. Acknowledgments 68 F. References 70
G. Appendix 1: The biological model 78
1. Rearing conditions 78 2. Stimuli detection 78
3. Fleeing behaviour for isolated individuals 79 H. Appendix 2: Groups with mobile individuals 80 I. Appendix 3: Mortality 81
J. Appendix 4: Position within the shelter 81 K. Appendix 5: Reaction latencies 84
L. Appendix 6: Summary of the parameter values 87
III. Anonymous fleeing follows positional personality during rest 89 A. Introduction 91
B. Materials & methods 92 1. Biological model 92 2. Experimental set-up 93
3. Experimental procedure 94
4. Analysis 95
C. Results 96
1. Overall behavioural consistency 96 2. Inter-individual differences 98
3. Relation between measurements 99 D. Discussion 102
E. Acknowledgments 106 F. References 107
IV. Collective resilience in a disturbed environment: stability of the activity rhythm and group personality in Periplaneta americana 113
A. Introduction 115
B. Materials and methods 120 1. Biological model 120 2. Experimental set-up 120
3. Experimental procedures and measurements 121
4. Analyses 123
C. Results 126
1. Daytime occupation 126 2. Night occupations 130 3. Presence in the shelters 135 4. Group personalities 136 D. Discussion 137
1. Resilience and stability of the choice 137 2. Migration 139
3. Perspectives 141
E. Acknowledgments 144
F. Compliance with ethical standards 144 G. References 145
H. Appendix 153
V. Modelling collective emigration in a disturbance-induced environment: the role of sociality and personality 155
A. Introduction 157
B. Methods 161
1. Biological model 161 2. Set-up 161
3. Experimental procedure and measurements 162
4. Analysis 163
C. Results: 167
1. Modelling the emigration dynamics and choice stability in the Disturbed and Undisturbed condition 167
2. Active phase behavior and the role of personality 170 D. Discussion: 175
1. Modelling the emigration dynamics and stability in the Disturbed and Undisturbed condition 175
2. Night dynamics and the role of personality 178 E. Acknowledgments 183
F. References 184
G. Appendix 190
VI. Conclusions & discussion 191
A. Collective fleeing & disturbance effects 193 1. Short timescale 193
2. Long timescale 195
B. Behavioural consistency 199
1. Isolated individuals during a disturbance 199
2. Individual and group personalities on the long-term 201 C. Perspectives 202
D. References 205
