Food ow and stock management in ant colonies
Aurélie Bun
August 2011
Contents
Acknowledgements v
Summary vii
Introduction 1
Method 13
Objectives 21
1 Feeding and stocking up: Radio-labeled food reveals exchange
patterns in ants 23
1.1 Introduction. . . 24
1.2 Methods . . . 26
1.3 Results. . . 30
1.3.1 Imagery . . . 30
1.3.2 Volume and radioactivity . . . 30
1.3.3 Dynamics of food-ow . . . 31
1.3.4 Dynamics of the contaminated surface . . . 33
1.3.5 Spatial distribution of the food . . . 35
1.4 Discussion . . . 39
2 Discreet starvation but continuous regulation in ants food man- agement 43 2.1 Introduction. . . 44
2.2 Methods . . . 46 i
2.2.1 Biological model . . . 46
2.2.2 Collections . . . 46
2.2.3 Experimental nests . . . 47
2.2.4 Food Source and scintigraphy . . . 47
2.2.5 Analysis . . . 48
2.3 Results. . . 50
2.3.1 Food retrieval and food ow. . . 50
2.3.2 Spatial dynamics: number of fed ants . . . 54
2.4 Discussion . . . 57
3 Collective regulatory stock management and spatiotemporal dynamics of the food ow in ants 61 3.1 Introduction. . . 62
3.2 Materials and Methods. . . 63
3.2.1 Biological model . . . 63
3.2.2 Collections . . . 64
3.2.3 Experimental nests . . . 64
3.2.4 Food source and scintigraphy . . . 64
3.2.5 Spatial analysis . . . 65
3.3 Results. . . 67
3.3.1 Radioactive surface. . . 67
3.3.2 Activity of the colony . . . 69
3.3.3 Distribution of food loads . . . 70
3.3.4 Aggregation of the stocks . . . 71
3.3.5 Stability of the patterns and food centralization. . . 72
3.4 Discussion . . . 74
3.5 Appendix . . . 80
3.5.1 Detailed calculation of the colony activity . . . 80
4 Double labeling to link food stores to the food ow in an ant colony 83 4.1 Introduction. . . 83
4.2 Methods . . . 85
4.3 Results. . . 88 ii
4.3.1 Nest radioactivity and radioactive surface . . . 88
4.3.2 Distribution of the pixels radioactivity . . . 89
4.3.3 Radioactivity spatial organization . . . 89
4.3.4 Aggregation level of radioactivity . . . 91
4.3.5 Spatial stability. . . 93
4.3.6 Tracers match . . . 93
4.4 Discussion . . . 97
Discussion 101 5.1 Validation of the methodology. . . 101
5.1.1 Volume, radioactivity, ants and radioactive surface . . . 101
5.1.2 Tracers accuracy . . . 102
5.2 Dynamics of the feeding process. . . 104
5.2.1 Food quantity. . . 104
5.2.2 Number of ants . . . 105
5.2.3 Number of ants as function of the harvest . . . 105
5.2.4 Colony activity . . . 107
5.3 Spatial food distribution . . . 108
5.3.1 Distribution among workers . . . 108
5.3.2 Centre of masses position and shifts . . . 110
5.3.3 Food distribution within the aggregate . . . 111
Perspectives 113
Appendix: Trophallaxis in Lasius niger: a variable frequency and
constant duration for three food types 115
References 150
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