ORCID Profile
0000-0002-3062-4215
Current Organisations
Université de Toulouse
,
Centre National de la Recherche Scientifique
,
Université de Provence
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Publisher: Elsevier BV
Date: 12-2006
DOI: 10.1016/J.JTBI.2006.06.018
Abstract: Many biological networks grow under strong spatial constraints, where the large-scale structure emerges from the extension, the branching and intersection of growing parts of the network. One ex le is provided by ant tunnelling networks, which represent the most common nest architecture in ants. Our goal was to understand how these network structures emerge from the tunnel growth dynamics. We used a standardized two-dimensional set-up shaped as a disk and studied the characteristics of tunnel growth in terms of initiation, propagation and termination of new digging sites and found that they can be described with simple probabilistic laws. We show that a model based on these simple laws and for which parameters were measured from the sand disks experiments can account for the emergence of several topological properties that were observed in experimental networks. In particular, the model accurately reproduced an allometric relation between the number of edges and the number of nodes, as well as an invariance of the node degree distribution. The model was then used to make predictions about the resulting networks' topology when the geometry of the sand substrate was shaped as a square. Experiments aimed at testing the model's predictions showed that the predictions were indeed validated. Both in the model and in the experiments, there was a similar trend for the node degree distribution tail to be steeper in the square sand patch than in the disk sand patch, while other characteristics such as the meshedness (i.e. how densely the network is internally connected) remained constant. Because network growth based on branching/fusion events is widespread in biological systems, this general model might provide useful insights for the study of other systems and, more generally, the evolution of spatial networks in biological systems.
Publisher: Springer Science and Business Media LLC
Date: 05-02-2005
Publisher: Springer Science and Business Media LLC
Date: 08-03-2018
Publisher: Springer Science and Business Media LLC
Date: 02-2006
Publisher: Springer Science and Business Media LLC
Date: 27-10-2004
DOI: 10.1007/S00114-004-0577-X
Abstract: Collective digging activity was studied in the ant Messor sancta Forel in laboratory conditions and with a two dimensional set-up. We analyzed the digging dynamics and topology of tunneling networks excavated by groups of workers ranging from 50 to 200 in iduals over 3 days. In all conditions, the dynamics of excavated sand volume were clearly non-linear. Excavation began with an exponential growth and after 3 days reached a saturation phase in which activity was almost totally stopped. The final volume of sand excavated was positively correlated with the number of workers. At the end of the experiments, the two-dimensional tunneling networks were mapped onto planar graphs where the vertices represent small chambers or intersections between tunnels and the edges represent tunnels. We found that all the networks belonged to a same topological family and exhibited several striking invariants such as the distribution of vertex degree that follows a power law. When increasing the number of ants, some changes occurred in the network structure, mainly an increase in the number of edges and vertices, and the progressive emergence of enlarged and highly connected vertices.
Publisher: Springer Science and Business Media LLC
Date: 11-2004
Publisher: Public Library of Science (PLoS)
Date: 15-10-2014
Publisher: American Association for the Advancement of Science (AAAS)
Date: 03-2019
Abstract: Ventilation and drainage in termite nests are controlled by microscale morphological features of the outer walls.
No related grants have been discovered for Guy Theraulaz.