Comment on P. Nouvellet, J.P. Bacon, D. Waxman, “Testing the level of ant activity associated with quorum sensing: An empirical approach leading to the establishment and test of a null-model”

Richardson, Thomas O.; Robinson, Elva J. H.; Christensen, Kim; Jensen, Johannes H.; Franks, Nigel R.; Sendova‐Franks, Ana B.

doi:10.1016/j.jtbi.2010.11.004

Cited by 4 publications

(2 citation statements)

References 9 publications

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“…This conclusion was challenged by Nouvellet et al [68], who performed new experiments where the exit process could more simply be described by standard Poisson statistics, the result expected if the ants move randomly and independently in and out of their nest. The question is of course whether the two sets of experiments really were equivalent [69]. More important from our vantage point is the mecha-nism producing the gradual entrenchment of dynamical trajectories in more long-lived metastable configurations.…”

Section: Movement In Ant Coloniesmentioning

confidence: 99%

Record dynamics of evolving metastable systems: theory and applications

Sibani,

Boettcher,

Jensen

2020

Preprint

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Record Dynamics (RD) deals with complex systems evolving through a sequence of metastable stages. These are macroscopically distinguishable and appear stationary, except for the sudden and rapid changes, called quakes, which induce the transitions from one stage to the next. This phenomenology is well known in physics as "physical aging", but from the vantage point of RD the evolution of a class of systems of physical, biological and cultural origin is rooted in a hierarchically structured configuration space and can therefore be analyzed by similar statistical tools. This colloquium paper strives to present in a coherent fashion methods and ideas that have gradually evolved over time. To this end, it first describes the differences and similarities between RD and two widespread paradigms of complex dynamics, Self Organized Criticality and Continuous Time Random Walks. It then outlines the Poissonian nature of records events in white noise time series, and connects it to the statistics of quakes in metastable hierarchical systems, arguing that the relaxation effects of quakes can generally be described by power laws unrelated to criticality. Several different applications of RD have been developed over the years. Some of these are described, showinghe basic RD hypothesis, the log time homogeneity of quake dynamics, can be empirically verified in a given context. The discussion summarizes the paper and briefly mentions applications not discussed in detail. Finally, the outlook points to possible improvements and to new areas of research where RG could be of use. I.

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Section: Movement In Ant Coloniesmentioning

confidence: 99%

Record dynamics of evolving metastable systems: theory and applications

Sibani,

Boettcher,

Jensen

2020

Preprint

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“…The results could be described by a 'null' model, where ants act independently and where the activity is described by a standard Poisson process, as fitting for a stationary and time homogeneous situation. In their reply [7], Richardson et al stressed that the two sets of experiments were performed under different conditions and claimed that this would lead to different event statistics. For completeness, we also mention that Nouvellet et al recently replied [8] to the comment of Richardson et al. The discussion between the two groups raises two important theoretical issues.…”

Section: Introductionmentioning

confidence: 99%

Non-stationary aging dynamics in ant societies

Sibani¹,

Christiansen²

2011

Journal of Theoretical Biology

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In recent experiments by Richardson et al. (2010) [Richardson, T.O., Robinson, E.J.H., Christensen, K., Jensen, H.J., Franks, N.R., Sendova-Franks, A.B., 2010. PLoS ONE 5, e9621.] ant motion out of the nest is shown to be a non-stationary process intriguingly similar to the dynamics encountered in physical aging of glassy systems. Specifically, exit events can be described as a Poisson process in logarithmic time, or, for short, a log-Poisson process. Nouvellet et al. (2010) [Nouvellet, P., Bacon, J.P.,Waxman, D., 2010. J. Theor. Biol. 266, 573.] criticized these conclusions and performed new experiments where the exit process could more simply be described by standard Poisson statistics. In their reply Richardson et al. (2011b) [Richardson, T.O., Robinson, E.J.H., Christensen, K., Jensen, J.H., Christensen, K., Jensen, H.J., Franks, N.R., Sendova-Franks, A.B., 2011b. J. Theor. Biol. 269, 356-358.] stressed that the two sets of experiments were performed under very different conditions and claimed that this was the likely source of the discrepancy. Ignoring any technical issues which are part of the above discussion, the focal point of this work is to ascertain whether or not both log-Poisson and Poisson statistics are possible in an ant society under different external conditions. To this end, a model is introduced where interacting ants move in a stochastic fashion from one site to a neighboring site on a finite 2D lattice. The probability of each move is determined by the ensuing changes of a utility function which is a sum of pairwise interactions between ants, weighted by distance. Depending on how the interactions are defined and on a control parameter dubbed 'degree of stochasticity' (DS), the dynamics either quickly converges to a stationary state, where movements are a standard Poisson process, or may enter a non-stationary regime, where exits can be described as suggested by Richardson et al. Other aspects of the model behavior are also discussed, i.e. the time dependence of the average value of the utility function, and the statistics of spatial re-arrangements happening anywhere in the system. Finally, we discuss the role of record events and their statistics in the context of ant societies and suggest the possibility that a transition from non-stationary to stationary dynamics can be triggered experimentally.

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