| 1. |
- Nicolis, Stamatios C., et al.
(författare)
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The effect of aggregates on interaction rate in ant colonies
- 2005
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Ingår i: Animal Behaviour. - : Elsevier BV. - 0003-3472. ; 69:3, s. 535-540
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Tidskriftsartikel (refereegranskat)abstract
- Direct contact between individuals is important for the organization of social insects. The question has been raised whether in ant colonies contact may also provide a mechanism to allow ants to estimate the density of the population in a nest and regulate their behaviour accordingly, as reflected by a subquadratic dependence of the number of interactions as a function of the density. We developed a kinetic model of encounters between individuals, and conducted an experiment with different densities of the species Lasius niger. These suggested that the subquadratic law is not due to active regulation by ants but arises, rather, as a consequence of the kinetics of the encounter process and the presence of small, temporary clusters of individuals. (c) 2004 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
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| 2. |
- Perna, Andrea, et al.
(författare)
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Individual Rules for Trail Pattern Formation in Argentine Ants (Linepithema humile)
- 2012
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Ingår i: PloS Computational Biology. - : Public Library of Science (PLoS). - 1553-734X .- 1553-7358. ; 8:7, s. e1002592-
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Tidskriftsartikel (refereegranskat)abstract
- Many ant species produce large dendritic networks of trails around their nest. These networks result from self-organized feedback mechanisms: ants leave small amounts of a chemical -a pheromone- as they move across space. In turn, they are attracted by this same pheromone so that eventually a trail is formed. In our study, we introduce a new image analysis technique to estimate the concentrations of pheromone directly on the trails. In this way, we can characterise the ingredients of the feedback loop that ultimately leads to the formation of trails. We show that the response to pheromone concentrations is linear: an ant will turn to the left with frequency proportional to the difference between the pheromone concentrations on its left and right sides. Such a linear individual response was rejected by previous literature, as it would be incompatible with the results of a large number of experiments: trails can only be reinforced if the ants have a disproportionally higher probability to select the trail with higher pheromone concentration. However, we show that the required non-linearity does not reside in the perceptual response of the ants, but in the noise associated with their movement.
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| 3. |
- Theraulaz, Guy, et al.
(författare)
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Spatial patterns in ant colonies
- 2002
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Ingår i: Proceedings Of The National Academy Of Sciences Of The United States Of America. - : Proceedings of the National Academy of Sciences. ; 99:15, s. 9645-9649
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Tidskriftsartikel (refereegranskat)abstract
- The origins of large-scale spatial patterns in biology have been an important source of theoretical speculation since the pioneering work by Turing (1952) on the chemical basis of morphogenesis. Knowing how these patterns emerge and their functional role is important to our understanding of the evolution of biocomplexity and the role played by self organization. However, so far, conclusive evidence for local activation-long-range inhibition mechanisms in real biological systems has been elusive. Here a well-defined experimental and theoretical analysis of the pattern formation dynamics exhibited by clustering behavior in ant colonies is presented. These experiments and a simple mathematical model show that these colonies do indeed use this type of mechanism. All microscopic variables have been measured and provide the first evidence, to our knowledge, for this type of self-organized behavior in complex biological systems, supporting early conjectures about its role in the organization of insect societies.
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