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Mechanics of fire ant aggregations

Nature Materials volume 15, pages 54–59 (2016)Cite this article

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Abstract

Fire ants link their bodies to form aggregations; these can adopt a variety of structures1,2,3,4, they can drip2 and spread4, or withstand applied loads5,6. Here, by using oscillatory rheology, we show that fire ant aggregations are viscoelastic. We find that, at the lowest ant densities probed and in the linear regime, the elastic and viscous moduli are essentially identical over the spanned frequency range, which highlights the absence of a dominant mode of structural relaxation7. As ant density increases, the elastic modulus rises, which we interpret by alluding to ant crowding and subsequent jamming. When deformed beyond the linear regime, the aggregation flows, exhibiting shear-thinning behaviour with a stress load that is comparable to the maximum load the aggregation can withstand before individual ants are torn apart. Our findings illustrate the rich, collective mechanical behaviour that can arise in aggregations of active, interacting building blocks.

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Figure 1: Liquid-like and solid-like behaviour of fire ant aggregations.
Figure 2: Shear thinning of fire ant aggregations.
Figure 3: Creep behaviour of fire ant aggregations.
Figure 4: Viscoelasticity of fire ant aggregations.
Figure 5: Elastic modulus of fire ant aggregations.

References

  1. Anderson, C., Theraulaz, G. & Deneubourg, J.-L. Self-assemblages in insect societies. Insect. Soc. 49, 99–110 (2002).

    Article  Google Scholar 

  2. Bonabeau, E. et al. Dripping faucet with ants. Phys. Rev. E 57, 5904–5907 (1998).

    CAS  Google Scholar 

  3. Hölldobler, B. The Ants (Harvard Univ. Press, 1990).

    Book  Google Scholar 

  4. Mlot, N. J., Tovey, C. A. & Hu, D. L. Fire ants self-assemble into waterproof rafts to survive floods. Proc. Natl Acad. Sci. USA 108, 7669–7673 (2011).

    Article  CAS  Google Scholar 

  5. Foster, P. C., Mlot, N. J., Lin, A. & Hu, D. L. Fire ants actively control spacing and orientation within self-assemblages. J. Exp. Biol. 217, 2089–2100 (2014).

    Article  Google Scholar 

  6. Schneirla, T. C. Army Ants: A Study in Social Organization (W. H. Freeman, 1971).

    Google Scholar 

  7. Winter, H. H. & Mours, M. Neutron Spin Echo Spectroscopy Viscoelasticity Rheology 165–234 (Springer, 1997).

    Book  Google Scholar 

  8. Chhabra, R. P. Bubbles, Drops, and Particles in Non-Newtonian Fluids (CRC Press, 2006).

    Book  Google Scholar 

  9. Zill, S. N., Chaudhry, S., Büschges, A. & Schmitz, J. Directional specificity and encoding of muscle forces and loads by stick insect tibial campaniform sensilla, including receptors with round cuticular caps. Arth. Struct. Dev. 42, 455–467 (2013).

    Article  Google Scholar 

  10. Couzin, I. D. & Krause, J. in Advances in the Study of Behavior Vol. 32, 1–75 (Academic Press, 2003).

    Google Scholar 

  11. Sumpter, D. J. The principles of collective animal behaviour. Phil. Trans. R Soc. Lond. B 361, 5–22 (2006).

    Article  CAS  Google Scholar 

  12. Alcaraz, J. et al. Microrheology of human lung epithelial cells measured by atomic force microscopy. Biophys. J. 84, 2071–2079 (2003).

    Article  CAS  Google Scholar 

  13. Gisler, T. & Weitz, D. A. Scaling of the microrheology of semidilute F-actin solutions. Phys. Rev. Lett. 82, 1606 (1999).

    Article  CAS  Google Scholar 

  14. Marchetti, M. C. Active matter: Spontaneous flows and self-propelled drops. Nature 491, 340–341 (2012).

    Article  CAS  Google Scholar 

  15. Sanchez, T., Chen, D. T. N., DeCamp, S. J., Heymann, M. & Dogic, Z. Spontaneous motion in hierarchically assembled active matter. Nature 491, 431–434 (2012).

    Article  CAS  Google Scholar 

  16. Stone, M. & Goldbart, P. Mathematics for Physics: A Guided Tour for Graduate Students (Cambridge Univ. Press, 2009).

    Book  Google Scholar 

  17. Bird, R. B., Armstrong, R. C. & Hassager, O. Dynamics of Polymeric Liquids, Fluid Mechanics 2nd edn (Wiley, 1987).

    Google Scholar 

  18. Winter, H. H. & Chambon, F. Analysis of linear viscoelasticity of a crosslinking polymer at the gel point. J. Rheol. 30, 367–382 (1986).

    Article  CAS  Google Scholar 

  19. Krall, A. H. & Weitz, D. A. Internal dynamics and elasticity of fractal colloidal gels. Phys. Rev. Lett. 80, 778–781 (1998).

    Article  CAS  Google Scholar 

  20. Fabry, B. et al. Scaling the microrheology of living cells. Phys. Rev. Lett. 87, 148102 (2001).

    Article  CAS  Google Scholar 

  21. Ng, T. S. K. & McKinley, G. H. Power law gels at finite strains: The nonlinear rheology of gluten gels. J. Rheol. 52, 417 (2008).

    Article  CAS  Google Scholar 

  22. Trappe, V. & Sandkühler, P. Colloidal gels—low-density disordered solid-like states. Curr. Opin. Colloid Interface Sci. 8, 494–500 (2004).

    Article  CAS  Google Scholar 

  23. Mason, T., Bibette, J. & Weitz, D. Elasticity of compressed emulsions. Phys. Rev. Lett. 75, 2051–2054 (1995).

    Article  CAS  Google Scholar 

  24. Angelini, T. E. et al. Glass-like dynamics of collective cell migration. Proc. Natl Acad. Sci. USA 108, 4714–4719 (2011).

    Article  CAS  Google Scholar 

  25. Berthier, L. Nonequilibrium glassy dynamics of self-propelled hard disks. Phys. Rev. Lett. 112, 220602 (2014).

    Article  Google Scholar 

  26. Gonzalez-Rodriguez, D., Guevorkian, K., Douezan, S. & Brochard-Wyart, F. Soft matter models of developing tissues and tumors. Science 338, 910–917 (2012).

    Article  CAS  Google Scholar 

  27. Ni, R., Stuart, M. A. C. & Dijkstra, M. Pushing the glass transition towards random close packing using self-propelled hard spheres. Nature Commun. 4, 2704 (2013).

    Article  Google Scholar 

  28. Rubenstein, M., Cornejo, A. & Nagpal, R. Programmable self-assembly in a thousand-robot swarm. Science 345, 795–799 (2014).

    Article  CAS  Google Scholar 

  29. Werfel, J., Petersen, K. & Nagpal, R. Designing collective behavior in a termite-inspired robot construction team. Science 343, 754–758 (2014).

    Article  CAS  Google Scholar 

  30. Janmey, P. A. & Weitz, D. A. Dealing with mechanics: Mechanisms of force transduction in cells. Trends Biochem. Sci. 29, 364–370 (2004).

    Article  CAS  Google Scholar 

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Acknowledgements

This research is supported by the US Army Research Laboratory and the US Army Research Office Mechanical Sciences Division, Complex Dynamics and Systems Program, under contract numbers W911NF-12-R-0011 and W911NF-14-1-0487. We are also grateful to L. Mahadevan and G. McKinley for useful discussions.

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Authors and Affiliations

  1. School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA

    Michael Tennenbaum & Alberto Fernandez-Nieves

  2. School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA

    Zhongyang Liu & David Hu

Authors
  1. Michael Tennenbaum
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  2. Zhongyang Liu
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  3. David Hu
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  4. Alberto Fernandez-Nieves
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Contributions

M.T. and Z.L. performed experiments. M.T., D.H. and A.F.-N. designed experiments. M.T., D.H. and A.F.-N. analysed and interpreted data. M.T., D.H. and A.F.-N. wrote the paper.

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Correspondence to David Hu.

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The authors declare no competing financial interests.

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Tennenbaum, M., Liu, Z., Hu, D. et al. Mechanics of fire ant aggregations. Nature Mater 15, 54–59 (2016). https://doi.org/10.1038/nmat4450

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