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  • Open Access

Robotectonics: Emergent Phototactic Aggregation-Disaggregation in Swarms

Fabio Giardina1,*, S. Ganga Prasath1,2,*, and L. Mahadevan1,3,4,†

  • 1School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
  • 2Department of Applied Mechanics & Biomedical Engineering, IIT Madras, Chennai 600036, Tamil Nadu, India
  • 3Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
  • 4Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138, USA

  • *These authors contributed equally to this work.
  • †Contact author: lmahadev@g.harvard.edu
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PRX Life 4, 023005 – Published 10 April, 2026

DOI: https://doi.org/10.1103/cx3h-bwhc

Abstract

The collective construction of complex architectures by social insects involves the use of decentralized spatiotemporal signals in a dynamical environment that changes the behavior of the insects and is changed by them. Inspired by this original example of “stigmergy,” we show that a robot collective can nucleate, construct, and deconstruct aggregates via a trapping instability by simply altering their local transport behavior. We quantify these observations in terms of a two-dimensional phase space that encompasses agent-agent interaction and the agent-environment interaction (collection and deposition). Our results show how coordinated function can emerge spontaneously through simple local rules for sensing and action without the need for global representation, planning, or optimization/control algorithms, in sharp contrast with the traditional views of complex task execution. More broadly, our study shows that embodied collectives can leverage the environment as both a communication channel and a spatiotemporal memory, coupling organismal behavior to environmental remodeling leading to “exbodied intelligence.”

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PRX Life 4, 023005– Published 10 April, 2026
  • Received 30 June 2025
  • Accepted 4 February 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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