TY - JOUR
T1 - Hysteresis stabilizes dynamic control of self-assembled army ant constructions
AU - McCreery, Helen F.
AU - Gemayel, Georgina
AU - Pais, Ana Isabel
AU - Garnier, Simon
AU - Nagpal, Radhika
N1 - Funding Information:
We thank Chris Reid and Matt Lutz for their advice and discussions regarding fieldwork and experiments. The staff of the Smithsonian Tropical Research Institute, Barro Colorado Island, Panama provided assistance and support. We thank Courtney Rockenbach, Cesar Gutierrez, and Jane McCreery for their assistance in the field. Mike Rubenstein and Melinda Malley participated in early discussions and field explorations, and we thank Mike Rubenstein for also providing comments on the manuscript. Grace Haynes performed some manual data extraction. We thank Jordan Kennedy, the Self-Organizing Systems Research Group at Harvard, and Albert Kao for helpful discussions and support. H.F.M. acknowledges support from a James S. McDonnell Postdoctoral Fellowship Award.
Funding Information:
We thank Chris Reid and Matt Lutz for their advice and discussions regarding fieldwork and experiments. The staff of the Smithsonian Tropical Research Institute, Barro Colorado Island, Panama provided assistance and support. We thank Courtney Rockenbach, Cesar Gutierrez, and Jane McCreery for their assistance in the field. Mike Rubenstein and Melinda Malley participated in early discussions and field explorations, and we thank Mike Rubenstein for also providing comments on the manuscript. Grace Haynes performed some manual data extraction. We thank Jordan Kennedy, the Self-Organizing Systems Research Group at Harvard, and Albert Kao for helpful discussions and support. H.F.M. acknowledges support from a James S. McDonnell Postdoctoral Fellowship Award.
Publisher Copyright:
© 2022, The Author(s).
PY - 2022/12
Y1 - 2022/12
N2 - Biological systems must adjust to changing external conditions, and their resilience depends on their control mechanisms. How is dynamic control implemented in noisy, decentralized systems? Army ants’ self-assembled bridges are built on unstable features, like leaves, which frequently move. Using field experiments and simulations, we characterize the bridges’ response as the gaps they span change in size, identify the control mechanism, and explore how this emerges from individuals’ decisions. For a given gap size, bridges were larger after the gap increased rather than decreased. This hysteresis was best explained by an accumulator model, in which individual decisions to join or leave a bridge depend on the difference between its current and equilibrium state. This produces robust collective structures that adjust to lasting perturbations while ignoring small, momentary shifts. Our field data support separate joining and leaving cues; joining is prompted by high bridge performance and leaving by an excess of ants. This leads to stabilizing hysteresis, an important feature of many biological and engineered systems.
AB - Biological systems must adjust to changing external conditions, and their resilience depends on their control mechanisms. How is dynamic control implemented in noisy, decentralized systems? Army ants’ self-assembled bridges are built on unstable features, like leaves, which frequently move. Using field experiments and simulations, we characterize the bridges’ response as the gaps they span change in size, identify the control mechanism, and explore how this emerges from individuals’ decisions. For a given gap size, bridges were larger after the gap increased rather than decreased. This hysteresis was best explained by an accumulator model, in which individual decisions to join or leave a bridge depend on the difference between its current and equilibrium state. This produces robust collective structures that adjust to lasting perturbations while ignoring small, momentary shifts. Our field data support separate joining and leaving cues; joining is prompted by high bridge performance and leaving by an excess of ants. This leads to stabilizing hysteresis, an important feature of many biological and engineered systems.
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U2 - 10.1038/s41467-022-28773-z
DO - 10.1038/s41467-022-28773-z
M3 - Article
C2 - 35246567
AN - SCOPUS:85125838407
SN - 2041-1723
VL - 13
JO - Nature Communications
JF - Nature Communications
IS - 1
M1 - 1160
ER -