Dynamic self-organization in fire ant rafts underpins collective longevity and threat responsiveness

Many living collectives must balance strategies between long-term energy conservation and short-term threat response; the ability for groups to dynamically self-organize into a variety of structures to address these needs is therefore essential. We show that fire ant Solenopsis invicta rafts which form buoyant bilayers in hostile flooded environments, adapt to conserve energy by separating into active and stationary phases. A simple kinetic model incorporating motility induced phase separation provides a useful framework to understand this transition, where ants form clusters by slowing down to participate in social interactions. We find that external stimuli either weakens or strengths these interactions. The former leads to dissolution of clusters and fast-mobilization of surface ants, revealing how clusters could serve a secondary purpose with rapid mobilization aiding exploration through formation of bridges. These results highlight how living collectives can adapt survival strategi..., , , # Supplementary Data

[https://doi.org/10.5061/dryad.d51c5b0cv](https://doi.org/10.5061/dryad.d51c5b0cv)

## Description of the data and file structure

All supplementary and extended raw video data were captured using an iPhone 12 with 1 second intervals. Supplementary videos are labeled according to how they appear in the supplementary information file. Raw video data is labeled according to the trial number and date they were conducted. Information pertaining to the colony used and type of experiment is outlined in the supplementary information Table S1.

Code is stored in the matlab (.m) format. No separate packages are required to run.
### Files and variables

#### File: SupplementaryVideos.zip

**Description:** This archive contains supplementary video data referenced within the main manuscript and is labelled as **\"SupplementalVideoNUM_STIMULUS.avi\"** where **NUM** references the label number and** STIMULUS** references a brief description of the experiment type used in each vide...,