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Explore the speed vs. accuracy tradeoff in ant colonies' decision-making process. Investigate the impact of forced emigrations on decision speed. Discover the key factors influencing recruitment and population growth in ant societies.
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A tunable algorithm for collectivedecision-making by ant colonies Stephen Pratt Department of Ecology and Evolutionary Biology Princeton University David J.T. Sumpter Department of Zoology Oxford University
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Do colonies trade off the speed and accuracy of decision-making? Unforced emigration Forced emigration
In forced emigrations, decisions are faster… Unforced emigration Forced emigration 10 Time until completion (hours) Wilcoxon test, P < 0.001 5 0
In forced emigrations, decisions are faster… Unforced emigration Forced emigration 10 Time until completion (hours) Wilcoxon test, P < 0.001 5 0 …but less accurate 10 8 Number of colonies Wilcoxon test, P < 0.05 6 4 2 0 0.0 0.2 0.4 0.6 0.8 1.0 0.0 0.2 0.4 0.6 0.8 1.0 Proportion of colony in good nest
Better nests experience more recruitmentand faster population growth
Quorum rule: probability of transport increases with site population
Searchers: Assessors: Recruiters: Passive ants: Recruitment decision model
Summary of individual decision rules • Quality-dependent recruitment latency • Faster population growth at better sites • Investment of time to gain information • Quorum rule for start of transport • Amplifier of recruitment rate differences • Error check on individual behavior
Speed/accuracy tradeoff Speed of emigration Proportion in good nest 20 20 Quorum size 0 0 1 600 1 600 Recruitment latency (min) 0 0.55 1.0 500 min
Investigation of individual behavior underlying tradeoff Unforced emigrations Forced emigrations Good nests Mediocre nests
ANOVA: p < 0.0001 Ants in forced emigrationsuse lower quorrum
Acknowledgements Association for the Study of Animal Behaviour Pew Charitable Trusts Human Frontiers Science Program