Diverse stochasticity leads a colony of ants to optimal foraging

•Strategy of diverse stochasticity(SDS) optimizes the group foraging of ants.•SDS extends the well-known idea of the strategy of errors (Deneubourg 1983 JTB).•Efficiency of SDS was checked using a phenomenological model of garden ants’ foraging.•Optimal distribution for SDS drastically changes with the environmental condition.•Optimal colony consists of highly and weakly stochastic ants in typical environments. A mathematical model of garden ants (Lasius japonicus) is introduced herein to investigate the relationship between the distribution of the degree of stochasticity in following pheromone trails and the group foraging efficiency. Numerical simulations of the model indicate that depending on the systematic change of the feeding environment, the optimal distribution of stochasticity shifts from a mixture of almost deterministic and mildly stochastic ants to a contrasted mixture of almost deterministic ants and highly stochastic ants. In addition, the interaction between the stochasticity and the pheromone path regulates the dynamics of the foraging efficiency optimization. Stochasticity could strengthen the collective efficiency when the variance in the sensitivity to pheromone for ants is introduced in the model.