Social decision making in a fluctuating world: A simulation model of a Producer-Scrounger foraging game

The producer-scrounger model is a frequency-dependent cooperation/conflict game describing social situations where the efforts of certain individuals (producers) are exploited by others (scroungers). In a social foraging context, producers discover patches of food and scroungers join the producers at already discovered patches. Theoretical work has identified which parameters influence the equilibrium frequencies of the two tactics in a group, and many of the results have been confirmed in experimental studies on birds. However, analytical results do not predict whether the ESS is comprised of fixed strategists or mixed strategists playing each tactic with ESS probability, or when we also expect the evolution of conditional strategists that have to gather information about their social environment in order to show adaptive plasticity between producing versus scrounging. We extend existing theoretical treatments with an evolutionary simulation model, where genes for the social reaction norm evolve across generations, and we examine the evolutionary stability of fixed, mixed and conditionally plastic strategies, and how these are affected by environmental or demographic stochasticity. We also investigate whether conditional strategists should best assess their social environment through private or public information, and the value of memory and learning under different patterns of environmental fluctuation.