Motivated by the fact that the same social dilemma can be perceived differently by different players, we here study evolutionary multigames in structured populations. While the core game is the weak prisoner's dilemma, a fraction of the population adopts either a positive or a negative value of the sucker's payoff, thus playing either the traditional prisoner's dilemma or the snowdrift game. We show that the higher the fraction of the population adopting a different payoff matrix the more the evolution of cooperation is promoted. The microscopic mechanism responsible for this outcome is unique to structured populations, and it is due to the payoff heterogeneity, which spontaneously introduces strong cooperative leaders that give rise to an asymmetric strategy imitation flow in favor of cooperation. We demonstrate that the reported evolutionary outcomes are robust against variations of the interaction network, and they also remain valid if players are allowed to vary which game they play over time. These results corroborate existing evidence in favor of heterogeneity-enhanced network reciprocity, and they reveal how different perceptions of social dilemmas may contribute to their resolution.

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We study the evolution of cooperation in evolutionary spatial games when the payoff correlates with the increasing age of players (the level of correlation is set through a single parameter, α). The demographic heterogeneous age distribution, directly affecting the outcome of the game, is thus shown to be responsible for enhancing the cooperative behavior in the population. In particular, moderate values of α allow cooperators not only to survive but to outcompete defectors, even when the temptation to defect is large and the ageless, standard α = 0 model does not sustain cooperation. The interplay between age structure and noise is also considered, and we obtain the conditions for optimal levels of cooperation.

Agricultural soil is the main source of nitrous oxide (N2O) emissions which contribute to global warming and stratospheric ozone depletion. In recent decades, atmospheric nitrogen (N) deposition has increased dramatically as an important agricultural soil N input, while its effect on soil N2O emissions in the current and future climate change remains unknown. Here, we conducted a thorough analysis of the effect of N deposition and climate change on soil N2O emissions as well as their trends. Soil N2O emissions induced by N deposition accounted for 25% of global cropland soil N2O emissions. Global soil N2O emissions over croplands increased by 2% yr–1 during 1996–2013, of which N deposition could explain 15% of the increase. The emission factor of N deposition was ∼7 times that of N fertilizer plus manure (∼1%) through a more direct way, since N deposition including nitrate (NO3 –) and ammonium (NH4 +) could be directly used for nitrification and denitrification. By 2100, N deposition will increase by 80% and cropland soil N2O emissions will increase by 241% under the RCP8.5 scenario in comparison with the 2010 baseline. These results suggest that, under the background of increasing global N deposition, it is essential to consider its effects on soil N2O emissions in climatic change studies.