Meta-community selection favours reciprocal cooperation but depresses exploitation between competitors

摘要

The evolution of cooperation and mutualism has mainly been explored through individual- and group-level processes. However, community-level processes could also impose selection pressure on species interactions. By using a dome-shaped nonmonotonic interaction (DS interaction) with cooperation at low-density and competition at high-density, we studied how cooperation and exploitation are selected at the meta-community level. Our results showed that population densities of species and communities were both significantly associated with the number of DS interactions and the species interaction modes. The more cooperation a species received via DS interactions, the higher its density was. A community with more DS interactions, especially more reciprocal cooperation, showed a higher total population density. Both reciprocal cooperators and exploiters in a local community were more favoured than unidirectional cooperators within a closed community. When facing competition from a community without cooperators (with only competitors), both reciprocal cooperators and exploiters were favoured in a local community, but only reciprocal cooperators were more favoured when facing competition from another community with cooperators. Our results suggest that selection at the meta-community level could be an alternative mechanism for the evolution of cooperation and the depression of exploitation between competitors.