From inter-group conflict to inter-group cooperation: insights from social insects

Antonio M M Rodrigues, Jessica Barker, Elva Joan Hilda Robinson

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Conflict between social groups is widespread, often imposing significant costs across multiple groups. The social insects make an ideal system for investigating inter-group relationships, because their interaction types span the full harming-helping continuum, from aggressive conflict, to mutual tolerance, to cooperation between spatially separate groups. Here we review inter-group conflict in the social insects, and the various means by which they reduce the costs of conflict, including individual or colony- level avoidance, ritualistic behaviours, and even group fusion. At the opposite extreme of the harming- helping continuum, social insect groups may peacefully exchange resources and thus cooperate between groups in a manner rare outside human societies. We discuss the role of population viscosity in favouring inter-group cooperation. We present a model encompassing intra- and inter-group interactions, and local and long-distance dispersal. We show that in this multi-level population structure, the increased likelihood of cooperative partners being kin is balanced by increased kin competition, such that neither cooperation (helping) nor conflict (harming) is favoured. This model provides a baseline context in which other intra- and inter-group processes act, tipping the balance towards or away from conflict. We discuss future directions for research into the ecological factors shaping the evolution of inter-group interactions.
Original languageEnglish
JournalPhilosophical Transactions of the Royal Society B: Biological Sciences
Publication statusPublished - 4 Apr 2022

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  • class-structure
  • inclusive fitness
  • intergroup conflict
  • intergroup cooperation
  • population viscosity
  • dispersal
  • local dispersal
  • movement
  • patch model
  • spatial model
  • social insects
  • ants
  • bees
  • wasps
  • termites
  • conflict
  • cooperation
  • tolerance

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