Social insects and the level of selection

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Biological diversity - social insects+the level of selection 

  • eusociality - evolutionary advanced state - colonialism - separation, colonies - different roles - usually 1 reproductive individual+many sterile/semi sterile workers
  • Hymenoptera (ants,bees+wasps)+Isoptera (termites)+thrips, aphids, beetles
  • eusociality - mammals = naked mole rat
  • extreme examples - indivduals separated - many castes - specific roles
  • development, individuals - set castes - determined many factors:
    • bee queens determined - diet recieved as larvae (royal jelly - protein supplements secreted - worker bee glands). jelly turns off key gene - otherwise mean larva developed - worker
    • termites - pheromones secreted - secondary queens affect - larva - ensure they develop - sterile workers - go through moult
  • presence - eusociality leads - complex colonies - multiple castes+adoption - highly advanced practises, colonies - exploit food sources. eg leaf cutter ants
  • ants = polymorphic+tasks range - garden tending+broad care, defence foraging lines, foraging, leaf carrying - soldiers+queens
  • problem - come up against - altruism = act which does not benefit individual itself - benefits another individual
  • not confined - eusocial animals - all social animals exhibit apparent altruism - some degree
  • altruistic behaviour - selection happens - level of group
  • terms of fitness - important thing = group's reproductive success not individual organism = theory "group selection" - Wymne Edwards 1960s

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