Holman, Luke2015-12-131045-2249http://hdl.handle.net/1885/75849The nonreproductive helpers of many arthropod, bird and mammal species are a perennial puzzle for evolutionary biologists. Theory and evidence suggests that helping is favored by high relatedness between social partners and by certain ecological factors.Conditional helping and evolutionary transitions to eusociality and cooperative breeding201410.1093/beheco/aru1002015-12-11