Table 1.

Summary of models

Model	Variables	Male fitness	Evolution to mi = 1 if
Communal care (10)	mi, ci		α < β(N − 1)
Mate guarding	mi, gi		γ < β
Food for mating	mi, pi		α < (β − γ)(N − 1)
Mate provisioning	mi, pi		α < (β − γ)(N − 1)
Pair bonding	mi, pi		SI Appendix