Male–male courtship behaviour, not relatedness, affects the intensity of contest competition in the field cricket

Males often compete intensely against rival males because access to females is a major factor contrib- uting to their reproductive success. However, there is controversy over whether maleemale competition is weakened when rival males are related, with reduced aggressiveness leading to inclusive fitness benefits. Furthermore, same-sex sexual behaviour is also expected to mitigate maleemale contests. Here, I examined how relatedness, developmental familiarity (i.e. males reared in the same container or not) and same sex sexual behaviour affect the intensity of maleemale competition in wild-caught field crickets, Teleogryllus occipitalis. Relatedness and familiarity had no significant effect on the intensity of maleemale contest behaviour. However, same-sex sexual behaviour did weaken maleemale competi- tion. In conclusion, my results indicate that same-sex sexual behaviour in this cricket has adaptive sig- nificance by mitigating risky maleemale contest behaviour.