Wild male crickets act more aggressively in fights and put on flashier victory displays if other crickets are watching.


Lauren Fitzsimmons and Susan Bertram at Carleton University in Ottawa placed pairs of male spring field crickets (Gryllus veletis, pictured) together to fight. For some of the contests, the authors added a third cricket that could watch and hear the pair through a transparent, perforated wall. Wild-caught crickets' behaviour changed in the presence of spectators, becoming considerably more aggressive. Those that won fights also engaged in more flamboyant strutting (jerking their bodies and chirping) if a third male cricket was present. Lab-reared crickets did not exhibit such marked behaviour, suggesting that it might be shaped by social experience.

Although audience effects are well-documented in vertebrates, this is the first evidence that invertebrates modify contest behaviour in the presence of an observer, the authors say.

Biol. Lett. 9, 20130449 (2013)