Supplementary material for: "Reduced male pheromone production and an increased female ratio promote same-sex sexual behaviour in male Indian meal moths"

Experimental evolution was used to study male same-sex sexual behaviour (SSSB). Male SSSB frequency increased when females were present in the arena. Males missing hair pencils were subject to more rival male mating attempts.Findings highlight the role of male pheromones in close-range sex identification. SSSBs may be an outcome of a promiscuous mating system.