Body size influences male pheromone signals but not the outcome of mating contests in Nasonia vitripennis

► We tested the impact of male body size on mate choice in Nasonia vitripennis wasps. ► We quantified the sex pheromone of large and small males and performed mating contests. ► Large males produced and released much more of the pheromone than small males. ► Virgin females clearly preferred pheromone doses released by large males. ► In mating contests, however, large and small males were equally successful.