Pheromone Dialects in European Turnip Moths Agrotis segetum

Abstract

Female pheromone gland extracts from cultures of Agrotis segetum (Schiff.), originating from Sweden, France, Hungary and England [UK] were analysed for pheromone components and precursors (fatty acids). The pheromone blends were similar in the moths from the Swedish, English and Hungarian populations, whereas the French diverged with a much higher amount of (Z)-5-decenyl acetate relative to the homologous pheromone components (Z)-7-dodecenyl acetate and (Z)-9-tetradecenyl acetate. The frequency of receptor cells sensitive to (Z)-5-decenyl acetate on male antennae, was also highest in the French insects. In correspondence with the earlier reported behavioural significance of (Z)-5-decenyl acetate in the French turnip moth, this is indicative of a French pheromone dialect. The biosynthetic basis for the shift in pheromone production as well as ecological and evolutionary implications of the findings are discussed.