Geographic variation in sex pheromone of Asian corn borer, Ostrinia furnacalis, in Japan

Geographic variation in the sex pheromone of the Asian corn borer, Ostrinia furnacalis (Guenee), was surveyed in populations sampled at four locations ranging from 39.7 degrees N to 32.9 degrees N in Japan. The sex pheromone of the three northern populations was composed of Q- and (Z)-12-tetradeceny l acetates with a mean E proportion of 36-39%. The southernmost population (Nishigoshi) had the same components but with a significantly higher E comp osition of 44%. The frequency distribution of the E ratio in the Nishigoshi population exhibited a small peak near 38% and a major peak near 46%. A fa mily-wise analysis of the sex pheromone of this population confirmed that t here were two distinct phenotypes regarding the E ratio. An "approximate to 46% E strain" inhabits southern parts of Japan, in addition to an " approx imate to 38% E strain," which seems to be predominant in other regions of J apan.