Abstract: 【Aim】 The mating behavior of insects is closely related to their age and the development of reproductive system. This study aims to explore the relationship between the mating activity and age, sex ratio and the testicular volume of male moths of the Asian corn borer (ACB), Ostrinia furnacalis, so as to provide the theoretical basis for the application of ACB sex pheromone in mass trapping and mating disruption in the field. 【Methods】 The mating rate and frequency of ACB were determined by mating experiments in the laboratory with different pairing nights, age and sex ratios, and the relationship between the testicular volume and the mating frequency of male moths was analyzed by testicular anatomy. 【Results】 The mating rate of ACB increased with the number of pairing nights, but the increase was more rapid from the 1st to the 5th night than that from the 6th to the 7th night. The mating rate of moths increased with the age from 1-day-old to 4-day-old, but the mating rate of the 5-day-old moths decreased significantly. There was no significant difference in the mating rate between the 1-3 day-old moths pairing one night and pairing 2-4 nights after eclosion. ACB could mate 1-3 times, but the proportion of moths mating thrice was very low. When the number of pairing female moths increased from 1 to 2, the mating rate of male moth increased significantly. However, when the number of female moths increased to 3, the mating rate of male moth decreased significantly, the mortality rate of male moths increased significantly, and the proportion of moths mating twice increased. Male moth preferred to mate with virgin female for its second mating. The testicular volume of male moths mating once was always significantly larger than that of the unmated males at the same day-old, and the testicular shrinkage of males was slightly delayed by mating. Mating twice significantly increased the testicular shrinkage of male moths. 【Conclusion】 This study clarifies the relationship between the mating of ACB and the age, the sex ratio and the testicular volume of male moth. The results provide a theoretical basis for the development of mating disruption and mass trapping by sex pheromone and confirm the effectiveness of its application in the field.

Key words:  Ostrinia furnacalis, mating, testis, sex pheromone, delayed mating, mass trapping