The emergence and mating rhythms of the legume pod borer, Maruca vitrata (Fabricius, 1787) (Lepidoptera: Pyralidae)

The legume pod borer, Maruca vitrata (Fabricius, 1787) is a serious pantropical insect pest of grain legumes. The emergence and mating rhythms of the legume pod borer adults were investigated at 29 +/- 1 degrees C and 75-80% r.h. under 14L:10D. The results showed that emergence activity of M vitrata occurred throughout the day, 86%, of females and 73% of males emerged at night. The highest emergence frequency occurred at 2300-2400 h and 0200-0300 h for females and males, respectively. The highest mating frequency occurred between 2300 and 2400 h for 3-day-old moths. Single mating peaks were observed for 1-, 6-and 7-day-old moths and double mating peaks were observed for 2- to 5-day-old moths. The percentage of pairs mating at the first peak was higher than at the second peak. More time was spent in mating during the first half of scotophase than the second one. The mating behaviour of M. vitrata was age-dependent. Young and old pairs spent more time in mating than middle-aged pairs. Advanced onset of time and peak for mating were observed directly by older moths. The emergence activities of both sexes were almost synchronous. Emergence peaks were almost synchronous with the two peaks of mating at different time of day.