솔수염하늘소 유충의 두폭 성장과 포장상태에서 영기 수의 추정

Abstract

This study was conducted to establish the number of instars for Monochamus alternatus larvae in the fields, by appling the meta analysis for the head capsule width (HCW) in previous studies and actual empirical experiments. The larvae of M. alternatus developed to the 12th instar at 26℃ when pine barks were fed in the laboratory, and they finished their development at the 9th and 10th instar at 18℃ and 30℃, respectively. The larval development was retarded after the 3rd instar in the laboratory rearing, while the development through the 1st to 3rd instar likely showed normal process, which instars were small and might not be affected largely by food resource. Thus, the HCW was significantly separated among instars during the 1st to 3rd instars with high Dyar's ratios. Consequently, our results could represent actually the HCW for the 1st, 2nd and 3rd instar of M. alternatus larvae, with that we comprehensively compared with previous reports in HCW. The newly proposed mean HCW 0.896 mm of the 1st instar in our study was more reasonable than 0.729 mm in Japan or 1.218 mm in China, which is presumed to be caused by sampling error in collecting 1st instars or large individual variation among the 1st instar larvae. The mean HCW of the 2nd and 3rd instars will be a 1.291 mm and 1.707 mm according to our results, respectively, considering adjusted the 1st HCW and the Dyar's ratios. Integrating the meta-analysis for the frequency distributions of HCW, it is suggested that there are at lest five instars of M. alternatus larvae in the fields. Thus, the previous argument of four larval instars should will be re-examined. The means HCW of 4th and 5th instar are estimated to be in the range of 2.483-2.632 mm and 3.615-3.753 mm, respectively, by accepting previous reports.