Development of Monochamus alternatus Hope (Coleoptera: Cerambycidae) in Relation to Oviposition Time

Abstract

Monochamus alternatus requires 1 or 2 years to complete a life cycle. The development was investigated using the populations produced in Pinus densiflora logs by caged adult populations at different times from June to September. Many individuals produced in June and July became 4th instar larvae in pupal chambers by November, and then pupated without resuming feeding in June of the following year and emerged. The populations produced in August developed into 3rd (60-70%) or 4th (30-40%) instar larvae in November, thirty to fifty percent of which formed pupal chambers. In the next spring ten to forty percent of the larvae resumed feeding, and more than ninety percent of the larvae pupated and emerged. The populations produced in September developed into 1st to 3rd instar larvae in November, many of which were under the bark, and resumed feeding in the next spring. By September of the next year after oviposition sixty percent of the larvae developed into adults in a seashore pine stand while six percent in a pine stand at an elevation of 140m. Remaining larvae would overwinter once more. Such individuals overwintered as 1st or 2nd instar larvae, developed into the 3rd or 4th instar larvae in the next year, overwintered again, and emerged as adults 2 years after oviposition. A hypothesis was presented on the regulatory mechanism of M. alternatus life cycle. © 1989, JAPANESE SOCIETY OF APPLIED ENTOMOLOGY AND ZOOLOGY. All rights reserved.