Life history of the oak borer, Platypus quercivorus (Murayama) (Coleoptera : Platypodidae)

Abstract

We studied the life history and the seasonal changes in the number of individuals inhabiting galleries of the oak borer, Platypus quercivorus (Murayama) (Coleoptera : Platypodidae), during the period from May 1994 to August 1996. Adult males started the formation of galleries in June. Adult females began to deposit eggs at the terminal parts of tunnels two to three weeks after the commencement of gallery formation. The number of individuals per gallery increased with the development of galleries throughout September. About 50 and 60 individuals, on average, inhabited a gallery in the 1994-1995 and the 1995-1996 generations, respectively. The maximum number of individuals was 161 and 136 in these two generations. About 40% of the broods reached the adult stage during August and September. The majority of new adults left their maternal galleries in September and October but some new adults remained in the galleries until spring and then died. The rest of the broods attained the 5th larval stage by the end of November and overwintered in pupal chambers. Pupation started in May, and adults emerged again in June and July. Mortality rates were low for all stages in the galleries.