LIFE-HISTORY OF THE OAK BORER, PLATYPUS-QUERCIVORUS (MURAYAMA) (COLEOPTERA, PLATYPODIDAE)

We studied the life history and the seasonal changes in the number of individuals inhabiting galleries of the oak borer, Platypus quercivoru s (Murayama) (Coleoptera: Platypodidae), during the period from May 19 94 to August 1996. Adult males started the formation of galleries in J une. Adult females began to deposit eggs at the terminal parts of tunn els two to three weeks after the commencement of gallery formation. Th e number of individuals per gallery increased with the development of galleries throughout September. About 50 and 60 individuals, on averag e, inhabited a gallery in the 1994-1995 and the 1995-1996 generations, respectively. The maximum number of individuals was 161 and 136 in th ese two generations. About 40% of the broods reached the adult stage d uring August and September. The majority of new adults left their mate rnal galleries in September and October but some new adults remained i n the galleries until spring and then died. The rest of the broods att ained the 5th larval stage by the end of November and overwintered in pupal chambers. Pupation started in May, and adults emerged again in J une and July. Mortality rates were low for all stages in the galleries .