Abstract
In order to understand the latent photoperiodic period of post-diapause development of larvae of the Japanese pine sawyer, mature larvae in their pupal chambers were collected from bolts which had been placed in outodoor or indoor cages on 21 Nov. 1997 and then kept in glass bottles at 25-C under defferent photoperiods, i.e., at LD10:14, LD13:11, LD14:10, LD15:9 and LD16:8. For larvae collected from outdoor cages, the proportion pupating within three months were 14.3, 58.3, 65.4, 91.7 and 89.7%, respectively, and the latent period was thought to be around LD13:11 but it had a wide range. For larvae collected from indoor cages, the proportion pupating were 11.8, 12.0, 47.6, 76.2 and 82.6%, respectively, and the latent period was longer by one hour. Since higher temperatures and a longer light phase in the indoor cages before larval collection may have caused a lower degree of diapause termination, the propotion of larvae pupating was lower for larvae collected from indoor cages. Duration from the start of warming to pupation tended to be shorter as the light phase became longer.
