2004 Volume 86 Issue 2 Pages 158-163
Adults of Monochamus alternatus emerging from pine logs were collected at 0 : 00, 4 : 00, 8 : 00, 12 : 00, 16 : 00, and 20 : 00 in a field cage for two consecutive weeks and in a homeothermal room for nine days. In the homeothermal room, diurnal emergence of M. alternatus didn't show a peak. In the field cage, there were more emerging adults from 8 : 00 to 12 : 00 and from 16 : 00 to 20 : 00. From the multiple linear regression analysis where the dependent variable was the number of emerging adults and the indepen dent variables were temperature, precipitation and hours of daylight, it was considered that M. alternatus inactively emerged from 8 : 00 to 12 : 00 became of high temperature, more hours of daylight and precipitation and actively emerged from 16 : 00 to 20 : 00 became of high temperature from the daytime to the sunset. Temperature was thought to be the ruling factor in determining the diurnal emergence. There were five patterns of combinations of the time zones when the largest and the second largest number of emerging adults were recorded, and each pattern differed according to the temperature resume. Consequently, the diurnal emergence of M. alternatus under field conditions seemed to be subject to the weather conditions and to be little influenced by the innate rhythm of the insect.
