Abstract
Changes of the number of adults which entered a “shelter” set in a rearing cage were investigated to determine the effects of feeding and temperature after adult moult on the hiding-behaviour of diapausing Cletus punctiger in hibernacula. The number of adults which entered the shelter (abbr. NAES) was compared among five treatments; no feeding, 10 day, 20 day, 30 day feeding, and continuous feeding after adult moult. Under a 12L-12D regime and at the constant temperature of 25°C, NAES increased soon after the food was removed when adults fed for more than 10 days, though the increase was not remarkable when adults fed for more than 20 days. NAES in the continuous feeding treatment gradually increased at about 20 days after adult moult. Under a 12L-12D and alternating temperature (25°C in photophase, 10°C in scotophase regime), NAES increased soon after the food was removed when the adults fed for more than 20 days. NAES in the continuous feeding treatment gradually increased at about 40 days after adult moult. In the 20 and 30 day feeding and continuous feeding treatments under alternating temperature conditions, the percentage of adults which entered the shelter was higher than that under constant 25°C conditions. To compare the behaviour of the diapausing adults, the non-diapausing adults were tested under a 16L-8D and alternating temperature regime. NAES was very low in each treatment compared with that of the diapausing adults. Based on these results, the hiding-behaviour of diapausing adults in hibernacula was considered to be triggered by the reduction of food supply, including withering of food plants, after a given period of feeding. The temperature conditions also appeared to influence the behaviour.
