Abstract: The heat tolerance and sensitivity to temperature of Guangdong and Beijing populations of Propylea japonica (Thunberg), was studied at different temperatures (26℃-36℃). The growth and fecundity of P. japonica at different temperatures, the lethal high temperatures of P. japonica larvae, and the survival rates of 4th larvae at lethal temperatures after pretreatment at lethal high temperature were observed, and the soluble protein content of P. japonica after heat shock at high temperatures was assayed with Bradford's method. The growth and fecundity of two populations were significantly obstructed at 36℃, with durations of developmental stages extended, and survival rates and fecundity decreased. From 26℃ to 36℃, the sex ratio of female to male changed markedly as the temperature increased. At 36℃, the adults were all male. The lethal high temperatures to larvae of both Guangdong and Beijing populations were same, as 1st-2nd instar larva, 3rd instar larva, and 4th instar larva all died after treatment respectively at 44℃, 45℃, and 46℃ for an hour. The survival rates of the 4th instar larvae of Guangdong and Beijing populations at 46℃ were improved after pretreatment at lethal high temperature 39℃ for 120 or 150 min, with the survival rate of Guangdong population higher than that of Beijing population. With the temperature increasing within 26℃ to 34℃, the soluble protein content of adult and the 4th larvae increased. But after heated at 39℃, 41℃ and 43℃ for one hour, the soluble protein content of the 4th larvae increased while that of the adult decreased. The soluble protein content of adult and the 4th larvae of Guangdong population was highest after being heated at 39℃ for one hour, as Beijing population was highest after being heated at 43℃ for one hour. Within the temperature range of 26℃ to 36℃, the heat tolerance were not much different between Guangdong and Beijing populations.

Key words: Propylea japonica, Guangdong population, Beijing population, temperature, heat tolerance