Abstract:Winter-spring fallow waterlogged paddy fields (WWF) make up a subtropical type of rice fields in the hilly areas of southern China and generally last 6-8 months and actually experience autumn, winter and spring in southwestern China, especially in Sichuan province and Chongqing municipality. In this study, we aim to evaluate the effects of temperature change on predation of the main predatory natural enemies in WWF during the postharvest fallow period. Therefore, the predation effect, searching efficiency, intraspecific density interference and predation preference of adults of rove beetle Paederus fuscipes, adults and subadults of spiders Pirata subpiraticus and Pardosa pseudoannulata to adults of springtail Homidia tiantaiensis and leafhopper Thaia rubiginosa were studied in lab at 22℃ and 12℃ representing two typical temperatures from WWF seasons. In addition, the supercooling point (SCP) and freezing point (FP) of these predators induced under the two temperature conditions were measured by the thermistor-based method that is to clarify the effects of ambient temperature change on their predation. The results showed that the change of temperature significantly affected the functional response of the predators, the searching efficiency and the intraspecific density interference of the predators. The functional responses of these predators fitted well with the Holling II model at 22℃ or 12℃. According to the functional response, the predation numbers of these predators to the two preys at 22℃ were higher than those at 12℃, and they consumed significantly more prey numbers of H. tiantaiensis than that of T. rubiginosa at the two temperatures. The instant attack rates, the maximum predation number and a/Th value of these predators to the springtail and leafhopper at 22℃ were higher than those of 12℃, and their handling time at 22℃ was shorter than that at 12℃. No matter in leafhopper experiment or in springtail experiment, the instant attack rate, the maximum predation number and a/Th value of subadults of P. subpiraticus and P. pseudoannulata were higher than those of their adults, and their handling time was significantly shorter than that of their adults. The maximum predation numbers and a/Th value of P. fuscipes were the largest in the leafhopper experiment at 12℃, while the treatment time was the smallest; and yet these values of other parameters of P. fuscipes in two prey treatments at two temperatures were between those of spider adults and subadults. The influence of temperature change on the searching efficiency of these predators was related to the species or stages of predators and prey species, and the searching efficiency at 22℃ was higher than that at 12℃. Under the two temperature conditions, the searching efficiency of these predators to the two preys was negatively correlated with the prey density, and both decreased with the increase of prey density. The predation activity ratio of these predators to the two preys decreased with the increase of self-density. The values of searching parameter and interference effect coefficient of subadults of P. subpiraticus and P. pseudoannulata to the two preys at 22℃ or the springtail at 12℃ were the highest, whereas the two values of P. pseudoannulata subadult and P. fuscipes adults were the highest at 12℃. When both the two preys were available, the food selectivity index of all predators was greater than that of one, which indicates that these predators had a predation preference for the two preys, and prefered to prey on the springtail H. tiantaiensis. Although the food selectivity index of these predators at 22℃ was higher than that at 12℃, the change of temperature had no effect on the predator's preference. Generally, the decrease of temperature can induce the drops in the SCP and FP of subadults of P. subpiraticus and P. pseudoannulata, and the rise of the two values in the adults of the two spider species and the smaller change of SCP in the adults of P. fuscipes, which indicates that there is a certain correlation between the cold tolerance of these predators and their predation.