Abstract:[Objectives] Pastor roseus is the important natural enemy of grassland grasshoppers in Xinjiang, China. This study aims to clarify the breeding ecological characteristics of P. roseus. [Methods] The study was conducted at the third company at the horse ranch and Songshutang community in Yizhou District, Hami City, Xinjiang. During the breeding season of P. roseus from 2022 to 2023, we combined the grasshopper occurrence data provided by the “monitoring and reporting workstation to prevention and control of grasshopper and mouse in Hami District” with the results of our field investigation, to analyze the factors influencing the breeding site selection and migration time of P. roseus. Ten nests of P. roseus were selected each year to monitor the reproductive behavior and nestling development using infrared cameras. The total recording duration was 38 d, with a valid data duration of 2 337 h (n = 20 nests). The behavioral characteristics of nesting, egg-laying, hatching and brooding were analyzed using single factor analysis of variance and Friedman test in SPSS 26 software. At the same time, growth and development indicators of weight and tarsometatarsal length of nestlings were fitted based on the logistic growth curve model, and growth curves were plotted. [Results] 1) The population densities of grasshoppers in the study areas were higher than that in other areas during 2022﹣2023 (Table 1). No P. roseus was seen in other areas with low grasshopper densities. Both immigration and emigration times of P. roseus coincided with the grasshopper occurrence time during the two years. 2) After mating, females laid white or cyan eggs (Fig. 2). The clutch size was 3﹣7, and the hatching rate was 88.89% (n = 54 eggs). 3) Eggs were incubated alternately by the male and female, and nestlings were fed by both parents. The daily feeding peak for nestlings was from 10:00 to 12:00, and feeding times during this period were significantly higher than those during other periods (P < 0.05) (Table 3). 4) Growth of body weight and tarsometatarsus of nestlings were consistent with the logistic models (Fig. 5). [Conclusion] The selection of breeding sites and migration time of P. roseus was mainly related to population density of grasshoppers. Both males and females raise offspring. The nestlings are altricial, and the growth and development trend is S-shaped. The results provided basic parameters for the protection and attraction of P. roseus.
