[Objectives]  Dastarcus helophoroides is an important insect predator of wood borers, especially cerambycids. This paper tests the influence of adult body size on the mortality rate and fecundity of adult D. helophoroides in order to improve the mass husbandry of this species. [Methods]  D. helophoroides adults were divided into three groups according to body size; small, medium and large and the survival rates and fecundities of these groups were recorded at 20, 24 and 28 ℃, respectively. [Results]  Mortality increased with temperature for adults in the same body size group. Mortality rates did not differ significantly among the three groups at 24 ℃ and 28 ℃, but did at 20 ℃, at which temperature mortality was significantly higher in the small group. Temperature had a significant effect on fecundity in the medium group; fecundity was higher at 24 ℃ and 28 ℃ than that at 20 ℃. Fecundity varied significantly with body size; at the same temperature, the large group had the highest fecundity. [Conclusion]  Body size did not significantly affect the mortality of D. helophoroides adults but did affect fecundity.