Comparative life tables of Trissolcus japonicus and Trissolcus mitsukurii, egg parasitoids of Halyomorpha halys

Abstract

Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae) and Trissolcus mitsukurii (Ashmead) (Hymenoptera: Scelionidae) are Asian egg parasitoids that are considered important natural enemies of the brown marmorated stink bug Halyomorpha halys (Stål) (Hemiptera: Pentatomidae). These species are expanding their geographic distribution outside their native area, which suggests investigating their adaptability to environmental conditions. In a laboratory experiment, we investigated the life table parameters of these two egg parasitoid species under four constant temperatures, i.e., 16, 21, 26 and 31 °C. Results showed that the longevity of T. japonicus was higher than that of T. mitsukurii at all temperatures considered. The net reproductive rate (Ro) of T. japonicus was higher than that of T. mitsukurii at 26 and 31 °C. However, the intrinsic rate of increase (rm) at 26 and 31 °C was similar between the two species, and at 21 °C, T. mitsukurii exhibited a higher intrinsic and finite rate of increase. The two species complete their development at 16 °C, but with the lowest performances. Results suggest a higher increase of T. mitsukurii population when mean temperatures are equal to 21 °C, while the population increase of T. japonicus is expected to be favoured at higher temperatures.