Comparative demographics, population projections and egg maturation patterns of four eupelmid egg parasitoids on the...

The genera Anastatus and Mesocomys (both Hymenoptera: Eupelmidae) are important solitary egg endoparasitoids as biological control agents for lepidopterous and hemipterous pests worldwide. Here, we comparatively evaluated the demographic parameters of four important eupelmid egg parasitoids (Anastatus fulloi, A. japonicus, Mesocomys albitarsis and M. trabalae) reared on the factitious host eggs of the Chinese oak silkworm Antheraea pernyi, using age-stage two-sex life tables, their population projections as well as egg maturation patterns.

Both the age-specific net reproductive rate (l_x m_x ) and reproductive value (v_xj ) increased initially and then gradually decreased with increasing age in all four parasitoid species. Overall, the two Mesocomys species had higher survival rates at stable age-stage distribution, peak reproductive values, and intrinsic rates of increase than the two Anastatus species. Mesocomys albitarsis had the longest longevity, whereas A. japonicus had the longest oviposition days and mean generation time. The two Mesocomys species are thus projected to have faster population increase than the two Anastatus species. Adult females of all four parasitoid species emerged with only a few mature eggs (< 6 eggs) and most of their eggs were matured post-emergence (strict synovigeny). The estimated 90% of lifetime complement of reproduction (offspring) and realized days were 374 and 32 for A. japonicus, 337 and 22 for M. trabalae, 330 and 19 for M. albitarsis and 147 and 28 for A. fulloi.

Our results indicated that the two Mesocomys species have higher control capacity than the two Anastatus species. Provision of adult food for these strictly synovigenic parasitoids would be essential to prolong their lifespan and continuously produce eggs for parasitizing their hosts for mass rearing or augmentative biological control programs. © 2023 Society of Chemical Industry.