Host suitability and its effects on parasitoid biology in Coccygomimus turionellae (Hymenoptera: Ichneumonidae) [Endoparasite of woodland pests in Europe, biological control of gypsy moth (Porthetria dispar) in North America, ecologic aspects]

The progeny of C. turionellae (L.) varied significantly in size and development time when reared on five host species. Regression analysis revealed that factors other than host weight affected parasitoid development. Within a particular host species, parasitoid size and development time were highly correlated to host weight. The age of the host also influenced its suitability; larval instars did not permit parasitoid development, whereas the late prepupae were 50% as effective as the pupae. There was a significant negative linear relationship between host age and parasitoid size within the pupal stadium. However, the relationship between the parasitoid's developmental period and its size broke down when host age increased. This indicated a relative increase in development period per unit weight with increased host age.