Offspring performance in the pupal parasitoid Pimpla (=Coccygomimus) luctuosa (Hymenoptera: Ichneumonidae) as influenced by host age and size

The age and size of hosts are known to have a profound effect on host suitability for many species of parasitoid wasps. Relationships between host suitability and host type are essential information in determining an appropriate range of hosts that is used for mass rearing of parasitoids but this information is lacking for Pimpla (=Coccygomimus) luctuosa Smith, a pupal solitary parasitoid wasp of many lepidopteran pests. Accordingly, the effects of host age and size on the offspring survival and fitness of P. luctuosa were examined in the present study. Old host pupae produced fewer wasp offspring than young host pupae did. The size of hosts also affected the offspring survival, and the mortality of offspring was higher in smaller hosts. No significant interaction was detected between host age and size effects on the offspring survival. Smaller wasp offspring were produced when hosts were smaller. Likewise, smaller wasp offspring emerged from older host pupae. Thus, the results demonstrated that old hosts were of poor quality for the developing wasp offspring of P. luctuosa. The relationships between host type and offspring performance in P. luctuosa were discussed.