HYMENOPTERAN PARASITOIDS: LABORATORY REARING AND EVALUATION OF STORAGE TECHNIQUES

The present work focused on O. pityocampae (Mercet) (Hymenoptera Encyrtidae), an indigenous and polyphagous egg-parasitoid that might play a role in biological control programs against Thaumetopoea pityocampa (Den. & Shiff.) (Lepidoptera Notodontidae). Therefore biological parameters of this encyrtid reared on alternative host eggs were analyzed by testing its behavior and reproductive parameters. Time between oviposition and progeny emergence, sex ratio of offspring, parasitization rate and offspring production were recorded. Thereafter, in a second set of experiments, the stages of O. pityocampae juveniles developing within eggs of Nezara viridula (L.) (Heteroptera Pentaomidae) were also identified by morphological analysis and measurements. Egg-to-adult temperature-dependent development of O. pityocampae within eggs of the alternative host Graphosoma lineatum (L.) (Heteroptera Pentaomidae) was also investigated in order to determine development times. Moreover, because parasitoid development within host eggs is often influenced by host egg age, trials were carried out to determine the capacity of this encyrtid to accept and exploit eggs from different age classes. Since maintenance of living organisms is particularly useful in mass rearing programs, the second part of the project was aimed at evaluating cold storage potential of O. pityocampae for long periods. For this reason cold tolerance of this parasitoid was evaluated by storing different juvenile stages within eggs of G. lineatum at several low temperatures for 10 days. The effect of cooling and heating rates on the survival of stored immatures was also assessed for each thermal treatment.