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| Author(s): |
Silvia Monteil Gomes
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Piracicaba. |
| Institution: | Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC) |
| Defense date: | 2002-05-15 |
| Advisor: | José Roberto Postali Parra |
| Abstract | |
The goal of this research was to evaluate different artificial media for Trichogramma pretiosum Riley, 1879 rearing and development, to study its protein assimilation ability in artificial media, as well as the role of Wolbachia symbionts in the biology of these parasitoids. Artificial media elaborated with pupal holotissues of Mamestra brassicae L. were more adequate in relationship with those elaborated with pupal hemolymph, providing higher emergence and originating higher protein content pupae. Media elaborated with pupal hemolymph and supplemented with casein and bovine serum albumin proteins at different concentrations were also evaluated. The casein was added to the diet at concentrations of 1.6 and 3.2%. The T. pretiosum emergence was higher when the concentration of that protein was 1.6%. The addition of 3.2% casein inhibited the oviposition of the parasitoid and decreased the emergence, however, increasing the production of normal adults and producing parasitoids with a higher amount of proteins. The bovine serum albumin was added to the artificial medium at concentrations of 1.75 and 3.5%. The oviposition was higher in the artificial medium supplemented with 1.75% of that protein, however, the emergence was higher in the artificial medium at 3.5%. Large amounts of normal adults were obtained from the media supplemented with that protein in relationship with the one elaborated with pupal hemolymph. The insects deriving from bovine serum albumin media showed higher protein content. Amino acids composition analyses of pupae deriving from every artificial media showed qualitative similarities, although quantitative differences were observed. Through the isotopic dilution principle, one developed a methodology capable of showing that T. pretiosum assimilates the artificial media proteins, supplemented or not with casein and bovine serum albumin proteins at different concentrations. The role of genus Wolbachia symbionts was also studied, through the development of a methodology of elimination of such symbiont with a single antibiotic treatment, added to the artificial parasitoid development medium. This way four symbiont-free strains were achieved, allowing the study of the symbiont influence on the biological aspects of the parasitoid, since they had the same genome as the original strain. Wolbachia-infected females had higher parasitism ability in relationship with symbiont-free females. The females deriving from the symbiont-infected artificial diet, although of lesser size in comparison with a Wolbachia-free strain, had higher fecundity. (AU) | |