RESUMO
The generation of electricity in nuclear power plants produces an increase in background radiation that could possibly have some impact on the organisms that live in that area. In order to identify and quantify any such possible effect, the natural populations of two sibling species, D. melanogaster and D. simulans, that live in the immediate vicinity of the first Mexican Nuclear Power Plant were analyzed for a period of 10 years. Collections of flies were made at two sites, one close to and one farther from the power plant, during the pre and operational stages of the reactor, and their egg-to-adult viability was analyzed. The data obtained indicate that in both sites, the egg-to-adult viability was generally higher in D. melanogaster than in D. simulans. Further, a relationship was found between egg-to-adult viability and the season of the year (warm-wet or cool-dry season). Some differences were found between the two sites. It may be concluded that there is no negative impact on the Drosophila populations studied.
Assuntos
Contaminação Radioativa do Ar/efeitos adversos , Drosophila melanogaster/crescimento & desenvolvimento , Drosophila melanogaster/efeitos da radiação , Centrais Elétricas , Animais , Monitoramento Ambiental/métodos , Crescimento DemográficoRESUMO
PURPOSE: To identify and quantify if the generation of electricity by nuclear power plants produces an increase in background radiation that might affect the radioresistance of organisms that live in that area. MATERIALS AND METHODS: Natural populations of two sibling species of Drosophila, D. melanogaster and D. simulans, living in the immediate vicinity of the Mexican Nuclear Power Plant in Laguna Verde were studied for 10 years. Collections of flies were made at two sites, one close to and one further from two reactors, during both the pre-operational and operational stages of the reactors. The effect of exposure to various doses of gamma-rays on egg-to-adult survival of the flies was analysed. RESULTS: The data obtained indicate that in both sites, egg-to-adult survival was higher in D. melanogaster than in D. simulans. There was an increase in the egg-to-adult survival during the pre-operational period of one of the reactors and the possible causes are discussed. No differences were found between the two sites. CONCLUSIONS: The analysis indicates that the reactors do not have a negative impact on the Drosophila populations studied.
Assuntos
Adaptação Fisiológica/efeitos da radiação , Drosophila/crescimento & desenvolvimento , Drosophila/efeitos da radiação , Raios gama , Centrais Elétricas , Tolerância a Radiação/efeitos da radiação , Animais , Relação Dose-Resposta à Radiação , Drosophila/classificação , Exposição Ambiental , Feminino , Doses de Radiação , Taxa de Sobrevida , Zigoto/crescimento & desenvolvimento , Zigoto/efeitos da radiaçãoRESUMO
Drosophila pseudoobscura populations of Central Mexico are chromosomally highly polymorphic. Five gene arangements in the third chromosome are endemic, including the two newly described in the present article. The phylogenetic tree of the gene arrangements known in the species is shown in Figure 1. The ones found in Central Mexico all belong to the Santa Cruz "phylad", while in the northern part of the species area both Santa Cruz and Standard phylads are widespread. Some inferences concerning the evolutionary history of the species are presented.