In this study, chromosomal inversion polymorphism data for a natural population of Drosophila subobscura from a swampy region near the town of Apatin (Serbia) were compared with data for the same population collected approximately 15 years earlier. The pattern of chromosomal inversion polymorphism changed over time. There were significant increases in the frequency of characteristic southern latitude ("warm" adapted) chromosomal arrangements and significant decreases in the frequency of characteristic northern latitude ("cold" adapted) chromosomal arrangements in the O and U chromosomes. The chromosomal arrangements O3+4 and O3+4+22 (derived from the O3+4 arrangement) showed significant increases in 2008 and 2009 with regard to the 1994 sample. There was also a significant increase (~50%) in the U1+2 arrangement, while U1+8+2 (a typical southern arrangement) was detected for the first time. Since the Apatin swampy population of D. subobscura has existed for a long time in a stable habitat with high humidity that has not been changed by man our results indicate that natural selection has produced chromosomal changes in response to the increase in temperature that has occurred in the Balkan Peninsula of central southeastern European.

The O5 chromosomal inversion has been a cornerstone for understanding different aspects of the American colonization by Drosophila subobscura. To obtain more information of this evolutionary event it is important to know the pattern of bands of this inversion in detail. Comparing this pattern with that of D. melanogaster it is possible to predict which genes are located inside or close to the O5 inversion and use them as genetic markers. In this study, the complete band pattern of the O5 inversion is presented. Furthermore, the most important genes located inside it have been predicted. Finally, a constriction located close to the proximal breakage point of the O5 inversion has been observed many times and its possible genetic significance is discussed.

A plasticidade fenotípica de alguns caracteres quantitativos foi estudada em duas populações colonizadoras de Drosophila subobscura (Davis e Eureka, Califórnia). Analisaram-se tanto o efeito da temperatura como o da criação em laboratório. A criação em laboratório durante quatro gerações a 18°C aumentou significativamente o comprimento da asa e da tíbia. Este incremento foi semelhante ao obtido quando as moscas foram cultivadas a 13°C durante duas gerações. O ambiente de temperatura baixa pode ser considerado mais estressante para as fêmeas, pois elas apresentaram um aumento na variância fenotípica. As duas populações analisadas apresentaram uma grande plasticidade fenotípica, apesar do "gargalo" genético produzido durante o processo colonizador. Nossos estudos mostram que a manutenção das moscas no laboratório por um período de tempo relativamente curto é capaz de mudar significativamente alguns caracteres quantitativos, sendo fundamental analisar as moscas imediatamente após capturá-las, para se obterem estimativas confiáveis na análise de tais caracteres nas populações naturais.

The phenotypic plasticity of some quantitative traits of two colonizing populations of Drosophila subobscura (Davis and Eureka, California) was studied. Temperature effects and the effect of rearing in the laboratory were studied. Laboratory rearing during four generations at 18ºC significantly increased the wing and tibial length. This increase was similar to that obtained when the flies were reared at 13ºC during two generations.The low temperature environment can be considered more stressful for females than for males, as shown by the increase of phenotypic variance. The two populations analyzed had great phenotypic plasticity in spite of the genetic bottleneck during the colonization event. Our study shows that keeping flies for a relatively short time in the laboratory significantly changes some quantitative traits, emphasizing the need to analyze flies immediately after collecting them in order to obtain reliable estimates for the analysis of these traits in natural populations.

Estudou-se uma linhagem de Drosophila subobscura com apenas uma asa. A asa ausente é substituída por uma estrutura maciça com macro e microquetas, com aspecto de estrutura torácica. Cruzamentos genéticos mostram que não é possível selecionar o caráter por cruzamento simples. O número de moscas com uma asa nas várias gerações foi sempre baixo. Em um caso, uma mosca sem asa foi também obtida. O caráter tem um padrão genético desconhecido

A line of one-winged Drosophila subobscura was studied. The absent wing is substituted by a bulky structure with macro and microchaetes, showing a thoracic appearance. Genetic crosses showed that there is no way to select for the trait by simple crossing. The number of one-winged flies in the various generations was always low. In one case a wingless fly was also obtained. The trait presents an unknown genetic pattern.