Morphometric and isoenzymatic data have showed little variation among Drosophila antonietae populations. This suggests historic gene flow, due to the distribution of these populations, which are associated with cacti along rivers, and natural selection on these markers. Microsatellite loci have high variability and are ideal for detecting gene flow and analysing population structure. Here we describe the isolation of seven polymorphic microsatellite loci in D. antonietae.

The process of speciation occurs through the evolution of any of several forms of reproductive isolation between taxa, including inviability of hybrids. In this work, strains derived from allopatric populations of Drosophila buzzatii cluster species were experimentally crossed in order to evaluate their reproductive and cytogenetic relationships, and to contribute toward understanding the reproductive isolation in this group of sibling species. Although intrastrain crosses were highly fertile, we consider it relevant to discuss the differences in intra-and interspecific fertility and fecundity here. Among 30 interspecific crosses, about 63% were partially or completely sterile. Fifty three percent of interspecific F1 crosses (female and male F1 crossed) were also partially or completely sterile, in contrast to only one out of 24 intraspecific F1 crosses that was partially sterile. An analysis of hybrid polytene chromosomes revealed complete synapsis, except in the microchromosomes (VI) and in the proximal region of the X chromosome. The intraspecific divergence observed in this study and the variable degree of chromosome pairing shown here reveal part of the complexity of the speciation process pertinent to Drosophila buzzatii cluster, which is consistent with different traits studied in this cluster.Keywords: Drosophila buzzatii cluster, reproductive isolation, polytene chromosome synapse. RESUMORelações reprodutivas e grau de sinapse nos cromossomos politênicos de espécies de Drosophila do cluster buzzatii O processo de especiação ocorre pela evolução de qualquer uma das diversas formas de isolamento reprodutivo entre táxons, incluindo inviabilidade de híbridos. Neste trabalho, linhagens provenientes de populações alopátricas de espécies de Drosophila do cluster buzzatii foram cruzadas experimentalmente com o objetivo de avaliar suas relações reprodutivas e citogenéticas, e contribuir para o entendimento do isolamento reprodutivo neste grupo de espécies intimamente relacionadas. Os cruzamentos dentro de uma mesma linhagem foram altamente férteis, contudo as diferenças na fertilidade e fecundidade encontradas intra e interespecificamente são discutidas neste artigo. Dos 30 cruzamentos interespecíficos, 63% foram parcialmente ou completamente estéreis. Cinqüenta e três por cento dos cruzamentos de F1 interespecíficos (fêmeas e machos F1 cruzados entre si) também foram parcialmente ou completamente estéreis, em contraste com apenas um, em 24 cruzamentos de F1 intra-específicos, que foi parcialmente estéril. A análise dos cromossomos politênicos nos híbridos revelou sinapse completa, exceto nos microcromossomos (VI) e na região proximal do cromossomo X. A divergência intra-específica e o grau variável de pareamento 280 MACHADO, L. P. B., MADI-RAVAZZI, L. and TADEI, W. J.

Flies from the Drosophilidae family are model organisms for biological studies and are often suggested as bioindicators of environmental quality. The Araucaria Forest, one of Atlantic Forest phyto-physiognomy, displays a highly fragmented distribution due to the expansion of agriculture and urbanization. Thus, this work aimed to evaluate and compare the drosophilid assemblages from two highland Araucaria Forest fragments, one a conservation unit (PMA -Parque Municipal das Araucárias) and the other a private property without any conservational policy (FBL -Fazenda Brandalise), in space and time, using species abundances and richness, ecological indexes and Neotropical and exotic species proportions as parameters to establish the level of environmental quality of these fragments. Our results showed that the observed diversity in PMA (H' = 2.221) was approximately 40% higher than in FBL (H' = 1.592). This could be due to higher preservation quality and habitat diversity in PMA, indicating the importance of conservation units. However, richness were similar for these areas, with PMA (D mg = 6.602) only 8% higher than FBL (D mg = 6.128), which suggest that the larger distance from city limits and the larger size of FBL forested area could be compensating the higher disturbance caused by antrophic extractive exploitation of this fragment. This points out that, besides the quality of presevertion, the size and/or connection with other fragments should be considered for areas destined for biodiversity conservation. In general, both areas presented similar drosophilid assemblages, and the expressive abundance of both Neotropical species (mostly of the subgroup willistoni) and the exotic species D. kikkawai suggests that these areas are in intermediate stages of conservation.Keywords: ecological indexes, Mixed Ombrophylous Forest, exotic species, Drosophila, Atlantic Forest, Neotropical region. Comparação das assembleias de Drosophilidae (Diptera) de dois fragmentos de floresta de araucária de altitude, com e sem políticas de conservação ambiental ResumoMoscas da família Drosophilidae são organismos modelo para estudos biológicos e frequentemente sugeridas como bioindicadoras da qualidade ambiental. A Mata de Araucária, uma das fitofisionomias da Mata Atlântica, apresenta-se altamente fragmentada devido a expansão da agricultura e da urbanização. Assim, este trabalho teve como objetivo avaliar e comparar as assembleias de drosofilídeos de dois fragmentos de Mata de Araucária de altitude, uma área de preservação (PMA -Parque Municipal das Araucárias) e uma propriedade particular e sem política de conservação (FBL -Fazenda Brandalise), no tempo e no espaço, utilizando abundâncias e riquezas das espécies, índices ecológicos e proporções de espécies neotropicais e espécies exóticas como parâmetros para estabelecer o nível de qualidade ambiental destes fragmentos. Nossos resultados mostraram que a diversidade observada em PMA (H' = 2,221) foi 40% maior do que em FBL (H' = 1,592). Isto pode ser devido a maior qualidade ...

In the Drosophila repleta group the establishment of subgroups and complexes made on the basis of morphological and cytological evidences is supported by tests of reproductive isolation. Among species in the repleta group, the buzzatii cluster, due to its polymorphism and polytipism, is an excellent material for ecological and speciation studies. Some interspecific crosses involving Drosophila seriema, Drosophila sp. B, D. koepferae and D. buzzatii strains were completely sterile while others involving strains from these species produced F1 hybrids that did not yield F2. In the present work, data on courtship duration and copula occurrence obtained in the analysis of flies from parental sterile crosses and on spermatozoon mobility observed in F1 hybrids that did not yield F2 are presented. Copula did not occur during one hour of observation and the spermatozoon also did not show mobility at any of the analyzed stages (3, 7, 9 and 10 days old). There was a high variation in courtship average duration and in the percentage of males that courted the females. The reproductive isolation mechanisms indicated by these observations were pre and post-zygotic, as supported by the absence of copula and male sterility. Data obtained also showed the occurrence of different degrees of reproductive compatibility among the strains classified as the same species but from distinct geographic localities.

Drosophila antonietae belongs to the Drosophila buzzatii cluster, a cactophilic group of species naturally endemic to South America. Morphological and genetic analyses indicate that its populations are the most homogenous in the cluster and that the diversity observed is mainly a result of variation within populations. Seven polymorphic microsatellite loci were described for this species and used in the present study to investigate the genetic diversity of natural populations of D. antonietae by both length and sequence variation. The study aimed to understand how homoplasy and null alleles affect inferences about the population history of this species and to obtain an accurate interpretation of population inferences where these loci could be applied. The results provide useful information on the interpretation of genetic data derived from the microsatellite loci described for D. antonietae and on evolutionary aspects of cactophilic Drosophila. Importantly, the results indicate that size homoplasy and null alleles do not represent significant problems for the population genetics analyses because the large amount of variability at microsatellite loci compensate the low frequency of these problems in the populations.

The Quaternary period was marked by considerable changes in climate. Such palaeoclimatic changes affected the population dynamics of many species, both in the Northern and in the Southern Hemisphere. However, the extent of these impacts on the demographic patterns of Neotropical species presenting different ecological requirements remains unclear. Drosophila maculifrons DUDA 1947 belongs to the guaramunu group of Drosophila and represents a potential indicator of the genetic consequences caused by the climatic fluctuations of the Quaternary, because it seems to be sensitive to temperature and humidity shifts. The aim of this study was to evaluate the evolutionary processes subjacent to the patterns of intraspecific diversity and structure of different populations of D. maculifrons. In total, 152 individuals were collected in the south and south‐east Brazil. Phylogenetic and phylogeographical analyses were performed based on sequences of COI and COII mitochondrial genes. In general, the results pointed to Brazilian populations of D. maculifrons being extremely impoverished in terms of mitochondrial diversity and population structure, which could be explained by a recent population expansion event dated to approximately 12 000 years ago. In fact, with the assistance of species palaeo‐distribution modelling strategies, it was possible to infer that most of the sampled region did not present the D. maculifrons environmental suitability requirements at least during the period of the Last Glacial Maximum. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 112, 55–66.

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ABSTRACT. Adult sex ratio effects on male survivorship of Drosophila melanogaster Meigen (Diptera, Drosophilidae). The behavioral biology has a central role in evolutionary biology mainly because the antagonistic relations that occur in the sexual reproduction. One involves the effect of reproduction on the future life expectation. In this scenario, changes in male operational sex ratio could lead to an increase in mortality due to costs associated with excessive courtship and mating displays. Thus, this work experimentally altered the male sex ratio of Drosophila melanogaster Meigen, 1830, to determine its impact on mortality. The results indicated that mortality increases as the sex ratio changes, including modifications in the survivorship curve type and in the curve concavity, measured by entropy.KEYWORDS. Adult sex ratio; entropy; survivor.RESUMO. Efeito da razão sexual de adultos na curva de sobrevivência de machos de Drosophila melanogaster Meigen (Diptera, Drosophilidae). A biologia comportamental tem um papel central na biologia evolutiva principalmente pelas relações antagônicas que ocorrem na reprodução sexuada. Uma destas relações envolve o efeito da reprodução sobre a expectativa de vida futura. Neste cenário, alterações na razão sexual operacional de machos podem levar a um aumento na mortalidade por causa dos custos associados com o excesso de displays de corte e cópulas. Neste sentido este trabalho alterou experimentalmente a razão sexual em machos de Drosophila melanogaster Meigen, 1830, para determinar os efeitos em termos de mortalidade. Os resultados indicam que a mortalidade aumenta a medida que a razão sexual se enviesa incluindo alterações no tipo de curva de sobrevivência e da concavidade da curva, medida pela entropia.PALAVRAS-CHAVE. Entropia; razão sexual de adultos; sobrevivência.