Rhinoleucophenga joaquina sp. nov. (Diptera: Drosophilidae) from the Neotropical region / Rhinoleucophenga joaquina sp. nov. (Diptera: Drosophilidae) da região Neotropical

O gênero Rhinoleucophenga Hendel compreende 18 espécies nominais e possui distribuição Neotropical e Neártica. Uma nova espécie foi encontrada em coleta realizada em Florianópolis, SC, e é descrita como Rhinoleucophenga joaquina sp. nov. Os espécimes encontrados emergiram de flores de Dyckia encholirioides (Bromeliaceae) coletadas em região de restinga sobre dunas. Este é o primeiro registro da utilização de flores como sítio de oviposição para Rhinoleucophenga.

The genus Rhinoleucophenga Hendel comprises 18 nominal species and has a Neotropical and Nearctic distribution. A new species was found in a collection in Florianópolis, SC, Brazil, and is described as Rhinoleucophenga joaquina sp. nov. The specimens found were reared from flowers of Dyckia encholirioides (Bromeliaceae), collected in a region of restinga on the dunes. The use of flowers as breeding site for Rhinoleucophenga has never been reported before.

Adaptation to different climates results in divergent phenotypic plasticity of wing size and shape in an invasive drosophilid.

The phenotypic plasticity of wing size and wing shape of Zaprionus indianus was investigated in relation to growth temperature (17 degrees C to 31 degrees C) in two natural populations living under different climates, equatorial and subtropical. The two populations were clearly distinguished not only by their wing size (the populations from the colder climate being bigger in size), but also by the shape of the response curves to growth temperature i.e., their reaction norms. In this respect, the temperature at which the size of the wing was maximum was about 3 degrees C higher in the equatorial population. Such a difference in size plasticity is already found in two other nonclosely related species, might be a general evolutionary pattern in drosophilids. Wing shape was investigated by calculating an ellipse included into the wing blade, then by considering the ratio of the two axes, and also by analysing the angular position of 10 wing-vein landmarks. For an overall shape index (ratio of the two axes of the ellipse), a regular and almost linear increase was observed with increasing temperature i.e., a more round shape at high temperatures. Wing shape was also analysed by considering the variations of the various angles according to temperature. A diversity of response curves was observed, revealing either a monotonous increase or decrease with increasing temperature, and sometimes a bell shape curve. An interesting conclusion is that, in most cases, a significant difference was observed between the two populations, and the difference was more pronounced at low temperatures. These angular variations are difficult to interpret in an evolutionary context. More comparative studies should be undertaken before reaching some general conclusions.

On the use of open or closed traps in the capture of drosophilids / Sobre o uso de armadilhas abertas ou fechadas na captura de drosofilídeos

The use of open or closed traps in order to standardize the drosophilid collection is still a matter of discussion among researchers. In this paper, comparative data of drosophilid collections, using open and closed traps are presented. The collections were made monthly, during one year, in one fragment of a semidecidual forest located in the São Paulo State, Brazil. The efficiency of the traps was evaluated by the use of community descriptors: population abundance and richness and diversity of species. Closed traps were more efficient than the open ones in relation to the population abundance and the species richness, indicating their adequacy for standardization of drosophilid collection in studies of biodiversity and seasonality.

Uma discussão ainda em pauta refere-se ao uso de armadilhas abertas ou fechadas na padronização das coletas de drosofilideos para alguns estudos específicos. Neste trabalho são apresentados dados comparativos das coletas de drosofilídeos utilizando armadilhas abertas e fechadas em um período de 12 meses, em um fragmento de floresta semidecidual, localizada no Estado de São Paulo, Brasil. A eficiência das armadilhas foi avaliada usando os seguintes descritores da comunidade: abundância populacional, riqueza e diversidade de espécies. As armadilhas fechadas foram mais eficientes em relação à abundância populacional e à riqueza de espécies. Os resultados indicam que as armadilhas fechadas constituem o tipo mais adequado para padronização de coleta de drosofilídeos, em estudos de biodiversidade e sazonalidade.

Changes in Brazilian Drosophilidae (Diptera) assemblages across an urbanisation gradient

The present study aims to characterise the assemblages of Drosophilidae sampled from four sites subject to different levels of urbanisation, in the city of Florianópolis, South Brazil. Five samples were collected between August 2000 and August 2001 and five between August 2002 and August 2003 in each site. A gradual change in the dominant species was observed in the urbanisation gradient, with an increase in relative abundance of exotic species in urban areas. Among the native species, the relative abundance of Drosophila capricorni Dobzhansky & Pavan had an expressive decrease. In the other hand the richness in the low urbanisation site increased, probably due to the presence of urban gardens. The diversity index did not vary significantly among sites, but its correlation with evenness and richness changed.

O presente estudo objetiva caracterizar as assembléias de Drosophilidae amostradas em quatro pontos sujeitos a diferentes níveis de urbanização, na cidade de Florianópolis, Sul do Brasil. Foram realizadas cinco amostragens entre agosto/2000 e agosto/2001 e cinco entre agosto/2002 e agosto/2003 em cada ponto. Uma mudança gradual nas espécies dominantes foi observada no gradiente de urbanização, com acréscimo na abundância relativa das espécies exóticas nas áreas urbanas. Entre as espécies nativas, houve um decréscimo expressivo na abundância relativa de Drosophila capricorni Dobzhansky & Pavan. Por outro lado, a riqueza no ponto de baixa urbanização aumentou, provavelmente devido à presença de áreas verdes na cidade. O índice de diversidade não variou significativamente entre os pontos, mas sua correlação com a eqüitabilidade e a riqueza se alterou.

Mesosternal bristle number in a cosmopolitan drosophilid: an X-linked variable trait independent of sternopleural bristles.

Mesosternal (MS) bristles in Drosophila are a pair of machrochaetae found at the sternal end of the sternopleural (STP) microchaetae, and are thought to be invariable. In a closely related drosophilid genus, Zaprionus, their number is four and, in contrast to Drosophila, they show interspecific and intraspecific variability. The genetic basis of MS bristle number variability was studied in Z. indianus, the only cosmopolitan species of the genus. The trait responded rapidly to selection and two lines were obtained, one lacking any bristles (0-0) and the other bearing the normal phenotype (2-2). Other symmetrical phenotypes, (1-1) and (3-3), could also be selected for, but with lesser success. By contrast, STP bristle number did not vary significantly between the two lines (0-0) and (2-2), revealing its genetic independence from MS bristle number. Reciprocal crosses between these two lines showed that MS bristle number is mainly influenced by a major gene on the X chromosome (i.e. F(1) males always resembled their mothers) with codominant expression (i.e. heterozygous F(1) females harboured an average phenotype of 2 bristles). However, trait penetrance was incomplete and backcrosses revealed that this variability was partly due to genetic modifiers, most likely autosomal. The canalization of MS bristle number was investigated under different temperatures, and the increased appearance of abnormal phenotypes mainly occurred at extreme temperatures. There was a bias, however, towards bristle loss, as shown by a liability (developmental map) analysis. Finally, when ancestral and introduced populations were compared, the latter were far less stable, suggesting that genetic bottlenecks may perturb the MS bristle number canalization system. MS bristle number, thus, appears to be an excellent model for investigating developmental canalization at both the quantitative and the molecular level.

Study of the Drosophilidae (Diptera) communities on Atlantic Forest islands of Santa Catarina State, Brazil

A study of the community dynamics of Drosophilidae was carried out in six insular communities and two others on the mainland. Seasonal collections were carried out throughout two years in Santa Catarina State, southern of Brazil. The diversity index calculations show high values when compared with temperate climate communities. The sites on the mainland (Serra do Tabuleiro) presented the highest diversity, which was measured by the Diversity Index (H'). These sites are covered by primary Atlantic Forest and theoretically should have a higher variation of ecological niches. A dendogram showing the similarity between the communities, calculated by Morisita Index, points to a level of similarity equal to 60 percent for all communities. In this diagram, we can see two clades: one on the mainland and the other on the islands. The six island sites are grouped into one clade and separated into two subclades, one including the sites on Santa Catarina Island and the other consisting of the islands adjacent to this last and very much larger one. These groupings show the very important role of the spatial component on the prediction of the structure of the communities. This fact raises the discussion about the high complexity of the Atlantic Forest ecosystem and consequently the unpredictability of its fauna, highlighting the need of its conservation.

Foi realizado um estudo de dinâmica de assembléias de drosofilídeos em seis comunidades insulares e duas continentais em visitas estacionais ao longo de dois anos, em Santa Catarina. Os índices de diversidade foram elevados se comparados com os de assembléias de clima temperado. Com relação ao índice de heterogeneidade de espécies de Shannon-Wiener (H'), os pontos localizados no continente (Serra do Tabuleiro) foram os mais elevados. Esses sítios apresentam Mata Atlântica primária e, teoricamente, deteriam a maior variabilidade de nichos ecológicos. Um dendograma mostrando a similaridade entre as assembléias (medida pelo índice de Morisita), apontou para 60 por cento de similaridade. Nele os pontos continentais e insulares foram os que mais se diferenciaram. Os seis pontos insulares se separam em dois grupos: um que inclui os pontos da Ilha de Santa Catarina, e outro compreendendo as demais ilhas adjacentes a essa ilha maior. Os agrupamentos mostram a importância do componente espacial na previsão da estrutura das comunidades. Esse fato levanta a discussão a respeito da grande complexidade do ecossistema de Mata Atlântica e, conseqüentemente, sua imprevisibilidade, em termos de composição faunística, evidenciando a necessidade de sua conservação.

Learning of courtship components in Drosophila mercatorum (Paterson & Wheller) (Diptera, Drosophilidae)

In Drosophila, courtship is an elaborate sequence of behavioural patterns that enables the flies to identify conspecific mates from those of closely related species. This is important because drosophilids usually gather in feeding sites, where males of various species court females vigorously. We investigated the effects of previous experience on D. mercatorum courtship, by testing if virgin males learn to improve their courtship by observing other flies (social learning), or by adjusting their pre-existent behaviour based on previous experiences (facilitation). Behaviours recorded in a controlled environment were courtship latency, courtship (orientation, tapping and wing vibration), mating and other behaviours not related to sexual activities. This study demonstrated that males of D. mercatorum were capable of improving their mating ability based on prior experiences, but they had no social learning on the development of courtship.

Em Drosophila, a corte sexual consiste em uma elaborada seqüência de padrões comportamentais que possibilita às moscas reconhecer parceiros conspecíficos dentre indivíduos de outras espécies. Essa discriminação é importante uma vez que drosofilídeos geralmente se agregam em sítios de alimentação, onde machos de diversas espécies cortejam as fêmeas vigorosamente. Neste estudo, testamos se machos virgens aprimoram seu comportamento de corte mediante a observação do cortejo de outras moscas da população (aprendizado social), ou mediante experiências próprias anteriores (facilitação). O comportamento de corte das moscas, observado em ambiente controlado, foi registrado com relação aos seguintes componentes: latência da corte, duração da corte (orientação, "tapping" e vibração das asas), cópula, e outros comportamentos não relacionados à corte sexual. Os resultados aqui obtidos sugerem que machos de D. mercatorum são capazes de aprimorar sua habilidade de cortejar fêmeas em função de experiências próprias anteriores, mas não encontramos nenhuma evidência de aprendizado social para esse comportamento.

Taxonomic survey of Drosophilidae (Diptera) from mangrove forests of Santa Catarina Island, Southern Brazil

Assemblages of drosophilids have been characterised in several environments of the Brazilian territory, like the Atlantic Rain Forest, urban areas, cerrados, the Amazon Forest, and others. The present survey is the first attempt to characterise the fauna of Drosophilidae in mangrove forests, an environment typical of tropical coasts worldwide. Twenty-eight samples were collected from the three main mangrove forests of Santa Catarina Island, southern Brazil, using banana-baited traps hung in trees. Samples were taken in January (summer), April (autumn), July (winter) and October (spring) between July 2002 and July 2005. In total, 82,942 specimens of drosophilids were caught, belonging to 69 species of six genera - Amiota Loew, Drosophila Fallén, Leucophenga Mik, Scaptodrosophila Duda, Zaprionus Coquillett and Zygothrica Wiedemann. The high abundance of D. simulans Sturtevant was remarkable, with some notable peaks of D. malerkotliana Parshad & Paika in autumn samples. Other common species were Zaprionus indianus Gupta, D. mediostriata Duda and D. willistoni Sturtevant. We also collected 45,826 flies of family Curtonotidae, the sister-group of Drosophilidae virtually absent in other environments. The assemblages of drosophilids were very similar in the three mangrove forests surveyed, despite the different surrounding environments. In general, the species sampled in the mangroves were the same as those observed in the surrounding environments, but in varying abundances. This suggests that drosophilids are differently affected by environmental pressures operating in mangroves.

Assembléias de drosofilídeos têm sido caracterizadas em vários ambientes no Brasil, como Mata Atlântica, áreas urbanas, cerrados, Floresta Amazônica e outros. Este trabalho é a primeira tentativa em caracterizar a fauna de Drosophilidae nos manguezais, ambiente presente nos litorais tropicais de todo o mundo. Vinte e oito amostras foram coletadas nos três principais manguezais da ilha de Santa Catarina, utilizando-se armadilhas com isca de banana suspensas em árvores. As amostras foram obtidas nos meses de janeiro (verão), abril (outono), julho (inverno) e outubro (primavera), entre julho de 2002 e julho de 2005. O total de 82.942 indivíduos foi coletado, incluindo 69 espécies de seis gêneros - Amiota Loew, Drosophila Fallén, Leucophenga Mik, Scaptodrosophila Duda, Zaprionus Coquillett e Zygothrica Wiedemann. Mostrou-se marcante a alta abundância de D. simulans Sturtevant, com alguns picos pronunciados de D. malerkotliana Parshad & Paika nas amostras de outono. Outras espécies comuns foram Zaprionus indianus Gupta, D. mediostriata Duda e D. willistoni Sturtevant. Também foram coletados 45.826 espécimes da família Curtonotidae, grupo irmão de Drosophilidae, virtualmente ausente em outros ambientes. As assembléias de drosofilídeos mostraram-se bastante homogêneas entre os três manguezais pesquisados, apesar das diferenças nos ambientes que os circundam. Em geral, as espécies encontradas nos manguezais são as mesmas encontradas nos ambientes vizinhos, porém suas abundâncias são bastante modificadas, sugerindo que várias espécies estejam respondendo diferentemente às pressões ambientais em ação nos manguezais, que podem ser mais restritivas para algumas do que para outras.

Homology of polytene elements between Drosophila and Zaprionus determined by in situ hybridization in Zaprionus indianus

The drosophilid Zaprionus indianus due to its economical importance as an insect pest in Brazil deserves more investigation into its genetics. Its mitotic karyotype and a line-drawing map of its polytene chromosomes are already available. This paper presents a photomap of Z. indianus polytene chromosomes, which was used as the reference map for identification of sections marked by in situ hybridization with gene probes. Hybridization signals for Hsp70 and Hsr-omega were detected, respectively, in sections 34B and 32C of chromosome V of Z. indianus, which indicates its homology to the chromosomal arm 3R of Drosophila melanogaster and, therefore, to Muller's element E. The main signal for Hsp83 gene probe hybridization was in section 17C of Z. indianus chromosome III, suggesting its homology to arm 3L of D. melanogaster and to element D of Muller. The Ubi probe hybridized in sections 10C of chromosome II and 17A of chromosome III. Probably the 17A is the polyubiquitin locus, with homology to arm 3L of D. melanogaster and to the mullerian D element, as suggested also by Hsp83 gene location. The Br-C gene was mapped in section 1D, near the tip of the X chromosome, indicating its homology to the X chromosome of D. melanogaster and to mullerian element A. The Dpp gene probe hybridized mainly in the section 32A of chromosome V and, at lower frequencies to other sections, although no signal was observed as expected in the correspondent mullerian B element. This result led to the suggestion of a rearrangement including the Dpp locus in Z. indianus, the secondary signals possibly pointing to related genes of the TGF-beta family. In conclusion, the results indicate that chromosomes X, III, V of Z. indianus are respectively correspondents to elements A, D, and E of Muller. At least chromosome V of Z. indianus seems to share synteny with the 3R arm of D. melanogaster, as indicated by the relative positions of Hsp70 and Hsr-omega, although the Dpp gene indicates a disruption of synteny in its distal region.

A new spot-thoraxed species of Drosophila from the Atlantic Forest of southeastern Brazil (Diptera, Drosophilidae)

Drosophila boraceia sp. nov. é descrita, e sua terminália masculina ilustrada, a partir de um macho coletado na Estação Biológica de Boracéia, Salesópolis, Estado de São Paulo, Brasil. A primeira vista, ela pode ser facilmente confundida com as espécies de Drosophila do subgrupo fasciola do grupo repleta, por apresentar um padrão de fusão das pintas do tórax semelhante àquele típico das espécies daquele subgrupo, das quais difere principalmente por possuir uma terminália masculina estruturalmente diferente. Entretanto, alguns componentes da terminália masculina de Drosophila boraceia sp. nov. apresentam uma certa semelhança com aqueles encontrados em Drosophila atalaia Vilela & Sene, 1982, espécie não agrupada e que também apresenta pintas no tórax.