Identification key for drosophilid species (Diptera, Drosophilidae) exotic to the Neotropical Region and occurring in Brazil

Abstract Thirteen species of drosophilid exotic to the Neotropical Region are recorded in Brazil, and some of them are highly invasive and threaten significantly fruit cultures. We provide an illustrated key for identifying these species, and briefly discuss their taxonomic status, distribution, and occurrence in the Neotropics. The key should not only support newcomers to the study of Drosophila but also facilitate their identification by those interested in insects associated with cultivated areas.

Spatial and temporal dynamics of drosophilid larval assemblages associated to fruits

The study of organisms and their resources is critical to further understanding population dynamics in space and time. Although drosophilids have been widely used as biological models, their relationship with breeding and feeding sites has received little attention. Here, we investigate drosophilids breeding in fruits in the Brazilian Savanna, in two contrasting vegetation types, throughout 16 months. Specifically, larval assemblages were compared between savannas and forests, as well as between rainy and dry seasons. The relationships between resource availability and drosophilid abundance and richness were also tested. The community (4,022 drosophilids of 23 species and 2,496 fruits of 57 plant taxa) varied widely in space and time. Drosophilid assemblages experienced a strong bottleneck during the dry season, decreasing to only 0.5% of the abundance of the rainy season. Additionally, savannas displayed lower richness and higher abundance than the forests, and were dominated by exotic species. Both differences in larval assemblages throughout the year and between savannas and gallery forests are consistent with those previously seen in adults. Although the causes of this dynamic are clearly multifactorial, resource availability (richness and abundance of rotten fruits) was a good predictor of the fly assemblage structure.

Breeding sites of drosophilids (Diptera) in the Brazilian Savanna. I. Fallen fruits of Emmotum nitens (Icacinaceae), Hancornia speciosa (Apocynaceae) and Anacardium humile (Anacardiaceae) / Sítios de criação de drosofilídeos (Diptera) no bioma Cerrado. I. Frutos caídos de Emmotum nitens (Icacinaceae), Hancornia speciosa (Apocynaceae) e Anacardium humile (Anacardiaceae)

In this study, drosophilids that bred in fruits of three common plant species of the Brazilian Savanna were investigated: Emmotum nitens, Hancornia speciosa and Anacardium humile, along with the temporal and spatial distribution of these insects among fruits obtained from six individuals of E. nitens. Fallen fruits were collected in natural environments, placed on moist sand in individual containers and all drosophilids that emerged from these resources during 15 days were collected, counted and identified. From 3,651 fruits collected (3,435 of E. nitens, 179 of A. humile and 37 of H. speciosa) 4,541 flies emerged and were classified into 19 species of Drosophilidae. Their distribution was unequal among the three resources, also over time, and among the six individuals of E. nitens. Such fluctuations probably reflect the availability of resources in time and space and probably the action of selective factors such as larval competition.

Neste estudo, são investigados os drosofilídeos que se criam em frutos de três espécies de plantas comuns do Cerrado brasileiro: Emmotum nitens, Hancornia speciosa e Anacardium humile, juntamente com a distribuição temporal e espacial desses insetos entre os frutos obtidos de seis indivíduos de E. nitens. Frutos recolhidos sobre a serrapilheira, em ambientes naturais, foram mantidos no laboratório e os drosofilídeos que deles emergiram foram contados e identificados. Dos 3.651 frutos coletados (3.435 de E. nitens, 179 de A. humile e 37 de H. speciosa) emergiram 4.541 drosofilídeos, classificados em 19 espécies. A distribuição dessas espécies foi desigual entre os três tipos de recursos, ao longo do tempo, e também entre os seis indivíduos de E. nitens. Essas flutuações refletem a disponibilidade dos recursos no tempo e no espaço, e provavelmente a ação de forças seletivas como a competição entre as larvas.

Biogeographical aspects of drosophilids (Diptera, Drosophilidae) of the Brazilian savanna / Aspectos biogeográficos dos drosofilídeos (Diptera, Drosophilidae) da savana brasileira

Some species of drosophilids have been intensely studied, especially in the areas of genetics and molecular biology. However, little is known about their ecology and biogeography. Here, we revise the records of Drosophilidae species in the Cerrado domain, in order to organize the available information and to recognize patterns of geographic distribution and endemism. The 43 sampled sites in this domain reveal 100 species of drosophilids (10 of them exotic to the Neotropical region), distributed in eight genera. The collections were concentrated mainly in the States of Goiás (including the Federal District) and Minas Gerais. Serra do Cipó is the site with the highest richness of these insects. Of the 90 neotropical species found in the Cerrado, 77 also occur outside this domain, most of which are in the Atlantic Forest. Since extensive areas of this domain were poorly sampled for drosophilids and most studies used only baited traps to collect the flies, this absence of endemism should be carefully considered. It is recommended new inventories in poorly sampled regions, especially in the northeastern part of the domain. Also diversification of collection methods and improvement in the taxonomy of these flies are proposed. These directions should provide a significant increase in the list of species of drosophilids of the Cerrado; and thus, increase our knowledge about its biodiversity.

Algumas espécies de drosofilídeos têm sido intensamente estudadas, principalmente nas áreas de genética e biologia molecular. Entretanto, a ecologia e biogeografia do grupo ainda são pouco conhecidas. Aqui revisamos os registros das espécies de Drosophilidae no domínio do Cerrado, visando organizar a informação disponível e reconhecer eventuais padrões de distribuição geográfica e endemismos. As 43 localidades amostradas no domínio apresentaram 100 espécies de drosofilídeos (10 delas exóticas à região Neotropical), distribuídas em oito gêneros. As coletas estão concentradas principalmente nos Estados de Goiás (incluindo Distrito Federal) e Minas Gerais. A Serra do Cipó é o local com maior riqueza desses insetos. Das 90 espécies neotropicais encontradas no Cerrado, 77 também ocorrem fora do domínio, a maioria na Mata Atlântica. Como áreas extensas do domínio foram pouco amostradas para drosofilídeos e a maior parte dos estudos utilizaram apenas iscas de banana para coletar as moscas, a ausência de endemismos deve ser analisada com precaução. São recomendados novos inventários em regiões pobremente amostradas, especialmente na parte noroeste do domínio. Também são propostas a diversificação dos métodos de coleta e o aumento do esforço de identificação taxonômico dessas moscas. Essas diretrizes devem permitir um aumento significativo na lista de espécies de drosofilídeos do Cerrado e, consequentemente, no conhecimento da biodiversidade do domínio.

Drosophilids (Insecta, Diptera) of the Paranã Valley: eight new records for the Cerrado biome / Drosofilídeos do Vale do Paranã: oito novas ocorrências para o bioma Cerrado

The Paranã Valley, located in the Central Brazil Plateau, within the domain of the Cerrado biome, is frequently cited as a center of endemism and diversity. Nonetheless, this region is poorly known, mainly considering its invertebrate fauna. Here, drosophilid flies were used as biological tools to contribute to a broader inventory, whose goals were mapping the Cerrado biodiversity and identifying areas to be conserved. Three previously unsampled areas in the Paranã Valley were sampled. Amongst the 12,297 specimens collected 45 species were identified, which represents 50 percent of the drosophilid species previously recorded in the Cerrado. Moreover, this sampling presented eight new occurrences for the biome (Drosophila annulosa, D. calloptera, D. papei, D. neomorpha, D. roehrae, Gitona bivisualis, Rhinoleucophenga lopesi, and the genus Diathoneura) and three species that had only one record for the biome, or that were recorded only in a specific area. Therefore, this study confirms the importance of the Paranã Valley as a center of biodiversity in the Cerrado biome, and recommends the establishment of conservation units in this region.

O Vale do Paranã localiza-se no Brasil Central, no domínio do bioma Cerrado, e é freqüentemente citado como um centro de diversidade e endemismo. Entretanto, essa região ainda é pouco conhecida, principalmente no que se refere à fauna de invertebrados. Este estudo apresenta a fauna de drosofilídeos de três áreas nunca avaliadas anteriormente no Vale do Paranã, visando contribuir para um inventário mais amplo, cujos objetivos foram mapear a biodiversidade da região e identificar áreas para serem preservadas. Dentre os 12.297 espécimes coletados foram identificadas 45 espécies, correspondendo a 50 por cento dos drosofilídeos previamente registrados no Cerrado. Além disso, este trabalho acrescentou oito novas ocorrências para o Cerrado (Drosophila annulosa, D. calloptera, D. papei, D. neomorpha, D. roehrae, Gitona bivisualis, Rhinoleucophenga lopesi e o gênero Diathoneura) e três outras espécies com apenas uma única ocorrência para o Cerrado, ou registradas em apenas uma área específica do bioma. Nesse contexto, este estudo confirma a importância do Vale do Paranã como um centro de biodiversidade do Cerrado, e recomenda o estabelecimento de unidades de conservação nessa região.

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.

Teaching evolutionary biology

Evolutionary Biology integrates several disciplines of Biology in a complex and interactive manner, where a deep understanding of the subject demands knowledge in diverse areas. Since this knowledge is often inaccessible to the majority of specialized professionals, including the teachers, we present some reflections in order to stimulate discussions aimed at the improvement of the conditions of education in this area. We examine the profile of evolutionary teaching in Brazil, based on questionnaires distributed to teachers in Secondary Education in the Federal District, on data provided by the "National Institute for Educational Studies and Research", and on information collected from teachers working in various regions of this country. Issues related to biological misconceptions, curriculum and didactic material are discussed, and some proposals are presented with the objective of aiding discussions aimed at the improvement of the teaching of evolutionary biology.