The subgenus Scaptodrosophila (Diptera: Drosophilidae)

Four major subgenera, Drosophila, Sophophora, Hirtodrosophila and Scaptodrosophila, and several minor subgenera, have been recognized in the genus Drosophila. The hitherto little studied subgenus Scaptodrosophila, possessing a complicated synonymy, contains 144 named species, or about 11% of the total described in the genus; it is likely that many more Scaptodrosophila species await discovery. Scaptodrosophila probably originated in tropical Asia, and the greatest Scaptodrosophila faunas occur in Asia, south-east Asia, New Guinea, Australia and Africa, with very few species in north and south America and Europe. Scaptodrosophila species usually possess a pair of prescutellar bristles, a propleural bristle, and three large subequal sternopleural bristles; other morphological features are more variable. Ecological information concerning the majority of Scaprodrosophila species is scanty or absent, but known feeding or breeding sites include tree sap, fungi, fruit, flowers and 1eaf litter; larvae of at least one species are gall forming in plant tissues. The establishment of species groups is complicated by lack of detailed knowledge of many species, but six groups containing four or more species are recognized.     

Structure of cephalic abnormalities in Drosophila melanogaster (Diptera: Drosophilidae)

Scanning and transmission electron microscopy were utilized in studying the cephalic abnormalities of the tu-h strain of Drosophila melanogaster. Abnormalities, appearing as protuberances (growths) of different shapes and sizes, were observed only on or in close proximity to receptor cites. Compound eyes of some flies, besides having such protuberances, either had modified corneal lenses or were absent altogether. Cuticles of the growths were thinner than that of the normal surrounding layer. The epidermal cells associated with setae on the growths or underlying modified corneal lenses remained undifferntiated. Both setae and growths lacked innervation. The receptor portions (retinular sensory cells and secondary pigment cells) of the abnormal compound eye, where the dioptric portions were replaced by protuberances or remained undifferentiated, were unaffected by the mutation. Nuclei of several cells, including oenocytes and fat bodies, close to or underlying epidermal cells of abnormalities, were large and contained compact nucleoli without nucleonemas. Viruslike particles were observed in several nuclei of growth cells. It was concluded from the present study that the alterations induced by the mutation can be only a localized phenomenon restricted to at least several cephalic epidermal cells and/or their derivatives.     

Density and Lek Displays in Drosophila grimshawi (Diptera: Drosophilidae)

Frequencies of stereotyped lek displays of male Drosophila grimshawi were measured in groups of different sizes (2, 4, 8, or 16 ♂♂ per container). In one experiment ♀♀ were absent, and in a second experiment two ♀♀ were present in each male group. In both experiments the frequency of courtship displays was linearly dependent upon density. Two agonistic displays and a communal display were density-dependent only when ♀♀ were present. The strategy ♂♂ adopted only in the presence of ♀♀ was: (1) to balance the relative frequencies of communal and aggressive behavior, and (2) to increase the ratio of contact to noncontact aggression with increasing density.     

Mitotic chromosomes of species in the subgenusDrosophila (Diptera:Drosophilidae)

The karyotypes of 17 species in the subgenusDrosophila are compared according to their taxonomical relationships. Although closely related species often possess similar karyotypes, the karyotypes diverge considerably within the subgenus. Thus extensive chromosome rearrangements did occur during the speciation. Species with higher chromosome numbers do not necessarily have higher average of total chromosome length per cell.     

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.     

Hierarchical structure in the Drosophila mojavensis cluster (Diptera: Drosophilidae)

Sequences from three gene regions from the nuclear and mitochondrial genomes were used to examine the extent and nature of hierarchical structure in the Drosophilamojavensis cluster (Drosophila arizonae, D. mojavensis and D. navojoa) of the D. repleta species group. To determine the genetic divergence of these three species, sequence data were analyzed using maximum parsimony and population aggregation analysis. Individual and combined gene genealogies indicate that D. arizonae and D. mojavensis are neither diagnosable nor monophyletic with respect to one another. Although D. navojoa has differentiated from D. arizonae and D. mojavensis, as diagnosed by nuclear gene sequences, it may have undergone a reticulation event with D. arizonae. Our results suggest that either these taxa are still undergoing differentiation at the molecular level or have experienced gene flow in the recent past.     

Assemblage of drosophilids (Diptera,Drosophilidae) inhabiting flooded and nonflooded areas in the extreme South of Brazil

Several studies on the potential use of drosophilid assemblages as bioindicator systems have been carried out in the last years. Nevertheless, the successful application of these organisms in these systems requires adequate filling of several knowledge gaps. In this sense, little is known about drosophilid assemblages in wetlands and flooded areas. The present study provides the first survey of drosophilid species inhabiting such environments in the extreme South of Brazil and compares general beta-diversity patterns between assemblages of flooded versus nonflooded areas. The specimens were collected with banana-baited traps, and the assemblages recovered in eight wetlands of the southernmost coast of Brazil were compared to those recovered from seven nonflooded areas of the Pampa and Atlantic Forest biomes. A total of 5028 and 2571 individuals encompassing 27 and 37 species were collected in the flooded and nonflooded areas, respectively. The differential species composition patterns presented between these areas was statistically supported, which seems to be related to the lower beta-diversity presented by swamps, especially in regard to dominance patterns. So, the open and climatically harsher environment provided by wetlands possibly constitutes a hostile environment for the entry and, mainly, for the persistence of several native Drosophilidae species, in contrast to some exotic and more plastic species (as Drosophila simulans and Zaprionus indianus). Since the diversity gradient of flooded areas does not seem to be related to the conservation status of the swamp, our results question the use of Drosophilidae species as bioindicators of environmental disturbance and antropic influence in wetlands.     

Revision of Neotropical Metopia Meigen (Diptera: Sarcophagidae)

ABSTRACT. The Neotropical species of Metopia Meigen are revised, and a total of fifteen species recorded from the region. Five species are described as new; M.aurigans sp.n., M.pulverulenta sp.n., M.hispidimana sp.n., M.flava sp.n., and M.cubitosetigera sp.n. Three species are recorded for the first time from the Neotropical region; M.inermis Allen, 1926, M.krombeini Sabrosky, 1953, and M.sinipalpis Allen, 1926. Four new synonyms are proposed; M.tessellata Allen, 1926, syn.n. of M.perpendicularis Wulp, 1890, M.macrocera Dodge, 1968, syn.n. of M.brasiliana (Townsend, 1929), M.astuta Dodge, 1968, syn.n. of M.brasiliana (Town-send, 1929), and M.lucipeda Reinhard, 1961, syn.n. of M.campestris (Fallen, 1810). Males of M.polita (Townsend, 1935) and M.juquiana (Townsend, 1934) are recorded for the first time. A key to all American species of Metopia is provided, and the phylogenetic affinities of the Neotropical species are briefly discussed.     

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% 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.     

Humidity affects populations of Drosophila suzukii (Diptera: Drosophilidae) in blueberry

Temperature and humidity affect insect physiology, survival, fecundity, reproductive status and behaviour. Complementing previous work investigating the effects of temperature on adult survival and fecundity of the invasive frugivorous pest, Drosophila suzukii (Matsumura), this study was conducted to determine the effect of humidity on D. suzukii larval development, adult survival, fecundity and reproductive status using blueberry as a host substrate. The five constant humidity levels in laboratory bioassays were 20, 33, 71, 82 and 94% RH at 20.6 ± 0.2°C. As RH increased, fecundity and longevity increased. At the higher humidity levels, RH had limited impact on mean generation times (T), larval development and eclosion times. The highest net reproductive rate (R_o = 68) and highest intrinsic rate of population increase (r_m = 0.17) were both recorded at 94% RH. The reproductive status of females, as indicated by the number of mature oocytes per female, was significantly greater at 82 and 94% RH, compared to 71% RH. In addition to the laboratory procedures, we correlated field trap captures over an 81‐day summer period to relative humidity (RH) levels in close proximity to those traps. In the field, low ambient humidity levels resulted in decreased trap captures. A humidity‐dependent population model predicted lower densities of D. suzukii relative to populations at higher humidity. This study supports the hypothesis that cultural practices that minimize lower humidity levels in crops can contribute to the management of D. suzukii. Such methods may include open pruning, drip irrigation and field floor management.     

Predator-mediated coexistence in laboratory communities of mycophagous Drosophila (Diptera: Drosophilidae)

Abstract. 1. This laboratory experiment examined the effects of interspecific competition and predation by Ontholestes cingulatus Gravenhorst (Coleoptera: Staphylinidae) on three species of mycophagous Drosophila (Diptera: Drosophilidae): D.tripunctata Loew, D.falleni Wheeler and D.putrida Sturtevant.
2. Single-species and three-species assemblages were exposed to single commercial mushrooms on wet pine shavings in 200 ml culture bottles. A predacious rove beetle (Ontholestes cingulatus) was present in half of the three-species replicates. The stocked adult flies and beetles were removed after 4 days, and the number, biomass and mean mass of emerging progeny was recorded.
3. For all three species the abundance and biomass of the progeny emerging in the 'no predator' communities' was significantly less than for the progeny emerging in single-species replicates, suggesting an interspecific competitive effect. D.tripunctata was the competitive dominant; it emerged in abundance from all seven three-species 'no predator' communities while D.putrida and D.falleni were often excluded.
4. The decrease in production was attributed to strong interspecific competition among larva and not interference among ovipositing adults.
5. Predation on ovipositing adults significantly reduced the number and biomass of D.tripunctata progeny emerging, and indirectly facilitated the number and biomass of emerging D.falleni and D.putrida.Predation on adults reduced larval recruitment, relaxed larval competition, and released the inferior competitors.     

Polyphyly of Lordiphosa and its relationships in Drosophilinae (Diptera: Drosophilidae)

The phylogenetic relationships of Lordiphosa and some taxa in Drosophilinae were analysed on the basis of a total of forty‐one selected drosophilid species. These included eighteen species of five Lordiphosa species‐groups as the main target, twenty‐three species representative of the major drosophiline ingroup taxa and four species of Steganinae as outgroup. Sixty‐eight morphological characters of adults were subjected to cladistic analysis. From the results it is concluded that Lordiphosa is polyphyletic; the Lo. tenuicauda species‐group and genus Nesiodrosophila form a single monophyletic group; Lordiphosa proper (i.e. Lordiphosa spp. minus the tenuicauda group) comprises another monophyletic group; within Lordiphosa proper the fenestrarum, nigricolor and denticeps groups are all monophyletic, but monophyly of the miki group is not strongly supported; genera Hirtodrosophila and Scaptomyza and subgenus Sophophora are all monophyletic; and within Drosophilinae, genus Scaptodrosophila is the first to have split from the main lineage, but the branching order of other clades, Chymomyza, Lordiphosa proper, Sophophora, Hirtodrosophila, Nesiodrosophila+ Lo. tenuicauda group, Scaptomyza, Dorsilopha and subgenus Drosophila, remains unresolved. The topology of maximum parsimony cladograms suggests that Lordiphosa proper lies close to Sophophora as proposed previously, although its phylogenetic position could not be determined conclusively. By contrast, bootstrap values tended to contradict another hypothesis that Lordiphosa and Scaptomyza are sister groups.     

Intra‐specific variability in Rhinoleucophenga punctulata populations (Diptera: Drosophilidae) from Neotropical biomes: Combined analyses of morphological and molecular data

Despite the fact that Drosophilidae is a very diverse and well‐studied taxon, the New World genus Rhinoleucophenga is yet poorly understood even in regard to species distribution and morphological variability pattern. In this sense, R. punctulata is a species widely distributed in the Neotropical region. Specimens of R. punctulata were collected from different biomes in Brazil: Pampa, Cerrado and Caatinga sensu strictu, and a southern Amazonian savannah enclave area. Geographical variations in the external body morphology and in the morphology of spermatheca were noticed among the different populations. The hypothesis that each population could be a different species was tested through molecular data. A fragment of the mitochondrial cytochrome c oxydase subunit I (COI) gene was sequenced to perform phylogenetic analyses through neighbor‐joining and Bayesian inferences. Pairwise genetic divergences of COI sequences were calculated using DNA barcode premises. The analyzed populations presented different variation levels in both morphology and molecular traits. However, new species were not proposed because the intra‐population nucleotide variations exceeded the inter‐population ones. The noticeable morphological and genetic variations revealed among the four studied populations of R. punctulata in different biomes of Brazil suggest the necessity that morphological, distributional and molecular data at the population level should be integrated into complementary datasets to better understand the biological diversity of Rhinoleucophenga through Neotropical environments.     

Blood-eye barrier of the developing drosophila melanogaster (Diptera : Drosophilidae)

For the past quarter century, it has been known that a blood-eye barrier exists in adult insects. However, the life stage at which the barrier arises and the anatomical correlate of the barrier were not known. Compound eye development in Drosophila melanogaster (Diptera : Drosophilidae) is essentially complete at approximately 140 h after pupariation ; or about 20 h prior to eclosion. A search for a blood-eye barrier spanned late third-instar larvae, through late pupal life sampled at 40 and 140 h post-pupariation. No blood-eye barrier is present in the eye discs of last-instar larvae, based on the presence of lanthanum tracer among ommatidial cells and their processes. Pleated-sheet septate junctions, which link larval ommatidial cells, are not yet capable of totally blocking tracer from paracellular passage. The blood-eye barrier is constructed in the early phase (0–60 h) of pupal development in the wake of apoptosis and new cellular reorganization. In the developing compound eye, mature photoreceptor neurons must then be protected from the ionic vagaries of hemolymph to become electrophysically competent. First vestiges of a barrier with occluding septate junctions are seen in the 40-h old pupa, and by 140 h, the barrier is complete. The barrier prevails throughout adult life.     

拱背果蝇属三新种记述(双翅目:果蝇科)

记述了拱背果蝇属 (Lordiphosa)黑色拱背果蝇种组 (nigricolorspecies group) 3新种 :黑腿拱背果蝇 (Lordiphosanigrifemursp nov )、鲁甸拱背果蝇 (Lordiphosaludianensissp nov )和施氏拱背果蝇 (Lordiphosashiisp nov )。     

Drosophilidae (Diptera) of Australia's Northern Territory: ecology and biogeography

Abstract   The drosophilid fauna is well documented in eastern Australia but is poorly known in other parts of the continent. This paper summarises what is known of this fauna in the Northern Territory (NT), and includes results from banana trapping in the humid and arid zones. The 42 recorded species include species that breed in fruit, fungi and/or flowers, and a larval predator of scale insects. Drosophilids occur in all three major climate zones (humid, semiarid and arid) but predominate in the humid zone. Banana-attracted species in the humid zone (wet-dry tropics) were common in all sampled habitats: urban, rainforest and open woodland. They included predominantly urban and/or rainforest species. Of the species collected in open woodland, some are likely to be breeding there, whereas others may have been intercepted during movement across the area. The semiarid fauna is a depauperate version of that found in the humid region. Only three species have been recorded in the arid region: an endemic arid specialist, and two cosmopolitan species ( D. simulans and D. melanogaster ) in urban Alice Springs. Overall, the NT drosophilid fauna represents a depauperate version of that found in eastern Australia, probably because of climatic factors and natural barriers to range expansion. There is little evidence of regional endemism, with probably only one (and at most three) species endemic to the NT, and no evidence of independent, natural dispersion from nearby Indonesia.     

Radiation effects on Drosophila suzukii (Diptera: Drosophilidae) reproductive behaviour

Female remating is a widespread behaviour, reported in several insect species. This behaviour can affect the efficiency of sterile insect technique (SIT); however, little is known about the postcopulatory behaviour of some pest species considered as candidates to be controlled by this technique, such as Drosophila suzukii (Matsumura, 1931) (Diptera: Drosophilidae). In this study, we investigated the effects of male and female sterilization on mating and remating behaviour of D. suzukii. First, we tested the occurrence of multiple mating in different combinations between sterile and fertile males and females. Then, we tested the effects of male and female sterility on female propensity to mate and remate. We found an overall low remating rate by D. suzukii females. Male sterility did not influence mating and remating likelihood; however, copula duration of sterile males was shorter compared to fertile males. On the other hand, sterile females were less likely to mate. Our findings encourage further research regarding the use of SIT to control D. suzukii.     

Scenario of the spread of the invasive species Zaprionus indianus Gupta, 1970 (Diptera, Drosophilidae) in Brazil

Zaprionus indianus was first recorded in Brazil in 1999 and rapidly spread throughout the country. We have obtained data on esterase loci polymorphisms (Est2 and Est3), and analyzed them, using Landscape Shape Interpolation and the Monmonier Maximum Difference Algorithm to discover how regional invasion occurred. Hence, it was apparent that Z. indianus, after first arriving in São Paulo state, spread throughout the country, probably together with the transportation of commercial fruits by way of the two main Brazilian freeways, BR 153, to the south and the surrounding countryside, and the BR 116 along the coast and throughout the north-east.