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1.
Aim To elucidate the role of vicariance versus dispersal at the microevolutionary scale in annual killifish populations belonging to the Austrolebias bellottii species complex (Rivulidae). Within this complex, A. bellottii and A. apaii have low vagility and occur widely within the study area, making them excellent models for testing biogeographic hypotheses of differentiation. Location South America, in the Paraná–Uruguay–La Plata river basin. Methods Molecular data and morphometric analyses were used to reconstruct the phylogeographic history and morphological variation of 24 populations of two taxa of the A. bellottii species complex. Phylogenetic analyses using maximum likelihood (ML) and Bayesian inference (BI) model‐based methods, estimates of clade divergence times implemented in beast , non‐metric multidimensional scaling, analysis of molecular variance results, and morphological analyses elucidated the role of vicariance versus dispersal hypotheses in population differentiation in the aforementioned river basin. Results In the A. bellottii species complex from the Paraná–Uruguay–La Plata river basin, past allopatric fragmentation from vicariance events seems to be the most plausible scenario for diversification since the Late Miocene and more recently since the Plio‐Pleistocene. The Plio‐Pleistocene vicariance produced the differentiation of three major clades in A. bellottii populations. One clade from the eastern Uruguay River drainage was separated from another in western Uruguay and the Paraná–La Plata River drainages. A later vicariance event split populations to the south (lower Paraná–La Plata Basin) and north (middle Paraná) of the western Paraná River drainage. However, our results do not exclude the possibility of dispersal events among A. bellottii populations from both the Uruguay and Paraná river drainages, which could occur in these river basins during hypothesized connectivity cycles of the Late Pliocene and Pleistocene. Main conclusions Past allopatric fragmentation caused by different vicariance events seems to be the main driver of diversification in the A. bellottii species complex since the Plio‐Pleistocene. However, the current molecular data suggest that populations from both drainages of the Paraná–Uruguay rivers may have experienced cycles of connectivity during the Pleistocene, perhaps including multiple vicariance or dispersal events from populations located in the western lower Uruguay River drainage, which encompassed climatic and geological changes in the Paraná–Uruguay–La Plata Basin.  相似文献   

2.
Records of sympatry between Alouatta caraya and A. clamitans are rare despite their extensive range overlap. An example of their current sympatry and the rediscovery of free-ranging potential hybrids of A. caraya and A. clamitans in the forests of the Upper Paraná River, Southern Brazil, are reported in this paper. Eight groups were observed in the study area: five monospecific groups of A. caraya, two of A. clamitans, and a group containing two adult males and two adult females of A. caraya and a sub-adult male and two adult females identified as Alouatta sp. The color of the last three individuals was a mosaic between the two species; this is consistent with previously described variations in museum specimens collected in the Paraná River in the 1940s that had been identified as potential hybrids. The results from this study emphasize the need for scientific studies in the region of the Ilha Grande National Park, one of the few regions in the Paraná River that currently harbors both howler species. Contribution number 1637 of the Departamento de Zoologia, Universidade Federal do Paraná, Caixa Postal 19020, 81531-980, Curitiba, Paraná, Brasil.  相似文献   

3.
Evidence for the extinction of the bumblebee Bombus bellicosus in Paraná state, in Brazil, is presented. The species is found in areas covered with open grass fields and shrub vegetation, originally ranging from northwestern Argentina to Paraná, where it reached its northeastern limit. Until the early 1980s, B. bellicosus was relatively abundant in Paraná, when the last known specimens were collected. In recent surveys conducted from 2002 to 2005, no specimens were recovered at sites in which the species was previously known to occur. Possible causes for local extinction of this species are discussed, including habitat conversion, pollution and climate change.  相似文献   

4.
《Journal of Asia》2002,5(2):209-214
After examining the effectiveness of preservation methods of the Asian ladybird, Harmonia axyridis, we were able to preserve the overwintering populations of ladybirds in Fabix plastic boxes or milk paper packs at 4°C and 8°C without food over 4 months with an 84% survival rate. Also, by preserving the 3rd and 4th instar larva with microwave popcorn, we were able to decrease cannibalism by reducing the contact frequency between individuals. Although the preserving efficiency somewhat decreased, it was possible to store the ladybird larva with microwave popcorn for up to 10 days without predation. After preservation with microwave popcorn in the incubator at 10°C, the feeding ability related to preservation was investigated. These results showed that there was no difference in aphid predation between the normal individuals and the preserved ones. Finally, the 3rd and 4th instar larva, which were preserved with microwave popcorn, were released in a strawberry greenhouse where the strawberry capitophorus aphid (Chaetosiphon miner) and the strawberry root aphid (Aphis forbesi) had been present. After the release, the changes of aphid population densities were investigated every week for a month.  相似文献   

5.
Prochilodus lineatus is a highly migratory fish species that sustains the most important commercial fishery of Paraná-Paraguay basin. Migratory patterns are poorly known and only few population genetic studies are available for this species in the Upper Paraná. To assess genetic population structure, we genotyped a sample of 93 individuals from the Lower Uruguay River close to Gualeguaychú city (Entre Ríos, Argentina) at three different times, July 2008 (Winter), September 2008 (Spring) and May 2009 (Fall). All individuals were genotyped for 12 microsatellite loci previously found to be informative to assess populations of P. lineatus. Our results show seasonal variation of the genetic sub-structuring at this locality that may be related to the presence of different migratory stocks throughout the year. The Fall sample includes an additional genetic cluster of individuals not detected in Winter and Spring, suggesting that this species should be considered a mixed stock fishery.  相似文献   

6.
The invasive bivalve Limnoperna fortunei (Dunker 1857) was introduced in South America in 1991, with the first occurrence in Brazil in 1998. In the Iguassu River, the species was recorded in 2001; however, it is unknown how it was introduced and spread. Adults and larvae were sampled in Iguassu and Paraná Rivers, and the genetic profiles were compared. The species was absent in the upper reaches and only larvae were found, in low densities, in intermediary reaches. The L. fortunei populations from the lower Iguassu River presented no genetic differentiation among themselves, suggesting strong connectivity, and were significantly different from the Paraná River populations, most likely because of Iguassu Falls. Furthermore, the results suggest that the Paraná River represents the source of propagules to the Iguassu River. Generally, no significant differences were observed between the genetic structure inferred from adults and larvae. Only the population from the Iguassu National Park, a lotic environment, differed from the remaining subpopulations. The characterization of genetic profile using larval stages of L. fortunei populations was satisfactory, and represents an important protocol for studying the population genetics of aquatic species with planktonic larval stages.  相似文献   

7.
Isozyme electrophoresis was used as a method to provide a measure of relationship among Italia, Rubi, Benitaka, and Brasil cv of Vitis vinifera traditionally grown in Marialva, a town in the northwestern region of the state of Paraná, southern Brazil. No allelic variation was observed for esterase (EST), malate dehydrogenase (MDH), peroxidase (POD), glutamate dehydrogenase (GTDH), alkaline phosphatase (AKP), acid phosphatase (ACP), and aspartate amino transferase (AAT). Tissue specific and variation in staining intensity of EST, MDH, POD, and GTDH isozymes indicate differential gene expression in colour grape varieties. Regulatory genes may be operative in determining the number of molecules of enzymes in a cell and determining the berry skin polymorphism in four cultivars. Change frequency for berry skin colour suggest the occurrence of somatic crossing-over in naturally cultivated plants and a periclinal chimerism in Brasil cv. The four grape colour cultivars seem to be clones of the same cultivar.  相似文献   

8.
The red palm mite (RPM), Raoiella indica (Hirst) (Acari: Tenuipalpidae), was found for the first time in the Paraná State, in southern Brazil. The first observations occurred in September 2015, on strawberry (Fragaria × ananassa Duch) leaves, which is not considered a typical host plant of RPM. It is probable that its occurrence on this plant was serendipitous. Visual surveys for RPM were carried out on four typical host plants (banana, coconut, foxtail palm, and real palm), in five cities of the Paraná State (Bela Vista do Paraíso, Londrina, Maringá, Marialva, and Sarandi). RPM was found on each of the four typical host plants, in each of the five cities. Our survey extends RPM occurrence to the southern region of Brazil and indicates that the pest could be widespread in the country.  相似文献   

9.
Aim The main drainages of the Plata Basin – the Paraná, Paraguay and Uruguay rivers – begin in tropical latitudes and run in a north–south direction into subtropical–temperate latitudes. Consequently, the biota of these rivers has tropical elements that contrast with temperate biomes through which the rivers run. We apply a panbiogeographical approach, to test whether the large rivers of the Plata Basin have a differential influence on distributional patterns of tropical snakes in subtropical and temperate latitudes of South America. Location Subtropical and temperate sections of the major Plata Basin rivers, South America. Methods We compared the individual tracks of 94 snake taxa. The track analysis consisted of: (1) plotting the localities of each taxon on maps, (2) connecting the localities of each taxon using a minimal geographical proximity determinant of the ‘individual tracks’, and (3) superimposing the individual tracks to determine generalized tracks. To detect tropical snakes that reach higher latitudes through the rivers we used the preferential direction of distribution concept. For each taxon we measured the angular deviations between the line of its individual track and the course of the rivers in a 100 × 100 km scaled grid. Average angular values < 45° indicated a positive association with the rivers. Results Thirty‐five of 94 taxa showed distributions associated with the major rivers of the Plata Basin, including fauna from distinct biogeographical lineages, supported by the occurrence of five generalized tracks as follows: (1) the Paraguay–Middle Paraná, (2) the Paraguay–Paraná fluvial axis, Upper Paraná and Middle Paraná to Upper Delta, (3) the Lower Paraguay, Paraná and Uruguay rivers, excluding the sectors High Paraná and High Uruguay, (4) the Uruguay River and Upper Paraná, and (5) the High Paraná. The Atlantic species occurred with significantly higher frequency in the Uruguay River and High Paraná river sections, the Amazon species were found with significantly higher frequency in the Paraguay and Middle Paraná sections, and the species with a Pantanal distribution were found in all sections. Main conclusions The observed distributional patterns may be explained by the interaction of ecological, geographical and historical factors. Previous authors have developed ecological (hydrological or environmental similarity) or dispersalist (effect of rivers as migration routes) explanations. The coincidence between generalized tracks and past geomorphological events that caused displacements and changed relationships between the Paraguay, Paraná and Uruguay river sections supports hypotheses involving the strong influence of historical factors in the present configuration of tropical snake distribution in temperate latitudes.  相似文献   

10.
Testate amoeba communities are influenced by temporal variation in the productivity levels in the environment, and may be used as an indicator group for these changing conditions. Here, we analysed the effect of temporal variation in the levels of productivity variables on testate amoeba community of the upper Paraná River floodplain. We evaluated the hypothesis that the frequency and abundance of the testate amoeba community change along an environmental gradient, with different taxa establishing at different points along the gradient in response to changes in the levels of productivity variables. We predicted that the number of species would increase and decrease at points associated with higher and lower levels of productivity variables, respectively. Testate amoeba species were sampled quarterly between 2000 and 2012 from six lakes in the upper Paraná River floodplain, Brazil. We recorded 110 species belonging to 11 families. Threshold Indicator Taxa Analysis identified positive and negative significant shift points in response to the concentration of chlorophyll-a, total nitrogen, and total phosphorus on the frequency and abundance of the testate amoeba community. Our results indicated that change intervals in the levels of productivity variables were associated with the establishment of different taxa. The main bioindicator species of productivity were Difflugia acuminata, D. amphoralis, D. helvetica multilobata, D. kempny, D. lobostoma multilobata, D. parva, D. schurmanni, D. ventricosa, and Lesquereusia ovalis. These species were linked to the increase and decrease in the levels of productivity, confirming the ecological importance of the role of these organisms as bioindicators in aquatic ecosystems.  相似文献   

11.
Lamnid teeth close to but more plesiomorph than Carcharodon carcharias were collected in the late Miocene beds of the Paraná Formation in the central eastern Argentina. We propose, as other authors, that some species formerly assigned to Isurus or to Cosmopolitodus should be included in Carcharodon. Some workers suggested that C. carcharias originated by phyletic evolution in the Pacific basin. The teeth from Paraná could pertain to a new species of Carcharodon already known from Perú. In contrast with the Pacific basin, Carcharodon sp. was sympatric with the wide toothed species Carcharodon plicatilis in central Argentina. This is the oldest record of Carcharodon in the southern Atlantic.  相似文献   

12.
We investigated, within two cereal fields in Southern England, the within-canopy spatial distribution of the aphids Sitobion avenae and Metopolophium dirhodum in relation to crop yield and plant nitrogen. We extended the study to investigate the spatial distribution of aphids that fell to, or returned from, the ground in order to estimate availability of the within-canopy aphid population to ground-active predators. We revealed that crop canopy aphid spatial pattern was associated with nitrogen or yield. Differences were evident between species: S. avenae was generally negatively associated with yield or plant nitrogen, whilst M. dirhodum exhibited positive association. For both aphid species, we observed strong spatial pattern for aphids falling to the ground and conclude that this could, in part, mediate the effectiveness of ground-active predators as pest control agents.  相似文献   

13.
The Upper River Paraná Floodplain System comprises the rivers Ivinheima, Baía and Paraná, which with their associated waterbodies form three subsystems, each showing individual characteristics. Hydrilla verticillata recently invaded the Upper Paraná Floodplain, while Egeria najas is the native most abundant submersed macrophyte. A large flood-pulse, during January–March 2007, abruptly reduced macrophyte stands in many areas to near-zero and dispersed propagules over the entire floodplain. From April 2007 to April 2008, we conducted three surveys sampling for the presence–absence of H. verticillata and E. najas and environmental variables aiming to answer: (1) How rapid is the colonization–regeneration process for both species? (2) Which habitats seem to be more susceptible to their colonization? (3) Which environmental factors can best predict their occurrence? Neither H. verticillata nor E. najas colonized the Ivinheima subsystem. In the Baía subsystem, E. najas had only two occurrences while H. verticillata was not present. In the Paraná subsystem, E. najas predominantly occurred in river channels, but it was also common in floodplain lakes. In April 2007, it was found in 13% of the sites in the Paraná subsystem, increasing to 30% in November 2007 and reaching 34% in April 2008. H. verticillata did not successfully colonize floodplain lakes of the Paraná subsystem. In channels, it had 34% occurrence in April 2007, increasing to 62% in November 2007 and remaining at 62% in April 2008. The role of environmental variables in predicting species occurrence changed depending upon the scale of the analysis. Considering the whole Upper Paraná floodplain, water transparency followed by electrical conductivity were the strongest predictors for both species. Colonization by submersed plants seems improbable in the Ivinheima subsystem owing to its low water transparency besides frequent localized floods; in the Baía subsystem, it seems inhibited by transparency and low alkalinity. Considering just the Paraná subsystem, the proportion of organic matter in sediment, ten times higher in floodplain lakes than in channels, was the best predictor for H. verticillata occurrence (also related to water pH and transparency), while E. najas was only significantly explained by transparency.  相似文献   

14.
The material was been collected in 1972 during a field trip performed by the research vessel of the National Institute of Limnology, Argentina, along the main course of the Paraná River from the Santa Fe harbor down to the Río de la Plata. Sixty sampling stations were covered. In the lower course of the river sampling was carried out in the Paraná Guazú and the Paraná Bravo branches down to its confluence with the Uruguay River, and the Paraná de las Palmas and the Rio de la Plata down to the Buenos Aires harbor. Water samples for chemical analysis were collected and some physical parameters were measured.

Due to the characteristics of the part of the river under consideration, we have divided it into four sectors.

Sixty six species were seen. The rotifers were always the most important. Trichocerca rattus was the predominant species.

The Zooplankton density and specific diversity showing differences between those from industrialized areas and not industrialized ones.  相似文献   

15.
Piabina argentea is a species of Characidae family that is widely distributed in the hydrographic basins of the São Francisco and Paraná Rivers and in some Atlantic coastal drainages of South America. The genus contains only one other species, which is restricted to the Tietê River headwaters (the Upper Paraná River Basin) and is considered monophyletic within the Stevardiinae subfamily. Despite the apparent morphological conservation of at least six well-structured clades, great genetic distance revealed by DNA barcoding has already been reported. In an attempt to evaluate the effect of the watershed of the two river basins in the Arc of Upper Paranaíba region (Upper Paraná and São Francisco River basins), we analyzed the populations from both basins using mitochondrial DNA sequences and morphometry and constructed a distribution scenario for the species in both basins.  相似文献   

16.
The invasion process comprises not only the characteristics of nonindigenous species but also the attributes of the invaded environment which make it susceptible to the establishment of nonindigenous species. Habitat attributes operate like filters in determining the establishment of introduced species and the invasibility of a region. In the Upper Paraná River Basin, Brazil, the practice of introducing species was quite common and frequently carried out by hydroelectric companies. The target species of the present study, the peacock-bass Cichla kelberi, is native to the Amazon Basin. This species was introduced into several reservoirs of the Upper Paraná River Basin and is dispersing rapidly throughout the system. This study shows which characteristics of the reservoirs facilitate their invasibility after testing for the effect of propagule pressure. We conclude that a set of abiotic factors favors the invasibility of these reservoirs. To be more precise, the largest, deepest, most transparent and warmest reservoirs are the most likely to be colonized by Cichla kelberi. It is possible that other environments with similar characteristics to these reservoirs, such as the lagoons from the Upper Paraná River Basin floodplain, can also be colonized by Cichla kelberi.  相似文献   

17.
Two new species of Coronigoniella Young are described and illustrated: C. osborni, sp. n., from SE. and S. Brazil (Espírito Santo, Minas Gerais, Rio de Janeiro, and Paraná states), and C. formosa, sp. n., from central W. and SE. Brazil (Goiás and Minas Gerais states, and the Distrito Federal). The presence of a sclerotized plate from the abdominal sternum VIII is reported in females of Coronigoniella for the first time. Taxonomic and morphological notes are given for C. spinosa (Osborn) based on specimens from its type-locality in Mato Grosso State. Tettigonia ruficaput (Walker), a species from Colombia previously considered of uncertain taxonomic position, is transferred to Coronigoniella. Possible host plants of C. osborni, sp. n. are Coleus sp. (Lamiaceae), Symphytum sp. (Boraginaceae), and Vernonia sp. (Asteraceae). The genus Coronigoniella is newly recorded from Alagoas, Bahia, Espírito Santo, Goiás, Minas Gerais, Paraná, and São Paulo states, as well as from the Distrito Federal, Brazil. A map showing the known geographic distribution of the two new species is presented. Resumo Duas novas espécies de Coronigoniella Young são descritas e ilustradas: C. osborni, sp. n., do sudeste e sul do Brasil (estados do Espírito Santo, Minas Gerais, Rio de Janeiro e Paraná), e C. formosa, sp. n., do centro-oeste e sudeste do Brasil (estados de Goiás e Minas Gerais, assim como o Distrito Federal). A presença de uma placa esclerosada do esterno abdominal VIII é registrada em fêmeas de Coronigoniella pela primeira vez. Notas taxonômicas e morfológicas sobre C. spinosa (Osborn) são fornecidas, com base em espécimes provenientes da sua localidade-tipo no Estado do Mato Grosso. Tettigonia ruficaput (Walker), uma espécie da Colômbia anteriormente considerada como de posição taxonômica incerta, é transferida para Coronigoniella. Coleus sp. (Lamiaceae), Symphytum sp. (Boraginaceae) e Vernonia sp. (Asteraceae) são possíveis plantas hospedeiras de C. osborni, sp. n. O gênero Coronigoniella é pela primeira vez registrado nos estados de Alagoas, Bahia, Espírito Santo, Goiás, Minas Gerais, Paraná e São Paulo, assim como no Distrito Federal, Brasil. Um mapa mostrando a distribuição geográfica conhecida das duas novas espécies é apresentado.  相似文献   

18.
Despite of the widespread co-occurrence of multiple invaders, little is known on their combined ecological impacts and on their effects on different life stages of native species. We assessed the joint impacts of four non-native mammals (cattle, horse, European hare Lepus europaeus, and wild boar Sus scrofa) on seed surplus and seedling abundance of the Paraná pine (Araucaria angustifolia), a critically-endangered species of the Atlantic Forest. We found that its seeds constitute an autumn food resource for a native community richer than previously thought, with 70 bird and mammal species as confirmed or potential seed consumers, of which 40 were not previously recognized as such. We also recorded the number of uneaten seeds and seedlings at the middle-end of autumn under 520 female Paraná pine trees across the species’ distribution and identified signs of the species consuming seeds from each tree through direct observations combined with camera trapping. Most of the sampled trees (98%) were visited by at least one seed consumer species, and over 60% were visited by at least one non-native mammal. Seed surplus strongly declined in the presence of cattle, horses and wild boars, their impacts being additive, whereas the number of seedlings declined in the presence of European hares. Our results emphasize the importance of Paraná pine seeds for native fauna and the additive impact of invaders in a species-rich ecosystem. Seed predation by non-native species reduces the potential regeneration of Paraná pine forests, and may severely reduce food supply for its native consumers.  相似文献   

19.
Fluctuations in temporal and spatial abundance are remarkable features of all animal populations. Regional synchrony of local population dynamics has been verified in several studies. This study investigated the existence of coherent patterns in temporal fluctuations of the principal testate amoebae population abundance in plankton from the upper Paraná river floodplain in Brazil. Testate amoebae sampling was carried out every three months, from February 2000 to November 2002, and twice in 2003. Sampling occurred in 12 environments associated with three different rivers. Samples were obtained at the subsurface of the pelagic region, using a motorized pump and a 68 μm mesh plankton net. Ninety–three testate amoebae species from eight families were identified. The families Difflugiidae, Arcellidae, and Centropyxidae had the greatest number of species. Arcella conica, A. discoides, A. vulgaris, Centropyxis aculeata, C. ecornis, Difflugia gramen, D. pseudogramen and Cucurbitella dentata were the most abundant species, and they were chosen for spatial synchrony analysis. No coherent pattern of abundance fluctuation was found, in any of the floodplain environments studied. Nevertheless, when analyzing only the channels, spatial synchrony was observed to Centropyxis ecornis. Mantel tests showed that the synchrony level, as identified by Spearman and Pearson correlations, was not correlated to geographic distance between environments. We conclude that regional factors in the Upper Paraná River floodplain are not the main determinants of the population dynamics of testate amoebae. The high floodplain heterogeneity seems determine a great relevance of local factors. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

20.
A second species of the poorly known sharpshooter genus Nannogonalia Young, 1977 is described and illustrated from the Atlantic Forest of south Brazil (state of Paraná). Types are deposited in DZUP. Nannogonalia inusitata n. sp. can be distinguished from the type-species (Tettigonia circumcincta Signoret, 1855) mainly by the color pattern and form of the male subgenital plates and female sternite VII. Nannogonalia circumcincta is newly recorded from the state of Paraná. The female genitalia of Nannogonalia are described in detail for the first time, based on the type-species and the new species. We discuss some peculiar features of the first and second ovipositor valvulae of this genus that were previously observed in Versigonalia Young, 1977.  相似文献   

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