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Sample records for chironomidae

  1. Hibernal Emergence of Chironomidae in Ukraine

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    Viktor Baranov

    2013-12-01

    Full Text Available Twenty-seven species of Chironomidae were detected emerging in the Crimea during the period from December 2010 to March 2013. Twenty-three are Orthocladiinae and 4 are Chironominae (one Chironomini and three Tanytarsini species. Nine species are recorded for the first time in Crimea. At the genus-level the hibernal emergence in Crimea shows resemblance to the patterns reported for streams in Kansas.

  2. Mass occurrence and sporadic distribution of Corynocera ambigua Zetterstedt (Diptera, Chironomidae) in Danish lakes. Neo- and palaeolimnological records

    DEFF Research Database (Denmark)

    Brodersen, Klaus Peter; Lindegaard, C.

    1999-01-01

    Corynocera ambigua, Chironomidae, zoobenthos, charophytes, palaeolimnology, late-glacial, Denmark......Corynocera ambigua, Chironomidae, zoobenthos, charophytes, palaeolimnology, late-glacial, Denmark...

  3. CHIRONOMIDAE TYPES AT THE MUSEUM OF COMPARATIVE ZOOLOGY, BOSTON

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    Fabio Laurindo da Silva

    2011-11-01

    Full Text Available The Chironomidae (Insecta: Diptera type collection deposited at the Museum of Comparative Zoology (MCZ are listed and reviewed. It is represented by 23 primary types, as well as paratypes and paralectotypes for an additional 29 species, mostly resulting from research endeavors of H. Loew and H. K Townes. Notes updating the taxonomic status of several species are provided.

  4. Chironomidae (Insecta, Diptera from Alto Paranapanema Basin, southeastern Brazil

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    Kathia Sonoda

    2010-11-01

    Full Text Available We investigated the community of Chironomidae from three rivers belonging to the same river basin in Southern Brazil. Our objective was to analyze if the Chironomidae communities from rivers of the same basin were similar and relate this to land-use and water quality variables. Samples of insects were taken using artificial substrate baskets and left 44 days in the field for colonization during the dry season in 2002. Study reaches with the relevant land-use category present for at least 500 m along both river banks above and alongside the study reach were selected and land-use, terrain slope of the river basin and chemical and physical variables of the water were analysed. Faunal data were analyzed by number of individuals, richness of genera and community indices. Statistical analyses were performed in order to investigate the relationship between abiotic variables and the Chironomidae communities. Twenty-two genera were identified; Rheotanytarsus (Thienemann & Bause was the most abundant in all assemblages. Some genera showed preferences in their distribution, and were observed in only one of the rivers. Land-use and slope of the terrain were similar for all rivers, while the water quality variables were different for the Taquari River compared to the two other sites. This may explain the differences in the Chironomidae community observed for this locality

  5. NEW RECORDS OF CHIRONOMIDAE (DIPTERA) FROM CONTINENTAL FRANCE

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    Joel Moubayed-Breil

    2009-01-01

    AbstractMaterial recently collected in Continental Francehas allowed me to generate a list of 83 taxa ofchironomids, including 37 new records to thefauna of France. According to published data onthe chironomid fauna of France 718 chironomidspecies are hitherto known from the Frenchterritories. The nomenclature and taxonomy ofthe species listed are based on the last version ofthe Chironomidae data in Fauna Europaea, onrecent revisions of genera and other recentpublications relevant to taxonomy...

  6. Species of Oukuriella Epler (Diptera, Chironomidae inside freshwater sponges in Brazil

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    Fabio de Oliveira Roque

    2004-06-01

    Full Text Available Larvae of Oukuriella Epler, 1986 (Diptera, Chironomidae inside freshwater sponges are reported for the first time in Brazil.Espécies de Oukuriella Epler (Diptera, Chironomidae no interior de esponjas de água doce no Brasil. Larvas de Oukuriella Epler, 1986 no interior de esponjas de água doce são registradas pela primeira vez no Brasil.

  7. Cytogenetics of a parthenogenetic Arctic species of Micropsectra (Diptera, Chironomidae

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    David Porter

    2011-11-01

    Full Text Available Micropsectra sedna (Oliver, 1976 is a parthenogenetic midge from the Canadian Arctic. The parthenogenetic mechanism is apomictic thelytoky, with a restitutional division during oogenesis, as found in other parthenogenetic Chironomidae. It is triploid, with two similar chromosome sets, and the third is relatively dissimilar, pairing little with the diploid set. Two karyotypes were observed: a single individual with eight polytene elements in the salivary glands (3n=12, considered standard, while the majority of larvae showed only seven polytene chromosomes (3n=11. Hybrid speciation is considered likely, although chromosomal recombination following the origin of thelytoky has played some part in karyotype evolution. A single morphologically distinct larva was also found, which might be the donor of the haploid chromosome set. The apomictic restitutional system is compared to that of the other, independently derived, parthenogenetic Chironomids to assess the extent of similarity between species.

  8. Chironomid (Diptera, Chironomidae species assemblages in northeastern Algerian hydrosystems

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    N. Chaib

    2013-04-01

    Full Text Available The aim of this paper was to analyze the distribution of chironomids (Diptera, Chironomidae, and determine their substrate preferences, from two hydrosystems located in northeastern Algeria: the Kebir-East and the Seybouse wadis. Sixty-five species were recorded in 49 sampling sites distributed along the main courses of the two hydrographic nets and their tributaries. The majority of taxa comprised cosmopolitan species widely distributed along these two hydrosystems. Cricotopus (Cricotopus bicinctus showed the highest abundance and frequency of occurrence (29.52% and was widespread in almost all the sampling sites. Species richness ranged from 4 to 23, Shannon diversity between 0.15 and 0.90, Evenness from 0.23 to 1. A cluster analysis was carried out to represent the different groups of sites sharing similar species composition. Agglomerative cluster analysis grouped the sampling sites into four clusters according to the community data. An Indval analysis was then carried out to detect indicator species for each group of the sampling sites. Cricotopus (Isocladius sylvestris was indicator of the first group of the sampling sites. Orthocladius pedestris, Rheocricotopus chalybeatus and C. bicinctus were indicators of the second group, and Polypedilum cultellatum of the third group. The fourth group was not characterized by any species. Indval analysis allowed also to determine species preferences for substrate size: Corynoneura scutellata and Dicrotendipes nervosus emphasized a preference to fine gravel, and Glyptotendipes pallens to fine sand.

  9. Observations of cocooned Hydrobaenus (Diptera: Chironomidae) larvae in Lake Michigan

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    Tucker, Taaja R.; Hudson, Patrick L.; Riley, Stephen

    2016-01-01

    Larvae of the family Chironomidae have developed a variety of ways to tolerate environmental stress, including the formation of cocoons, which allows larvae to avoid unfavorable temperature conditions, drought, or competition with other chironomids. Summer cocoon formation by younger instars of the genus Hydrobaenus Fries allows persistence through increased temperatures and/or intermittent dry periods in arid regions or temporary habitats, but this behavior was not observed in the Great Lakes until the current study. Cocoon-aestivating Hydrobaenus sp. larvae were found in benthic grab samples collected in 2010–2013 near Sleeping Bear Dunes National Lakeshore in northern Lake Michigan with densities up to 7329/m2. The aestivating species was identified as Hydrobaenus johannseni (Sublette, 1967), and the associated chironomid community was typical for an oligotrophic nearshore system. Hydrobaenus cocoon formation in the Great Lakes was likely previously unnoticed due to the discrepancies between the genus' life history and typical benthos sampling procedures which has consequences for describing chironomid communities where Hydrobaenus is present.

  10. MÉTODO PARA LA CRÍA EN LABORATORIO DE CHIRONOMIDAE (DIPTERA DE AMBIENTES LÓTICOS

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    Juan Pablo Zanotto Arpellino

    2016-04-01

    Full Text Available La taxonomía de Chironomidae se apoya fuertemente en la integración de las características morfológicas de todas las fases del ciclo de vida, las cuales se pueden obtener mediante la cría en laboratorio. Este estudio desarrolló un método de cría en laboratorio de larvas de Chironomidae de ambientes lóticos. El método consta de una circulación constante de agua y distintos ítems alimenticios. Esta metodología ha permitido obtener asociaciones de los estados de larva, pupa y adulto para la identificación de especies presentes en una región de Argentina en la que el estado de conocimiento de la familia Chironomidae es incipiente.Laboratory Rearing Methodology for Chironomidae (Diptera of Lotic EnvironmentsThe taxonomy of Chironomidae is strongly supported by the integration of morphological characteristics of all stages of the life cycle, which can be obtained through laboratory rearing. This study was developed in laboratory to test rearing method for lotic Chironomidae larvae. The method included constant water circulation and different food items. This methodology allowed obtaining associations of larva, pupa and adult stages for the identification of species from an Argentinean region in which the knowledge of Chironomidae family is incipient.

  11. Growth of immature Chironomus calligraphus (Diptera, Chironomidae in laboratory conditions

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    Rita de Cássia S.A. Canteiro

    2011-12-01

    Full Text Available Chironomidae larvae are important macroinvertebrates in limnic environments, but little knowledge exists about their biometrics development characteristics. This study aims to describe the immature Chironomus calligraphus Goeldi, 1905 under laboratory conditions by the accomplishment of thirteen egg masses from eggs eclosion to adults emergency, at controlled room temperature (25ºC and photoperiod (12-12h. Larvae were feed ad libitum with "Alcon Basic - MEP 200 Complex" fish food and commercial dehydrated Spirulina. The postures had a mean length of 9 ± 1 mm (n = 13 and 348 ± 66 eggs. The brownish colored eggs with elliptical shape had length of 160.3 ± 17.7 µm (n = 130, being arranged as an organized string in a pseudo spiral form. The time duration from the first to the four instars were three, four, four and eight days, and the average length of a cephalic capsule to each one of the instars (66.3 ± 12.3 µm, 102.9 ± 22.1 µm, 159 ± 24.6 µm, 249.2 ± 29.7 µm, n = 456 were significantly different (ANOVA, p Larvas de Chironomidae são importantes componentes emambientes límnicos, mas pouca informação está disponívelsobre as características biométricas em seu desenvolvimento. Este estudo objetivou descrever os imaturos de Chironomus calligraphus Goeldi, 1905 em condições de laboratório, através do acompanhamento de treze posturas da espécie desde aeclosão dos ovos até a emergência dos adultos, sob temperatura (25ºC e fotoperíodo controlados (12-12 h. As larvas foram alimentadas com ração para peixes "Alcon Basic - MEP 200 Complex" e Spirulina comercial desidratada. A postura apresentou comprimento médio de 9 ± 1 mm (n = 13 e348 ± 66 ovos. Estes, de cor amarronzada e formato elíptico, apresentaram comprimento de 160,3 ± 17,7 µm (n = 130, arranjados como uma fita em formato pseudo-espiralado. Aduração do primeiro ao quarto estágio foi de três, quatro,quatro e oito dias, e os comprimentos médios da c

  12. Chironomid (Chironomidae: Diptera checklist from Nahuel Huapi National Park, Patagonia, Argentina Lista de los quironómidos (Chironomidae: Diptera del Parque Nacional Nahuel Huapi, Patagonia, Argentina

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    Mariano Donato

    2008-06-01

    Full Text Available This paper presents the first inventory of modern and subfossil taxa of the Family Chironomidae (Insecta: Diptera from Nahuel Huapi National Park in Patagonia, Argentina. The catalogued fauna contains 104 species in 48 genera and 6 sub-families for modern fauna and 52 morphotypes in 36 genera and 4 subfamilies for sub-fossil fauna.Este trabajo presenta el primer catálogo de taxones modernos y subfósiles de la familia Chironomidae (Insecta: Diptera del Parque Nacional Nahuel Huapi en Patagonia, Argentina. La fauna catalogada contiene 104 especies en 48 géneros y 6 subfamilias para la fauna moderna y 52 morfotipos en 36 géneros y 4 subfamilias para la fauna subfósil.

  13. Sobre uma nova espécie do gênero Aedokritus Roback, 1958 (Diptera: Chironomidae On a new species of the genus Aedokritus Roback, 1958 (Diptera: Chironomidae

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    Sebastião José de Oliveira

    1989-01-01

    Full Text Available In this paper we describe a new species of a non-biting midge of the genus Aedokritus Roback, 1958 (Chironominae, Chironomidae from Brazil and Bolívia. That is the fifth species of this genus. The other species of the genus are: A. penicilligerus (Edwards, 1931, from Argentina and Peru; A. pruinescens (Edwards, 1931, from Argentina; A. platycnemis (Edwards, 1931, from Argentina; and A. sartis Roback, 1960, from Brazil.

  14. Larvae of North American Eukiefferiella and Tvetenia (Diptera: Chironomidae). Bulletin No. 452.

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    Bode, Robert W.

    "Eukiefferiella" and "Tvetenia" are closely related genera belonging to the subfamily Orthocladiinae within the Chironomidae, a family of non-biting midges. All known larvae in these genera are aquatic, being found predominantly in running water. Most species prefer cold, swift-flowing, well-oxygenated streams. Although larvae…

  15. Chironomidae and Oligochaeta for water quality evaluation in an urban river in southeastern Brazil.

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    Rosa, Beatriz Jabour Figueiraujo Vescovi; Rodrigues, Luciana Falci Theza; de Oliveira, Gilmar Simões; da Gama Alves, Roberto

    2014-11-01

    Considering the importance of benthic macroinvertebrates for diagnosis of variations in the ecological conditions of aquatic habitats, the aim of this study was to investigate the structure of the Chironomidae and Oligochaeta assemblages along an organic pollution gradient. The fauna specimens were obtained with the use of artificial substrates, and the environmental variables were recorded at five sites of the São Lourenço River, during 12 months. Metrics of the assemblage and detrended correspondence analysis were used to verify the response of the fauna to the pollution gradient. Procrustes analysis was used to verify whether the data on the Chironomidae and Oligochaeta assemblages, as well as the taxonomic and numerical resolution of these groups, provide similar results in relation to the pollution gradient. The richness, evenness, and taxonomic composition of the Chironomidae and Oligochaeta assemblages varied significantly among the collection sites, with distinct conservation conditions. Genera of the subfamilies Orthocladiinae and Tanypodinae were associated with the sites upstream of the urban area, where the dissolved oxygen levels are higher. Species of Oligochaeta and the genus Chironomus were associated with more organically polluted sites. No concordance was observed in the response of the Chironomidae and Oligochaeta assemblages in relation to the environmental variables, indicating the need to use both groups in biomonitoring studies. On the other hand, both the data on composition (presence or absence) and those on the lowest taxonomic resolution (abundance of subfamilies) were effective to diagnose the pollution gradient in the river studied. Therefore, when the environmental conditions along a river's gradient are contrasting, we suggest the use of the lowest taxonomic resolution of Chironomidae and Oligochaeta in biomonitoring. That procedure considerably reduces the assessment time, besides being a method that can be used by people not

  16. The importance of scanning electron microscopy (sem in taxonomy and morphology of Chironomidae (Diptera

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    Andrzej Kownacki

    2015-07-01

    Full Text Available The paper reports on the value of scanning electron microscopy (SEM in the taxonomy and morphology of Chironomidae. This method has been relatively rarely used in Chironomidae studies. Our studies suggest that the SEM method provides a lot of new information. For example, the plastron plate of the thoracic horn of Macropelopia nebulosa (Meigen under light microscopy is visible as points, while under SEM we have found that it consists of a reticular structure with holes. By using SEM a more precise picture of the body structure of Chironomidae can be revealed. It allows researchers to explain inconsistencies in the existing descriptions of species. Another advantage of the SEM method is obtaining spatial images of the body and organs of Chironomidae. However, the SEM method also has some limitations. The main problem is dirt or debris (e.g. algae, mud, secretions, mucus, bacteria, etc., which often settles on the external surface of structures, especially those which are uneven or covered with hair. The dirt should be removed after collection of chironomid material because if left in place it can become chemically fixed to various surfaces. It unnecessarily remains at the surface and final microscopic images may contain artifacts that obscure chironomid structures being investigated. In this way many details of the surface are thus unreadable. The results reported here indicate that SEM examination helps us to identify new morphological features and details that will facilitate the identification of species of Chironomidae and may help to clarify the function of various parts of the body. Fast development of electron microscope technique allows us to learn more about structure of different organisms.

  17. Fossil Chironomidae (Insecta: Diptera) as Paleothermometers in the African Tropics

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    Eggermont, H.; Heiri, O.; Russell, J.; Vuille, M.; Audenaert, L.; Klaassen, G.; Verschuren, D.

    2008-12-01

    Reconstruction of Africa's temperature history from natural climate archives such as lake sediments is essential to amend the current scarcity of information on natural tropical climate and ecosystem variability. Chironomids are well-established paleothermometers in north-temperate/boreal regions, but their potential in tropical lakes has never before been assessed. We surveyed sub-fossil chironomid assemblages in surface sediments from 65 lakes and permanent pools in southwestern Uganda and central/southern Kenya, spanning elevations between 489 and 4575 m asl. Using various subsets of lakes and corresponding Surface-Water Temperatures (SWTemp) and Mean Annual Air Temperatures (MATemp), we developed a series of inference models for quantitative paleotemperature reconstruction. Models using both low-, mid- and high-elevation sites suffer to some extent from the small number of samples between 2500 and 3500 m asl, and from the presence of ecologically distinct but morphologically indistinguishable taxa. Models confined to mountain sites produce poorer error statistics, but are less prone to the biogeographical and taxonomic complexities associated with long climatic gradients. Overall, error statistics compare favourably with those of inference models developed for temperate regions, indicating that fossil assemblages of African Chironomidae can be valuable indicators of past temperature change. We subsequently used these models to evaluate whether high-elevation lakes in the Rwenzori Mountains (>3000 m asl) have been impacted by climate warming in recent centuries by comparing temperatures inferred from chironomid assemblages in modern sediments with those derived from chironomid assemblages in sediments deposited within or briefly after the Little Ice Age (1270-1850 AD). Depending on the model used, between 44 and 63% of the 16 lakes studied indicate significantly warmer temperatures in recent times (corresponding with an average MATemp rise of 0.88 ° C, and

  18. Effects of bioirrigation of non-biting midges (Diptera: Chironomidae) on lake sediment respiration

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    Baranov, Viktor; Lewandowski, Jörg; Romeijn, Paul; Singer, Gabriel; Krause, Stefan

    2016-06-01

    Bioirrigation or the transport of fluids into the sediment matrix due to the activities of organisms such as bloodworms (larvae of Diptera, Chironomidae), has substantial impacts on sediment respiration in lakes. However, previous quantifications of bioirrigation impacts of Chironomidae have been limited by technical challenges such as the difficulty to separate faunal and bacterial respiration. This paper describes a novel method based on the bioreactive tracer resazurin for measuring respiration in-situ in non-sealed systems with constant oxygen supply. Applying this new method in microcosm experiments revealed that bioirrigation enhanced sediment respiration by up to 2.5 times. The new method is yielding lower oxygen consumption than previously reported, as it is only sensitive to aerobic heterotrophous respiration and not to other processes causing oxygen decrease. Hence it decouples the quantification of respiration of animals and inorganic oxygen consumption from microbe respiration in sediment.

  19. Chironomid (Chironomidae: Diptera checklist from Nahuel Huapi National Park, Patagonia, Argentina

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    Mariano DONATO

    2008-01-01

    Full Text Available Este trabajo presenta el primer catálogo de taxones modernos y subfósiles de la familia Chironomidae (Insecta: Diptera del Parque Nacional Nahuel Huapi en Patagonia, Argentina. La fauna catalogada contiene 104 especies en 48 géneros y 6 subfamilias para la fauna moderna y 52 morfotipos en 36 géneros y 4 subfamilias para la fauna subfósil.

  20. MÉTODO PARA LA CRÍA EN LABORATORIO DE CHIRONOMIDAE (DIPTERA DE AMBIENTES LÓTICOS

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    Juan Pablo ZANOTTO ARPELLINO

    2016-01-01

    Full Text Available La taxonomía de Chironomidae se apoya fuertemente en la integración de las características morfológicas de todas las fases del ciclo de vida, las cuales se pueden obtener mediante la cría en laboratorio. Este estudio desarrolló un método de cría en laboratorio de larvas de Chironomidae de ambientes lóticos. El método consta de una circulación constante de agua y distintos ítems alimenticios. Esta metodología ha permitido obtener asociaciones de los estados de larva, pupa y adulto para la identificación de especies presentes en una región de Argentina en la que el estado de conocimiento de la familia Chironomidae es incipiente.

  1. Diversity and distribution of Chironomidae (Insecta: Diptera of protected areas in North Tunisia

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    Boulaaba S.

    2014-01-01

    Full Text Available In North Africa seasonal streams called wadi are an unique habitats with serve hydrological and thermal regime. Non-biting midges take an important part of freshwater biodiversity in North Africa. We present new data on the distribution and diversity of Chironomidae in North Tunisia. Larvae, pupal exuviae and adult males of chironomids were collected from a various freshwater ecosystems from May 2005 till April 2006. The aim of this study was to recognize the pattern of midge diversity in North Tunisia to estimate ecological value of running waters in the region. In total, 79 taxa were identified. Nearly all of the taxa were typical representatives of the Palaearctic and Mediterranean complexes. The majority of the investigated sites belonged to the protected areas in North Tunisia, such as the Ichkeul National Park, the Kroumerie Mountains and the El Feija National Park, part of the Intercontinental Reserve of the Mediterranean Biosphere. Altitudinal zonation of the communities composition was found in the lowland (250 m a.s.l. with maximum of 760 m. Whereas among the data 39 species are recorded from Tunisia for the first time, the species richness of Chironomidae is higher than previously estimated.

  2. Chironomidae of semiaquatic lake shore habitats in the Karelian Isthmus (northwestern Russia

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    Andrey Przhiboro

    2012-10-01

    Full Text Available Shores of lentic waters are poorly studied as habitats of Chironomidae. We investigated floating shore marsh surrounding the lakes Bol’shoe Rakovoe (Äyräpäänjärvi or Eteläjärvi and Okhotnich’e (Muolaanlampi, shallow mesotrophic wetlands in the Karelian Isthmus. Our research aimed to identify species structure of immature chironomid assemblages in this peculiar habitat and to provide their quantitative assessment. Five sites of the water margin zone (a 20-m part of floating marsh adjoining the lake littoral were studied using two techniques, quantitative samples taken with a grab-net and laboratory rearings of adults from substrata. Thirty-two samples were taken in July and October; 2970 emerging chironomid adults were identified. Nineteen species were found, 3 of Tanypodinae, 10 of Orthocladiinae and 6 of Chironominae. Tavastia yggdrasilia, Thienemanniella minuscula and Polypedilum trigonus are first recorded from Russia, and 8 more species, from NW Russia. Orthocladiinae accounted for over 99% emerging adults, with 3 species predominant and numerous on all sites, Paraphaenocladius impensus, Limnophyes minimus and L. natalensis. Species structure is discussed and compared with the data on similar habitats. Chironomid larvae were most numerous macroinvertebrates. Mean abundance of chironomid immatures varied from 1246 to 32060 ind./m2, mean biomass, 0.104 to 3.591 g(wet weight/m2, depending on site and season. In July, Chironomidae comprised 3-15% of Diptera biomass and 1-5% of macroinvertebrates biomass; in October, 13-49% and 7-20%, respectively.doi: 10.5324/fn.v31i0.1410.Published online: 17 October 2012.

  3. Estado del conocimiento taxonómico de la fauna de Chironomidae (Diptera: Nematocera de la Patagonia

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    Mariano DONATO

    2009-01-01

    Full Text Available La familia Chironomidae (Diptera: Nematocera es uno de los grupos de insectos más ampliamente distribuidos y abundantes en cuerpos de agua dulce. Los representantes de esta familia pueden explotar áreas con amplios gradientes ambientales. La información que se presenta está basada en la recopilación de datos distribucionales bibliográficos, del estudio del material tipo de las especies de Chironomidae depositadas en el Natural History Museum (UK y del material de colección del Museo de La Plata (Argentina. En la Patagonia, se registran 9 subfamilias, la subfamilia monotípica Chilenomyiinae es endémica de esta área. Dentro de estas subfamilias, 53 de los 111 géneros conocidos para América del Sur están presentes en la Patagonia. Del total de géneros de la Patagonia, el 20 % es endémico y 7 de ellos muestran relaciones transantárticas. En la Patagonia, se registran 177 especies de Chironomidae, el 98% de éstas son endémicas, el 3 % son consideradas nomina dubia y el 17% requiere revisión ya que su ubicación sistemática es dudosa. Las descripciones originales de las especies patagónicas de Chironomidae están basadas principalmente sobre machos (n=58 y machos y hembras (n=43, ambas representan el 57% del total; el resto de las especies han sido descriptas con diferentes combinaciones de estadios del ciclo de desarrollo.

  4. Cardiocladius oliffi (Diptera: Chironomidae as a potential biological control agent against Simulium squamosum (Diptera: Simuliidae

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    Wilson Michael D

    2009-04-01

    Full Text Available Abstract Background The control of onchocerciasis in the African region is currently based mainly on the mass drug administration of ivermectin. Whilst this has been found to limit morbidity, it does not stop transmission. In the absence of a macrofilaricide, there is a need for an integrated approach for disease management, which includes vector control. Vector control using chemical insecticides is expensive to apply, and therefore the use of other measures such as biological control agents is needed. Immature stages of Simulium squamosum, reared in the laboratory from egg masses collected from the field at Boti Falls and Huhunya (River Pawnpawn in Ghana, were observed to be attacked and fed upon by larvae of the chironomid Cardiocladius oliffi Freeman, 1956 (Diptera: Chironomidae. Methods Cardiocladius oliffi was successfully reared in the rearing system developed for S. damnosum s.l. and evaluated for its importance as a biological control agent in the laboratory. Results Even at a ratio of one C. oliffi to five S. squamosum, they caused a significant decrease in the number of adult S. squamosum emerging from the systems (treatments. Predation was confirmed by the amplification of Simulium DNA from C. oliffi observed to have fed on S. squamosum pupae. The study also established that the chironomid flies could successfully complete their development on a fish food diet only. Conclusion Cardiocladius oliffi has been demonstrated as potential biological control agent against S. squamosum.

  5. Chironomidae (Diptera, Nematocera) fauna in three small streams of Skania, Sweden.

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    Janssens de Bisthoven, L; Gerhardt, A

    2003-03-01

    Two unpolluted streams and one chemically and thermally polluted stream in Skania, Sweden, were investigated in summer 1995 for their temporary chironomid fauna and the occurrence of buccal deformities. The unpolluted streams 'Ovedsan' and 'Skäralidbäcken' each contained, respectively, 13 and 16 taxa, with a dominance of Microtendipes pedellus group and Micropsectra spp., respectively. Most taxa were found in the pebbles and the submerged vegetation. Deformities were insignificant. The degraded stream Ybbarpsan in Perstorp contained 5 taxa, dominated by Procladius choreus. This species had 14% deformed larvae, interpreted as an effect of the chemical pollution. Shannon H and equitability J reflected the differences in chironomid community structure between the two unpolluted and the polluted sites. The Belgian Biotic Index scored maximally '10' in Skäralid, however only '6' in Oved and '5' in Perstorp. The combination of rapid assessment of macrobenthos and description of communities of Chironomidae, with mention of deformed larvae, adds a bonus of information about the temporary state of a stream.

  6. Low malathion concentrations influence metabolism in Chironomus sancticaroli (Diptera, Chironomidae in acute and chronic toxicity tests

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    Débora Rebechi

    2014-09-01

    Full Text Available Low malathion concentrations influence metabolism in Chironomus sancticaroli (Diptera, Chironomidae in acute and chronic toxicity tests. Organophosphate compounds are used in agro-systems, and in programs to control pathogen vectors. Because they are continuously applied, organophosphates often reach water sources and may have an impact on aquatic life. The effects of acute and chronic exposure to the organophosphate insecticide malathion on the midge Chironomus sancticaroli are evaluated. To that end, three biochemical biomarkers, acetylcholinesterase (AChE, alpha (EST-α and beta (EST-β esterase were used. Acute bioassays with five concentrations of malathion, and chronic bioassays with two concentrations of malathion were carried out. In the acute exposure test, AChE, EST-α and EST-β activities declined by 66, 40 and 37%, respectively, at 0.251 µg L-1 and more than 80% at 1.37, 1.96 and 2.51 µg L-1. In chronic exposure tests, AChE and EST-α activities declined by 28 and 15% at 0.251 µg L-1. Results of the present study show that low concentrations of malathion can influence larval metabolism, indicating high toxicity for Chironomus sancticaroli and environmental risk associated with the use of organophosphates.

  7. Taxonomic and numeric structure of Chironomidae (Diptera in different habitats of a Neotropical floodplain

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    Cristina Márcia de Menezes Butakka

    2014-09-01

    Full Text Available We characterized the local benthic Chironomidae by analyzing the numerical density, biomass, diversity index of Shannon-Wiener and dominance of larvae in the main channel of the Ivinhema River, in a secondary channel, in five lakes connected to the main channel and in five lakes without connection. Of the 68 taxa identified, Aedokritus sp., Tanytarsus sp., Chironomus strenzkei Fittkau, 1968 and Procladius sp.1 were found in all sampling sites and were considered morphospecies with greater of greatest ecological plasticity. Chironomus strenzkei Fittkau, 1968, contributed with the greatest biomass in the central region of lakes without connection, whereas Aedokritus sp. dominated in the littoral of lakes. The greater values of diversity indices in the littoral region of channels were due to the greater water flow and to the higher food availability in these areas. The dominance indices, by contrast, were greater on the central region of these environments. The littoral region has exclusive characteristics, representing habitats that could play important controlling in the numerical density and index diversity on the ecosystem, whereas that the biomass of benthic invertebrates in the central region in some biotopes would have different spatial probably according organisms drift.

  8. Toxicity of eight metals to Malaysian freshwater midge larvae Chironomus javanus (Diptera, Chironomidae).

    Science.gov (United States)

    Shuhaimi-Othman, Mohammad; Yakub, Nadzifah; Umirah, Nur Shahirul; Abas, Ahmad

    2011-11-01

    Fourth instars larvae of freshwater midge Chironomus javanus (Diptera, Chironomidae) were exposed for a 4-day period in laboratory conditions to a range of copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), nickel (Ni), iron (Fe), aluminium (Al) and manganese (Mn) concentrations. Mortality was assessed and median lethal concentrations (LC(50)) were calculated. LC(50) increased with the decrease in mean exposure times, for all metals. LC(50)s for 96 hours for Cu, Cd, Zn, Pb, Ni, Fe, Al and Mn were 0.17, 0.06, 5.57, 0.72, 5.32, 0.62, 1.43 and 5.27 mg/L, respectively. Metals bioconcentration in C. javanus increases with exposure to increasing concentrations and Cd was the most toxic to C. javanus, followed by Cu, Fe, Pb, Al, Mn, Zn and Ni (Cd > Cu > Fe > Pb > Al > Mn > Zn > Ni). Comparison of LC(50) values for metals for this species with those for other freshwater midges reveals that C. javanus is equally or more sensitive to metals than most other tested dipteran.

  9. Estado del conocimiento taxonómico de la fauna de Chironomidae (Diptera: Nematocera de la Patagonia Current state of the taxonomic knowledge of the Chironomidae fauna (Diptera: Nematocera from Patagonia

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    Mariano Donato

    2009-06-01

    Full Text Available La familia Chironomidae (Diptera: Nematocera es uno de los grupos de insectos más ampliamente distribuidos y abundantes en cuerpos de agua dulce. Los representantes de esta familia pueden explotar áreas con amplios gradientes ambientales. La información que se presenta está basada en la recopilación de datos distribucionales bibliográficos, del estudio del material tipo de las especies de Chironomidae depositadas en el Natural History Museum (UK y del material de colección del Museo de La Plata (Argentina. En la Patagonia, se registran 9 subfamilias, la subfamilia monotípica Chilenomyiinae es endémica de esta área. Dentro de estas subfamilias, 53 de los 111 géneros conocidos para América del Sur están presentes en la Patagonia. Del total de géneros de la Patagonia, el 20 % es endémico y 7 de ellos muestran relaciones transantárticas. En la Patagonia, se registran 177 especies de Chironomidae, el 98% de éstas son endémicas, el 3 % son consideradas nomina dubia y el 17% requiere revisión ya que su ubicación sistemática es dudosa. Las descripciones originales de las especies patagónicas de Chironomidae están basadas principalmente sobre machos (n=58 y machos y hembras (n=43, ambas representan el 57% del total; el resto de las especies han sido descriptas con diferentes combinaciones de estadios del ciclo de desarrollo.The Chironomidae (Diptera: Nematocera family is one of the most widely distributed group of insects and often the most abundant in freshwater environments. Representatives of this family can exploit a wide range of environmental gradients. The information here presented is based on the compilation of distributional data obtained from bibliography, the study of the type material deposited in the Natural History Museum (UK and the collection material from Museo de La Plata (Argentina. Nine subfamilies are recorded from Patagonia, being the monotypic subfamily Chilenomyiinae endemic for the area. From the 111 known

  10. High altitude Chironomidae (Diptera of Serra da Estrela (Portugal: Additions to the Portuguese and Iberian Peninsula fauna

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    Rieradevall, M.

    2007-12-01

    Full Text Available A Chironomidae (Diptera fauna list for headwater streams of high altitude areas in Serra da Estrela (Portugal is presented, doubling the previously established species richness for the region. The findings include 17 new records for Portugal, which represent an increase to 219 species for the Continental Portugal Chironomidae fauna. Two new records were detected for the Iberian Peninsula: one species (Tvetenia duodenaria, and one subgenus –Psectrocladius (Mesopsectrocladius–; and the presence of the genus Natarsia is confirmed. The last two occurrences correspond to monoespecific taxa of the Palearctic region. However, as taxonomic identification has been based on larval material, instead of pupae, pupal exuviae or imagoes, species level assignment is still uncertain.

    Se presenta una lista de especies de Chironomidae (Diptera recolectadas en los ríos de cabecera de zonas de alta montaña en la Serra da Estrela (Portugal. Con esta aportación se duplica la riqueza de especies regional conocida hasta el momento y se eleva la fauna de quironómidos del Portugal continental a 219 especies. Se incluyen dos nuevas citas para la Península Ibérica, una especie (Tvetenia duodenaria y un subgénero –Psectrocladius (Mesopsectrocladius–, y se confirma la presencia del género Natarsia. En los dos últimos casos se trata de larvas de taxones hasta el momento monoespecíficos en la región paleárctica, pero al no haberse recolectado pupas o adultos no se puede asegurar la identificación específica.

  11. The Chironomidae collection at the Zoological Institute (St Petersburg: history, current state and role for further research

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    Andrey Przhiboro

    2012-10-01

    Full Text Available This paper briefly reviews the collection of Chironomidae (Diptera housed at the Zoological Institute of Russian Academy of Sciences in St Petersburg (ZIN. Although it is the oldest and one of the largest Chironomidae collections in Russia, most of the collection has been unknown to specialists for decades. The collection consists of three main parts: dry specimens (about 20000 pinned adults, material in ethanol (over 25000 vials with larvae, pupae and adults and permanent slides (over 12000 slides with larvae, pupae and adults. Based on a study of the collection itself, published sources and archival data, major periods for the formation of the collection are here described. Collectors and expeditions, whose contributions were most important, are listed, as well as the regions where the material was collected. The role of chironomid researchers, who made important contributions to the creation, enrichment or study of the collection, is also described. The contributions by Aleksei Chernovskii and Vera Pankratova are considered in more detail. According to a preliminary estimate, the collection contains type specimens of no less than 150 species described by 24 authors, and thousands of specimens determined by experts. The Chironomidae collection of ZIN is particularly important because it hopefully will enable us to correctly interpret many species names proposed in 1930-1980’s, mostly based on brief descriptions of larvae and currently often considered nomina dubia. In addition, the collection includes the unprocessed material from vast territory of the former Soviet Union, including many distant regions, which are still difficult to access. doi: 10.5324/fn.v31i0.1402.Published online: 17 October 2012.

  12. Genome Instability of Chironomus riparius Mg. (Diptera, Chironomidae from Polluted Water Basins in Bulgaria

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    Julia Ilkova

    2014-04-01

    Full Text Available Larvae of Chironomus riparius Mg. (Chironomidae, Diptera collected from two polluted water basins in Bulgaria, the Maritsa and Chaya Rivers (adjacent to Plovdiv and Asenovgrad respectively, a small pool (near Plovdiv plus controls reared in the laboratory were studied. High concentrations of the heavy metals Pb, Cu and Cd were recorded in the sediments of the polluted stations. Marked somatic structural chromosome aberrations were found in C. riparius salivary polytene chromosomes from the field stations and their frequency was significantly higher (p<0.01 compared to the control. The observed somatic chromosome changes are discussed as a response of the chironomid genome to aquatic pollution. A new cytogenetic index based on the number of aberrations found in larvae from polluted regions in comparison with the control was applied to the data to more easily evaluate the degree of heavy metal pollution in aquatic ecosystems. Our study of a polluted site near the River Chaya showed that the somatic index was very high at 3.35 for 2010 and 11.66 for 2013 compared to 0.5 in the control. The cytogenetic index was effective in showing that all studied sites were highly polluted in comparison with the control. To determine the mechanism involved in the concentration of aberration breakpoints within specific regions of the chironomid polytene chromosome the FISH method was applied. The localization of a transposable element TFB1 along the polytene chromosomes of C. riparius was analyzed and the sites of localization were compared with breakpoints of chromosome aberrations. A significant correlation (p<0.05 was found which shows that most of the aberrations do not appear randomly but are concentrated in sites rich in transposable elements.

  13. Composition and structure of the Chironomidae (Insecta: Diptera) community associated with bryophytes in a first-order stream in the Atlantic forest, Brazil.

    Science.gov (United States)

    Rosa, B F J V; Dias-Silva, M V D; Alves, R G

    2013-02-01

    This study describes the structure of the Chironomidae community associated with bryophytes in a first-order stream located in a biological reserve of the Atlantic Forest, during two seasons. Samples of bryophytes adhered to rocks along a 100-m stretch of the stream were removed with a metal blade, and 200-mL pots were filled with the samples. The numerical density (individuals per gram of dry weight), Shannon's diversity index, Pielou's evenness index, the dominance index (DI), and estimated richness were calculated for each collection period (dry and rainy). Linear regression analysis was employed to test the existence of a correlation between rainfall and the individual's density and richness. The high numerical density and richness of Chironomidae taxa observed are probably related to the peculiar conditions of the bryophyte habitat. The retention of larvae during periods of higher rainfall contributed to the high density and richness of Chironomidae larvae. The rarefaction analysis showed higher richness in the rainy season related to the greater retention of food particles. The data from this study show that bryophytes provide stable habitats for the colonization by and refuge of Chironomidae larvae, mainly under conductions of faster water flow and higher precipitation.

  14. A Guide to Basic Taxonomic Literature for the Genera of North American Chironomidae (Diptera) - Adults, Pupae, and Larvae. Bulletin No. 447.

    Science.gov (United States)

    Simpson, Karl W.

    A generic list of North American Chironomidae (Diptera) is presented to help aquatic biologists quickly locate important taxonomic references for the adults, larvae, and pupae of each genus. The list (in chart format) includes literature published through 1981. When recent literature is available, older references are omitted, since the purpose of…

  15. Preliminary Study of Phylogenetic Relationship of Rice Field Chironomidae (Diptera Inferred From DNA Sequences of Mitochondrial Cytochrome Oxidase Subunit I

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    Salman A. Al-Shami

    2009-01-01

    Full Text Available Problem statement: Chironomidae have been recorded in rice fields throughout the world including in many countries such as India, Australia and the USA. Although some studies provide the key to genera level and note the difficulty of identifying the larvae to species level. Chironomid researches have been hindered because of difficulties in specimen preparation, identification, morphology and literature. Systematics, phylogenetics and taxonomic studies of insects developed quickly with emergence of molecular techniques. These techniques provide an effective tool toward more accurate identification of ambiguous chironomid species. Approach: Samples of chironomids larvae were collected from rice plots at Bukit Merah Agricultural Experimental Station (BMAES, Penang, Malaysia. A 710 bp fragment of mitochondrial gene Cytochrome Oxidase subunit I (COI was amplified and sequenced. Results: Five species of Chironomidae; three species of subfamily Chironominae, Chironomus kiiensis, Polypedilum trigonus, Tanytarsus formosanus, two species of subfamily Tanypodinae, Clinotanypus sp and Tanypus punctipennis were morphologically identified. The phylogenetic relationship among these species was been investigated. High sequence divergence was observed between two individuals of the presumed C. kiiensis and it is suggested that more than one species may be present. However the intraspecific sequence divergence was lower between the other species of Tanypodinae subfamily. Interestingly, Tanytarsus formosanus showed close phylogenetic relationship to Tanypodinae species and this presumably reflect co-evolutionary traits of different subfamilies. Conclusion: The sequence of the mtDNA cytochrome oxidase subunit I gene has proven useful to investigate the phylogenetic relationship among the ambiguous species of chironomids.

  16. The direct and indirect effects of a glyphosate-based herbicide and nutrients on Chironomidae (Diptera) emerging from small wetlands.

    Science.gov (United States)

    Baker, Leanne F; Mudge, Joseph F; Houlahan, Jeff E; Thompson, Dean G; Kidd, Karen A

    2014-09-01

    Laboratory and mesocosm experiments have demonstrated that some glyphosate-based herbicides can have negative effects on benthic invertebrate species. Although these herbicides are among the most widely used in agriculture, there have been few multiple-stressor, natural system-based investigations of the impacts of glyphosate-based herbicides in combination with fertilizers on the emergence patterns of chironomids from wetlands. Using a replicated, split-wetland experiment, the authors examined the effects of 2 nominal concentrations (2.88 mg acid equivalents/L and 0.21 mg acid equivalents/L) of the glyphosate herbicide Roundup WeatherMax, alone or in combination with nutrient additions, on the emergence of Chironomidae (Diptera) before and after herbicide-induced damage to macrophytes. There were no direct effects of treatment on the structure of the Chironomidae community or on the overall emergence rates. However, after macrophyte cover declined as a result of herbicide application, there were statistically significant increases in emergence in all but the highest herbicide treatment, which had also received no nutrients. There was a negative relationship between chironomid abundance and macrophyte cover on the treated sides of wetlands. Fertilizer application did not appear to compound the effects of the herbicide treatments. Although direct toxicity of Roundup WeatherMax was not apparent, the authors observed longer-term impacts, suggesting that the indirect effects of this herbicide deserve more consideration when assessing the ecological risk of using herbicides in proximity to wetlands.

  17. First record of larvae of Chironomidae (Insecta, Diptera as prey of Temnocephala sp. (Platyhelminthes, Temnocephalidae, an ectosymbiont on larvae of Corydalidae (Megaloptera Primeiro registro de larvas de Chironomidae como presas de Temnocephala sp. (Platyhelminthes, Temnocephalidae, um ectosimbionte de larvas de Corydalidae (Maegaloptera

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    Susana Trivinho-Strixino

    2012-09-01

    Full Text Available First record of larvae of Chironomidae (Insecta, Diptera as prey of Temnocephala sp. (Platyhelminthes, Temnocephalidae, an ectosymbiont on larvae of Corydalidae (Megaloptera. This study constitutes the first record of Temnocephala Blanchard, an ectosymbiont on Corydalidae, as a possible predator of chironomid larvae. Twenty-eight Corydalidae larvae (Corydalus and Protochauliodes were examined under stereomicroscopic in search for Temnocephala and Chironomidae larvae, of which five megalopteran larvae had 24 Temnocephala sp. associated. Furthermore, eight of these Temnocephala worms had chironomid larvae in their gut contents, an interaction previously unknown. Gut content analyses revealed Corynoneura as the commonest chironomid, but larvae of Larsia, Rheotanytarsus and Tanytarsus were recorded as well. This study included Corydalus and Protochauliodes as hosts for Temnocephala, which might be important for this worm dispersion and population dynamics.Primeiro registro de larvas de Chironomidae como presas de Temnocephala sp. (Platyhelminthes, Temnocephalidae, um ectosimbionte de larvas de Corydalidae (Maegaloptera. Este estudo constitui o primeiro registro de Temnocephala Blanchard (Platyhelminthes, Temnocephalidae, um ectosimbionte em larvas de Megaloptera, como um possível predador de larvas de Chironomidae. Vinte e oito larvas de Corydalidae (Corydalus e Protochauliodes foram examinadas sobre estereomicroscópio na busca por Temnocephala e larvas de Chironomidae, das quais cinco larvas de Megaloptera continham 24 Temnocephala sp. associadas. Além disso, oito Temnocephala possuíam em seu conteúdo estomacal larvas de Chironomidae, uma interação desconhecida anteriormente. A análise do conteúdo estomacal revelou Corynoneura como o quironomídeo mais abundante, e também algumas larvas de Larsia, Rheotanytarsus e Tanytarsus. Este estudo inclui Corydalus e Protochauliodes como hospedeiros de Temnocephala, os quais podem ser importantes

  18. Setting the reference for the use of Chironomus sancticaroli (Diptera: Chironomidae as bioindicator: Ontogenetic pattern of larval head structures

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    Débora Rebechi

    2012-04-01

    Full Text Available Species of Chironomidae are widely used as bioindicators of water quality, since their larvae undergo morphological deformities when in contact with sediment contaminated with chemicals. In this work we endeavored to study the morphology of head structures (antennae, mandible, mentum, pecten epipharyngis, ventromental plate and premandible throughout the development of the four larval instars of Chironomus sancticaroli Strixino & Strixino, 1981, which can be used in environmental impact analyses. Our results show that it is possible to differentiate among larval instars by doing a quantitative analysis on the number of striae on the ventromental plates. The six structures analyzed changed during larval ontogeny. These changes are part of the ontogeny of the immature stages not exposed to xenobiotics. We believe that the morphological pattern defined in this work can be used for comparisons with ontogenetic changes observed in field studies conducted in polluted environments.

  19. [Chromosomal variation in Chironomus plumosus L. (Diptera, Chironomidae) from populations of Bryansk region, Saratov region (Russia), and Gomel region (Belarus)].

    Science.gov (United States)

    Belyanina, S I

    2015-02-01

    Cytogenetic analysis was performed on samples of Chironomus plumosus L. (Diptera, Chironomidae) taken from waterbodies of various types in Bryansk region (Russia) and Gomel region (Belarus). Karyotypes of specimens taken from stream pools of the Volga were used as reference samples. The populations of Bryansk and Gomel regions (except for a population of Lake Strativa in Starodubskii district, Bryansk region) exhibit broad structural variation, including somatic mosaicism for morphotypes of the salivary gland chromosome set, decondensation of telomeric sites, and the presence of small structural changes, as opposed to populations of Saratov region. As compared with Saratov and Bryansk regions, the Balbiani ring in the B-arm of chromosome I is repressed in populations of Gomel region. It is concluded that the chromosome set of Ch. plumosus in a range of waterbodies of Bryansk and Gomel regions is unstable.

  20. From the Gut of an Insect to the Global Climate: Denitrification and Nitrous Oxide Production inside Lake Chironomidae

    DEFF Research Database (Denmark)

    Stief, Peter; Nielsen, Lars Peter; Revsbech, Niels Peter

    2006-01-01

    FROM THE GUT OF AN INSECT TO THE GLOBAL CLIMATE: DENITRIFICATION AND NITROUS OXIDE PRODUCTION INSIDE LAKE CHIRONOMIDAE P. Stief, L.P. Nielsen, N.P. Revsbech, A. Schramm Department of Biological Sciences, Microbiology, University of Aarhus, Denmark Denitrifying bacteria in lake sediments drive...... an environmentally relevant ecosystem function by reducing nitrate to dinitrogen gas. Thereby, they remove inorganic nitrogen that originates from organic matter mineralisation and anthropogenic pollution. Nitrous oxide, a greenhouse gas 300 times more potent than carbon dioxide, is emitted from lakes only...... as a minor fraction of the nitrate reduced. However, when lake sediments are densely colonised by macrofauna, the rates of nitrous oxide emission increase significantly. We hypothesise that the guts of bacterivorous macrofauna represent short-term habitats in which high denitrification activity...

  1. Chironomidae (Insecta: Diptera from the eastern Canadian Arctic and subarctic with descriptions of new life stages, a possible new genus, and new geographical records

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    A. Namayandeh

    2016-08-01

    Full Text Available Chironomidae larvae constituted the largest proportion of benthic invertebrates collected from 99 rivers stretching from northern Labrador (latitude 58°N to northern parts of Ellesmere Island (82°N. We describe 92 species of Chironomidae (mainly larval forms providing new descriptions, a revision for the adult female of Parametriocnemus boreoalpinus Gowin et Thienemann, a possible new genus (larval form only, and 9 larval forms that may represent a new species. In addition, new geographical distribution records are specified for 1 Nearctic species, 6 species in Canada, 10 for Labrador, and 17 for Nunavut. This work contributes to Environment Canada’s International Polar Year output (2007-2009.

  2. First record of larvae of Chironomidae (Insecta, Diptera as prey of Temnocephala sp. (Platyhelminthes, Temnocephalidae, an ectosymbiont on larvae of Corydalidae (Megaloptera

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    Susana Trivinho-Strixino

    2012-09-01

    Full Text Available First record of larvae of Chironomidae (Insecta, Diptera as prey of Temnocephala sp. (Platyhelminthes, Temnocephalidae, an ectosymbiont on larvae of Corydalidae (Megaloptera. This study constitutes the first record of Temnocephala Blanchard, an ectosymbiont on Corydalidae, as a possible predator of chironomid larvae. Twenty-eight Corydalidae larvae (Corydalus and Protochauliodes were examined under stereomicroscopic in search for Temnocephala and Chironomidae larvae, of which five megalopteran larvae had 24 Temnocephala sp. associated. Furthermore, eight of these Temnocephala worms had chironomid larvae in their gut contents, an interaction previously unknown. Gut content analyses revealed Corynoneura as the commonest chironomid, but larvae of Larsia, Rheotanytarsus and Tanytarsus were recorded as well. This study included Corydalus and Protochauliodes as hosts for Temnocephala, which might be important for this worm dispersion and population dynamics.

  3. Application of kinetic model of bioaccumulation across a pH and salinity gradient for the prediction of cadmium uptake by the sediment dwelling Chironomidae

    Energy Technology Data Exchange (ETDEWEB)

    Bendell-Young, L.I. [Simon Fraser Univ., Burnaby, British Columbia (Canada). Dept. of Biological Sciences

    1999-05-01

    A kinetic model for the prediction of metal concentrations in aquatic organisms was applied for the prediction of cadmium concentrations in the sediment dwelling dipertan larvae, Chironomidae. Cadmium concentrations were determined in Chironomidae sampled along two distinct environmental gradients: (1) an acidity gradient (from pH 5.0--6.5) and (2) a salinity gradient. Comparison of predicted and observed values indicated that the kinetic model was successful in predicting concentrations in chironomids sampled along the acidity gradient but not the salinity gradient. Separation of routes of cadmium uptake into food and solute sources indicated that ingested sediment accounted for 60--100% of total invertebrate cadmium concentrations, however, the relative importance of water increased as a function of decreasing acidity and salinity. These results support the refinement of a kinetic model for predicting cadmium concentrations in sediment-living invertebrates, such as Chironomidae. By allowing for uptake from food and water the model highlighted the potential for routes of cadmium uptake to be pH and salinity dependent. For monitoring purposes, both vectors and the potential for the relative importance for each vector to change needs to be considered when assessing the degree of metal exposure to sediment ingesting invertebrates which inhabit systems with either a natural or anthropogenically induced garment in key water chemistry variables such as salinity or pH.

  4. Emergence, growth, and dispersal of Chironomidae in reclaimed wetlands in the Athabasca oil sands region of Alberta

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, K.; Ciborowski, J. [Windsor Univ., ON (Canada)

    2010-07-01

    Concerns over the environmental impacts of oil sands extraction in northeastern Alberta has increased as the industry continues to expand. This study examined if the emergence, growth, and dispersal of Chironomidae differ in reclaimed wetlands constructed with oil sands process materials (OSPM) when compared with growth in reference wetlands. Five floating 30 cm diameter halo traps were deployed in various wetlands for a 24 hour period. Exuviae trapped in the surface water film were then collected, identified, and counted. Chironomids grown in laboratories from egg masses collected from 2 OSPM-affected wetlands and 2 reference wetlands were paired according to geographic proximity under controlled conditions for 1 generation. Chironomid larval growth was quantified in situ in the wetlands by reciprocally transferring second instar, second generation culture larva. The dispersal of the larvae was quantified by tabulating the number of adults caught in sticky insect traps located along 3 radially-arranged transects in each wetland. A preliminary analysis has suggested that fewer chironomids emerged from the OSPM-affected wetlands. No differences in dispersal distance between the OSPM-affected and reference wetlands were observed.

  5. Time-Efficiency of Sorting Chironomidae Surface-Floating Pupal Exuviae Samples from Urban Trout Streams in Northeast Minnesota, USA

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    Alyssa M Anderson

    2012-10-01

    Full Text Available Collections of Chironomidae surface-floating pupal exuviae (SFPE provide an effective means of assessing water quality in streams. Although not widely used in the United States, the technique is not new and has been shown to be more cost-efficient than traditional dip-net sampling techniques in organically enriched stream in an urban landscape. The intent of this research was to document the efficiency of sorting SFPE samples relative to dip-net samples in trout streams with catchments varying in amount of urbanization and differences in impervious surface. Samples of both SFPE and dip-nets were collected from 17 sample sites located on 12 trout streams in Duluth, MN, USA. We quantified time needed to sort subsamples of 100 macroinvertebrates from dip-net samples, and less than or greater than 100 chironomid exuviae from SFPE samples. For larger samples of SFPE, the time required to subsample up to 300 exuviae was also recorded. The average time to sort subsamples of 100 specimens was 22.5 minutes for SFPE samples, compared to 32.7 minutes for 100 macroinvertebrates in dip-net samples. Average time to sort up to 300 exuviae was 37.7 minutes. These results indicate that sorting SFPE samples is more time-efficient than traditional dip-net techniques in trout streams with varying catchment characteristics.doi: 10.5324/fn.v31i0.1380.Published online: 17 October 2012.

  6. The influence of supplement feed preparation on the fatty acid composition of carp and Chironomidae larvae in a semi-intensive production system

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    Živić Ivana

    2013-01-01

    Full Text Available In order to examine how extruded and pelleted feed affects the fatty acid composition of carp meat and Chironomidae larvae, two-month-old carp specimens were set in two fishponds (L1 and L2. The fatty acid composition of extruded and pelleted feed is characterized by a significantly higher content of ω-3 fatty acids and higher ω-3 to ω-6 fatty acids ratio (ω-3/ω-6 in extruded (11.34±0.12% and 0.315±0.005, respectively compared to pelleted feed (7.72±0.08%, 0.180±0.001, respectively. The fatty acid composition of carp meat is characterized by higher ω-3 fatty acid content and ω-3/ω-6 in carp fed with extruded feed (L1, 6.98±0.53% and 0.295±0.022, respectively compared to carp fed with extruded feed (L2, 5.46±0.07% and 0.232±0.009, respectively. Chironomidae larvae from the fishpond L2 had significantly higher ω-3 fatty acid content (8.22±0.89%, and therefore higher ω-3/ω-6 (0.81±0.09 in comparison to Chironomidae from the L1 fishpond where these parameters were 4.48±0.06% and 0.21±0.01, respectively. [Projekat Ministarstva nauke Republike Srbije, br. TR 31075 i br. 173040

  7. Distribución espacio-temporal de larvas de Chironomidae (Diptera en un arroyo andino (Uspallata, Mendoza, Argentina Spatial and temporal distribution of larvae of Chironomidae (Diptera in an Andean stream (Uspallata, Mendoza, Argentina

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    Erica E. Scheibler

    2008-12-01

    Full Text Available Se realizó un estudio sobre la composición larval de la familia Chironomidae en un arroyo andino en la localidad de Uspallata (Mendoza, Argentina. Se realizaron muestreos estacionales durante un ciclo anual completo (2001/2002 en tres sitios, siguiendo un gradiente altitudinal. Se midieron variables físico-químicas en campo y laboratorio. La relación entre presencia y abundancia de quironómidos y parámetros ambientales se exploró mediante un análisis de Correspondencia Canónica. Se identificaron siete géneros pertenecientes a cuatro subfamilias: Chironominae, Orthocladiinae, Podonominae y Tanypodinae. Orthocladiinae fue la subfamilia que tuvo mayor riqueza genérica (Cricotopus van der Wulp, Onconeura Andersen & Saether y Parametriocnemus Goetghebuer, densidad y frecuencia de aparición a nivel estacional y espacial. Podonominae (Podonomus Philippi y Podonomopsis Brundin se halló únicamente en SA mientras que Chironominae (Polypedilum Kieffer estuvo presente en UD. Tanypodinae (Pentaneura Philippi se encontró en los tres sitios de muestreo aunque con una densidad menor. Se detectó incremento de la conductividad y temperatura del agua, y disminución del tamaño del sustrato desde SA a UD, lo que coincide con la desaparición de Podonomus y Podonomopsis y la aparición de Polypedilum hacia UD. De este estudio se concluye que el sistema presenta baja riqueza genérica comparada con otros sistemas montañosos de Argentina.A study was conducted on the larval composition of the family Chironomidae in an Andean stream in Uspallata locality (Mendoza, Argentina. Seasonal samplings were performed over a full annual cycle (2001/2002 at three sites, along an altitudinal gradient. Physical and chemical variables were measured in both the field and the laboratory. Relationship between presence and abundance of chironomids and environmental parameters was explored using a Canonical Correspondence analysis. Seven genera were identified

  8. Larvas de Chironomidae arvas (Diptera da planície de inundação do alto rio Paraná: distribuição e composição em diferentes ambientes e períodos hidrológicos = Chironomidae larvae (Diptera from the upper Paraná river floodplain: distribution and composition in different environments and hydrological periods

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    Gisele Cristina Rosin

    2007-01-01

    Full Text Available O presente estudo teve por objetivos, identificar possíveis diferenças na estrutura da comunidade de larvas de Chironomidae em quatro ambientes da planície de inundação do alto rio Paraná com diferentes características e analisar a influência dos fatores abióticos e das variações do nível hidrométrico sobre a comunidade. As coletas foram realizadas em março e setembro de 2003. Em cada um dos 12 pontos coletados foram realizadas quatro amostragens: três para análise biológica e uma para análise sedimentológica. O material biológico foi lavado em conjunto de peneiras com malhas de abertura 2, 1 e 0,2 mm e fixado em álcool 70%. As larvas de Chironomidae foram identificadas até a categoria de gênero. Foram encontradas 1478larvas de Chironomidae pertencentes a 19 gêneros. Polypedilum, Tanytarsus e Chironomus foram registrados em todos os ambientes. As maiores densidades e diversidade de Chironomidae foram registradas nos períodos de águas baixas, especialmente em ambientes lênticos. Avariação da densidade, dominância e diversidade de Chironomidae entre as duas coletas foi influenciada, principalmente, pelo ciclo hidrológico e pelo oxigênio dissolvido, enquanto que a variação espacial esteve associada ao tipo de sedimento, porcentagem de matéria orgânica e a presença ou ausência de macrófitas aquáticas.The present study had the aim to identify possible differences in the community structure of Chironomidae larvae in four different environments of the upper Paraná river floodplain with different characteristics and to analyze the influence of abiotic factors and variations in the hydrometric level of the community. Samplings were carried out in March and September, 2003. Four samplings were taken from each of the 12 collecting points: three for biological analysis and one for sediment analysis. Biological contents were washed with the aid of a system with 2.0; 1.0 and 0.2 mm sieves. Chironomidae larvae were

  9. Surface-Floating Pupal Exuviae of Chironomidae (Diptera in Urban Streams: is There a Best Time of Day to Sample Them?

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    Herick Santana

    2016-08-01

    Resumo. O uso de exúvias de pupa é um método que permite avaliar condições ambientais utilizando informações da diversidade de Chironomidae. Exúvias de pupas podem se dispersar em distâncias de até 100 m dos locais onde os adultos emergiram, permitindo realizar estudos sobre a comunidade local. O objetivo deste estudo foi verificar se existem diferenças na riqueza taxonômica e abundância em exúvias surgidas de pupa de Chironomidae durante diferentes períodos do dia em córregos urbanos do Bioma Cerrado. As amostras foram coletadas na estação seca de julho de 2011, em três riachos de primeira ordem localizados próximos à cidade de Anápolis, Goiás, Brasil, utilizando redes de deriva por um período que variou de 8-20 h, com remoção e substituição das redes a cada duas horas. Foram coletadas 6129 exúvias nos três córregos e os gêneros Onconeura e Polypedilum totalizaram 70% de todos os indivíduos coletados. O horário de 16 h foi o mais representativo em relação ao número de exuvias coletadas, enquanto que as exúvias coletadas às 8 h foram menos abundantes. A riqueza e a abundância de gêneros de exúvias não apresentaram mudanças de acordo com o horário do dia nos córregos estudados, indicando que não existe um período no qual há uma maior frequência de aparecimento de Chironomidae adulto.

  10. Chironomidae (Diptera in the Himalayan Lakes – A study of sub-fossil assemblages in the sediments of two high altitude lakes from Nepal

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    Subodh Sharma

    2012-11-01

    Full Text Available Chironomid head capsules were identified from sediment cores taken from Lake Gokyo (4750 m and Lake Gosaikunda (4350 m in the east-central Himalaya, to determine taxonomic composition of chironomid assemblages over time.  The sedimentation rate of Lake Gosaikunda was estimated at 0.05 cm/yr and that of Gokyo was estimated at 0.07 cm/yr by 210Pb and 137Cs dating.  Micropsectra sp. was dominant in the sediments of both lakes.  Lake Gokyo sediments also contained Pseudodiamesa sp., Eukiefferiella/Tvetenia sp., Orthocladius/Cricotopus sp. and Rheocricotopus sp.  The concentration of headcapsules was nearly an order of magnitude greater in the Lake Gosaikunda core, which contained mostly Micropsectra sp. and Pseudodiamesa sp.  These taxa are typical of cold oligotrophic lakes.  Differences in lake depth, dissolved minerals, plus epi- and hypolimnetic temperature and dissolved oxygen suggest that stratification and temperature-induced increases in primary production may affect chironomid assemblages in these pristine lakes.  Palaeolimnological studies of Himalayan lakes should include replicate cores within lake, to increase headcapsule sample sizes given potentially high rates of sedimentation from glacial runoff. Key words: high altitude lakes, Himalaya, Chironomidae, palaeolimnology, Nepal

  11. Análise da dieta das larvas de 4º estádio de Cricotopus sp. (Diptera: Chironomidae, em diferentes substratos artificiais e fases hídricas, no trecho superior do rio Paraná = Diet analysis of Cricotopus sp. larvae (Diptera: Chironomidae, fourth stage, in different artificial substrates and hydrological phases, in the upper Paraná river

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    Adriana Felix dos Anjos

    2009-10-01

    Full Text Available No Brasil, estudos sobre hábitos alimentares das larvas de Chironomidae ainda são escassos e estas informações são importantes para entender a estrutura trófica e a organização dos ecossistemas aquáticos. Neste estudo, teve-se como objetivo identificar osprincipais itens alimentares ingeridos por Cricotopus sp. e comparar as possíveis diferenças na dieta das larvas em diferentes substratos artificiais e fases hídricas. Foram utilizados quatro tipos de substratos artificiais: madeira em forma de X (MADX, placas de nitacetal em forma de X (NITX, PVC em forma de tubo (PVCT e metal galvanizado em forma de tubo (METT, cada um com três réplicas. As coletas foram realizadas quinzenalmente, entre os meses de agosto de 2004 e dezembro de 2005. A dieta de Cricotopus sp. foi constituída por detritos, algas e hifas de fungos. Detrito foi o principal item alimentar, com valores superiores a 50% do total consumido. Os resultados indicaram que Cricotopus sp. é uma espécie coletora e, independentemente do substrato, as larvas alimentam-se dos recursos disponíveis no ambiente. Entretanto, mudanças no regime hidrológico do rio Paraná podem influenciar a disponibilidade de alimento, principalmente algumas diatomaceas como Melosira sp., consumidas em maior quantidade apenas na fase de águas baixas.In Brazil, studies on the diet of Chironomidae larvae are still scarce and these data are important to understand the trophic structure and organization of aquatic ecosystems. In this study, we identified the main food items consumed by Cricotopus sp. and compared possible differences in the larval diet at different artificial substrates and hydrological phases. We used four types of artificial substrates: X-shaped wood (MADX; X-shaped nitacetal plates (NITX; tube-shaped PVC (PVCT and tube-shaped galvanizedmetal (METT, each with three replicates. Samplings were undertaken fortnightly, between August 2004 and December 2005. Cricotopus sp. diet was

  12. Leaf litter as a possible food source for chironomids (Diptera in Brazilian and Portuguese headwater streams Detritos foliares como possível fonte de alimento para Chironomidae (Diptera em riachos de cabeceira brasileiros e portugueses

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    Marcos Callisto

    2007-06-01

    Full Text Available Our objective was to evaluate the potential use of leaf detritus by chironomid larvae. Field and laboratory experiments were performed using leaves and chironomid species collected in Portugal and Brazil. Laboratory experiments under controlled conditions were done using microbial conditioned senescent leaves of Alnus glutinosa (L. Gaertn, Neriumoleander L., Protium heptaphilum (Aubl. March, Protium brasiliense (Spreng Engl., Myrcia guyanensis(Aubl. DC and Miconia chartacea Triana. Laboratory experiments were performed using specimens collected from leaf litter in local streams. Whenever possible, after the experiments, chironomids were allowed to emerge as adults and identified. In Portugal the following taxa were identified: Micropsectra apposita (Walker, 1856, Polypedilum albicorne (Meigen, 1838,Eukiefferiella claripennis Lundbeck (1898, Rheocricotopus (Psilocricotopus atripes Rempel (1937 and Ablabesmyia Johannsen (1905 (Diptera, Chironomidae. Consumption rates ranged from 0.15 ± 0.10 mg (AFDM of leaf animal-1 day-1 (Micropsectra apposita feeding on Alnus glutinosa up to 0.85 ± 0.33 mg (AFDM of leaf animal-1 day-1 (Polypedilum albicorne feeding on Miconia chartacea. In Brazil, the following taxa were identified from leaves: Phaenopsectra sp., Chironomus spp. and Polypedilum sp. and maximum consumption rates reached 0.47 ± 0.28 (AFDM of leaf mg.animal-1.day-1 (Chironomus Meigen (1803 feeding on Protium heptaphilum. Feeding experiments with laboratory cultured specimens, revealed that some chironomids were unable to feed on decomposing leaves (e.g., C. xanthus Rempel (1939 on P.brasiliensis and M.guyanensis. Our results suggest that some stream chironomids (not typical shredders can use leaf litter of riparian vegetation as a complementary food source.O objetivo foi avaliar o potencial uso de detritos foliares por larvas de Chironomidae. Foram realizados experimentos em campo e em laboratório utilizando folhas e larvas de Chironomidae

  13. Late Quaternary Environmental Changes Inferred from the stable Oxygen Isotope Composition of Aquatic Insects (Chironomidae: Diptera) and Stable Hydrogen Isotope Composition of bulk sediments from Idavain Lake, Southwest Alaska

    Science.gov (United States)

    Wang, Y.; Finney, B.; Wooller, M. J.

    2007-12-01

    Several techniques are available to examine the isotopic composition of historic lake waters, providing data that can subsequently be used to examine environmental changes. Recently-developed techniques are the stable oxygen isotope analysis of subfossil chironomid (Diptera: Chironomidae) head capsules (mostly chitin) preserved in lake sediments and stable hydrogen isotope analyses directly on bulk sediments. An advantage of using δ18O of chironomids is that the chitinous chironomid headcapsules preserve well in lake sediments, retaining the stable oxygen isotope signature of the lake in which they lived. An advantage of δD analyses of bulk sediments is that a sediment core can be analyzed relatively easily and when the %C (total organic carbon) and %H profiles correlate the data can be used to infer past δD changes of the organics in the sediments. We present results from these analyses of a lake sediment core from Idavain Lake (58°46'N, 155°57'W, 223m above sea level) in southwest Alaska in concert with other paleolimnological proxies, including δ15N, δ13C, LOI, magnetic susceptibility, organic content and opal concentrations for a better understanding of paleolimnological changes since deglaciation for the region. Our preliminilary result shows that downcore shifts of δ18O analyzed from chironomid head capsules coincide well with LOI and pollen changes. The δD of sediments and TOM showed large magnitude changes and reflected the relative lake level changes during the record. This study aim to test the correlation between stable isotope analyese on chiornomid head capsules, lake water, and bulk sediments. In the addition, our study will add to the relatively small database of paleoenvironmental reconstructions from terrestrial sites in Southwest Alaska.

  14. Análise da dieta das larvas de 4º estádio de Cricotopus sp. (Diptera: Chironomidae, em diferentes substratos artificiais e fases hídricas, no trecho superior do rio Paraná - DOI: 10.4025/actascibiolsci.v31i4.3522 Diet analysis of Cricotopus sp. larvae (Diptera: Chironomidae, fourth stage, in different artificial substrates and hydrological phases, in the upper Paraná river - DOI: 10.4025/actascibiolsci.v31i4.3522

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    Alice Michiyo Takeda

    2009-08-01

    Full Text Available No Brasil, estudos sobre hábitos alimentares das larvas de Chironomidae ainda são escassos e estas informações são importantes para entender a estrutura trófica e a organização dos ecossistemas aquáticos. Neste estudo, teve-se como objetivo identificar os principais itens alimentares ingeridos por Cricotopus sp. e comparar as possíveis diferenças na dieta das larvas em diferentes substratos artificiais e fases hídricas. Foram utilizados quatro tipos de substratos artificiais: madeira em forma de X (MADX, placas de nitacetal em forma de X (NITX, PVC em forma de tubo (PVCT e metal galvanizado em forma de tubo (METT, cada um com três réplicas. As coletas foram realizadas quinzenalmente, entre os meses de agosto de 2004 e dezembro de 2005. A dieta de Cricotopus sp. foi constituída por detritos, algas e hifas de fungos. Detrito foi o principal item alimentar, com valores superiores a 50% do total consumido. Os resultados indicaram que Cricotopus sp. é uma espécie coletora e, independentemente do substrato, as larvas alimentam-se dos recursos disponíveis no ambiente. Entretanto, mudanças no regime hidrológico do rio Paraná podem influenciar a disponibilidade de alimento, principalmente algumas diatomaceas como Melosira sp., consumidas em maior quantidade apenas na fase de águas baixasIn Brazil, studies on the diet of Chironomidae larvae are still scarce and these data are important to understand the trophic structure and organization of aquatic ecosystems. In this study, we identified the main food items consumed by Cricotopus sp. and compared possible differences in the larval diet at different artificial substrates and hydrological phases. We used four types of artificial substrates: X-shaped wood (MADX; X-shaped nitacetal plates (NITX; tube-shaped PVC (PVCT and tube-shaped galvanized metal (METT, each with three replicates. Samplings were undertaken fortnightly, between August 2004 and December 2005. Cricotopus sp. diet was

  15. Genotoxic effect of Phenanthrene on Chironomus sancticaroli (Diptera: Chironomidae

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    Gisele dos Santos Morais

    2014-08-01

    Full Text Available Phenanthrene, a Polycyclic Aromatic Hydrocarbon, remains adsorbed to sedimentary particles in aquatic environments. It affects mainly benthic organisms, and is considered potentially genotoxic. In ecotoxicology, species of Chironomus Meigen, 1803 are widely known as bioindicators of the effects of chemicals on aquatic organisms. This study investigates the effects of phenanthrene on the size of the head capsule of Chironomus sancticaroli Strixino & Strixino, 1981 larvae after chronic (eight days exposure, and DNA damage after acute (96 hours and chronic exposure (eight days, under laboratory conditions. DNA damage, evaluated using the alkaline comet assay, detected effects for both exposure periods, indicating that phenanthrene is toxic for C. sancticaroli. For the acute exposure, we analyzed five concentrations of phenanthrene, between 0.16 mg.l-1 and 1.60 mg.l-1, detecting significant differences (Kruskall-Wallis test with p < 0.05 in the degree of DNA damage in all groups. These effects were not dose-dependent. For the chronic exposure, two concentrations (0.16 mg.l-1, 0.83 mg.l-1 were analyzed, and DNA damage was observed in both. Again, the effects were not dose-dependent. This indicates that phenanthrene is genotoxic to larvae of C. sancticaroli even at low concentrations. The size of the head capsule was evaluated after chronic exposure to concentrations of 0.16 mg.l-1 and 0.83 mg.l-1. Significant differences (ANOVA test with p < 0.05 were detected in the two concentrations, and a reduction in the size of the larval head capsule was observed. This suggests that phenanthrene causes delay in larval development. These results indicate that phenanthrene affects the development of and causes DNA damage in C. sancticaroli larvae. Therefore, we suggest that C. sancticaroli can be used as a biological indicator for environmental contamination with phenanthrene.

  16. Parachironomus lenz from china and Japan (Diptera, chironomidae).

    Science.gov (United States)

    Yan, Chun-Cai; Yan, Jiao; Jiang, Li; Guo, Qin; Liu, Ting; Ge, Xin-Yu; Wang, Xin-Hua; Pan, Bao-Ping

    2015-01-01

    Members of the genus Parachironomus Lenz known from China and Japan are revised, and a key to their male adults is given. Parachironomuspoyangensis sp. n. is described in this life stage. Parachironomusfrequens (Johannsen) and Parachironomusmonochromus (van der Wulp) are recorded from China for the first time, thus are redescribed from Chinese specimens. Parachironomuskamaabeus Sasa & Tanaka and Parachironomustoneabeus Sasa & Tanaka are new junior synonyms of Parachironomusfrequens. Three Chinese or Japanese species formerly placed in Parachironomus are transferred to other genera, resulting in the new combinations Cryptochironomusinafegeus (Sasa, Kitami & Suzuki), Demicryptochironomus (Irmakia) lobus (Yan, Sæther, Jin & Wang), and Microchironomuslacteipennis (Kieffer). Chironomussauteri Kieffer, Parachironomuskisobilobalis Sasa & Kondo and Parachironomuskuramaexpandus Sasa are removed from Parachironomus; the last of these three denotes a valid species of uncertain generic placement, the first two are nomina dubia.

  17. Parachironomus Lenz from China and Japan (Diptera, Chironomidae

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    Chuncai Yan

    2015-04-01

    Full Text Available Members of the genus Parachironomus Lenz known from China and Japan are revised, and a key to their male adults is given. Parachironomus poyangensis sp. n. is described in this life stage. Parachironomus frequens (Johannsen and P. monochromus (van der Wulp are recorded from China for the first time, thus are redescribed from Chinese specimens. Parachironomus kamaabeus Sasa & Tanaka and P. toneabeus Sasa & Tanaka are new junior synonyms of P. frequens. Three Chinese or Japanese species formerly placed in Parachironomus are transferred to other genera, resulting in the new combinations Cryptochironomus inafegeus (Sasa, Kitami & Suzuki, Demicryptochironomus (Irmakia lobus (Yan, Sæther, Jin & Wang, and Microchironomus lacteipennis (Kieffer. Chironomus sauteri Kieffer, Parachironomus kisobilobalis Sasa & Kondo and P. kuramaexpandus Sasa are removed from Parachironomus; the last of these three denotes a valid species of uncertain generic placement, the first two are nomina dubia.

  18. Factors that alter the biochemical biomarkers of environmental contamination in Chironomus sancticaroli (Diptera, Chironomidae

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    Débora Rebechi-Baggio

    Full Text Available ABSTRACT Changes in physiology of the nervous system and metabolism can be detected through the activity of acetylcholinesterase (AChE, alpha esterase (EST-a and beta esterase (EST-ß in chironomids exposed to pollutants. However, to understand the real effect of xenobiotics on organisms, it is important to investigate how certain factors can interfere with enzyme activity. We investigated the effects of different temperatures, food stress and two steps of the enzymatic protocol on the activity of AChE, EST-a and EST-ß in Chironomus sancticaroli. In experiment of thermal stress individuals from the egg stage to the fourth larval instar were exposed to different temperatures (20, 25 and 30 °C. In food stress experiment, larvae were reared until IV instar in a standard setting (25 °C and 0.9 g weekly ration, but from fourth instar on they were divided into groups and offered different feeding regimes (24, 48 and 72 h with/without food. In sample freezing experiment, a group of samples was processed immediately after homogenization and another after freezing for 30 days. To test the effect of centrifugation on samples, enzyme activity was quantified from centrifuged and non-centrifuged samples. The activity of each enzyme reached an optimum at a different temperature. The absence of food triggered different changes in enzyme activity depending on the period of starvation. Freezing and centrifugation of the samples significantly reduced the activity of three enzymes. Based on these results we conclude that the four factors studied had an influence on AChE, EST-a and EST-ß and this influence should be considered in ecotoxicological approaches.

  19. Taxonomic notes on Chironomidae (Diptera from Okinawa Island, Japan, with the description of three new species

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    Masaru Yamamoto

    2015-07-01

    Full Text Available Three new species: Ionthosmittia cuneipenne sp. nov., Orthocladius (Euorthocladius okinawanus sp. nov. and Parakiefferiella semiovata sp. nov., are described from Okinawa Island, Ryukyus, Japan. In addition to these species, twelve species are newly recorded from this island. Diagnostic characters of Tokyobrillia tamamegaseta (Kobayashi et Sasa are emended. Pentapedilum yakuabeum Sasa et Suzuki syn. nov. and Polypedilum yakucedeum Sasa et Suizuki syn. nov. are junior synonyms of Ainuyusurika tuberculatum (Tokunaga. Einfeldia kanazawai (Yamamoto is transferred to the genus Chironomus Meigen and its systematic position is discussed.

  20. Chromosomal organization of the ribosomal RNA genes in the genus Chironomus (Diptera, Chironomidae

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    Larisa Gunderina

    2015-05-01

    Full Text Available Chromosomal localization of ribosomal RNA coding genes has been studied by using FISH (fluorescence in situ hybridization in 21 species from the genus Chironomus Meigen, 1803. Analysis of the data has shown intra- and interspecific variation in number and location of 5.8S rDNA hybridization sites in 17 species from the subgenus Chironomus and 4 species from the subgenus Camptochironomus Kieffer, 1914. In the majority of studied species the location of rDNA sites coincided with the sites where active NORs (nucleolus organizer regions were found. The number of hybridization sites in karyotypes of studied chironomids varied from 1 to 6. More than half of the species possessed only one NOR (12 out of 21. Two rDNA hybridization sites were found in karyotypes of five species, three – in two species, and five and six sites – in one species each. NORs were found in all chromosomal arms of species from the subgenus Chironomus with one of them always located on arm G. On the other hand, no hybridization sites were found on arm G in four studied species from the subgenus Camptochironomus. Two species from the subgenus Chironomus – Ch. balatonicus Devai, Wuelker & Scholl, 1983 and Ch. “annularius” sensu Strenzke, 1959 – showed intraspecific variability in the number of hybridization signals. Possible mechanisms of origin of variability in number and location of rRNA genes in the karyotypes of species from the genus Chironomus are discussed.

  1. Blind flight? A new troglobiotic orthoclad (Diptera, Chironomidae) from the Lukina Jama - Trojama Cave in Croatia

    OpenAIRE

    Trond Andersen; Viktor Baranov; Linn Katrine Hagenlund; Marija Ivković; Gunnar Mikalsen Kvifte; Martina Pavlek

    2016-01-01

    The genus Troglocladius Andersen, Baranov et Hagenlund, gen. n. is erected based on T. hajdi Andersen, Baranov et Hagenlund, sp. n. collected at 980 m depth in the Lukina jama-Trojama cave system in Croatia. Morphological features such as pale color, strongly reduced eyes and very long legs make it a typical cave animal. Surprisingly, it has also retained large wings and appears to be capable of flight which would make T. hajdi the first flying troglobiont worldwide, disproving previous belie...

  2. New records of non-biting midges (Diptera: Chironomidae, Orthocladiinae from Mallorca, Spain

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    Viktor Baranov

    2016-09-01

    Full Text Available Ten species of non-biting midges belonging to the subfamily Orthocladiinae were found in samples from predominantly madicolous habitats in Mallorca, Spain. One species, Bryophaenocladius nidorum (Edwards, 1929, has not previously been recorded from Spain, while Smittia pratorum (Goetghebuer, 1927, Bryophaenocladius inconstans (Brundin, 1947, Orthocladius (O. maius Goetghebuer, 1942, Paracladius conversus (Walker, 1856 and Paraphaenocladius impensus (Walker, 1856 are recorded for the first time from the Balearic Islands.

  3. A generic guide to the larvae of the Nearctic Tanytarsini, (Chironomidae:diptera)

    Science.gov (United States)

    Steiner, J.W.; Doughman, J.S.; Moore, C.R.

    1982-01-01

    Larvae of the tribe Tanytarsini occur in nearly every aquatic habitat in North America where they act as primary consumers in the food chain. This new taxonomic guide overcomes some deficiencies in existing keys to this tribe and the reviewed and updated taxonomy enables identification of the larvae that may be useful as ecological indicators. Over 2,000 specimens from 26 states were examined, identified and measured in this study. The following genera were included: Stempellinell, Zavrelia, Stempellina, Constempellina, Corynocera, Cladotanytarsus,.. Paratanytarsus, Rheotanytarsus,. Micropsectra, Lauterbornia, Nimbocera, Tanytarsus and Neozavrelia. Photographs illustrate mature larvae of these genera with the exception of Zavrelia and Neozavrelia which are not known to exist in North America. The morphological data, Which are summarized in a table of distinctive characteristics and the dichotomous key, enable identification to genus. Notes on range, habitat and food preference are included, and species identifications are presented where applicable.

  4. Distribution of chironomidae (Insecta: Diptera) in polluted rivers of the Juru River Basin, Penang, Malaysia.

    Science.gov (United States)

    Al-Shami, Salman A; Rawi, Che Salmah Md; HassanAhmad, Abu; Nor, Siti Azizah Mohd

    2010-01-01

    The influence of physical and chemical parameters on the abundance and diversity of chironomids was studied in six rivers with moderate to highly polluted water in the Juru River Basin. The rivers: Ceruk Tok Kun (CTKR) as reference site, and polluted rivers of Pasir (PR), Juru (JR), Permatang Rawa (PRR), Ara (AR) and Kilang Ubi (KUR) were sampled over a period of five months (November 2007-March 2008). Nine chirnomid species: Chironimus kiiensis, C. javanus, Polypedilum trigonus, Microchironomus sp., Dicrotendipes sp., Tanytarsus formosanus, Clinotanypus sp., Tanypus punctipennis and Fittkauimyia sp. were identified. Assessment of their relationships with several environmental parameters was performed using the canonical correspondence analysis (CCA). Tanytarsus formosanus was the most dominant in the relatively clean CTKR and moderately polluted JR with mean densities of 19.66 and 25.32 m(-2), respectively while C. kiiensis was abundant in more polluted rivers. Tanytarsus formosanus, Dicrotendipes sp. and Microchironomus sp. were grouped under moderate to high water temperature, total organic matter (TOM), total suspended solids (TSS), velocity, pH, phosphates and sulphates. However, Tanypus punctipennis, Fittkauimyia sp., and Clinotanypus sp. were associated with high contents of river sediment such as TOM, Zn and Mn and water ammonium-N and nitrate-N and they were associated with higher dissolved oxygen (DO) content in the water. Chironomus kiiensis, C. javanus and P. trigonus showed positive relationships with TOM, ammonium-N and nitrate-N as well as trace metals of Zn, Cu and Mn. These three species could be considered as tolerant species since they have the ability to survive in extreme environmental conditions with low DO and high concentrations of pollutants. Based on the water parameter scores in all rivers, the highest diversity of chironomid larvae was reported in CTKR. With higher concentrations of organic and/or inorganic pollutants as reported in PPR, KUR and AR, the chironomid larval diversity decreased, and the abundance of tolerant species, mainly Chironomus spp., increased.

  5. Blind Flight? A New Troglobiotic Orthoclad (Diptera, Chironomidae from the Lukina Jama - Trojama Cave in Croatia.

    Directory of Open Access Journals (Sweden)

    Trond Andersen

    Full Text Available The genus Troglocladius Andersen, Baranov et Hagenlund, gen. n. is erected based on T. hajdi Andersen, Baranov et Hagenlund, sp. n. collected at 980 m depth in the Lukina jama-Trojama cave system in Croatia. Morphological features such as pale color, strongly reduced eyes and very long legs make it a typical cave animal. Surprisingly, it has also retained large wings and appears to be capable of flight which would make T. hajdi the first flying troglobiont worldwide, disproving previous beliefs that bats are the only animals capable of flying in complete darkness. Morphologically the new species does not readily fit within any described genus, but shares characteristics with genera both in the tribes "Metriocnemini" and "Orthocladiini". Bayesian molecular phylogenetic analysis using the markers COI, 18S rDNAs, 28S rDNA, CADI, and CADIV groups it with the genera Tvetenia, Cardiocladius and Eukiefferiella in the tribe "Metriocnemini". Troglocladius hajdi may be parthenogenetic, as only females were collected. The discovery confirms the position of the Dinaric arch as a highly important hotspot of subterranean biodiversity.

  6. Two New and Four Unrecorded Species of Chironomidae (Diptera in Korea

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    Han-Il Ree

    2012-01-01

    Full Text Available Chironomid adults attracted to the light were collected at Dangsan-ri, Muju-eup, Muju-gun, Jeollabuk-do in 2008-2009. Two new species, Lymnophyes parakitanaides sp. nov. and Parakiefferiella mujuensis sp. nov., and four unrecorded species, Cardiolcladius capusinus, Thienemanniella vittata, Conchapelopia pallidula, and Nilotanypus dubius were found and are described with illustrations. The genera Thienemanniella and Nilotanypus have not been previously reported in Korea. The genus Thienemanniella which belongs to Orthocladiinae is characterized by the radial sector retracted and apically fused with the costa, and the genus Nilotanypus which belongs to Tanypodinae is characterized by the absence of R2+3, pubescent eyes and lack of the gonocoxal lobes.

  7. Polytene chromosomes of Chironomidae (Diptera as a bioassay of trace-metal-induced genome instability

    Directory of Open Access Journals (Sweden)

    Paraskeva Vladimirova Michailova

    2012-10-01

    Full Text Available Chironomids are a ubiquitous group of aquatic insects that are very sensitive to environmental stress. Due to the presence of polytene (‘giant’ salivary gland chromosomes, it is possible to define the genome response of several Chironomid species to various stress agents. The aim of this study was to assess the genotoxic changes in populations of widely distributed chironomid species from aquatic basins in Bulgaria, Italy, Russia, U.K. and Poland, which were exposed to high concentrations of trace metals. We analyzed the structural and functional alterations of polytene chromosomes of the salivary glands of larvae belonging to three different cytocomplexes of the genus Chironomus (“thummi”, “lacunarius”, “pseudothummi”, and genera Glyptotendipes and Kiefferulus. Somatic structural chromosome rearrangements (para- and pericentric heterozygous inversions, deletions, deficiencies and amplifications were used to estimate a Somatic index (S for each population. The highest S indexes were detected in Chironomus riparius populations from locations with high concentrations of trace metals in the sediment. Each species showed specific genome responses to stress agents which we discussed in the light of the specific DNA structures and cytogenetic characteristics of the species. In larvae from polluted sediments two key structures of the salivary gland chromosomes (Balbiani Rings and Nucleolar Organizer sharply reduced their activity to levels below those observed under non-polluted conditions. It is concluded that polytene chromosomes can be used as tools for evaluating the genotoxicity of the aquatic environment. Structural and functional chromosome alterations provide cost-effective early-warning signals of genotoxic concentrations of environmental pollutants.doi: 10.5324/fn.v31i0.1355.Published online: 17 October 2012.

  8. Description of the larva of Protanypus sp. A (Diptera, Chironomidae from the Italian Alps

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    Bruno Rossaro

    2012-05-01

    Full Text Available We describe the larva of Protanypus sp. A from the Italian Alps. All the larval characteristics fit the diagnosis of the genus, but it is impossible to assign the specimens examined to one of the known species. The low number of labral scales (12-14 and the serrated median lamellae of the medioventral appendix of the prementum exclude the identity of the species with P. morio or with the East Palaearctic P. pseudomorio. The antennal ratio (2.3 excludes the identity with P. caudatus or P. forcipatus, which are the other two Protanypus species known from the Alpine region. In Sæther’s key (1975 the larva fits with the Nearctic P. ramosus, but identification of the species needs to be supported by pupal and adult material. In the Southern Alps, the genus is restricted to cold lakes at high altitude and is confirmed as an indicator of oligotrophic lakes.

  9. LIFE CYCLE AND PRODUCTION OF CHIRONOMIDAE(DIPTERA) IN BIANDANTANG, A TYPICAL MACROPHYTIC LAKE (HUBEI, CHINA)

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The life cycle and annual production of four dominant species of Chironomids (Chironomus plumosus, Chironomus sp., Clinotanypus sp., Tokunagayusurika akamusi) were studied with samples taken monthly in Biandantang Lake at eight stations from April, 1996 to March, 1997. Instar-frequency data showed C. plumosus was univoltine, while the other three were bivoltine. Production in wet weight (g/(m2.a)) calculated by the size-frequency method for each species were: C. plumosus, 2.663; Chironomus sp.,1.161 ;Clinotanypus sp., 0.270; T. akamusi, 1.476. Based on the mean standing stock, their P/B ratios were 3.2, 4.0, 6.2 and 4.4, respectively.

  10. A Key to the Pupal Exuviae of the Midges (Diptera: Chironomidae) of Everglades National Park, Florida

    Science.gov (United States)

    Jacobsen, Richard E.

    2008-01-01

    A key has been developed for identifying the pupal exuviae of 132 taxa of chironomid midges collected in Everglades National Park, as well as 18 additional species from freshwater habitats adjacent to the Park. Descriptions and illustrations are based upon voucher specimens from extensive collections of chironomid pupal exuviae for faunal surveys and biomonitoring research conducted in ENP and surrounding freshwater areas from 1998 to 2007. The key includes taxonomic comments for confirming identifications, as well as brief summaries of the distribution and ecology of each species in southern Florida waters. Information is also provided on the morphology of chironomid pupal exuviae, recommended references for identifying pupal exuviae, techniques for making slides, and methods to confirm proper identification.

  11. A new species of the genus Microtendipes Kieffer, 1915 (Diptera, Chironomidae from Oriental China

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    Xin Qi

    2012-07-01

    Full Text Available A new species of the genus Microtendipes Kieffer, 1915, M. zhejiangensis sp.n., is described, and its morphological description and illustrations are given. A catalogue of the genus in Oriental Region is provided and a key to the males of Microtendipes in the Oriental Region is given.

  12. [Inversion polymorphism of Glyptotendipes glaucus Mg. (Diptera: Chironomidae) from the reservoirs of Kaliningrad].

    Science.gov (United States)

    Sharton, A Iu; Petrova, N A; Vinokurova, N V; Danilova, M V; Zolotova, S M

    2010-07-01

    The karyotypes of larvae Glyptotendipes glaucus Mg. 1804 from three reservoirs of Kaliningrad city (Pen'kovoe and Karasevka lakes and Chistyi pond) were studied. The levels of the natural inversion polymorphism for the three populations were determined. Ten new inversion sequences (gla B4, gla B5, gla B6, gla D5, gla E4, gla E6, gla E7, gla F6, and gla F7) were detected in the species studied. Inversion including the centromeric region in IIIEF (gla E6 + gla F7) was pericentric. Several cases ofgla B5 and gla B6 combination with gla B2 resulting in genotypic combination gla B2.5 and gla B2.6 were found. The dependence of the number of inversion sequences and genotype combinations from the content of heavy metal ions in sediments of the reservoirs was revealed. All populations were characterized by the prevalence of inversion sequence gla B2 in chromosome I.

  13. [Seasonal variability of the karyotype structure of Chironomus plumosus (Diptera, Chironomidae) from a biotope of Kaliningrad].

    Science.gov (United States)

    Petrova, N A; Vinokurova, N V; Danilova, M V; Maslova, V V

    2007-01-01

    Chironomus plumosus larvae from the polluted Shkolnoe lake, Kaliningrad, have 2n = 8 and 2n = 8 + B. In winter season we found 11 types of hetero- and homozygous inversions in A, B, C, D, E, and F arms whereas in summer season we registered 7 types of the same inversions in A, B, C, D, and E arms. All inversions with exception of the inversion in arm C correspond to Hardy-Weinberg equilibrium. The arm IVG shows homozygous increase of centromeric heterochromatin more frequently in summer than in winter (34.4% as compared with 1.8%). The arm E has asynapsis 2 times less frequently in summer than in winter (21.4% as compared with 44.6%).

  14. Complete mitochondrial genome of the Antarctic midge Parochlus steinenii (Diptera: Chironomidae).

    Science.gov (United States)

    Kim, Sanghee; Kim, Hanna; Shin, Seung Chul

    2016-09-01

    Parochlus steinenii is a winged midge found in the Antarctic Peninsula and its offshore islands. We determined the complete mitochondrial genome sequence of P. steinenii, which is comprised of 16 803 nucleotides and contains 13 protein-coding genes (PCGs), 22 tRNA genes, and the large (rrnL) and small (rrnS) rRNA genes. Its total A + T content is 72.5%. The PCG arrangement of P. steinenii is identical to that of the ancestral Diptera ground pattern. This is the first report on the mitogenome sequence of an Antarctic midge, and provides insights into the evolution of dipterans in Antarctica.

  15. Low species richness of non-biting midges (Diptera: Chironomidae) in Neotropical artificial urban water bodies

    DEFF Research Database (Denmark)

    Hamerlik, Ladislav; Jacobsen, Dean; Brodersen, Klaus Peter

    2011-01-01

    Chironomid assemblages of 22 artificial water bodies, mainly fountains, in two South American cities were surveyed. We found surprisingly low diversities, with a total of 11 taxa, averaging two taxa per site. The typical fountain assemblages mainly consisted of common species that have a wide...... distribution pattern and are tolerant to organic pollution. Also taxa independent of the natural aquatic sources, such as tap-water and semi-terrestrial species were represented. There was no significant difference between the taxa richness of the two S. American regions, however, the assemblage structures...

  16. Sediment microbes and biofilms increase the bioavailability of chlorpyrifos in Chironomus riparius (Chironomidae, Diptera).

    Science.gov (United States)

    Widenfalk, Anneli; Lundqvist, Anna; Goedkoop, Willem

    2008-10-01

    In a microcosm study, the importance of different sources of organic matter (humic acids, sterile sediment, sediment, and a microbial extract) for the bioavailability of the hydrophobic pesticide chlorpyrifos to Chironomus riparius larvae was quantified. In the last two treatments biofilms were allowed to grow before (14)C-chlorpyrifos addition. Chlorpyrifos accumulation was quantified after 25 h of exposure and after 21 h of depuration. Larval accumulation was twice as high in the microbial extract treatment (447+/-79 microg/kg ww larvae) and 1.7 times higher in the sediment treatment (371+/-33 microg/kg). After depuration, chlorpyrifos accumulation in larval tissue showed even higher differences; 3.1 times higher tissue concentrations in the microbial extract treatment (218+/-21 microg/kg) and 2.2 times higher in the sediment treatment (156+/-35 microg/kg). In contrast, chlorpyrifos accumulation in the humic acid and sterile sediment did not differ from that in controls. These results show that living microbes and biofilms, by creating a microenvironment and providing food for larvae, markedly increase the bioavailability of chlorpyrifos to Chironomus riparius.

  17. Paleoecología: el uso de los quironómidos fósiles (Diptera: Chironomidae en reconstrucciones paleoambientales durante el Cuaternario en la Patagonia Paleoecology: the use of fossil chironomids (Diptera: Chironomidae for paleoenvironmental reconstructions in Patagonia

    Directory of Open Access Journals (Sweden)

    Julieta Massaferro

    2009-06-01

    Full Text Available Entre los indicadores biológicos lacustres más utilizados en las reconstrucciones ambientales, se encuentran el polen, los ostrácodos y las diatomeas, y entre los insectos, los coleópteros y los quironómidos. Este grupo ha cobrado gran importancia en los últimos tiempos, debido a los resultados prometedores que se han obtenido en reconstrucciones climáticas realizadas en América del Norte y Europa. En América del Sur, el uso de los quironómidos fósiles en estudios cuaternarios es relativamente limitado, principalmente por su escaso conocimiento taxonómico regional. La mayor parte de estos estudios fueron realizados en lagos glaciares patagónicos de Argentina y Chile. Las larvas de quironómidos constituyen una valiosa herramienta paleolimnológica, por ser un grupo de organismos altamente sensible a cambios ambientales, tanto naturales como artificiales. Además, es un grupo de insectos ampliamente distribuido y con una abundancia y diversidad relativamente altas. Sus cápsulas cefálicas se preservan en los sedimentos lacustres y poseen caracteres importantes que permiten identificar géneros y muchas veces especies. El estudio de los ensambles de quironómidos en sedimentos lacustres puede ser utilizado con distintos objetivos, por ejemplo, para estudios de eutrofización, ya que responden rápidamente a cambios en la concentración de nutrientes, materia orgánica y otros elementos, como metales pesados. No obstante, uno de los potenciales más importantes de este grupo de insectos es su sensibilidad a los cambios de temperatura, por este motivo, la aplicación más importante de su estudio en sedimentos se centra en las reconstrucciones climáticas. Esta contribución es una síntesis de los resultados de los trabajos publicados en la Patagonia argentina y chilena, sobre la base del uso de los quironómidos fósiles en reconstrucciones paleoambientales.Pollen, ostracods, diatoms and insects such as beetles and chironomids are the biological indicators from lake sediments more useful in environmental reconstructions. Chironomids have recently acquired great importance due to the promising results obtained regarding climatic reconstructions mainly in Europe and North America. In South America, the use of fossil chironomids in Quaternary studies is still limited and the reason for that is the little regional taxonomic knowledge. Most of these studies were developed in glacial lakes in Patagonia both in Argentina and Chile. The larvae of chironomids are an invaluable paleolimnological tool due to the sensitiveness of these insects to natural and non-natural environmental changes. In addition to that, this group of insects is widely distributed with a high abundance and diversity. Their head capsules can preserve in sediments holding characters which allow their generic and sometimes specific identification. The study of chironomid assemblages can be used with different goals, for instance, to study eutrofication due to their quick response to changes in organic matter, nutrients and heavy metals. However, one of the most significant potentials of this group is its sensitivity to temperature variations, which is why the most important implementation of their study in sediments is centered in climatic reconstructions. This article is a review of the studies developed in Argentinean and Chilean Patagonia, using fossil chironomids for paleoenvironmental reconstructions.

  18. TOXICITY OF TWO HERBICIDES 2,4 -D DIMETHYLAMINE AND BENSULFURON METHYL TO RICE FIELD CHIRONOMUS KIIENSIS (TOKUNAGA) ( DIPTERA: CHIRONOMIDAE)

    Institute of Scientific and Technical Information of China (English)

    Al-Shami S A; Che Salmah M R; Siti Azizah M N; Abu Hassan A; Azmi M

    2006-01-01

    Fourth instar larvae of Chironomus kiiensis(Tokunaga) were exposed to various concentrations of two commonly used herbicides: 2,4 - D Dimethylamine and Bensulfuron methyl in the rice fields. The bioassay experiment was carried out in a rearing unit in the laboratory at a room temperature ( (27 ± 2) ℃ ). A thin layer of sand sediments and tissue papers were provided as substrate in each unit. Each concentration of all herbicides was prepared in 250 mL distilled water. The experiment was performed in triplicate and 20 chironomid larvae were placed in each rearing unit. The larvae were fed with fish food (Sanyuichiban(R)) at 2 d intervals and all units were aerated by air pumps. The experiment was monitored every 24 h for mortality of C. kiiensis. The 2,4 - D Dimethylamine bioassay was carried out for 24 h while Bensulfuron methyl was run for 72 h. Dead larvae, pupae and living or dead adults were counted and removed daily.The LC50 of 2,4 - D Dimethylamine was 2 638 mg ai L-1, more than 2 000 times higher than the recommended dose of 0.753 mg ai L-1 used for controlling weeds in the rice field. Bensulfuron methyl was more toxic than the 2,4 - D Dimethylamine. The LC50 of the Bensulfuron methyl was recorded at 1.29 mg ai L-1, and approximately was more 20 times than that of the recommended dose of 0. 057 mg ai L-1. Bensulfuron methyl was found to be slow acting. The mortality of the larvae was only observed after 72 h. However, this herbicide interfered with the emergence of C. kiiensis to adults at and above the recommended dose used in the rice fields. Based on their LC50 values, this study showed that applying these herbicides in the rice fields at doses recommended by the manufacturers was safe for C. kiiensis and presumably to other living organisms in the water.

  19. Evolutionary ecotoxicology of perfluoralkyl substances (PFASs) inferred from multigenerational exposure: a case study with Chironomus riparius (Diptera, Chironomidae).

    Science.gov (United States)

    Stefani, F; Rusconi, M; Valsecchi, S; Marziali, L

    2014-11-01

    A multigeneration toxicity test on Chironomus riparius was performed with the aim of investigating the evolutionary consequences of exposure to perfluoralkyl substances (perfluorooctane sulfonic acid, PFOS; perfluorooctanoic acid, PFOA; perfluorobutane sulfonate, PFBS). Six-hundred larvae were bred per treatment and per generation until emergence and egg deposition under a nominal concentration of 10μg/L of contaminants. Newborn larvae were used to start the next generation. Evolution of genetic variability was evaluated along a total of 10 consecutive generations based on 5 microsatellite loci. Analysis of life-history traits (survival, sex ratio and reproduction) was also carried out. Rapid genetic variability reduction was observed in all treatments, including controls, across generations due to the test conditions. Nevertheless, an increased mutation rate determined a stronger conservation of genetic variability in PFOS and, at minor extent, in PFBS exposed populations compared to controls. No significant effects were induced by exposure to PFOA. Direct mutagenicity or induced stress conditions may be at the base of increased mutation rate, indicating the potential risk of mutational load caused by exposure to PFOS and PFBS. The test provided the opportunity to evaluate the use of approximate Bayesian computation (ABC) and coalescent approaches in evolutionary ecotoxicology. A weak performance was evidenced for ABC, either in terms of bias or dispersion of effective population sizes and of estimates of mutation rate. On the contrary, coalescent simulations proved the sensitivity of traditional genetic endpoints (i.e. heterozygosity and number of alleles) to the alteration of mutation rate, but not to erosion of genetic effective size.

  20. New record of Parochlus carolinae (Chironomidae: Podonominae from the Ventania hill system with the description of the female

    Directory of Open Access Journals (Sweden)

    Augusto SIRI

    2014-01-01

    Full Text Available Se presenta el primer reporte de Parochlus Enderlein del sistema serrano de Ventania, el cual constituye el primer registro de este género de la provincia de Buenos Aires. Se describe e ilustra la hembra de Parochlus caroli - nae Rodriguez et al. y se enmiendan las descripciones originales del macho y de la larva. Se remarcan caracteres del cuerno torácico de la pupa para distinguir P. carolinae de otras especies del género Parochlus.

  1. Toxicity of cadmium and lead on tropical midge larvae, Chironomus kiiensis Tokunaga and Chironomus javanus Kieffer (Diptera:Chironomidae)

    Institute of Scientific and Technical Information of China (English)

    Warrin Ebau; Che Salmah Md Rawi; Zubir Din; Salman Abdo Al-Shami

    2012-01-01

    Objective: To investigate the acute toxicity of cadmium and lead on larvae of two tropical Chironomid species, Chironomus kiiensis (C. kiiensis) Tokunaga and Chironomus javanus (C. javanus) Kieffer. Methods: Different larval instars (first-fourth) were exposed using a static non-replacement testing procedures to various concentrations of cadmium and lead. Results:In general, younger larvae (first and second instars) of both species were more sensitive to both metals than older larvae (third and forth instars). The toxic effects of the metals on C. kiiensis and C. javanus were influenced by the age of the larvae (first to fourth instars), types of metals (cadmium or lead) and duration of larval exposure (24, 48, 72 and 96 h) to the metals. Conclusions: Cadmium was more toxic to the chironomids than lead and C. javanus was significantly more sensitive to both metals than C. kiiensis (P<0.05).

  2. Respiration of midges (Diptera; Chironomidae) in British Columbian lakes: oxy-regulation, temperature and their role as palaeo-indicators

    DEFF Research Database (Denmark)

    Brodersen, Klaus Peter; Pedersen, Ole; Walker, Ian R.;

    2008-01-01

    1. The specific respiration rate of 13 chironomid taxa and Chaoborus were measured to test the hypothesis of the relation between a species' ability to regulate their oxygen uptake and their distributional patterns among nine study lakes in British Columbia, Canada. 2. Respiration patterns...... of individual taxa were modelled using piecewise linear regression with break point and simple hyperbolic functions. Three types of respiration curves were identified: (i) classical oxy-conformers (e.g. littoral Cricotopus) which cannot sustain a sufficient oxygen uptake with decreasing oxygen availability; (ii......) oxy-regulators (e.g. profundal Chironomus) which can regulate and maintain a constant respiration until a certain critical point and (iii) oxy-stressors (Micropsectra) which increase their respiration rate with decreasing oxygen availability until a critical point. 3. Respiration was measured at two...

  3. Environmental controls on the distribution and diversity of lentic Chironomidae (Insecta: Diptera) across an altitudinal gradient in tropical South America

    NARCIS (Netherlands)

    F. Matthews-Bird; W.D. Gosling; A.L. Coe; M. Bush; F.E. Mayle; Y. Axford; S.J. Brooks

    2016-01-01

    To predict the response of aquatic ecosystems to future global climate change, data on the ecology and distribution of keystone groups in freshwater ecosystems are needed. In contrast to mid- and high-latitude zones, such data are scarce across tropical South America (Neotropics). We present the dis

  4. Environmental controls on the distribution and diversity of lentic Chironomidae (Insecta: Diptera) across an altitudinal gradient in tropical South America.

    Science.gov (United States)

    Matthews-Bird, Frazer; Gosling, William D; Coe, Angela L; Bush, Mark; Mayle, Francis E; Axford, Yarrow; Brooks, Stephen J

    2016-01-01

    To predict the response of aquatic ecosystems to future global climate change, data on the ecology and distribution of keystone groups in freshwater ecosystems are needed. In contrast to mid- and high-latitude zones, such data are scarce across tropical South America (Neotropics). We present the distribution and diversity of chironomid species using surface sediments of 59 lakes from the Andes to the Amazon (0.1-17°S and 64-78°W) within the Neotropics. We assess the spatial variation in community assemblages and identify the key variables influencing the distributional patterns. The relationships between environmental variables (pH, conductivity, depth, and sediment organic content), climatic data, and chironomid assemblages were assessed using multivariate statistics (detrended correspondence analysis and canonical correspondence analysis). Climatic parameters (temperature and precipitation) were most significant in describing the variance in chironomid assemblages. Temperature and precipitation are both predicted to change under future climate change scenarios in the tropical Andes. Our findings suggest taxa of Orthocladiinae, which show a preference to cold high-elevation oligotrophic lakes, will likely see range contraction under future anthropogenic-induced climate change. Taxa abundant in areas of high precipitation, such as Micropsectra and Phaenopsectra, will likely become restricted to the inner tropical Andes, as the outer tropical Andes become drier. The sensitivity of chironomids to climate parameters makes them important bio-indicators of regional climate change in the Neotropics. Furthermore, the distribution of chironomid taxa presented here is a vital first step toward providing urgently needed autecological data for interpreting fossil chironomid records of past ecological and climate change from the tropical Andes.

  5. Survivorship and longevity of adult Diamesa mendotae Muttkowski, 1915 (Diptera: Chironomidae) at controlled, sub-freezing temperatures

    Science.gov (United States)

    Mazack, Jane E.; Kranzfelder, Petra; Anderson, Alyssa M.; Bouchard, William; Perry, James; Vondracek, Bruce C.; Ferrington, Leonard C.

    2014-01-01

    Diamesa mendotae Muttkowski, 1915 is a winter-active species common in groundwater-buffered streams of Minnesota and Wisconsin. This species is capable of surviving under snow cover for at least 28 days. Field collections of adult D. mendotae were used to determine survivorship under long-term exposure to controlled sub-freezing conditions. Specimens were placed into a controlled temperature chamber at −5 °C, batches removed at weekly intervals, and subsequently held at 6 °C to determine survivorship and longevity. Our results indicate that overall survivorship is negatively related to treatment duration of sub-freezing treatment, individuals can survive sub-freezing temperatures for at least 70 days, with total longevity of 92 days. Additionally, males had a significantly higher rate of survivorship than females within treatments. Total longevity increased with treatment time, suggesting adult D. mendotae may survive long periods of below-freezing temperatures under natural conditions before mating, which may convey population-level advantages.

  6. Morphological identification and COI barcodes of adult flies help determine species identities of chironomid larvae (Diptera, Chironomidae)

    Science.gov (United States)

    Failla, Andrew Joseph; Vasquez, Adrian Amelio; Hudson, Patrick L.; Fujimoto, Masanori; Ram, Jeffrey L.

    2016-01-01

    Establishing reliable methods for the identification of benthic chironomid communities is important due to their significant contribution to biomass, ecology and the aquatic food web. Immature larval specimens are more difficult to identify to species level by traditional morphological methods than their fully developed adult counterparts, and few keys are available to identify the larval species. In order to develop molecular criteria to identify species of chironomid larvae, larval and adult chironomids from Western Lake Erie were subjected to both molecular and morphological taxonomic analysis. Mitochondrial cytochrome c oxidase I (COI) barcode sequences of 33 adults that were identified to species level by morphological methods were grouped with COI sequences of 189 larvae in a neighbor-joining taxon-ID tree. Most of these larvae could be identified only to genus level by morphological taxonomy (only 22 of the 189 sequenced larvae could be identified to species level). The taxon-ID tree of larval sequences had 45 operational taxonomic units (OTUs, defined as clusters with >97% identity or individual sequences differing from nearest neighbors by >3%; supported by analysis of all larval pairwise differences), of which seven could be identified to species or ‘species group’ level by larval morphology. Reference sequences from the GenBank and BOLD databases assigned six larval OTUs with presumptive species level identifications and confirmed one previously assigned species level identification. Sequences from morphologically identified adults in the present study grouped with and further classified the identity of 13 larval OTUs. The use of morphological identification and subsequent DNA barcoding of adult chironomids proved to be beneficial in revealing possible species level identifications of larval specimens. Sequence data from this study also contribute to currently inadequate public databases relevant to the Great Lakes region, while the neighbor-joining analysis reported here describes the application and confirmation of a useful tool that can accelerate identification and bioassesment of chironomid communities.

  7. Germ line transformation and in vivo labeling of nuclei in Diptera: report on Megaselia abdita (Phoridae) and Chironomus riparius (Chironomidae).

    Science.gov (United States)

    Caroti, Francesca; Urbansky, Silvia; Wosch, Maike; Lemke, Steffen

    2015-06-01

    To understand how and when developmental traits of the fruit fly Drosophila melanogaster originated during the course of insect evolution, similar traits are functionally studied in variably related satellite species. The experimental toolkit available for relevant fly models typically comprises gene expression and loss as well as gain-of-function analyses. Here, we extend the set of available molecular tools to piggyBac-based germ line transformation in two satellite fly models, Megaselia abdita and Chironomus riparius. As proof-of-concept application, we used a Gateway variant of the piggyBac transposon vector pBac{3xP3-eGFPafm} to generate a transgenic line that expresses His2Av-mCherry as fluorescent nuclear reporter ubiquitously in the gastrulating embryo of M. abdita. Our results open two phylogenetically important nodes of the insect order Diptera for advanced developmental evolutionary genetics.

  8. Influence of Chironomus riparius (Diptera, Chironomidae) and Tubifex tubifex (Annelida, Oligochaeta) on oxygen uptake by sediments. Consequences of uranium contamination

    Energy Technology Data Exchange (ETDEWEB)

    Lagauzere, S. [Laboratoire de Radioecologie et d' Ecotoxicologie, Institut de Radioprotection et de Surete Nucleaire (IRSN), DEI/SECRE/LRE, Cadarache 186, BP 3, F-13115 Cedex, Saint Paul Lez Durance (France)], E-mail: lagauzere@gmail.com; Pischedda, L.; Cuny, P. [Laboratoire de Microbiologie, Geochimie et Ecologie Marines, UMR 6117 CNRS/COM/Universite de la Mediterranee, Campus de Luminy, Case 901, F-13288 Cedex 09, Marseille (France); Gilbert, F. [EcoLab, Laboratoire d' Ecologie Fonctionnelle, UMR 5245 CNRS/INP/Universite Paul Sabatier, 29 Rue Jeanne Marvig, F-31055 Cedex 4, Toulouse (France); Stora, G. [Laboratoire de Microbiologie, Geochimie et Ecologie Marines, UMR 6117 CNRS/COM/Universite de la Mediterranee, Campus de Luminy, Case 901, F-13288 Cedex 09, Marseille (France); Bonzom, J.-M. [Laboratoire de Radioecologie et d' Ecotoxicologie, Institut de Radioprotection et de Surete Nucleaire (IRSN), DEI/SECRE/LRE, Cadarache 186, BP 3, F-13115 Cedex, Saint Paul Lez Durance (France)

    2009-04-15

    The diffusive oxygen uptake (DOU) of sediments inhabited by Chironomus riparius and Tubifex tubifex was investigated using a planar oxygen optode device, and complemented by measurements of bioturbation activity. Additional experiments were performed within contaminated sediments to assess the impact of uranium on these processes. After 72 h, the two invertebrate species significantly increased the DOU of sediments (13-14%), and no temporal variation occurred afterwards. Within contaminated sediments, it was already 24% higher before the introduction of the organisms, suggesting that uranium modified the sediment biogeochemistry. Although the two species firstly reacted by avoidance of contaminated sediment, they finally colonized it. Their bioturbation activity was reduced but, for T. tubifex, it remained sufficient to induce a release of uranium to the water column and an increase of the DOU (53%). These results highlight the necessity of further investigations to take into account the interactions between bioturbation, microbial metabolism and pollutants. - This study highlights the ecological importance of bioturbation in metal-contaminated sediments.

  9. A novel computational approach of image analysis to quantify behavioural response to heat shock in Chironomus Ramosus larvae (Diptera: Chironomidae

    Directory of Open Access Journals (Sweden)

    Bimalendu B. Nath

    2015-07-01

    Full Text Available All living cells respond to temperature stress through coordinated cellular, biochemical and molecular events known as “heat shock response” and its genetic basis has been found to be evolutionarily conserved. Despite marked advances in stress research, this ubiquitous heat shock response has never been analysed quantitatively at the whole organismal level using behavioural correlates. We have investigated behavioural response to heat shock in a tropical midge Chironomus ramosus Chaudhuri, Das and Sublette. The filter-feeding aquatic Chironomus larvae exhibit characteristic undulatory movement. This innate pattern of movement was taken as a behavioural parameter in the present study. We have developed a novel computer-aided image analysis tool “Chiro” for the quantification of behavioural responses to heat shock. Behavioural responses were quantified by recording the number of undulations performed by each larva per unit time at a given ambient temperature. Quantitative analysis of undulation frequency was carried out and this innate behavioural pattern was found to be modulated as a function of ambient temperature. Midge larvae are known to be bioindicators of aquatic environments. Therefore, the “Chiro” technique can be tested using other potential biomonitoring organisms obtained from natural aquatic habitats using undulatory motion as a behavioural parameter.

  10. Blind Flight? A New Troglobiotic Orthoclad (Diptera, Chironomidae) from the Lukina Jama – Trojama Cave in Croatia

    Science.gov (United States)

    Ivković, Marija; Kvifte, Gunnar Mikalsen; Pavlek, Martina

    2016-01-01

    The genus Troglocladius Andersen, Baranov et Hagenlund, gen. n. is erected based on T. hajdi Andersen, Baranov et Hagenlund, sp. n. collected at 980 m depth in the Lukina jama—Trojama cave system in Croatia. Morphological features such as pale color, strongly reduced eyes and very long legs make it a typical cave animal. Surprisingly, it has also retained large wings and appears to be capable of flight which would make T. hajdi the first flying troglobiont worldwide, disproving previous beliefs that bats are the only animals capable of flying in complete darkness. Morphologically the new species does not readily fit within any described genus, but shares characteristics with genera both in the tribes “Metriocnemini” and “Orthocladiini”. Bayesian molecular phylogenetic analysis using the markers COI, 18S rDNAs, 28S rDNA, CADI, and CADIV groups it with the genera Tvetenia, Cardiocladius and Eukiefferiella in the tribe “Metriocnemini”. Troglocladius hajdi may be parthenogenetic, as only females were collected. The discovery confirms the position of the Dinaric arch as a highly important hotspot of subterranean biodiversity. PMID:27119557

  11. Identification of anhydrobiosis-related genes from an expressed sequence tag database in the cryptobiotic midge Polypedilum vanderplanki (Diptera; Chironomidae).

    Science.gov (United States)

    Cornette, Richard; Kanamori, Yasushi; Watanabe, Masahiko; Nakahara, Yuichi; Gusev, Oleg; Mitsumasu, Kanako; Kadono-Okuda, Keiko; Shimomura, Michihiko; Mita, Kazuei; Kikawada, Takahiro; Okuda, Takashi

    2010-11-12

    Some organisms are able to survive the loss of almost all their body water content, entering a latent state known as anhydrobiosis. The sleeping chironomid (Polypedilum vanderplanki) lives in the semi-arid regions of Africa, and its larvae can survive desiccation in an anhydrobiotic form during the dry season. To unveil the molecular mechanisms of this resistance to desiccation, an anhydrobiosis-related Expressed Sequence Tag (EST) database was obtained from the sequences of three cDNA libraries constructed from P. vanderplanki larvae after 0, 12, and 36 h of desiccation. The database contained 15,056 ESTs distributed into 4,807 UniGene clusters. ESTs were classified according to gene ontology categories, and putative expression patterns were deduced for all clusters on the basis of the number of clones in each library; expression patterns were confirmed by real-time PCR for selected genes. Among up-regulated genes, antioxidants, late embryogenesis abundant (LEA) proteins, and heat shock proteins (Hsps) were identified as important groups for anhydrobiosis. Genes related to trehalose metabolism and various transporters were also strongly induced by desiccation. Those results suggest that the oxidative stress response plays a central role in successful anhydrobiosis. Similarly, protein denaturation and aggregation may be prevented by marked up-regulation of Hsps and the anhydrobiosis-specific LEA proteins. A third major feature is the predicted increase in trehalose synthesis and in the expression of various transporter proteins allowing the distribution of trehalose and other solutes to all tissues.

  12. A new orthoclad species of Rheocricotopus Thienemann & Harnisch (Diptera, Chironomidae from the Darjeeling-Sikkim Himalayas in India

    Directory of Open Access Journals (Sweden)

    Hazra, N.

    2004-12-01

    Full Text Available The adults and pupa of a new species, Rheocricotopus rarispina are described from the Darjeeling-Sikkim Himalayas in India. The species is distinguished by the few spines on the thoracic horn, anal lobe without fringe and bristle-like L setae and presence of ovoid humeral pit, nine squamal setae, structure of anal point and triangular and subterminal crista dorsalis in the adult male. With this new species, the number of Indian species of the genus rises to six.

  13. ELISA detection of multixenobiotic resistance transporter induction in indigenous freshwater Chironomidae larvae (Diptera): A biomarker calibration step for in situ monitoring of xenobiotic exposure

    Energy Technology Data Exchange (ETDEWEB)

    Moreau, X.; Saez, G.; Thiery, A. [Equipe ' Biomarqueurs and Bioindicateurs Environnementaux' , UMR-CNRS 6116 IMEP, Universite de Provence, 3 Place Victor Hugo, 13331 Marseille cedex 3 (France); Clot-Faybesse, O.; Guiraudie-Capraz, G. [' Neurobiologie Integrative et Adaptative' -UMR 6149, Universite de Provence, 3 Place Victor Hugo, 13331 Marseille cedex 3 (France); Bienboire-Frosini, C. [' Neurobiologie Integrative et Adaptative' -UMR 6149, Universite de Provence, 3 Place Victor Hugo, 13331 Marseille cedex 3 (France); Pherosynthese, Le Rieu Neuf, 84490 St Saturnin d' Apt (France); Martin, C. [Equipe ' Biomarqueurs and Bioindicateurs Environnementaux' , UMR-CNRS 6116 IMEP, UAPV, 33 rue Louis Pasteur, 84000 Avignon (France); De Jong, L. [Equipe ' Biomarqueurs and Bioindicateurs Environnementaux' , UMR-CNRS 6116 IMEP, Universite de Provence, 3 Place Victor Hugo, 13331 Marseille cedex 3 (France)], E-mail: laetitia.moreau@univ-provence.fr

    2008-06-15

    A new simple and sensitive method to distinguish chemically polluted from unpolluted situations in freshwater ecosystems is reported. For this purpose, Chironomus gr thumni larvae were collected from a polluted urban river downstream a sewage treatment plant. For the first time, ELISA assay was used to semi-quantify the multixenobiotic resistance transporters (MXR) in these small pertinent bioindicators. The use of samples immediately fixed in the field gives a delay to isolate larvae and allows multi-sampling along a longitudinal transect in a river at a given time. Results exhibit an induction of MXR proteins in larvae from the polluted river and a deinduction in larvae maintained 11 days in unpolluted water. They show new evidences to use midge larvae in biomonitoring environmental programs. They answer to first biomarker calibration steps for the ongoing development of MXR transporters as a detection tool of xenobiotic impacts on bioindicator invertebrates in their freshwater habitats. - Semi-quantification of midge larval MXR transporters by ELISA is a simple and sensitive method to detect chemically polluted situations in running freshwaters.

  14. Evaluation of mentum deformities of Chironomus spp. (Chironomidae: Diptera) larvae using modified toxic score index (MTSI) to assess the environmental stress in Juru River Basin, Penang, Malaysia.

    Science.gov (United States)

    Al-Shami, Salman Abdo; Salmah, Mad Rawi Che; Hassan, Ahmad Abu; Azizah, Mohd Nor Siti

    2011-06-01

    Morphological mentum deformities which represent sublethal effect of exposure to different types of pollutants were evaluated in Chironomus spp. larvae inhabiting three polluted rivers of Juru River Basin in northwestern peninsular Malaysia. Using mentum deformity incidences, the modified toxic score index (MTSI) was developed based on Lenat's toxic score index (TSI). The suggested MTSI was compared with TSI in terms of its effectiveness to identify different pollutants including heavy metals. The MTSI showed stronger relationship to total deformity incidence expressed as percentage. Additionally, the multivariate RDA model showed higher capability of MTSI to explain the variations in heavy metal contents of the river sediments. The MTSI was recommended in bioassessment of water and sediment quality using the mentum deformities of Chironomus spp. larvae from aquatic ecosystems receiving anthropogenic, agricultural, or industrial discharges.

  15. Effects of Lumbriculus variegatus (Annelida, Oligochaete) bioturbation on zinc sediment chemistry and toxicity to the epi-benthic invertebrate Chironomus tepperi (Diptera: Chironomidae).

    Science.gov (United States)

    Colombo, Valentina; Pettigrove, Vincent J; Hoffmann, Ary A; Golding, Lisa A

    2016-09-01

    Classical laboratory-based single-species sediment bioassays do not account for modifications to toxicity from bioturbation by benthic organisms which may impact predictions of contaminated sediment risk to biota in the field. This study aims to determine the effects of bioturbation on the toxicity of zinc measured in a standard laboratory bioassay conducted with chironomid larvae (Chironomus tepperi). The epi-benthic chironomid larvae were exposed to two different levels of sediment contamination (1600 and 1980 mg/kg of dry weight zinc) in the presence or absence of annelid worms (Lumbriculus variegatus) which are known to be tolerant to metal and to have a large impact on sediment properties through bioturbation. Chironomids had 5-6x higher survival in the presence of L. variegatus which shows that bioturbation had a beneficial effect on the chironomid larvae. Chemical analyses showed that bioturbation induced a flux of zinc from the pore water into the water column, thereby reducing the bioavailability of zinc in pore water to the chironomid larvae. This also suggested that pore water was the major exposure path for the chironomids to metals in sediment. During the study, annelid worms (Oligochaetes) produced a thin layer of faecal pellets at the sediment surface, a process known to: (i) create additional adsorption sites for zinc, thus reducing its availability, (ii) increase the microbial abundance that in turn could represent an additional food source for opportunistic C. tepperi larvae, and (iii) modify the microbial community's structure and alter the biogeochemical processes it governs thus indirectly impact zinc toxicity. This study represents a contribution in recognising bioturbating organisms as "ecological engineers" as they directly and indirectly influence metal bioavailability and impact other sediment-inhabiting species. This is significant and should be considered in risk assessment of zinc levels (and other metals) in contaminated sediment when extrapolating from laboratory studies to the field.

  16. Diagnoses for Nubensia, n. gen. (Diptera, Chironomidae, Chironomini), with the first full descriptions of the adult female and larva of N. nubens (Edwards, 1929).

    Science.gov (United States)

    Spies, Martin; Dettinger-Klemm, Andreas

    2015-07-30

    A new genus, Nubensia Spies, is proposed for N. nubens (Edwards, 1929), n. comb., based on morphological evaluation of both adult sexes, the pupa and larva. The material studied includes name-bearing syntype specimens and the first reared associations linking three life stages for individual members of this species. The larva represents a unique morphotype previously described incompletely only from studies of subfossil chironomid remains. The problems with placement of the species in any previously established genus are discussed in detail, and various related issues in taxonomy and nomenclature are commented on. The verified distribution of N. nubens ranges from the British Isles and central Europe to the western Mediterranean, including northern Africa, with possible extensions to Turkey and central Asia. Larvae have been found on mostly coarse, variously covered substrates near the shores of lakes and banks of slowly flowing running waters, under both oligotrophic and eutrophic conditions.

  17. A New Species Group in the Genus Tanytarsus van der Wulp(Diptera:Chironomidae)Based on a Fossil Record from Baltic Amber

    Institute of Scientific and Technical Information of China (English)

    Wojciech GI(L)KA

    2010-01-01

    A new fossil chironomid,Tanytarsus serafini,found in Baltic amber is described and illustrated based on adult males.The new species and similar extant species of the genus Tanytarsus van der Wulp are compared.Due to several distinct characters of wing,legs and hypopygium,a new species group for Tanytarsus serafini is proposed,and its diagnostic features are evaluated.

  18. A review of Rheocricotopus (Psilocricotopus chalybeatus species group from China, with the description of three new species (Diptera, Chironomidae

    Directory of Open Access Journals (Sweden)

    Wenbin Liu

    2014-03-01

    Full Text Available The Rheocricotopus (Psilocricotopus chalybeatus species group from China is reviewed. Three new species, R. (P. brochus sp. n., R. (P. rotundus sp. n. and R. (P. serratus sp. n. are described as adult males. R. (P. imperfectus Makarchenko & Makarchenko, 2005, R. (P. robacki (Beck & Beck, 1964 and R. (P. valgus Chaudhuri & Sinharay, 1983 are recorded from China for the first time and annotated. The diagnosis for the species group is emended and a key to adult males of the species group in China is presented.

  19. Multi-scale approach to the environmental factors effects on spatio-temporal variability of Chironomus salinarius (Diptera: Chironomidae) in a French coastal lagoon

    Science.gov (United States)

    Cartier, V.; Claret, C.; Garnier, R.; Fayolle, S.; Franquet, E.

    2010-03-01

    The complexity of the relationships between environmental factors and organisms can be revealed by sampling designs which consider the contribution to variability of different temporal and spatial scales, compared to total variability. From a management perspective, a multi-scale approach can lead to time-saving. Identifying environmental patterns that help maintain patchy distribution is fundamental in studying coastal lagoons, transition zones between continental and marine waters characterised by great environmental variability on spatial and temporal scales. They often present organic enrichment inducing decreased species richness and increased densities of opportunist species like C hironomus salinarius, a common species that tends to swarm and thus constitutes a nuisance for human populations. This species is dominant in the Bolmon lagoon, a French Mediterranean coastal lagoon under eutrophication. Our objective was to quantify variability due to both spatial and temporal scales and identify the contribution of different environmental factors to this variability. The population of C. salinarius was sampled from June 2007 to June 2008 every two months at 12 sites located in two areas of the Bolmon lagoon, at two different depths, with three sites per area-depth combination. Environmental factors (temperature, dissolved oxygen both in sediment and under water surface, sediment organic matter content and grain size) and microbial activities (i.e. hydrolase activities) were also considered as explanatory factors of chironomid densities and distribution. ANOVA analysis reveals significant spatial differences regarding the distribution of chironomid larvae for the area and the depth scales and their interaction. The spatial effect is also revealed for dissolved oxygen (water), salinity and fine particles (area scale), and for water column depth. All factors but water column depth show a temporal effect. Spearman's correlations highlight the seasonal effect (temperature, dissolved oxygen in sediment and water) as well as the effect of microbial activities on chironomid larvae. Our results show that a multi-scale approach identifies patchy distribution, even when there is relative environmental homogeneity.

  20. Nucleolar organizer (NO) size as a measure of instantaneous growth in Chironomus riparius larvae (Diptera: Chironomidae) : a tool for monitoring individual and population responses to stress

    Energy Technology Data Exchange (ETDEWEB)

    Martin, J.P.; Ciborowski, J.J.; Wytrykush, C. [Windsor Univ., Windsor, ON (Canada)

    2009-07-01

    This presentation reported on 2 laboratory experiments that were conducted using Chironomus riparius larvae to relate nucleolar growth (NO) size to chironomid growth. In one experiment, 5 treatments varied in diet quality only, which was manipulated by providing midge larvae with 1.0 mg of food per individual per day, but varying the ratio of Tetramin to non-nutritious methyl-cellulose. A second experiment followed a 2 x 2 factorial design. The factors were growth period and diet quality. Diet quality and growth period were found to influence the individual biomass considerably. NO size was related to the quality of the diet provided at the end of the experiment, regardless of larval biomass. Therefore, NO size appears to be related to growth rate at time of collection rather than larval size. The authors proposed using NO size of larvae in natural populations as a measure of growth on which to base estimates of secondary production and as a new way to monitor individual and population responses to environmental stress. Preliminary field measurements of larval production and NO size from oil sands-affected and reference wetlands were found to be consistent with laboratory results.

  1. Production dynamics and life cycle of dominant chironomids (diptera, chironomidae) in a subtropical stream in China: adaptation to variable flow conditions in summer and autumn

    Science.gov (United States)

    Yan, Yunjun; Li, Xiaoyu

    2007-07-01

    The production dynamics and trophic basis of 7 dominant species of chironomids were investigated in the area of a second-order river of the Hanjiang River basin, in central China from June 2003 to June 2004. The results showed that Tvetenia discoloripes was by far the most abundant chironomid, dominating the overall standing stock of the taxa. In terms of lif ecycle, Chaetocladius sp., Eukiefferiella potthasti and T. discoloripes developed 1 generation a year, whereas Microtendipes sp. and Pagastia sp. developed two, while Pentaneura sp. and Polypedilum sp. developed three. T. discoloripes was the most productive chironomid with 120.305 8 g/m2. a, Pentaneura sp. and E. potthasti had relatively high production values of >17 g/m2.a, and the rest were 0.5), especially for filter-collectors Microtendipes sp., Chaetocladius sp., Chaetocladius sp., T. discoloripes and Pagastia sp. All species except Pentaneura sp. consumed a large portion of amorphous detritus, constituting more than 90% of their diets, and contributing nearly 90% to their secondary production. All the 7 chironomids represent obvious adaptation to local highly variable climate in summer and autumn in life cycle pattern, production dynamics, and food type.

  2. [Molecular phylogeny and the time of divergence of minges (Chironomidae, Nematocera, Diptera) inferred from a partial nucleotide sequence of the cytochrome oxidase I gene (COI)].

    Science.gov (United States)

    Demin, A G; Polukonova, N V; Miuge, N S

    2011-10-01

    This is the first study to infer the phylogenetic structure of minges of the subfamily Chironominae from the amino acid sequence of cytochrome oxidase I (COI). The subdivision of Chironominae into two tribes, Chironomini and Tanytarsini, has been confirmed. The segregation of the genera Pseudochironomus and Riethia into a separate tribe has not been confirmed. Stenochironomus gibbus forms a branch considerably deviating from the subfamily Chironominae. The genus Micropsectra is formed by a large polyphyletic cluster that also includes the genera Virgotanytharsus, Reotanytharsus, Kenopsectra, and Parapsectra. Tanytarsus is the basal genus of the tribe Tanytarsini. The times of divergence of the main taxa of Chironominae have been estimated. The calculated time of divergence of the genus Chironomus disproves the assumption that it is phylogenetically old.

  3. Molecular Characterization and Expression Analysis of P38 MAPK Gene and Protein in Aquatic Midge, Chironomus riparius (Diptera: Chironomidae), Exposed to Environmental Contaminants.

    Science.gov (United States)

    Park, Sun-Young; Choi, Jinhee

    2017-04-01

    P38 Mitogen-activated protein kinase (MAPK), an important signaling protein involved in various cellular processes, including stress responses, has been well characterized in model organisms. P38 has been identified in a number of insects, including the genus Drosophila; however, its homologue in Chironomus riparius has not yet been identified. In this study, we identified and characterized p38 MAPK (Crp38) gene in C. riparius using a transcriptome database that was previously generated 454 GS-FLX pyrosequencing. Comparative and phylogenetic analyses were performed using the p38 homologue of other species, such as Drosophila melanogaster, Aedes aegypti, Bombyx mori, Caenorhabditis elegans, Homo sapiens, etc. Furthermore, to test its potential as a biomarker of environmental contamination, Crp38 gene expression was analyzed upon exposure to nonylphenol (NP), silver nanoparticles (AgNPs), and cadmium (Cd). Crp38 gene expression was up- or down-regulated depending on the concentration and exposure duration of chemicals. These results show the role of Crp38 gene in defense against environmental stresses, as well as its potential use as a biomarker for various environmental pollutants. We further synthesized p38 antibody based on the predicted amino acid sequence deduced from Crp38 cDNA and, using this customized antibody, examined p38 protein expression in Cd exposed C. riparius. Although transcriptional alteration was not translated to the protein level, this result showed the possible application of a protein level functional study using cDNA sequence information from next-generation sequencing database in nonmodel organisms.

  4. Chironomidae (Diptera en cursos de agua de Puna y Chaco Serrano de Catamarca (Argentina: primeros registros y distribución de géneros y especies

    Directory of Open Access Journals (Sweden)

    Gretel N. RODRÍGUEZ GARAY

    2015-01-01

    Full Text Available La distribución en América del Sur (Region Neotropical de Stictocladius prati Saether & Cranston, Podonomus. regalis Brundin y P. setosus Brundin 1966 es ampliada a partir de primeros registros de la Argentina. Podonomus fastigians Brundin, y Allocladius quadrus Andersen et al. se citan por primera vez de Catamarca Se describe el morfotipo pupal de Barbadocladius sp. “Chaco” (cerca de B. andinus Cranston & Krosh. Se incorporan las variables ambientales de los cursos de agua donde se registraron las especies. Los ríos de Puna presentan aguas muy alcalinas, pH (8.12-8.8, alta conductividad y alto contenido en MO, mientras que el arroyo de Chaco Serrano es de aguas débilmente alcalinas, pH (7, baja conductividad y bajo contenido en materia orgánica (MO. Las especies Stictocladius prati, Allocladius quadrus, Podonomus fastigians, P. setosus y P. regalis estuvieron presentes en ríos de altura con aguas alcalinas y alta conductividad, mientras Barbadocladius sp. “Chaco” se registró en un arroyo de menor altura, con aguas de baja alcalinidad y conductividad.

  5. A new Thalassosmittia Strenzke and Remmert, 1957 out of the sea: T. amazonica n. sp. from the Amazon rainforest, Brazil (Diptera: Chironomidae, Orthocladiinae

    Directory of Open Access Journals (Sweden)

    Trond Andersen

    2014-12-01

    Full Text Available The orthoclad Thalassosmittia amazonica n. sp. is described based on a male collected in a light trap in the Amazon rainforest. The species is easily separated from its congeners as it has a strongly reduced palp with only a single palpomere.Article submitted 12. October 2014, accepted 10. November 2014, published 22. December 2014.

  6. Production dynamics and life cycle of dominant chironomids (Diptera, Chironomidae) in a subtropical stream in China: adaptation to variable flow conditions in summer and autumn

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The production dynamics and trophic basis of 7 dominant species of chironomids were investigated in the area of a second-order river of the Hanjiang River basin, in central China from June 2003 to June 2004. The results showed that Tvetenia discoloripes was by far the most abundant chironomid, dominating the overall standing stock of the taxa. In terms of life cycle, Chaetocladius sp.,Eukiefferiella potthasti and T. discoloripes developed 1 generation a year, whereas Microtendipes sp. and Pagastia sp. developed two, while Pentaneura sp. and Polypedilum sp. developed three. T. discoloripes was the most productive chironomid with 120.305 8 g/m2.a, Pentaneura sp.and E. potthasti had relatively high production values of >17 g/m2.a, and the rest were <10 g/m2.a. All the production temporal variation tended to follow biomass patterns. T. discoloripes, Chaetocladius sp. and Pagastia sp. concentrated most of their production in winter, whereas E. potthasti, Pentaneura sp. and Polypedilum sp. had relatively higher production throughout the year. Only Microtendipes sp. had a production that peaked in summer.The overlap in temporal distribution of production among the chironomid species was generally high (>0.5), especially for filter-collectors Microtendipes sp., Chaetocladius sp., Chaetocladius sp., T.discoloripes and Pagastia sp. All species except Pentaneura sp. consumed a large portion of amorphous detritus, constituting more than 90% of their diets, and contributing nearly 90% to their secondary production. All the 7 chironomids represent obvious adaptation to local highly variable climate in summer and autumn in life cycle pattern, production dynamics, and food type.

  7. Taxonomic review on the subgenus Tripodura Townes (Diptera: Chironomidae: Polypedilum) from China with eleven new species and a supplementary world checklist.

    Science.gov (United States)

    Zhang, Ruilei; Song, Chao; Qi, Xin; Wang, Xinhua

    2016-07-05

    The subgenus Tripodura Townes of Polypedilum Kieffer from China including 26 species is reviewed. Eleven new species, named P. (T.) absensilobum Zhang & Wang sp. n., P. (T.) apiculusetosum Zhang & Wang sp. n., P. (T.) arcuatum Zhang & Wang sp. n., P. (T.) bilamella Zhang & Wang sp. n., P. (T.) conghuaense Zhang & Wang sp. n., P. (T.) dengae Zhang & Wang sp. n., P. (T.) mengmanense Zhang & Wang sp. n., P. (T.) napahaiense Zhang & Wang sp. n., P. (T.) parallelum Zhang & Wang sp. n., P. (T.) pollicium Zhang & Wang sp. n. and P. (T.) trapezium Zhang & Wang sp. n. are described and illustrated based on male imagines. Three species, P. (T.) quadriguttatum Kieffer, P. (T.) unifascia (Tokunaga) and P. (T.) udominutum Niitsuma are firstly recorded in China. A key to known male imagines of Chinese species and an updated world checklist of subgenus Tripodura are presented.

  8. Responses of Chironomidae (Diptera; Insecta) to the exclusion of shrimps and Ephemeroptera in a coastal forest stream, Rio de Janeiro, Brazil.

    Science.gov (United States)

    Souza, M L; Moulton, T P; Silveira, R M L; Krsulović, F A M; Brito, E F

    2007-02-01

    In a benthic community on a continuous flat granite substrate in a third-order coastal forest stream, the dominant chironomid (Cricotopus) increased in number when shrimps (Macrobrachium olfersi and Potimirim glabra) and baetid ephemeropterans were excluded by electricity. The response appeared to be mediated by an increase in periphyton and sediments, rather than a reduction of direct predation or interference. Chironomids, periphyton and sediments decreased significantly compared to the control when shrimps only were excluded. Baetid ephemeropteran appeared to be the most important determinants of periphyton and sediment mass; the density of chironomids appeared to follow the quantity of periphyton and sediments.

  9. Paleoecología: el uso de los quironómidos fósiles (Diptera: Chironomidae en reconstrucciones paleoambientales durante el Cuaternario en la Patagonia

    Directory of Open Access Journals (Sweden)

    Julieta MASSAFERRO

    2009-01-01

    Full Text Available Entre los indicadores biológicos lacustres más utilizados en las reconstrucciones ambientales, se encuentran el polen, los ostrácodos y las diatomeas, y entre los insectos, los coleópteros y los quironómidos. Este grupo ha cobrado gran importancia en los últimos tiempos, debido a los resultados prometedores que se han obtenido en reconstrucciones climáticas realizadas en América del Norte y Europa. En América del Sur, el uso de los quironómidos fósiles en estudios cuaternarios es relativamente limitado, principalmente por su escaso conocimiento taxonómico regional. La mayor parte de estos estudios fueron realizados en lagos glaciares patagónicos de Argentina y Chile. Las larvas de quironómidos constituyen una valiosa herramienta paleolimnológica, por ser un grupo de organismos altamente sensible a cambios ambientales, tanto naturales como artificiales. Además, es un grupo de insectos ampliamente distribuido y con una abundancia y diversidad relativamente altas. Sus cápsulas cefálicas se preservan en los sedimentos lacustres y poseen caracteres importantes que permiten identificar géneros y muchas veces especies. El estudio de los ensambles de quironómidos en sedimentos lacustres puede ser utilizado con distintos objetivos, por ejemplo, para estudios de eutrofización, ya que responden rápidamente a cambios en la concentración de nutrientes, materia orgánica y otros elementos, como metales pesados. No obstante, uno de los potenciales más importantes de este grupo de insectos es su sensibilidad a los cambios de temperatura, por este motivo, la aplicación más importante de su estudio en sedimentos se centra en las reconstrucciones climáticas. Esta contribución es una síntesis de los resultados de los trabajos publicados en la Patagonia argentina y chilena, sobre la base del uso de los quironómidos fósiles en reconstrucciones paleoambientales.

  10. Taxonomic study on the subgenus Uresipedilum (Diptera: Chironomidae: Polypedilum, with description of a new species from the Yaewyama Islands, Okinawa, Japan

    Directory of Open Access Journals (Sweden)

    Nao Yamamoto

    2015-07-01

    Full Text Available As a result of a multi-year survey, we recognized four species including a new species of the subgenus Uresipedilum from the Yaeyama Islands, the Ryukyus, Japan. Polypedilum (Uresipedilum paraconvictum sp. nov. is described. P. (U. classiglobum Zhang et Wang (2004 P. (U. bingoparadoxum Kawai et al. (1998 and P. (U. iriofegeum Sasa et Suzuki (2000 are re-described. The first species is newly recorded from Japan, and the second species is new to the Ryukyus. The diagnostic characters of the subgenus are discussed.

  11. Ocorrência de Polypedilum (Tripodura amataura Bidawid-Kafka, 1996 (Diptera; Chironomidae em Aquascypha hydrophora (berk. Reid (Fungi; Stereaceae, com descrição da pupa na Amazônia Central, Brasil Occurrence of Polypedilum (Tripodura amataura Bidawid-Kafka, 1996 (diptera; chironomidae in Aquascypha hydrophora (berk. Reid (Fungi; Stereaceae, with description of the pupae in the Central Amazonian, Brazil

    Directory of Open Access Journals (Sweden)

    Arlindo Serpa-Filho

    2007-01-01

    Full Text Available Quatro larvas foram coletadas em água retida pelo fungo Aquascypha hydrophora (Berk. Reid (Fungi: Stereaceae fixo em troncos de árvores eretas, na Reserva Florestal Adolpho Ducke, Amazonas, Brasil. Das larvas coletadas, apenas um exemplar desenvolveu até a fase adulta, sendo identificado como Polypedilum (Tripodura amataura Bidawid-Kafka, 1996. Esta é a primeira descrição para uma forma imatura deste gênero, e também o primeiro registro em micotelmata.Four larvae were collected in water with the fungus Aquascyphahydrophora (Berk. Reid (Fungi: Stereaceae, fixed in tree trunks found in the Adolpho Ducke Forest Reserve, Amazonas, Brazil. Only one specimem reached the adult phase, which was identified as Polypedilum (Tripodura amataura Bidawid-Kafka, 1996. This is the first description of an immature form of this genus, and also the first registered in mycotelmata.

  12. WATER QUALITY ANALYSIS OF LOTIC ECOSYSTEMS FROM UPPER MUREŞ RIVER CATCHMENT AREA USING DIFFERENT BIOTIC INDICES

    Directory of Open Access Journals (Sweden)

    Milca PETROVICI

    2012-01-01

    Full Text Available Present paper approach the issue of assessing the water quality of tributaries located in the upper basin of the river Mureş, taking into account changes in the value of biotic indices. In this sense, have been selected the next five biotic indices: Ephemeroptera Plecoptera Trichoptera index (EPT, Total Invertebrates index (T, Chironomidae index (Ch, EPT / Total invertebrates index (EPT / T, EPT / Chironomidae index (EPT / Ch and % Chironomidae index (% Chironomidae. Considering all these indices, it was found existence of a medium to best quality water in Mureş tributaries from Harghita Mountains and a good quality water which comes from the Maramureş Mountains and Transylvania Plateau.

  13. 摇蚊亚科中国一新纪录属——脊突摇蚊属(双翅目:摇蚊科)%A First Recorded Genus Cyphomella S(ae)ther(Diptera:Chironomidae)from China

    Institute of Scientific and Technical Information of China (English)

    闫春财; 李悦; 王新华

    2011-01-01

    The genus Cyphomella S(ae)ther,1977 is firstly recorded from China.Detail description and illustration of the species C. cornea,S(ae)ther,1977 and the key to males of genus Cyphomella S(ae)ther in the world are given.The specimen is deposited in College of Life Sciences,Nankai Universtiy,Tianjin of China.%记述了摇蚊亚科中国新纪录属--脊突摇蚊属Cyphomella Seether,1977.给出了膜脊突摇蚊 C.cornea S(ae)ther,1977的详细描述、绘图以及世界脊突摇蚊属雄成虫分种检索表.标本保存于南开大学生命科学学院.

  14. Studies on Entomophthora culicis ( Zygomycetes: Entomophthorales) infecting Chironomus sp. ( Diptera: Chironomidae) in Guangdong Province%广东省侵染摇蚊的库蚊虫霉研究

    Institute of Scientific and Technical Information of China (English)

    贾春生; 洪波

    2011-01-01

    This paper presents the first description of aspects of Entomophthora culicis infecting Chironomus sp. in China, including disease symptoms and occurrence dynamics. The primary conidia of E. culicis are campanulate,measure ( 14.6 ± 1.5 ) μm × ( 10. 8 ± 1.2 ) μm and have a distinct apical point. Secondary conidia are similar to primary ones but are smaller, measuring ( 11.0 ± 1.1 ) μm × ( 8.0 ± 0. 5 ) μm. Resting spores are ( 29. 3 ± 1.9 ) μm in size and spherical to subspherical in shape. Infected insects are fixed to the substrate by rhizoids. The sporulating mycelium is greenish and covers the host completely. The infection rate of E. culicis was obviously different in three trees. The infection rate varied between seasons, being lowest in summer (0) and highest in spring (90. 2% ). There was no significant change in infection rate (93.5%-95.7% ) from 2006 to 2009.%在中国首次报道了侵染摇蚊的库蚊虫霉(Entomophtora culichs)的形态特征、侵染症状以及发生动态等.库蚊虫霉初生分生孢子,钟罩形,顶部有一明显小尖突,(14.6±1.5)μm×(10.8±1.2)μm.次生分生孢子形似初生分生孢子,但略小,(11.0±1.1)μm×(8.0±0.5)μm.休眠孢子,球形至亚球形,直径(29.3±1.9)μm.被侵染摇蚊尸体以假根附着于基物上,通体覆盖着绿色的真菌子实层.库蚊虫霉侵染率在不同植物上明显不同.库蚊虫霉侵染率随季节不同波动很大,春季最高达90.2%,其次为秋季和冬季,夏季最低为0.2006-2009年库蚊虫霉侵染率为93.5%~95.7%,年际之间变动不大.

  15. Morphological deformities in Chironomus spp. (Diptera: Chironomidae) larvae as a tool for impact assessment of anthropogenic and environmental stresses on three rivers in the Juru river system, Penang, Malaysia.

    Science.gov (United States)

    Al-Shami, Salman; Rawi, Che Salmah M; Nor, Siti Azizah M; Ahmad, Abu Hassan; Ali, Arshad

    2010-02-01

    Morphological deformities in parts of the head capsule of Chironomus spp. larvae inhabiting three polluted rivers (Permatang Rawa [PRR], Pasir [PR], and Kilang Ubi [KUR]) in the Juru River Basin, northeastern peninsular Malaysia, were studied. Samples of the fourth-instar larvae at one location in each river were collected monthly from November 2007 to March 2008 and examined for deformities of the mentum, antenna, mandible, and epipharyngis. At each sample location, in situ measurements of water depth, river width, water pH, dissolved oxygen, and water temperature were made. Samples of river water and benthic sediments were also collected monthly from each larval sample location in each river and taken to the laboratory for appropriate analysis. Total suspended solids (TSSs), ammonium-N, nitrate-N, phosphate-P, chloride, sulfate, and aluminum content in water were analyzed. Total organic matter and nonresidual metals in the sediment samples were also analyzed. Among the three rivers, the highest mean deformity (47.17%) was recorded in larvae collected from KUR that received industrial discharges from surrounding garment and rubber factories, followed by PRR (33.71%) receiving primarily residues of fertilizers and pesticides from adjacent rice fields, and PR (30.34%) contaminated primarily by anthropogenic wastes from the surrounding residential areas. Among the various head capsule structures, deformity of the mentum was strongly reflective of environmental stress and amounted to 27.9, 20.87, and 30.19% in the PRR, PR, and KUR, respectively. Calculated Lenat's toxic score index satisfactorily explained the influence of prevailing environmental variables on the severity of mentum deformities. Redundancy analysis and forward selection selected TSSs, sediment Zn, Mn, Cu, and Ni, and water pH, dissolved oxygen, water temperature, total organic matter, nitrate-N, chloride, phosphate-P, ammonium-N, sulfate, and aluminum as parameters that significantly affected some proportion of deformities. The total deformities correlated closely with deformities of mentum but only weakly with deformities in other parts of head. The total deformity incidence was strongly correlated with high contents of sediment Mn and Ni. The mentum and epipharyngis deformities incidence was highly correlated with an increase of TSSs, total aluminum, and ammonium-N and a decrease in pH and dissolved oxygen.

  16. Using biofilms and grazing chironomids (Diptera: Chironomidae) to determine primary production, nitrogen stable isotopic baseline and enrichment within wetlands differing in anthropogenic stressors and located in the Athabasca oil sands region of Alberta

    Energy Technology Data Exchange (ETDEWEB)

    Frederick, K.; Ciborowski, J.J. [Windsor Univ., Windsor, ON (Canada); Wytrykush, C.M. [Syncrude Canada Ltd., Edmonton, AB (Canada)

    2009-07-01

    This presentation reported on a study that investigated the effects of oil sands process materials (OSPM) and construction disturbances on primary production and nitrogen stable isotope enrichment in reclaimed and reference wetlands at oil sands mines in the Athabasca basin. Productivity and food web analyses were instrumental in evaluating the succession and viability of reclaimed wetlands. Primary production was estimated through chlorophyll a (Chl a) concentrations and biomass. Carbon (C) and nitrogen (N) stable isotope ratios were used to identify energy sources, storage and the magnitude and direction of energy transfer within food webs. The objectives were to determine primary productivity, the N baseline, and N enrichment from biofilms and grazing invertebrates colonizing artificial substrates immersed in the water column of two OSPM-affected, two constructed reference and two natural reference wetlands. The lower biomass and Chl a concentrations in OSPM-affected and constructed wetlands suggests that both anthropogenic disturbance and OSPM have an adverse effect on primary productivity and overall wetland function.

  17. A New Species of Subgenus Polypedilum(s. str.) Kieffer (Diptera: Chironomidae) from China%中国多足揺蚊属指名亚属一新种(双翅目:摇蚊科)

    Institute of Scientific and Technical Information of China (English)

    张瑞雷; 王新华

    2007-01-01

    Polypedilum (Polypedilum) aequabe, sp. nov. is described as male imago from China. The species is easily distinguished from other members of the subgenus in equal length of hind tarsus II to tarsus III, the anal point with lateral setae, lateral seta of superior volsella present at subapical portion and the inferior volsella is expand apically.%记述中国多足摇蚊属指名亚属Polypedilum (s. str.) Kieffer 1新种——等跗多足摇蚊Polypedilum (Polypedilum) aequabe, sp. nov.,该新种雄虫可借以下组合特征与本亚属其它已知种类相区别:后足第2与第3跗节等长,肛尖具侧毛,上附器外侧毛位于近端部,下附器端部膨大.模式标本存放在南开大学生命科学学院摇蚊研究室.正模:♂,四川乡城硕曲河,2 700 m,1996-Ⅵ-12,灯诱,王新华采;副模: 18♂♂,同正模;1♂,云南丽江石鼓冲江河,1 750 m,1996-Ⅴ-25,灯诱,周长发采.

  18. 中国东洋区三突多足摇蚊亚属两新种(双翅目,摇蚊科)%TWO NEW SPECIES OF POLYPEDILUM (TRIPODURA ) TOWNES FROM ORIENTAL CHINA (DIPTERA, CHIRONOMIDAE)

    Institute of Scientific and Technical Information of China (English)

    张瑞雷; 王新华

    2007-01-01

    Polypedilum (Tripodura) bispinum sp. nov. and Polypedilum (Tripodura) spathum sp. nov., are described as male imagines from South China. P. ( T. ) bispinum sp. nov. differs from other species of the subgenus Tripodura in having spatulate anal point,the straight superior volsella with two transverse spine-like setae and developed lateral projection of anal point covered with microtrichiae. The spatula-shaped superior volsella of P. (T.) spathum sp. nov. is characteristic in Tripodura; as well as the high fore leg ration (2.63-2.89), high number of median setae (20-28) on tergite Ⅸ and the low number of setae (2-3) on the inferior volsella will separate P. ( T. ) spathum sp. nov. from other species in Tripodura.%记述了我国东洋区三突多足摇蚊亚属(Tripodura Townes)2新种.双刺多足摇蚊Polypedilum(Tripodura)bispinum sp.nov.(图1~5)本种与裸突多足摇蚊P.(T.)nudiprostatum Zhang & Wang相似,区别在于此新种r4+5翅室具有2个翅斑,m1+2和m3+4翅室端部具云状斑,肛尖矛尖状,肛尖侧突覆有微毛,上附器内侧中部具2个刺状刚毛.正模(♂),海南黎水县吊罗镇,1989-05-20,灯诱,王新华采.抹刀多足摇蚊,新种Polypedilum(Tripodura)spathum sp.nov.(图6~10)本种可借如下特征区别于本亚属已知种:上附器呈抹刀形;前足比高(2.63-2.89,2.75);第9背板中部刚毛少,2~3根;下附器长、刚毛少,具2~3根刚毛.正模(♂),云南勐腊县勐伦镇,1987-04-12,灯诱,邹环光采.本研究所用标本存放在南开大学生命科学学院摇蚊研究室.

  19. 中国异环足摇蚊属研究(双翅目:摇蚊科)%A REVIEW OF THE GENUS ACRICOTOPUS KIEFFER (DIPTERA:CHIRONOMIDAE) IN CHINA

    Institute of Scientific and Technical Information of China (English)

    张瑞雷; 王新华

    2004-01-01

    The genus Acricotopus Kieffer including three species from China is reviewed.Acricotopus lucens (Zetterstedt) is reexamined. Two species A. simplex sp. nov. and A.zhalingensis sp. nov. are described as male imagines. Acricotopus simplex sp. nov. was collected from Xizang, Sichuan and Qinghai Provinces; the species differs from others of the genus by the absence of hind tibial comb, temporal and clypeal seta. Acricotopus zhalingensis sp. nov. was collected from Qinghai Province; the species is recognized by a combination of characters: the larger body size; the clypeus without setae; anal lobe strongly produced, nearly hemispherical shape; inferior volsella triangular, strongly sclerotized; gonostylus with 13 very long setae. A key to the world males of the genus is presented. The generic diagnosis is emended.All the types described in this paper are deposited in Department of Biology, Nankai University,China (BDN).%异环足摇蚊属隶属于双翅目摇蚊科直突摇蚊亚科,全世界已记录4种.本文对中国产本属进行了系统研究.记述了2新种:简异环足摇蚊A simplex sp.nov.和扎陵异环足摇蚊A.zhalingensis sp.nov.,重新核定了亮异环足摇蚊Alucens(Zett.).提供了世界本属雄成虫检索表.依据中国标本和相关文献,对Cranston等1989年所描述的本属的触角比、前足比、下附器的形状等属级鉴别特征予以订正.模式标本均保存于南开大学生物系.简异环足摇蚊A.simplexsp.nov.:正模:雄性,西藏建日,9/3/1987,邓成玉采.与本属已知种的区别:后足胫节无栉;无额鬃和唇基毛;R2+3脉清晰.扎陵异环足摇蚊A.zhalingensis sp.nov.:正模:雄性,青海扎陵湖,8/20/1986,任淑智采.与本属已知种的区别:个体大;无唇基毛;翅臀叶强烈突出,半球状;下附器三角形,强烈骨化,抱器端节具有13根粗长的刚毛.

  20. North Fork Snoqualmie River Basin Wildlife Study.

    Science.gov (United States)

    1981-03-01

    sample of total Arthropoda Insecta Trichoptera Psychoglypha sp. 1 43.1 0.5 1.8 Diptera Chironomidae 35 1506.9 17.5 64.9 Odonata 1 43.1 0.5 1.8 Annelida...Odentoceridae --- unid. Hydropsychidae --- Psychoglypha sp. dragonflies and damselflies Odonata flies Diptera, midges Chironomidae crane flies

  1. Potential Use of Pyriproxyfen for Control of Aedes aegypti Diptera: Culicidae) in Iquitos, Peru

    Science.gov (United States)

    2005-01-20

    Cladocera, Copepoda, Ostracoda, Odonata , Dystisci- dae, Hydrophilidae, Chironomidae, and Cerato- pogonidae). In a separate study, Schaefer and Miura...no residues in rice plants (5 ppb). Slight aberrations in Odonata adults andminor reproductive suppressionof cladocerans and ostracods were noted

  2. Effects of Surface Texture of Articulated Concrete Mattress Blocks on Their Habitat Value. Lower Mississippi River Environmental Program Report 19

    Science.gov (United States)

    1992-09-01

    of trichoptera, chironomidae, ephemeroptera, odonata , collembola, amphipoda, isopoda, hydracarinia, gas- tropoda, bivalvia, naididae, hydrozoa...Ephemeroptera Baetis sp. CaenIs sp. Heptagenia sp. Isonychia sp. Stenocron sp. Odonata Neurocordulia moles ta (Continued) 21 Table 1 (Concluded) .Taxonomic

  3. Analysis of an alternative method for the study of bromeliad-associated fauna in plants with different foliar organization.

    Science.gov (United States)

    Müller, Gerson A; Name, Fernando T; Pacheco, Frederico C L; Marcondes, Carlos B

    2010-12-01

    The efficiency of an alternative method of collection (by suction of water) for the study of Culicidae and Chironomidae (Diptera), Scirtidae (Coleoptera) and Coenagrionidae (Odonata) in bromeliads with different foliar architecture in a restinga at Florianópolis, SC, Brazil, was studied. The alternative method was less efficient to collect Culicidae and Chironomidae (Wilcoxon test p 0.05) from Aechmea lindenii. This method was less efficient to collect insects of all groups from Vriesea friburgensis (Wilcoxon test p insects in both species of bromeliads. The higher mobility of immature forms of beetles and dragonflies, and the availability of only one tank in Aechea lindenii, contrasting to several tanks in Vriesea friburgensis that help the suction of these immature, probably influenced the results, which indicated that the suction method should not replace the dismantling in the study of Culicidae and Chironomidae. This method can be useful to get immature forms of Scirtidae and Coenagrionidae in one-tank bromeliads.

  4. Chironomid (Diptera species recorded from UK lakes as pupal exuviae

    Directory of Open Access Journals (Sweden)

    L.P. Ruse

    2013-09-01

    Full Text Available An inventory of chironomid species (Diptera, Chironomidae data collected from 221 lake basins or reservoirs is detailed together with major physical and chemical characteristics of these waterbodies. Aquatic species of Chironomidae must rise to the water surface for adult emergence. Floating exuviae are transported by wind and water currents to lakeshores. Species data were obtained by collecting lake marginal floating pupal exuviae representing juvenile stages dwelling from across the lake. Among the 450 species found, several were new records for the British Isles.

  5. Factors Affecting Fish Production and Fishing Quality in New Reservoirs, with Guidance on Timber Clearing, Basin Preparation, and Filling.

    Science.gov (United States)

    1981-08-01

    humus and fallen leaves; (b) leachate and particulate matter from submerged terrestrial vegetation (herbaceous and woody); (c) inflow from the...fauna colonization of a new reservoir with particular reference to the Chironomidae. J. Fish. Res. Board Can., 27:213-232. Paxton, K. 0. and F. Stevenson

  6. Analysis of an alternative method for the study of bromeliad-associated fauna in plants with different foliar organization

    Directory of Open Access Journals (Sweden)

    Gerson A. Müller

    2010-12-01

    Full Text Available The efficiency of an alternative method of collection (by suction of water for the study of Culicidae and Chironomidae (Diptera, Scirtidae (Coleoptera and Coenagrionidae (Odonata in bromeliads with different foliar architecture in a restinga at Florianópolis, SC, Brazil, was studied. The alternative method was less efficient to collect Culicidae and Chironomidae (Wilcoxon test p 0.05 from Aechmea lindenii. This method was less efficient to collect insects of all groups from Vriesea friburgensis (Wilcoxon test p A eficiência do método alternativo de coleta (por sucção da água para o estudo de Culicidae e Chironomidae (Diptera, Scirtidae (Coleoptera e Coenagrionidae (Odonata em bromélias com diferentes estruturas foliares de restinga em Florianópolis, SC, Brasil, foi estudada. O método alternativo foi menos eficiente para coletar Culicidae e Chironomidae (teste de Wilcoxon p 0, 05 a partir de Aechmea lindenii. Esse foi menos eficiente para coletar insetos de todos os grupos a partir de Vriesea friburgensis (teste de Wilcoxon p < 0,05. O método alternativo se mostrou eficiente em estimar a diversidade desses insetos nas duas espécies de bromélias. A alta mobilidade das formas imaturas dos coleópteros e libélulas e a disponibilidade de apenas um tanque em Aechea lindenii, em contraste com as várias axilas e Vriesea friburgensis, facilitando a sucção destas formas imaturas provavelmente influenciaram os resultados. Os resultados indicam que o método de sucção não deve substituir o desmanche no estudo de Culicidae e Chironomidae; ele pode ser útil para a obtenção de formas imaturas de Scirtidae e Coenagrionidae em bromélias de um só tanque.

  7. NATURAL DIET OF BARBEL BARBUS PELOPONNESIUS (VALENCIENNES, 1842 FROM THE SAVA RIVER

    Directory of Open Access Journals (Sweden)

    Marina Piria

    2007-01-01

    Full Text Available The barbel population (Barbus peloponnesius was studied in the Sava River at Medsave from July to October 2001. The main objective of the study was to obtain data on diet composition of this species in natural biotopes with relation to food availability in the river. In the spring, the dominant food items of barbel were Chironomidae, Oligochaeta and Cladocera. In the summer, they preferred Chironomidae, Ephemeroptera, and Trichoptera with a combination of plant foods Bacillariophyceae and Chlorophyceae. The main foods of this species in the autumn were larvae of Insecta and Bacillariophyceae. Smaller barbel preferred animal prey and less plant items, while larger sizes of this species preferred only animal prey. Diet selectivity with relation to food availability in the environment was diverse in various investigated period. Positive selectivity in June was found for Xantophyceae and makroavertebrates, in July for Chlorophyceae, Bacillariophyceae and macroinvertebrates and in October for Bacillariophyceae and macroinvertebrates.

  8. Natural diet of three species of shrimp in a tropical coastal lagoon

    Directory of Open Access Journals (Sweden)

    Albertoni Edélti Faria

    2003-01-01

    Full Text Available The gut content of 495 specimens of Farfantepenaeus brasiliensis, 131 of F. paulensis (Penaeidae and 102 of Macrobrachium acanthurus (Palaemonidae were analyzed to establish the composition of their diets F. brasiliensis had as the most important feeding items in its diet larvae of Chironomidae, Polychaeta and Heleobia australis (Mollusca. For F. paulensis, the most important items were the same as for F. brasiliensis, but the order of importance of H. australis and Polychaeta was inverted. M. acanthurus had detritus as the most important item, followed by Chironomidae larvae, Odonata nymphs, and fragments of the macroalgae Chara. The results showed that the three species were omnivorous, with a varied diet including both components of macrofauna of benthos and associated to the macroalgae Chara and plant fragments and detritus.

  9. Feeding of two sympatric species of Characidium, C. lanei and C. pterostictum (Characidiinae in a coastal stream of Atlantic Forest (Southern Brazil

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    Aranha José Marcelo R.

    2000-01-01

    Full Text Available The feeding strategy of Characidium lanei and C. pterostictum was studied in the "Cabral" stream, a coastal stream of the Atlantic Forest, in southern Brazil. The samples were taken using electric fishing between March/95 and February/96. We studied about 15 stomach contents for each species in each season of the year. The stomach contents of the studied species were composed of 39 different food items, 28 in C. lanei and 24 in C. pterostictum. Chironomidae larvae and Ephemeroptera nymph were the most important items for C. lanei, except in the summer when Acarina and not identified Arthropoda were the most important items. Chironomidae and Simulidae larvae were the most important items in C. pterostictum. These results indicated an insectivorous habits and opportunist feeding strategy to C. lanei and C. pterostictum with several items rare or not very frequent.

  10. Environmental Baseline Studies of St. Marys River Near Neebish Island, Michigan, Prior to Proposed Extension of Navigation Season, 1981. Great Lakes- St. Lawrence Seaway, Navigation Season Extension Program

    Science.gov (United States)

    1983-06-01

    Polycentropus sp. 7 32 Hydroptila sp. 0 14 Trianodes sp. 7 32 COLEOPTERA Haliplus sp. 7 0 ODONATA Enallagma sp. 0 32 LEPIDOPTERA Nymphula sp. 21 0...21 ODONATA Enallagma sp. 0 112 LEPIDOPTERA Paraponyx sp. 0 7 DIPTERA Ceratopogonidae 56 0 Chironomidae Ablabesmyia sp. 0 630 tlinotanypus sp. 0 43...TrichocorIxa sp. 56 0 Sigara sp. 7 77 ODONATA Enallagma sp. 0 121 LEPIDOPTERA Paraponyx sp. 0 7 Nymphula sp. 0 7 Continued 223 Table A8. Continued STATION

  11. Selenium Concentrations in Irrigation Drain Inflows to the Salton Sea, California, October 2006 and January 2007

    Science.gov (United States)

    May, Thomas W.; Walther, Mike W.; Brumbaugh, William G.

    2007-01-01

    This report presents raw data on selenium concentrations in samples of water, sediment, detritus, and selected food-chain matrices collected from selected agricultural drains in the southern portion of the Salton Sea during October 2006 and January 2007. Total selenium and selenium species were determined in water samples, whereas total selenium was determined in sediment, detritus, algae, plankton, midge larvae (Family Chironomidae), and two fish species (western mosquitofish, Gambusia affinis, and sailfin molly, Poecilia latipinna).

  12. Efeito de metais Cobre (Cu e Zinco (Zn sobre a comunidade de macroinvertebrados bentônicos em riachos do sul do Brasil - DOI: 10.4025/actascibiolsci.v30i3.677 The effect of metals (Cu and Zn on the benthic macroinvertebrate community in streams in southern Brazil - DOI: 10.4025/actascibiolsci.v30i3.677

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    Luiz Ubiratan Hepp

    2008-10-01

    Full Text Available O objetivo deste estudo foi avaliar os efeitos de metais (Cu e Zn sobre a comunidade de macroinverterados bentônicos. Foram amostrados, trimestralmente, entre setembro de 2006 e junho de 2007, organismos e água em oito trechos de riachos de duas bacias hidrográficas influenciadas por urbanização e agricultura. Foram estimados os valores de densidade de organismos, riqueza taxonômica e diversidade de Shannon. Para avaliação dos dados, foram utilizados testes de variância e regressão linear simples. Os resultados demonstraram variabilidade das concentrações dos metais e da macrofauna entre as estações do ano e riachos estudados. O metal Cobre (Cu apresentou influência apenas sobre a densidade Chironomidae e o metal Zinco (Zn apresentou efeito sobre a densidade total da macrofauna bentônica e de Chironomidae. Nenhum dos metais apresentou efeitos sobre a riqueza e diversidade de macroinvertebrados. Os resultados indicam potencial bioindicador da comunidade bentônica na avaliação da qualidade integrada do ambiente.The aim of this study was to evaluate the effect of metals (Cu and Zn on the benthic macroinvertebrate community. The organisms and water were collected quarterly between September 2006 and June 2007, in eight sites in streams of two hydrographic basins, influenced by urbanization and agriculture. The values of organism density, taxonomic richness and the Shannon diversity index were calculated. For data evaluation, tests of variance and simple linear regression were used. The results showed variability in the metal concentration and benthic community among seasons and studied streams. Cu showed influence only on Chironomidae density. Zn demonstrated effect on the benthic community and Chironomidae density. None of the metals presented effect on the macroinvertebrate richness and diversity. The results indicate a bioindicator potential of the benthic community in the evaluation of integral quality of the environment.

  13. Efeito de metais Cobre (Cu e Zinco (Zn sobre a comunidade de macroinvertebrados bentônicos em riachos do sul do Brasil = The effect of metals (Cu and Zn on the benthic macroinvertebrate community in streams in southern Brazil

    Directory of Open Access Journals (Sweden)

    Silvia Vendruscolo Milesi

    2008-07-01

    Full Text Available O objetivo deste estudo foi avaliar os efeitos de metais (Cu e Zn sobre a comunidade de macroinverterados bentônicos. Foram amostrados, trimestralmente, entre setembro de 2006 e junho de 2007, organismos e água em oito trechos de riachos de duas bacias hidrográficas influenciadas por urbanização e agricultura. Foram estimados os valores de densidade de organismos, riqueza taxonômica e diversidade de Shannon. Para avaliação dos dados, foram utilizados testes de variância e regressão linear simples. Os resultados demonstraram variabilidade das concentrações dos metais e da macrofauna entre as estações do ano e riachos estudados. O metal Cobre (Cu apresentou influência apenas sobre a densidade Chironomidae e o metal Zinco (Zn apresentou efeito sobre a densidade total da macrofauna bentônica e de Chironomidae. Nenhum dos metais apresentou efeitos sobre ariqueza e diversidade de macroinvertebrados. Os resultados indicam potencial bioindicador da comunidade bentônica na avaliação da qualidade integrada do ambiente.The aim of this study was to evaluate the effect of metals (Cu and Zn on the benthic macroinvertebrate community. The organismsand water were collected quarterly between September 2006 and June 2007, in eight sites in streams of two hydrographic basins, influenced by urbanization and agriculture. The values of organism density, taxonomic richness and the Shannon diversity index were calculated. For data evaluation, tests of variance and simple linear regression were used. The results showed variability in the metal concentration and benthic community among seasons and studied streams. Cu showed influence only on Chironomidae density. Zn demonstrated effect on the benthic community and Chironomidae density. None of the metals presented effect on the macroinvertebrate richness and diversity. The results indicate a bioindicatorpotential of the benthic community in the evaluation of integral quality of the environment.

  14. Impact of routine Bacillus thuringiensis israelensis (Bti) treatment on the availability of flying insects as prey for aerial feeding predators.

    Science.gov (United States)

    Timmermann, Ute; Becker, Norbert

    2017-02-16

    Since 1980, mosquito breeding habitats in the Upper Rhine Valley were routinely treated with Bacillus thuringiensis var. israelensis (Bti). Bti is considered to significantly reduce the number of mosquitoes, and - especially when used in higher dosages - to be toxic to other Nematocera species, e.g. Chironomidae, which could be food sources for aerial feeding predators. To investigate direct and indirect effects of routine Bti treatment on food sources for aerial feeding predators, the availability of flying insects in treated and untreated areas was compared. A car trap was used for insect collection, which allowed their exact spatiotemporal assignment. The statistical analysis revealed that insect taxa abundance was influenced differently by the factors season, temperature and time of day. Nematocera (Diptera) were the most frequently collected insects in all areas. Chironomidae were the predominant aquatic Nematocera. The comparison of treated and untreated sites did not show significant differences that would indicate any direct or indirect effect of routine Bti treatment on the availability of flying insects. Additional to food availability, food selection must be considered when investigating food resources for aerial feeding predators. In this study, food selection of Delichon urbicum (House Martin) as an example was investigated with the help of neck ring samples. The preferred prey of the investigated D. urbicum colony consisted of diurnal insects with terrestrial larvae (Aphidina, Brachycera, Coleoptera). Chironomidae were consumed, but not preferred.

  15. Similarity and diversity between aquatic insect populations in streams of first and second order, south of Brazil Diversidade e similaridade entre populações de insetos aquáticos em riachos de primeira e segunda ordem, sul do Brasil

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    Cibele Bender Raio

    2011-06-01

    Full Text Available Aquatic communities of macroinvertebrates are influencied by rapid velocity, habitat heterogeneity and other characteristics. This study examined a relationship between aquatic insects diversity with hydrologic order of two streams. We tested following hypothesis: diversity of insects associated with the same substrate in equal parts of streams, classified in different orders, are similar. Samples of litter were collected in middle stretches of stream Cascatinha (first order and stream João Pinheiro (second order, Tibagi river basin, Telêmaco Borba, Paraná, Brazil. Diversity of each stream was obtained by Shannon index. Diversity values were low for both streams (0.8 for the first order stream and 0.89 for the second order stream with no statistical difference (t = -1.12; p = 0. 27. Similarity between the streams was 0.51. These results allowed us to verify that, to studied streams, hydrological order has no effect on aquatic insects diversity (F= 0.14, p= 0.71, so the hypothesis was accepted. The most abundant taxon in both streams was Chironomidae (Diptera, representing 82.7% of total collected. However when Chironomidae was removed from analysis, the hypotesis was refused. An high abundance of Chironomidae individuals had influenced values of local diversity. A estrutura das comunidades de macroinvertebrados aquáticos é influenciada pela velocidade da correnteza do curso d’água e da heterogeneidade de habitats entre outras características. Este trabalho verificou a relação da diversidade de insetos aquáticos com a ordem hidrológica de dois riachos. Para isso, foi testada a seguinte hipótese: a diversidade de insetos associados ao mesmo substrato em trechos equivalentes de riachos classificados em diferentes ordens é semelhante. Amostras de folhiço foram coletas nos trechos médios do riacho Cascatinha (primeira ordem e do riacho João Pinheiro (segunda ordem, pertencentes à bacia do rio Tibagi, Telêmaco Borba, Paran

  16. Estrutura da comunidade de macroinvertebrados bentônicos de um riacho de serra em Itatinga, São Paulo, Brasil Structure of a benthic macroinvertebrates community in a mountain stream in Itatinga, São Paulo, Brazil

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    Ludmilla O. Ribeiro

    2005-09-01

    Full Text Available A comunidade de macroinvertebrados bentônicos de um riacho de terceira ordem foi analisada em duas estações do ano, chuvosa e seca. Substratos artificiais foram amostrados semanalmente, ao longo de 56 dias para a coleta de macroinvertebrados, nas duas estações do ano. A composição da comunidade foi caracterizada por uma baixa diversidade, ou seja, presença de muitas espécies raras e poucas espécies abundantes nas duas estações do ano. Uma alta dominância de Chironomidae (Diptera nas duas estações, seguida de Baetidae (Ephemeroptera e Ancylidae (Mollusca, respectivamente nas estações chuvosa e seca, foi característico. Os resultados obtidos reforçam a grande importância de Chironomidae na comunidade bentônica de riachos e salientam a influência da sazonalidade sobre a estruturação destes organismos.The benthic macroinvertebrates community of a third order stream was studied during the wet and dry seasons. The community was analyzed using artificial substrates sampled weekly during 56 days in each season. The community composition was characterized by low species diversity, with high number of rare species and few abundant species for both seasons. A high dominance of Chinonomidae (Diptera for both seasons, followed by Baetidae (Ephemeroptera and Ancylidae (Mollusca, respectively for the wet and dry seasons, was found. The results reinforced the high importance of Chironomidae and the seasonal effect determining the stream benthic community structure.

  17. Food web structure in a harsh glacier-fed river.

    Science.gov (United States)

    Clitherow, Leonie R; Carrivick, Jonathan L; Brown, Lee E

    2013-01-01

    Glacier retreat is occurring across the world, and associated river ecosystems are expected to respond more rapidly than those in flowing waters in other regions. The river environment directly downstream of a glacier snout is characterised by extreme low water temperature and unstable channel sediments but these habitats may become rarer with widespread glacier retreat. In these extreme environments food web dynamics have been little studied, yet they could offer opportunities to test food web theories using highly resolved food webs owing to their low taxonomic richness. This study examined the interactions of macroinvertebrate and diatom taxa in the Ödenwinkelkees river, Austrian central Alps between 2006 and 2011. The webs were characterised by low taxon richness (13-22), highly connected individuals (directed connectance up to 0.19) and short mean food chain length (2.00-2.36). The dominant macroinvertebrates were members of the Chironomidae genus Diamesa and had an omnivorous diet rich in detritus and diatoms as well as other Chironomidae. Simuliidae (typically detritivorous filterers) had a diet rich in diatoms but also showed evidence of predation on Chironomidae larvae. Food webs showed strong species-averaged and individual size structuring but mass-abundance scaling coefficients were larger than those predicted by metabolic theory, perhaps due to a combination of spatial averaging effects of patchily distributed consumers and resources, and/or consumers deriving unquantified resources from microorganisms attached to the large amounts of ingested rock fragments. Comparison of food web structural metrics with those from 62 published river webs suggest these glacier-fed river food web properties were extreme but in line with general food web scaling predictions, a finding which could prove useful to forecast the effects of anticipated future glacier retreat on the structure of aquatic food webs.

  18. Food web structure in a harsh glacier-fed river.

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    Leonie R Clitherow

    Full Text Available Glacier retreat is occurring across the world, and associated river ecosystems are expected to respond more rapidly than those in flowing waters in other regions. The river environment directly downstream of a glacier snout is characterised by extreme low water temperature and unstable channel sediments but these habitats may become rarer with widespread glacier retreat. In these extreme environments food web dynamics have been little studied, yet they could offer opportunities to test food web theories using highly resolved food webs owing to their low taxonomic richness. This study examined the interactions of macroinvertebrate and diatom taxa in the Ödenwinkelkees river, Austrian central Alps between 2006 and 2011. The webs were characterised by low taxon richness (13-22, highly connected individuals (directed connectance up to 0.19 and short mean food chain length (2.00-2.36. The dominant macroinvertebrates were members of the Chironomidae genus Diamesa and had an omnivorous diet rich in detritus and diatoms as well as other Chironomidae. Simuliidae (typically detritivorous filterers had a diet rich in diatoms but also showed evidence of predation on Chironomidae larvae. Food webs showed strong species-averaged and individual size structuring but mass-abundance scaling coefficients were larger than those predicted by metabolic theory, perhaps due to a combination of spatial averaging effects of patchily distributed consumers and resources, and/or consumers deriving unquantified resources from microorganisms attached to the large amounts of ingested rock fragments. Comparison of food web structural metrics with those from 62 published river webs suggest these glacier-fed river food web properties were extreme but in line with general food web scaling predictions, a finding which could prove useful to forecast the effects of anticipated future glacier retreat on the structure of aquatic food webs.

  19. Community Structure in the Amber Forest: Study of the Arthropod Syninclusia in the Rovno Amber(Late Eocene of Ukraine)

    Institute of Scientific and Technical Information of China (English)

    Evgeny E.PERKOVSKY; Alexandr P.RASNITSYN; Anatoly P.VLASKIN; Sergej P.RASNITSYN

    2010-01-01

    Arthropodan syninclusions in the Late Eocene Rovno amber were examined using x2 to reveal correlation of the component groups(some taxa of Diptera,ants,aphids,and mites)supposedly indicative of the biocoenotic relationships in the ancient amber forest.Three tightly correlated groups were identified,representing a putative aerial plankton guild(Chironomidae+Ceratopogonidae)and two tree-trunk guilds,one of which(Dolichopodidae+Germaraphis)is possibly connected to more open or/and more hygrophilous habitats than the other(Sciara zone Diptera+"Acarus"rhombeus).The ants were not linked with any of the above components.

  20. Checklist of the Diptera (Insecta of Finland: an introduction and a summary of results

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    Jere Kahanpää

    2014-09-01

    Full Text Available Nearly thirty-five years have passed since Hackman published his “Check list of the Finnish Diptera” (1980. The number of true flies (Diptera known from Finland has increased by more than two thousand species since then. At the same time, hundreds of erroneous records have been recognized and purged from the checklist. ZooKeys issue 441 provides a new checklist of the Diptera species of the Republic of Finland. This introductory paper presents the rationale behind the project, provides technical documentation on the checklist format and sources used, and summarizes the results. The remaining papers in this issue cover one or more Diptera families in detail. Two electronic appendices are provided: supporting data (additional references to first published records and the previous checklist and a complete list of Finnish Diptera taxa in Darwin Core compliant format for easy computer access and processing. The new checklist records 6920 fly species from Finland, 2932 belonging to the nematoceran or lower flies and 3989 to the suborder Brachycera. The changes since 1980 are most prominent in the Lower Diptera. For example, more than 400 non-biting midges (Chironomidae have been added since 1980, and the number of moth flies (Psychodidae known from Finland has more than tripled. Among the larger families, large increases in known Finnish species are also seen in Cecidomyiidae (161% increase, Pipunculidae (98%, and Chironomidae (90%.

  1. Macroinvertebrate communities associated with macrophyte habitats in a tropical man-made lake (Lake Taabo, Côte d’Ivoire

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    Kouamé M. K.

    2011-02-01

    Full Text Available An ecological study was done on Lake Taabo with the main objective of characterising macroinvertebrate communities associated with the microhabitats created mainly by Eichhornia crassipes and other littoral native macrophytes. We sampled organisms in patches of those aquatic macrophytes. Also, some abiotic variables (temperature, transparency, turbidity, pH, TDS, conductivity, dissolved oxygen, NH$_{4}^{+}$+4, NO$_{3}^{-}$−3, NO$_{2}^{-}$−2, PO$_{4}^{3-}$3−4 and SiO$_{2}^{-}$−2 were measured. Overall, forty-three taxa of macroinvertebrates were identified. Ten of them were exclusively associated with water hyacinth while five were only associated with littoral macrophytes. Macroinvertebrate taxa with some of the highest family richness were Gastropoda, Coleoptera, Heteroptera, Odonata and Diptera. The taxon with highest density in both microhabitats was Chironomidae. Although higher values of taxonomic richness (Rs, the Shannon index (H′ and evenness (J were obtained with the water hyacinth habitat, significant differences between the two microhabitats were not observed. Canonical Correspondence Analysis revealed that samples of E. crassipes collected in the dry season were characterised by Gastropoda and Odonata, as well as higher values of transparency and ammonia-nitrogen. Baetidae, Hydrophilidae, Chironomidae, Ceratopogonidae, Coenagrionidae, Naucoridae and Ostracoda were most abundant in both E. crassipes and littoral macrophyte habitats during the rainy season. This season was characterised by higher levels of nitrates and conductivity.

  2. Abundance of macrozoobenthos in relation to bottom soil textural types and water depth In aquaculture ponds

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    N. Nupur

    2013-12-01

    Full Text Available The present experiment was conducted to evaluate the effects of bottom soil textural classes and different water depths on abundance of macrozoobenthos in aquaculture ponds. Three treatments, i.e., ponds bottom with sandy loam (T1, with loam (TS2 and with clay loam (T3 were considered in this experiment. Samples were collected from three different depths (60.96 cm, 106.68 cm and 152.40 cm with three replications. The ranges of water quality parameters were suitable for the growth of macrozoobenthos during the experimental period. Similarly, chemical properties of soil were also within suitable ranges and every parameter showed comparatively higher ranges in T2. Eight genera were recorded belonging to major groups of Chironomidae, Oligochaeta, Mollusca and Ceratoponogonidae. The highest population densities of Oligochaeta (1200±4.25 per m2, Chironomidae (1422±4.88 per m2, Ceratopogonidae (399±1.56 per m2 and Mollusca (977±2.24 per m2 were found in T2. The population densities of macrozoobenthos showed fortnightly variations in all the treatments. Among the three depths, significantly highest densities of macrozoobenthos were recorded in 106.68 cm in every treatment. The mean abundance of macrozoobenthos was significantly highest in T2. The present study indicates that loamy soil pond bottom along with water depth 106.68 cm is suitable for the growth and production of macrozoobenthos in aquaculture ponds.

  3. Evaluation of the impact of Bacillus thuringiensis serovar israelensis and Temephos, used for the control of Simulium (Chirostilbia pertinax Kollar, 1832 (Diptera, Simuliidae on the associated entomofauna, Paraty, state of Rio de Janeiro, Brazil

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    Araújo-Coutinho Carlos José Pereira da Cunha de

    2003-01-01

    Full Text Available The study was set up to evaluate the impact of two commercial larvicide formulations, Bacillus thuringiensis serovar israelensis base (Bti at 15 ppm/1 min and temephos at 0.03 ppm of active ingredient, used to control Simulium pertinax populations, on associated non-target entomofauna occupying the same breeding sites. The experiments were carried out on the Pedra Branca and Muricana rivers, on the slopes of Serra do Mar massif, municipality of Paraty, state of Rio de Janeiro, Brazil. Bti was applied to the river Pedra Branca and temephosto theriver Muricana. On both rivers, treatment and control sections were labeled as such, each one with two observation posts: slow moving water and fast water regions respectively. Artificial substrata was used to evaluate the abundance of associated entomofauna. Attached immature stages of arthropods were removed from both of its surfaces fortnightly. Were collected, from the two rivers, 28 477 specimens of the entomofauna associated with S. pertinax. The families Hydropsychidae, Chironomidae, Bactidae, Simuliidae, Blephariceridae and Megapodagrionidae were represented. These was an impact of temephos on the entomofauna associated with S. pertinax only in Simuliidae and Chironomidae, and to Bti only in Simuliidae. However, the reduction in their numbers was not statistically significant.

  4. Comparison of the abiotic preferences of macroinvertebrates in tropical river basins.

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    Gert Everaert

    Full Text Available We assessed and compared abiotic preferences of aquatic macroinvertebrates in three river basins located in Ecuador, Ethiopia and Vietnam. Upon using logistic regression models we analyzed the relationship between the probability of occurrence of five macroinvertebrate families, ranging from pollution tolerant to pollution sensitive, (Chironomidae, Baetidae, Hydroptilidae, Libellulidae and Leptophlebiidae and physical-chemical water quality conditions. Within the investigated physical-chemical ranges, nine out of twenty-five interaction effects were significant. Our analyses suggested river basin dependent associations between the macroinvertebrate families and the corresponding physical-chemical conditions. It was found that pollution tolerant families showed no clear abiotic preference and occurred at most sampling locations, i.e. Chironomidae were present in 91%, 84% and 93% of the samples taken in Ecuador, Ethiopia and Vietnam. Pollution sensitive families were strongly associated with dissolved oxygen and stream velocity, e.g. Leptophlebiidae were only present in 48%, 2% and 18% of the samples in Ecuador, Ethiopia and Vietnam. Despite some limitations in the study design, we concluded that associations between macroinvertebrates and abiotic conditions can be river basin-specific and hence are not automatically transferable across river basins in the tropics.

  5. Comparison of the abiotic preferences of macroinvertebrates in tropical river basins.

    Science.gov (United States)

    Everaert, Gert; De Neve, Jan; Boets, Pieter; Dominguez-Granda, Luis; Mereta, Seid Tiku; Ambelu, Argaw; Hoang, Thu Huong; Goethals, Peter L M; Thas, Olivier

    2014-01-01

    We assessed and compared abiotic preferences of aquatic macroinvertebrates in three river basins located in Ecuador, Ethiopia and Vietnam. Upon using logistic regression models we analyzed the relationship between the probability of occurrence of five macroinvertebrate families, ranging from pollution tolerant to pollution sensitive, (Chironomidae, Baetidae, Hydroptilidae, Libellulidae and Leptophlebiidae) and physical-chemical water quality conditions. Within the investigated physical-chemical ranges, nine out of twenty-five interaction effects were significant. Our analyses suggested river basin dependent associations between the macroinvertebrate families and the corresponding physical-chemical conditions. It was found that pollution tolerant families showed no clear abiotic preference and occurred at most sampling locations, i.e. Chironomidae were present in 91%, 84% and 93% of the samples taken in Ecuador, Ethiopia and Vietnam. Pollution sensitive families were strongly associated with dissolved oxygen and stream velocity, e.g. Leptophlebiidae were only present in 48%, 2% and 18% of the samples in Ecuador, Ethiopia and Vietnam. Despite some limitations in the study design, we concluded that associations between macroinvertebrates and abiotic conditions can be river basin-specific and hence are not automatically transferable across river basins in the tropics.

  6. Food and growth parameters of juvenile chinook in the central Columbia River

    Energy Technology Data Exchange (ETDEWEB)

    Becker, C.D.

    1994-10-01

    Juvenile chinook, salmon (Oncorhynchus tshawytscha) in the Hanford area of the free-flowing central Columbia River, Washington consume almost entirely adult and larval stages of aquatic insects. The diet is dominated by midges (Diptera: Chironomidae). By numbers, adult midges provided 64 and 58% of the diet and larval midges 17 and 18% of the diet, in 1968 and 1969, respectively. The families Hydropsychidae (Trichoptera), Notonectidae (Hemiptera) and Hypogastruridae (Collembola) are of minor numerical importance with a combined utilization of 7% in 1968 and 15% in 1969. Distinctive features of food and feeding activity of juvenile chinook at Hanford are fourfold: (1) the fish utilize relatively few insect groups, predominantly Chironomidae; (2) they depend largely upon autochthonous river organisms; (3) they visually select living prey drifting, floating or swimming in the water; and (4) they are apparently habitat opportunists to a large extent. Analyses were made of variations in diet and numbers of insects consumed between six sampling stations distributed along a 38 km section of the river. Data are provided on feeding intensity, fish lengths, length-weight relationships, and coefficients of condition. Seasonal changes in river temperature and discharge, as well as variations in regulated flow levels are environmental features influencing feeding, growth, and emigration of fish in the Hanford environs.

  7. Feeding habits of an endemic fish, Oxygymnocypris stewartii, in the Yarlung Zangbo River in Tibet, China

    Science.gov (United States)

    Huo, Bin; Xie, Cong Xin; Madenjian, Charles P.; Ma, Bao Shan; Yang, Xue Feng; Huang, Hai Ping

    2014-01-01

    Feeding habits of Oxygymnocypris stewartii were investigated based on monthly sampling in the Yarlung Zangbo River from August 2008 to August 2009. The gut contents of 194 individuals were analysed and quantified with numerical and gravimetric methods. This species can be considered a generalized and opportunistic predator feeding both on teleosts and aquatic insects. A multivariate analysis revealed noticeable variation in O. stewartii diet composition with fish size and season. The smaller specimens fed primarily on Cobitidae and Hydropsychidae. As they grew, Cyprinidae and Chironomidae larvae became important prey. The preferred food items were teleosts in summer and autumn. For winter and spring, the predominant prey switched to chironomidae larvae. Diet composition did not significantly vary between the sexes. Finally, a significant and positive correlation between predator and prey length was found. These findings provide the fundamental information better understanding the role of this important endemic species in the Yarlung Zangbo River food web.

  8. Diet of Poecilia reticulata Peters, 1959 in streams from Paraná River basin: influence of the urbanization

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    Gustavo Henrique Zaia Alves

    2016-12-01

    Full Text Available This study aimed to assess the diet of Poecilia reticulata in rural (RS and urban stream (US and under seasonal influence. We hypothesized that rainfall have a strong negative impact on the diet of the species in the US, due to its abrupt effect on food resources; in RS this effect is less apparent. Both streams belong to Pirapó River sub-basin, Paraná River basin. Fishes were sampled bimonthly, between July 2007 and June 2008 in three sample sites along the longitudinal gradient of the streams, using electrofishing. According to the Feeding Index, in both streams the population consumed almost exclusively detritus associated with aquatic organisms (>95%, regardless of the hydrological period. The main taxa explored by fish were Simuliidae in RS and Chironomidae in US. The diet was significantly different between streams; however, the seasonal factor was not significant, showing that the results were partially consistent with the suggested proposal. In US stream the diet of the fish followed an ordinarily pattern found in urban environments. Thus, P. reticulata can be used as a tool to assess environmental conditions due to its ability to reach bioindicator organisms, such as Chironomidae species.

  9. Relations Between the Structure of Benthic Macro-Invertebrates and the Composition of Adult Water Beetle Diets from the Dytiscidae Family.

    Science.gov (United States)

    Frelik, Anna; Pakulnicka, Joanna

    2015-10-01

    This paper investigates the relations between the diet structure of predaceous adult water beetles from the Dytiscidae family and the structure of macrofauna inhabiting the same environments. The field studies were carried out from April until September in 2012 and 2013 in 1-mo intervals. In total, >1,000 water beetles and 5,115 benthic macro-invertebrates were collected during the whole period of the study. Subsequently, 784 specimens of adult water beetles (70.6% out of the total sampled) with benthic macro-invertebrates found in their proventriculi, were subject to analysis. The predators were divided into three categories depending on their body size: small beetles (2.3-5.0 mm), medium-sized beetles (13-15 mm), and large beetles (27-37 mm). All adult Dytiscidae consumed primarily Ephemeroptera and Chironomidae larvae. Although Asellidae were numerically dominant inhabitants of the sites, the adult water beetles did not feed on them. The analysis of feeding relations between predators and their prey revealed that abundance of Ephemeroptera, Chironomidae, and larval Dytiscidae between the environment and the diet of adult Dytiscidae were strongly correlated.

  10. Colonization of artificial substrate by freshwater macroinvertebrates, in the Jacuí River Delta, Rio Grande do Sul State, Brazil

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    Daniel Pereira

    2010-03-01

    Full Text Available Experiments to evaluate the limnic macroinvertebrates that colonize artificial substrates were performed at two experimental stations located in Jacui Channel (CJ and Cais do Porto (PO, both part of the Jacui Delta in Porto Alegre, RS, southern Brazil. Substrates were built in PET bottles containing an internal nylon screen. In CJ, L. fortunei (8229.0 ind.m-2, Chironomidae (188.9 ind.m-2, and Heleobia piscium (39.6 ind.m-2 presented the highest values of average density. In PO, L. fortunei (3233.0 ind.m-2, Chironomidae (288.9 ind.m-2, and Oligochaeta (211.1 ind.m-2 presented the highest values of average density. The freshwater sponge, Trochospongilla paulula, presented an incrustation area of 0.016m2, that corresponded to 31% of the total external substrate surface (PET bottles. Trochospongilla paulula also grew over the golden mussel valves (epizoism. Significant differences between average densities of Oligochaeta verified in the sustrates from CJ (lowest value and PO (highest value were found using the statistics Mann-Whitney Test (p=0.01. Other significant differences (p<0.0001 between the bioincrustation areas of T. paulula in the substrates from CJ (highest value and PO (lowest value were found. The average densities of other taxa in substrates from both CJ and PO did not differ statistically. The substrate was adequate for the sampling of macroinvertebrates, especially Porifera, a group that is difficult to sample.

  11. Controlling factors of benthic macroinvertebrates distribution in a small tropical pond, lateral to the Paranapanema River (São Paulo, Brazil Macroinvertebrados bentônicos e fatores controladores de sua distribuição em uma pequena lagoa tropical adjacente ao rio Paranapanema (São Paulo, Brasil

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    Erika Mayumi Shimabukuro

    2011-06-01

    Full Text Available AIM: The aim of the present study was to examine the benthic fauna in a marginal pond lateral to the Paranapanema River and to identify the main controlling factors of its distribution. Considering the small size of the lacustrine ecosystem, we expected that seasonal variations of the benthic community attributes are more important than spatial variations; METHODS: Two samplings, one in March and another in August, were carried out at nine sites in the pond. Sediment samples were obtained through a Van Veen grab for invertebrate sorting, granulometric analysis, and for quantification of organic matter in sediment. Other abiotic factors were measured, such as water transparency, dissolved oxygen, pH, electric conductivity, temperature, and depth of sediment sampling sites. Regarding the comparative analysis at spatial scale, no significant variations in density of the benthic invertebrate community were found. RESULTS: In relation to the studied abiotic factors, only depth presented significant differences among sampling sites; All the measured environmental parameters presented significant differences among sampling months, except depth and the physical and chemical characteristics of the sediment. The abundance of Chaoboridae and Chironomidae was the unique attribute with a significant difference in comparing the two months. A higher abundance of taxa occurred in August, especially for Oligochaeta, Nematoda, Chaoboridae, and Chironomidae; CONCLUSIONS: Because of the low structural complexity of the studied pond, we concluded that the changes in benthic macroinvertebrate community attributes were mainly due to seasonal effects.OBJETIVO: O presente estudo tem por objetivo examinar a fauna bentônica em lagoa marginal ao rio Paranapanema e os principais fatores reguladores da sua distribuição. Devido ao pequeno tamanho do ambiente lacustre, procurou-se mostrar que as variações sazonais dos atributos da comunidade bentônica são mais

  12. A tale of two fjords – en analyse af bundfauna samfund i Odense og Roskilde Fjord

    DEFF Research Database (Denmark)

    Banta, Gary Thomas; Delefosse, Matthieu; Canal Vergés, Paula;

    var dyndsnegle (Hydrobia sp.) og små orme (polychaeter og oligochaeter) mens biomassen var domineret af muslinger, især sandmuslingen (Mya arenaria). Der var betydelig variation i sammensætningen af de bentiske samfund på alle undersøgte rumlige skalaer. F.eks. var der ca. 38% forskel målt vha Bray...... gravende muslinger (f.eks. Cerastoderma spp.) mens Odense Fjord (OF) havde flere orme. Ligeledes så vi mange tubificide orme i den indre del af OF. I den indre del af RF så vi i stedet mange dansemyggelarver (Chironomidae). Af de undersøgte miljøvariable var vanddybde og salinitet (både niveauet og...

  13. MACROZOOBENTHIC COMMUNITIES STRUCTURE CHARACTERISTIC OF CERTAIN TRIBUTARIES OF THE SIRET RIVER FROM HARGHITA, MARAMUREŞ AND VRANCEA MOUNTAINS AND MOLDOVEI PLATEAU

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    Elena-Andreea GHIBUŞI

    2012-01-01

    Full Text Available 35 qualitative macrozoobentonic samples were collected in 2011 from many Siret river tributaries coming from the Harghita Mountains (5 stations, Maramureş Mountains (14 stations, Moldavian Plateau (4 stations and Vrancea Mountains (12 stations. Laboratory analysis of samples revealed the existence of the following 15 groups of benthic invertebrates: Ephemeroptera, Plecoptera, Trichoptera, Oligochaeta, Diptera (Chironomidae, Simuliidae, Ceratopogonidae, Limoniidae, Gastropoda, Bivalva, Coleoptera, Acarina, Odonata, Hirudinea, Isopoda, Heteroptera, Turbellariata and Collembola. Groups that have the highest frequencies were mayflies and dipterans (each with a frequency of 97.1%, followed by caddisflies (80%, amphipods (68.6%, oligochaetes (57.1% and stoneflies (54.3%. Presence of sensitive groups to water quality degradation (Ephemeroptera, Trichoptera and Plecoptera with high frequency shows good quality water at most stations investigated.

  14. Behavioral and catastrophic drift of invertebrates in two streams in northeastern Wyoming

    Science.gov (United States)

    Wangsness, David J.; Peterson, David A.

    1980-01-01

    Invertebrate drift samples were collected in August 1977 from two streams in the Powder River structural basin in northeastern Wyoming. The streams are Clear Creek, a mountain stream, and the Little Powder River, a plains stream. Two major patterns of drift were recognized. Clear Creek was sampled during a period of normal seasonal conditions. High drift rates occurred during the night indicating a behavioral drift pattern that is related to the benthic invertebrate density and carrying capacity of the stream substrates. The mayfly genes Baetis, a common drift organism, dominated the peak periods of drift in Clear Creek. The Little Powder River has a high discharge during the study period. Midge larvae of the families Chironomidae and Ceratopogonidae, ususally not common in drift, dominated the drift community. The dominance of midge larvae, the presence of several other organisms not common in drift, and the high discharge during the study period caused a catastrophic drift pattern. (USGS)

  15. DIET OF DIRECT-DEVELOPING FROGS (ANURA: CRAUGASTORIDAE: Pristimantis FROM THE ANDES OF WESTERN COLOMBIA

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    Juan Carlos GARCIA-R

    2014-05-01

    Full Text Available We studied the diet of 15 montane frog species of the genus Pristimantis (Craugastoridae from the Andes of Western Colombia to determine the diet range, breadth of niche and overlap among species.  We identified 499 prey items from stomach and intestinal contents of 154 specimens. Prey items were included in 74 different categories. The most common 15 prey categories accounted for 65 % of all frogs’ diet. The invertebrate families Isotomidae, Chironomidae, Formicidae, and Tipulidae were the most abundant categories and accounted for 32 % of the frogs’ diet. Ten of the 15 frog species were found with at least one item of Araneae. Coleoptera and Tipulidae were found in nine frog species, and Acari and Carabidae in eight frog species. In general, beetles were found in gastrointestinal tracts of all species examined, except for P. quantus, but interpretation needs caution because only one individual of this species was caught. Pristimantis hectus showed a specialized diet, consuming mainly dipterans of the family Chironomidae, while the remaining species showed a generalist diet. Pristimantis palmeri showed niche overlap with P. erythropleura (Фjk = 0.69, P. myops (Фjk = 0.64, and P. orpacobates (Фjk = 0.64. Our results suggest that most of the frogs species studied are generalist, foraging opportunistically on dipterans, arachnids, collembolans, coleopterans, and hymenopterans. Here, we report the diet of montane Pristimantis species and discuss the results in comparison with data on related species in montane and lowland regionsDieta de ranas de desarrollo directo (Anura: Craugastoridae: Pristimantis de los Andes occidentales de ColombiaEstudiamos la dieta de 15 especies de ranas montanas del género Pristimantis (Craugastoridae en la Cordillera Occidental de Colombia para determinar su variación, amplitud y traslape de nicho. En los contenidos estomacales e intestinales de 154 especímenes se identificaron 499 presas que fueron

  16. Trichomycetes living in the guts of aquatic insects of Misiones and Tierra del Fuego, Argentina.

    Science.gov (United States)

    López Lastra, Claudia C; Scorsetti, Ana C; Marti, Gerardo A; Coscarón, Sixto

    2005-01-01

    Fourteen species of Trichomycetes living in the guts of aquatic insects are reported from two provinces of Argentina, Misiones and Tierra del Fuego. Twelve of the species belong to the Harpellales and two are Amoebidiales. Five harpellid species are reported from Misiones in the extreme northeast of the country (Genistellospora homothallica, Harpella tica, Smittium culisetae, Smittium sp., Stachylina sp.) and seven are from Tierra del Fuego, the southern tip of South America (H. meridianalis, Glotzia sp., S. culicis, S. cellaspora, S. imitatum, Stachylina minima, Penella simulii). Insect hosts all were immature stages of Culicidae, Simuliidae, Chironomidae, Ceratopogonidae (Insecta: Diptera), and Ephemeroptera and Plecoptera. The lower diversity of Trichomycetes found at Misiones, which has a subtropical climate and rainforest vegetation, was due possibly to the warmer temperatures of the water (15-24 C), compared to the colder streams of Tierra del Fuego (9-15 C), with forests and steppes as typical vegetation.

  17. THE STUDY OF WATER QUALITY USING BENTHIC MACROINVERTEBRATES AS BIOINDICATORS IN THE CATCHMENT AREAS OF THE RIVERS JIU, OLT AND IALOMIŢA

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    Elena Daniela MITITELU

    2012-01-01

    Full Text Available The wide distribution of benthic invertebrates and their different sensitivity shown upon modifying the qualitative parameters of aquatic ecosystems led to a frequent use of these group as bioindicators in different studies. The present study aims at presenting a list concerning the different macroinvertebrates identified in the larva stage in three watersheds (Jiu, Olt, Ialomiţa and establishing the water quality of the monitored sections using this benthic macroinvertebrates. The sample collecting points were represented by 23 stations. The abundance and frequency values recorded for benthic communities varied according to the physical-chemical conditions specific to each sample collecting station. There were identified 15 groups in total. The most frequent were Ephemeroptera, Plecoptera, Trichoptera, Diptera (Chironomidae and others. The deterioration of water quality is marked by the decrease in the biotic index EPT/Ch value.

  18. Phylogenetic relationships of the Culicomorpha inferred from 18S and 5.8S ribosomal DNA sequences. (Diptera:Nematocera).

    Science.gov (United States)

    Miller, B R; Crabtree, M B; Savage, H M

    1997-05-01

    We investigated the evolutionary origins of the mosquito family Culicidae by examination of 18S and 5.8S ribosomal gene sequence divergence. Phylogenetic analyses demonstrated that within the infraorder Culicomorpha, taxa in the families Corethrellidae, Chaoboridae and Culicidae formed a monophyletic group; there was support for a sister relationship between this lineage and a representative of the Chironomidae. A chaoborid midge was the closest relative of the mosquitoes. Taxa from four genera of mosquitoes formed a monophyletic group; lack of a spacer in the 5.8S gene was unique to members of the Culicidae. A member of the genus Anopheles formed the most basal lineage among the mosquitoes analysed. Phylogenetic relationships were unresolved for representatives in the families Dixidae, Simuliidae and Ceratopogonidae.

  19. Compact genome of the Antarctic midge is likely an adaptation to an extreme environment.

    Science.gov (United States)

    Kelley, Joanna L; Peyton, Justin T; Fiston-Lavier, Anna-Sophie; Teets, Nicholas M; Yee, Muh-Ching; Johnston, J Spencer; Bustamante, Carlos D; Lee, Richard E; Denlinger, David L

    2014-08-12

    The midge, Belgica antarctica, is the only insect endemic to Antarctica, and thus it offers a powerful model for probing responses to extreme temperatures, freeze tolerance, dehydration, osmotic stress, ultraviolet radiation and other forms of environmental stress. Here we present the first genome assembly of an extremophile, the first dipteran in the family Chironomidae, and the first Antarctic eukaryote to be sequenced. At 99 megabases, B. antarctica has the smallest insect genome sequenced thus far. Although it has a similar number of genes as other Diptera, the midge genome has very low repeat density and a reduction in intron length. Environmental extremes appear to constrain genome architecture, not gene content. The few transposable elements present are mainly ancient, inactive retroelements. An abundance of genes associated with development, regulation of metabolism and responses to external stimuli may reflect adaptations for surviving in this harsh environment.

  20. Trichomycetes (Zygomycota) in the digestive tract of arthropods in Amazonas, Brazil.

    Science.gov (United States)

    Alencar, Yamile B; Ríos-Velásquez, Claudia M; Lichtwardt, Robert W; Hamada, Neusa

    2003-09-01

    Eight species of Harpellales and three species of Eccrinales (Zygomycota: Trichomycetes) were found associated with the digestive tract of arthropods from terrestrial and aquatic environments in the central Amazon region of Brazil. New species of Harpellales include: Harpella amazonica, Smittium brasiliense, Genistellospora tropicalis in Simuliidae larvae and Stachylina paucispora in Chironomidae larvae. Axenic cultures of S. brasiliense were obtained. Probable new species of Enterobryus (Eccrinales), Harpella, and Stachylina (Harpellales) are described but not named. Also reported are the previously known species of Eccrinales, Passalomyces compressus and Leidyomyces attenuatus in adult Coleoptera (Passalidae), and Smittium culisetae and Smittium aciculare (Harpellales) in Culicidae and Simuliidae larvae, respectively. Comments on the distribution of some of these fungi and their hosts in the Neotropics are provided.

  1. Trichomycetes (Zygomycota in the digestive tract of arthropods in Amazonas, Brazil

    Directory of Open Access Journals (Sweden)

    Yamile B Alencar

    2003-09-01

    Full Text Available Eight species of Harpellales and three species of Eccrinales (Zygomycota: Trichomycetes were found associated with the digestive tract of arthropods from terrestrial and aquatic environments in the central Amazon region of Brazil. New species of Harpellales include: Harpella amazonica, Smittium brasiliense, Genistellospora tropicalis in Simuliidae larvae and Stachylina paucispora in Chironomidae larvae. Axenic cultures of S. brasiliense were obtained. Probable new species of Enterobryus (Eccrinales, Harpella, and Stachylina (Harpellales are described but not named. Also reported are the previously known species of Eccrinales, Passalomyces compressus and Leidyomyces attenuatus in adult Coleoptera (Passalidae, and Smittium culisetae and Smittium aciculare (Harpellales in Culicidae and Simuliidae larvae, respectively. Comments on the distribution of some of these fungi and their hosts in the Neotropics are provided.

  2. Feeding of two Cichlidae species (Perciformes in an hypertrophic urban lake

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    Yafe Alejandro

    2002-01-01

    Full Text Available Diet of two cichlid species, Cichlasoma facetum (Jenyns, 1842, and Gymnogeophagus rhabdotus Hensel, 1870, was studied in Rodó Lake, an urban hypertrophic lake in Uruguay. The stomach contents from 192 individuals of C. facetum and 202 of G. rhabdotus, obtained through seasonal sampling in the year 2000, were analyzed. The occurrence frequency and the alimentary importance index of each food item were calculated for each season and size class in both species. Cichlasoma facetum fed upon insects (mainly chironomid larvae and pupae, fish (Cnesterodon decemmaculatus Jenyns, 1842, and vegetals (algae, periphyton and macrophytes debris; large individuals also fed upon the freshwater shrimp Palaemonetes argentinus Nobili, 1901. Gymnogeophagus rhabdotus consumed zooplankton (mainly copepods, vegetals (algae and detritus and Chironomidae larvae in a lesser extent.

  3. High quality draft genome sequence of Brachymonas chironomi AIMA4(T) (DSM 19884(T)) isolated from a Chironomus sp. egg mass.

    Science.gov (United States)

    Laviad, Sivan; Lapidus, Alla; Han, James; Haynes, Matthew; Reddy, Tbk; Huntemann, Marcel; Pati, Amrita; Ivanova, Natalia N; Mavromatis, Konstantinos; Lang, Elke; Rohde, Manfred; Markowitz, Victor; Woyke, Tanja; Klenk, Hans-Peter; Kyrpides, Nikos C; Halpern, Malka

    2015-01-01

    Brachymonas chironomi strain AIMA4(T) (Halpern et al., 2009) is a Gram-negative, non-motile, aerobic, chemoorganotroph bacterium. B. chironomi is a member of the Comamonadaceae, a family within the class Betaproteobacteria. This species was isolated from a chironomid (Diptera; Chironomidae) egg mass, sampled from a waste stabilization pond in northern Israel. Phylogenetic analysis based on the 16S rRNA gene sequences placed strain AIMA4(T) in the genus Brachymonas. Here we describe the features of this organism, together with the complete genome sequence and annotation. The DNA GC content is 63.5%. The chromosome length is 2,509,395 bp. It encodes 2,382 proteins and 68 RNA genes. Brachymonas chironomi genome is part of the Genomic Encyclopedia of Type Strains, Phase I: the one thousand microbial genomes (KMG) project.

  4. [Inversion polymorphism in the population of Camptochironomus tentans from Kaliningrad city].

    Science.gov (United States)

    Petrova, N A; Vinokurova, N V; Danilova, M V; Sharton, A Iu

    2011-01-01

    This paper present the map of polytene chromosomes and inversion polymorphism of widely distributed Chironomidae species, Camptochironomus tentans, from the most western locality of Russia--Kaliningrad city. Chromosomes banding pattern is designated according to Beermann, 1955. Only one larva (2.9%) had a standard banding pattern, and karyotypes of the rest (97.1%) were polymorphic. We have found 2.0 heterozygous inversions per individual, and the frequency of hetero- and homozygous inversions, taken together, amounted to 2.2 per individual. 17 inversion banding patterns and 20 genotypic combinations of these patterns were found. It was shown that the most frequent inversions in this population were identical to these in European populations.

  5. Estado de México

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    Norma A. Navarrete-Salgado

    2007-01-01

    Full Text Available Girardinichthys multiradiatus es endémico de México y con categoría vulnerable. Se determinaron sus hábitos alimenticios en el embalse La Goleta, analizando el contenido estomacal de 600 ejemplares por los métodos numérico, de frecuencia y volumétrico. Observamos que G. multiradiatus utiliza gran variedad de alimentos. El análisis de frecuencia resalta al alga Fragilaria con la mayor presencia en las cuatro estaciones. El análisis volumétrico mostró que para peces de 2.0-3.5 cm destacaron Chironomidae y Diaptomidae; en tanto que para peces de 3.6-5.0 cm fueron Diaptomidae, Trichocorixella mexicana, Fragilaria y Oedogonium, indicando un uso más variado de recursos alimenticios. Finalmente se concluye que es un pez omnívoro, que consume zooplancton, zoobentos y fitoplancton.

  6. A review of necrophagous insects colonising human and animal cadavers in south-east Queensland, Australia.

    Science.gov (United States)

    Farrell, Julianne F; Whittington, Andrew E; Zalucki, Myron P

    2015-12-01

    A review of insects collected from decomposing human remains in south-east Queensland yielded 32 species in three orders (Diptera, Coleoptera, Hymenoptera) and 11 families (Calliphoridae, Sarcophagidae, Muscidae, Phoridae, Sepsidae, Chironomidae, Dermestidae, Cleridae, Histeridae, Staphylinidae, Encyrtidae). There were 15 cases where remains were located indoors and five cases where remains were outdoors, in both terrestrial and aquatic environments. Coleoptera were strongly associated with outdoors remains, while dipteran species composition was similar in both indoor and outdoor habitats. Some Diptera were only associated with indoors remains, while others were similarly restricted to remains recovered outdoors. Hymenopteran parasitoids were active in both habitats. Comparative collections were made from other vertebrate remains, including road-kill and farmed animals throughout south-east Queensland (Qld) and northern New South Wales (NSW) during the same period.

  7. Predator-prey interactions and community structure: chironomids, mosquitoes and copepods in Heliconia imbricata (Musaceae).

    Science.gov (United States)

    Naeem, Shahid

    1988-11-01

    Evidence from both field observations and experimental work indicates that predation by larvae of a midge, Pentaneura n. sp. (Chironomidae), causes the low densities of mosquito larvae (Culicidae) found in the water filled bracts of Heliconia imbricata (Musaceae), microhabitats typically colonized by mosquitoes. This predation affects 2 species of mosquitoes, Wyeomyia pseudopecten, a resident species, and Trichoprosopon digitatum, a non-resident species. Predation keeps resident mosquito densities low while completely excluding the nonresident mosquito from the habitat. Both these effects of predation depend on the presence of an abundant alternative prey, an undescribed species of harpacticoid copepod found in the bracts. These copepod prey sustain chironomids when resident mosquito densities are low, permiting predator densities to remain high enough to exclude the non-resident mosquito. I discuss the evolutionary and ecological implications of predation structuring communities.

  8. O regime hidrológico do rio Ivinhema (Estado do Mato Grosso do Sul e sua influência na assembléia zoobentônica=Hydrologic regime of the Ivinhema river (Mato Grosso do Sul, State and its influence on zoobenthic assemblage

    Directory of Open Access Journals (Sweden)

    José Antonio Arenas-Ibarra

    2012-01-01

    Full Text Available O estudo foi realizado em diferentes ambientes da várzea do rio Ivinhema com o intuito de analisar a variação espacial e temporal da assembléia de invertebrados bentônicos, bem como sua relação com as variáveis físicas e químicas e o nível hidrométrico. Foram estudados quatro ambientes, o canal principal do rio, o canal Ipoitã, a lagoa Ventura (sem comunicação e a lagoa dos Patos (com comunicação. As coletas foram realizadas trimestralmente de fevereiro a novembro de 2002. O sistema rio Ivinhema foi caracterizado por um regime de potamofase bimodal com intensidades moderadas e grandes amplitudes, permanecendo em potamofase 184 dias em 2001 e 67 dias em 2002. Foram observadas as variações espacial e temporal, quanto às variáveis físicas e químicas, sumarizadas em uma PCA. Dos 37 táxons registrados, Nematoda, Corbiculidae, Oligochaeta, Acari, Ostracoda e Chironomidae foram os mais abundantes, sendo as larvas de Chironomidae o táxon predominante no canal Ipoitã e na lagoa Ventura. Entretanto, a análise da estrutura da assembléia (CA demonstrou que a assembléia bentônica do rio Ivinhema é dissimilar a das lagoas. A relação entre PCA e CA não foi significativa, indicando que no sistema Ivinhema há uma estrutura complexa e que a uniformidade espacial da densidade e temporal da assembléia bentônica deve-se à maior conectividade entre os ambientes.This study was developed in different environments of the Ivinhema river floodplain in order to analyze the spatial and temporal variation of benthic assemblages and their relationship with physical and chemical variables and water level. Samples were taken quarterly between February and November 2002 in four environments: Ivinhema main channel, Ipoitã channel, Patos lake (with direct connectivity and Ventura lake (without connectivity. The system was characterized by a bimodal potamophase cycle with moderate intensities and large amplitudes, remaining in potamophase for

  9. New and rare Harpellales from Portugal and northwestern Iberian Peninsula: discovering the hidden mycobiota of Galicia-Tras-os-Montes region.

    Science.gov (United States)

    Valle, Laia Guardia

    2013-01-01

    The species of Harpellales obtained from a survey of the gut fungi of aquatic arthropods in the Galaico-Portuguese region, also known as the Galicia-Trás-os-Montes Zone, are presented. New species include Orphella lusitanica, a close relative of O. helicospora in Plecoptera nymphs and Stachylina pleurospora, in Chironomiidae larvae, both from Galicia and Portugal. Tectimyces gallaecicus, in Ephemeroptera nymphs from Galicia, Spain, morphologically resembles the narrowly distributed T. robustus representing a genus known only from Europe. New geographical records from Portugal include Genistellospora homothallica, Graminella bulbosa, Harpella melusinae, Lancisporomyces vernalis, Legeriomyces ramosus, O. coronata, Simuliomyces microsporus and Smittium simulii. Also three rare taxa are reported from Galicia: Legeriomyces dolabrae and Baetimyces ancorae from Baetidae nymphs and Smittium inexpectans from Chironomidae larvae.

  10. Compact genome of the Antarctic midge is likely an adaptation to an extreme environment

    Science.gov (United States)

    Kelley, Joanna L.; Peyton, Justin T.; Fiston-Lavier, Anna-Sophie; Teets, Nicholas M.; Yee, Muh-Ching; Johnston, J. Spencer; Bustamante, Carlos D.; Lee, Richard E.; Denlinger, David L.

    2014-01-01

    The midge, Belgica antarctica, is the only insect endemic to Antarctica, and thus it offers a powerful model for probing responses to extreme temperatures, freeze tolerance, dehydration, osmotic stress, ultraviolet radiation and other forms of environmental stress. Here we present the first genome assembly of an extremophile, the first dipteran in the family Chironomidae, and the first Antarctic eukaryote to be sequenced. At 99 megabases, B. antarctica has the smallest insect genome sequenced thus far. Although it has a similar number of genes as other Diptera, the midge genome has very low repeat density and a reduction in intron length. Environmental extremes appear to constrain genome architecture, not gene content. The few transposable elements present are mainly ancient, inactive retroelements. An abundance of genes associated with development, regulation of metabolism and responses to external stimuli may reflect adaptations for surviving in this harsh environment. PMID:25118180

  11. OIL DECONTAMINATION OF BOTTOM SEDIMENTS EXPERIMENTAL WORK RESULTS

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    Lushnikov Sergey V.

    2006-08-01

    Full Text Available This article presents the results of experimental work during 2004-2005 on oil decontamination of bottom sediments of Lake Schuchye, situated in the Komi Republic (Northern Russia. The cause of thecontamination were huge oil spills occurred after a series of accidental ruptures on the Harjaga-Usinsk and Vozej-Usinsk oil-pipe lines in 1994. Flotation technology was used for the cleaning of bottom sediments.157 tons of crude oil were removed during the course of 2-year experimental work from an area of 4,1 ha.The content of aliphatic and alicyclic oil hydrocarbons was reduced from 53,3 g/kg to 2,2 g/kg, on average.Hydrobiological investigations revealed that bottom sediments started to be inhabited by benthos organisms, dominantly Oligochaeta. Besides Oligochaeta, Chironomidae maggots and Bivalvia were detected. Theappearance of Macrozoobenthos organisms can serve as a bioindicator of water quality.

  12. Exploring Genetic Divergence in a Species-Rich Insect Genus Using 2790 DNA Barcodes.

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    Xiaolong Lin

    Full Text Available DNA barcoding using a fragment of the mitochondrial cytochrome c oxidase subunit 1 gene (COI has proven to be successful for species-level identification in many animal groups. However, most studies have been focused on relatively small datasets or on large datasets of taxonomically high-ranked groups. We explore the quality of DNA barcodes to delimit species in the diverse chironomid genus Tanytarsus (Diptera: Chironomidae by using different analytical tools. The genus Tanytarsus is the most species-rich taxon of tribe Tanytarsini (Diptera: Chironomidae with more than 400 species worldwide, some of which can be notoriously difficult to identify to species-level using morphology. Our dataset, based on sequences generated from own material and publicly available data in BOLD, consist of 2790 DNA barcodes with a fragment length of at least 500 base pairs. A neighbor joining tree of this dataset comprises 131 well separated clusters representing 121 morphological species of Tanytarsus: 77 named, 16 unnamed and 28 unidentified theoretical species. For our geographically widespread dataset, DNA barcodes unambiguously discriminate 94.6% of the Tanytarsus species recognized through prior morphological study. Deep intraspecific divergences exist in some species complexes, and need further taxonomic studies using appropriate nuclear markers as well as morphological and ecological data to be resolved. The DNA barcodes cluster into 120-242 molecular operational taxonomic units (OTUs depending on whether Objective Clustering, Automatic Barcode Gap Discovery (ABGD, Generalized Mixed Yule Coalescent model (GMYC, Poisson Tree Process (PTP, subjective evaluation of the neighbor joining tree or Barcode Index Numbers (BINs are used. We suggest that a 4-5% threshold is appropriate to delineate species of Tanytarsus non-biting midges.

  13. The rainy season increases the abundance and richness of the aquatic insect community in a Neotropical reservoir

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    HS Santana

    Full Text Available Alterations in aquatic systems and changes in water levels, whether due to rains or dam-mediated control can cause changes in community structure, forcing the community to readjust to the new environment. This study tested the hypothesis that there is an increase in the richness and abundance of aquatic insects during the rainy season in the Serra da Mesa Reservoir, with the premise that increasing the reservoir level provides greater external material input and habitat diversity, and, therefore, conditions that promote colonization by more species. We used the paired t test to test the differences in richness, beta diversity, and abundance, and a Non-metric Multidimensional Scaling (NMDS was performed to identify patterns in the community under study. Additionally, Pearson correlations were analyzed between the richness, abundance, and beta diversity and the level of the reservoir. We collected 35,028 aquatic insect larvae (9,513 in dry period and 25,515 in the rainy season, predominantly of the Chironomidae family, followed by orders Ephemeroptera, Trichoptera, and Odonata. Among the 33 families collected, only 12 occurred in the dry season, while all occurred in the rainy season. These families are common in lentic environments, and the dominance of Chironomidae was associated with its fast colonization, their behavior of living at high densities and the great tolerance to low levels of oxygen in the environment. The hypothesis was confirmed, as the richness, beta diversity, and abundance were positively affected by the increase in water levels due to the rainy season, which most likely led to greater external material input, greater heterogeneity of habitat, and better conditions for colonization by several families.

  14. DIET OF DIRECT-DEVELOPING FROGS (ANURA: CRAUGASTORIDAE: Pristimantis FROM THE ANDES OF WESTERN COLOMBIA

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    Juan Carlos GARCIA-R

    2015-01-01

    Full Text Available Estudiamos la dieta de 15 especies de ranas montanas del género Pristimantis (Craugastoridae en la Cordillera Occidental de Colombia para determinar su variación, amplitud y traslape de nicho. En los contenidos estomacales e intestinales de 154 especímenes se identificaron 499 presas que fueron organizadas en 74 categorías diferentes. Las 15 categorías de presas más comunes representaron el 65 % de la dieta. Las familias de invertebrados Isotomidae, Chironomidae, Formicidae y Tipulidae fueron las más abundantes, representando el 32 % de la dieta de las ranas. Diez de las 15 especies de ranas presentaron al menos un ítem de Araneae. Coleoptera y Tipulidae fueron otras categorías frecuentemente encontradas en los tractos digestivos de las ranas (nueve especies de ranas presentaron estos ítems, seguidas de Acari y Carabidae (ocho especies. En general, los escarabajos fueron encontrados en los tractos gastrointestinales de todas las especies, excepto en P. quantus , pero este resultado debe tratarse con precaución porque solo un individuo de esta especie fue capturado. Pristimantis hectus mostró una dieta especializada consumiendo principalmente dípteros de la familia Chironomidae, mientras que las especies restantes mostraron una dieta generalista. Pristimantis palmeri presentó superposiciones de nicho con P. erythropleura ( Ф jk = 0,69, P. myops ( Ф jk = 0,64, y P. orpacobates ( Ф jk = 0,64. Nuestros resultados sugieren que la mayoría de las especies estudiadas son generalistas que se alimentan de manera oportunista de dípteros, arácnidos, colémbolos, coleópteros e himenópteros. Aquí, reportamos la dieta de especies montanas de Pristimantis y discutimos los resultados con datos de otros estudios en especies relacionadas de regiones montanas y tierras bajas.

  15. Quantifying climate changes of the Common Era for Finland

    Science.gov (United States)

    Luoto, Tomi P.; Nevalainen, Liisa

    2016-11-01

    In this study, we aim to quantify summer air temperatures from sediment records from Southern, Central and Northern Finland over the past 2000 years. We use lake sediment archives to estimate paleotemperatures applying fossil Chironomidae assemblages and the transfer function approach. The used enhanced Chironomidae-based temperature calibration set was validated in a 70-year high-resolution sediment record against instrumentally measured temperatures. Since the inferred and observed temperatures showed close correlation, we deduced that the new calibration model is reliable for reconstructions beyond the monitoring records. The 700-year long temperature reconstructions from three sites at multi-decadal temporal resolution showed similar trends, although they had differences in timing of the cold Little Ice Age (LIA) and the initiation of recent warming. The 2000-year multi-centennial reconstructions from three different sites showed resemblance with each other having clear signals of the Medieval Climate Anomaly (MCA) and LIA, but with differences in their timing. The influence of external forcing on climate of the southern and central sites appeared to be complex at the decadal scale, but the North Atlantic Oscillation (NAO) was closely linked to the temperature development of the northern site. Solar activity appears to be synchronous with the temperature fluctuations at the multi-centennial scale in all the sites. The present study provides new insights into centennial and decadal variability in air temperature dynamics in Northern Europe and on the external forcing behind these trends. These results are particularly useful in comparing regional responses and lags of temperature trends between different parts of Scandinavia.

  16. Sphagnum mosses as a microhabitat for invertebrates in acidified lakes and the colour adaptation and substrate preference in Leucorrhinia dubia (Odonata, Anisoptera)

    Energy Technology Data Exchange (ETDEWEB)

    Henrikson, B.-I. (Dept. of Zoology, Sect. of Animal Ecology, Univ. of Goeteborg, Goeteborg (Sweden))

    1993-01-01

    The increase of peat mosses, Sphagnum spp., in acidified lakes leads to a changed microhabitat structure for benthic invertebrates. The importance of this change was investigated for some benthic invertebrates. Comparisons between quantitative samples of Sphagnum and debris within the acidified Lake Stora Haestevatten, in the Lake Gaardsjoen catchment of SW Sweden, showed significantly higher abundances of Chironomidae, Ceratopogonidae, Odonata, Trichoptera, Cladocera and Argyroneta aquatica (Araneae) in Sphagnum. For chironomidae and Cladocera the differences were tenfold. Special reference was made to the libellulid Leucorrhinia dubia which is common in acid lakes. In a laboratory test, late instar larvae of L. dubia were shown to change colour to correspond to the brown and green colour of Sphagnum. This result was completed with a field test where larvae of L. dubia were significantly more common in Sphagnum of the same colour as the larvae. The ability to change colour may have an adaptive value when coexisting with visual predators. Small larvae were more prevalent in Sphagnum and they also showed a preference for this substrate in the laboratory test. Laboratory tests showed mediumsized larvae preferred Sphagnum. Larvae of L. dubia were more successful as predators on Asellus aquaticus in Sphagnum substrate than in debris in the laboratory test. Laboratory predation tests with notonecta glauca, Corixa dentipes, Acilius sulcatus, Hyphydrus ovatus and L. dubia showed that they could all feed on larvae of L. dubia. The complex habitat structure of Sphagnum is probably the reason for the high abundance of invertebrates since it may serve as both shelter against predation and as foraging sites. it is probably important as a key habitat for young instars of, for example, L. dubia. In lakes with large Sphagnum mats, L. dubia can coexist with fish. The expansion of Sphagnum due to acidification will probably benefit many acid-tolerant invertebrate species. (au)

  17. Evaluación de la calidad de las aguas del estero Limache (Chile central, mediante bioindicadores y bioensayos Water quality assessment in the Limache stream (central Chile, using bioindicators and bioassays

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    Salomé Córdova

    2009-01-01

    Full Text Available Se evaluó la calidad de las aguas del estero Limache en cinco estaciones de muestreo en el período de bajo caudal. En cada estación se colectaron macroinvertebrados acuáticos, se midió in situ pH, conductividad, oxígeno disuelto, y sólidos disueltos totales. En el laboratorio se determinó la demanda biológica de oxígeno (DBO, fósforo total y nitrógeno total. También se determinó la toxicidad del agua mediante bioensayos con la microalga Pseudokirchrneriella subcapitata. Se determinaron 33 familias de macroinvertebrados, los taxa dominantes fueron Dugessidae, Oligochaeta y Chironomidae. Se encontró correlación significativa entre el índice biótico de familias (ChIBF, la conductividad eléctrica y los sólidos disueltos totales (r = 0,92; p The water quality in the Limache stream was evaluated at five sampling stations during the pe-riod of low water flow. At each station, aquatic macroinvertebrates were collected and the following parame-ters were measured in situ: pH, conductivity, dissolved oxygen, and total dissolved solids. The biological oxy-gen demand, total phosphorus, and total nitrogen were determined in the laboratory. Water toxicity was deter-mined through toxicity bioassays with the microalga Pseudokirchrneriella subcapitata. Thirty-three macroin-vertebrate families were found and the dominant taxa were Dugessidae, Oligochaeta and Chironomidae. A significant correlation was found among the Family Biotic índex ChFBI, conductivity, and total dissolved solids (r = 0.92; p < 0.05. Species diversity was lowest, as was the growth rate of P. subcapitata, at the stations with the greatest anthropogenic activity and in the discharge zone of a domestic wastewater treatment plant.

  18. Carnivory during Ontogeny of the Plagioscion squamosissimus: A Successful Non-Native Fish in a Lentic Environment of the Upper Parana River Basin.

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    Mayara Pereira Neves

    Full Text Available This study evaluated feeding patterns and ontogenetic variations in a non-native fish species (Plagioscion squamosissimus in an isolated lake in the Upper Paraná River floodplain. Quarterly samplings were performed from April 2005 to February 2006 using plankton nets to capture larvae, seining nets for juveniles, and gill nets and trammel for adults. Stomach contents (n = 378 were examined according to the volumetric method in which the volume of each food item was estimated using graduated test tubes or a glass counting plate. During early development (larval stage, P. squamosissimus consumed mainly Cladocera and Copepoda. Juveniles showed a more diverse diet, including shrimp (Macrobrachium amazonicum, fish, aquatic insects (Trichoptera, Ephemeroptera, Chironomidae and pupae of Diptera and plants. It was notable the high proportion of cannibalism (23.3% in this stage. Adults consumed predominantly shrimp and fish. The use of food resources varied significantly between development stages (ANOSIM; r = 0.458; p<0.005, showing changes in food preferences during ontogeny. The Similarity Percentage Analysis (SIMPER indicated that Cladocera and Copepoda were responsible for the differences observed between the larval stages of pre-flexion, flexion and post-flexion. M. amazonicum and Chironomidae were responsible for the differences between juvenile and larval stages, while M. amazonicum and other fishes caused the differences between adults and other ontogenetic stages. These results are confirmed by the relationship between standard length and developmental periods (ANCOVA; r2 = 0.94; p<0.0001. In general, there were low values of trophic niche breadth. The essentially carnivorous habit from the early stages of P. squamosissimus and the predominant use of M. amazonicum by adults have important roles in feeding patterns of the species, suggesting a major contribution to its success and establishment, especially in lentic environments.

  19. Changes in consumption by alewives and lake whitefish after dreissenid mussel invasions in Lakes Michigan and Huron

    Science.gov (United States)

    Pothoven, S.A.; Madenjian, C.P.

    2008-01-01

    Growth of alewives Alosa pseudoharengus and lake whitefish Coregonus clupeaformis has declined since the arrival and spread of dreissenid mussels in Lakes Michigan and Huron. Alewives are the main forage for the salmonids in Lake Michigan, and lake whitefish are the most important commercial species in both lakes. Bioenergetics modeling was used to determine consumption by the average individual fish before and after the dreissenid invasion and to provide insight into the invasion's effects on fish growth and food web dynamics. Alewives feed on both Zooplankton and benthic macroinvertebrates, and lake whitefish are benthivores. Annual consumption of zooplankton by an average alewife in Lake Michigan was 37% lower and consumption of benthic macroinvertebrates (amphipods Diporeia spp., opossum shrimp Mysis relicta, and Chironomidae) was 19% lower during the postinvasion period (1995-2005) than during the preinvasion period (1983-1994). Reduced consumption by alewives corresponded with reduced alewife growth. In Lakes Michigan and Huron, consumption of nonmollusk macroinvertebrates (Diporeia spp., opossum shrimp, Chironomidae) by the average lake whitefish was 46-96% lower and consumption of mollusks (mainly dreissenids and gastropods) was 2-5 times greater during the postinvasion period than during the preinvasion period. Even though total food consumption by lake whitefish did not differ between the two periods in Lake Huron or the Southern Management Unit in Lake Michigan, postinvasion weight at age was at least 38% lower than preinvasion weight at age. Under the current postinvasion diet regime, consumption by lake whitefish would have to increase by up to 122% to achieve preinvasion growth rates. ?? Copyright by the American Fisheries Society 2008.

  20. Small ecosystem engineers as important regulators of lake's sediment respiration.

    Science.gov (United States)

    Baranov, Victor; Lewandowski, Joerg; Krause, Stefan; Romeijn, Paul

    2016-04-01

    Although shallow lakes are covering only about 1.5% of the land surface of the Earth, they are responsible for sequestration of carbon amounts similar or even larger than those sequestered in all marine sediments. One of the most important drivers of the carbon sequestration in lakes is sediment respiration. Especially in shallow lakes, bioturbation, i.e. the biogenic reworking of the sediment matrix and the transport of fluids within the sediment, severely impacts on sediment respiration. Widespread freshwater bioturbators such as chironomid larvae (Diptera, Chironomidae) are building tubes in the sediment and actively pump water through their burrows (ventilation). In the present work we study how different organism densities and temperatures (5-30°C) impact on respiration rates. In a microcosm experiment the bioreactive resazurin/resorufin smart tracer system was applied for quantifying the impacts of different densities of Chironomidae (Diptera) larvae (0, 1000, 2000 larvae/m2) on sediment respiration. Tracer transformation rates (and sediment respiration) were correlated with larval densities with highest transformation rates occurring in microcosms with highest larval densities. Respiration differences between defaunated sediment and sediment with 1000 and 2000 larvae per m2 was insignificant at 5 °C, and was progressively increasing with rising temperatures. At 30 °C respiration rates of sediment with 2000 larvae per m2 was 4.8 times higher than those of defaunated sediment. We interpret this as an effect of temperature on larval metabolic and locomotory activity. Furthermore, bacterial communities are benefiting from the combination of the high water temperatures and bioirrigation as bacterial community are able to maintain high metabolic rates due to oxygen supplied by bioirrigation. In the context of global climate change that means that chironomid ecosystem engineering activity will have a profound and increasing impact on lake sediment respiration

  1. THE FLOOD PULSE INFLUENCE IN ECOLIMNOLOGICAL PANTANAL LAKES: A STUDY TO UNDERSTAND THE BIODIVERSITY DYNAMICS OF AQUATIC INVERTEBRATES = A INFLUÊNCIA DO PULSO DE INUNDAÇÃO NA ECOLIMNOLOGIA DE BAÍAS PANTANEIRAS: UM ESTUDO NA DINÂMICA DE INVERTEBRADOS AQUÁTICOS

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    Ernandes Sobreira Oliveira Junior

    2013-01-01

    Full Text Available This study aimed to compare the environmental variables with this biota in two bays in the Pantanal near the city of Cáceres-MT. Data of biotic and abiotic variables of the water sampling were analyzed on six sampling points for one year survey comprising four Pantanal hydrological periods. Rich invertebrate fauna associated with aquatic macrophytes were found; with the Class Insecta is that with greater representativeness. There were significant differences between periods for hydrological variables dissolved oxygen, transparency and depth. The most significant correlations occurred between groups Nematoda, Ostracoda, Decapoda, Chironomidae, Copepoda and Dityscidae with dissolved oxygen, conductivity and depth. These data may indicate that the limnological variables influence in the aquatic invertebrates community and changes in water quality may result in a change in the microbiota, which is plays a fundamental role in the flow of matter and nutrient cycling within an ecosystem. = Este estudo se propôs relacionar as variáveis ambientais com a biota presente em duas baías do Pantanal Matogrossense, próximas à cidade de Cáceres-MT. Foram coletados dados de variáveis bióticas e abióticas da água em seis pontos de amostragem durante um ano de pesquisa, compreendendo os quatro períodos hidrológicos do Pantanal. Foi encontrada rica fauna de invertebrados aquáticos associados à macrófitas, tendo a Classe Insecta maior representatividade. As variáveis oxigênio dissolvido, transparência e profundidade apresentaram diferenças estatisticamente significativas entre os períodos hidrológicos. Os grupos Nematoda, Ostracoda, Decapoda, Chironomidae, Dityscidae e Copepoda estiveram significativamente correlacionados com as variáveis estudadas. Estes resultados podem indicar que as variáveis limnológicas exerceram influência na comunidade de invertebrados aquáticos e que modificações na qualidade da água podem resultar em uma altera

  2. Sucessão de invertebrados durante o processo de decomposição de duas plantas aquáticas (Eichhornia azurea e Polygonum ferrugineum = Succession of invertebrates during the decomposition process of two aquatic plants (Eichhornia azurea and Polygonum ferrugineum

    Directory of Open Access Journals (Sweden)

    Roger Paulo Mormul

    2006-04-01

    Full Text Available A colonização de invertebrados durante o período de 56 dias de decomposição de duas espécies de plantas aquáticas (Eichhornia azurea e Polygonum ferrugineum foi investigada para determinar o papel de macroinvertebrados no processo de fragmentação da folha. Durante aanálise do material, foi constatado um total de 2096 invertebrados, associados a E.azurea e 6154 invertebrados associados a P. ferrugineum, identificados dentro de 18 táxons, com predominânciade larvas de Diptera da família Chironomidae, seguido por espécimes de Oligochaeta, microcrustáceos como Cladocera e Copepoda. Em ambas as plantas, os macroinvertebrados mostraram um aumento significativo de densidade ao longo do processo de decomposição, o que provavelmente está associado à perda de compostos fenólicos. Os resultados sugerem que as espécies de macrófitas apresentam associações específicas com seus consumidores, ou seja, o processo de sucessão da colonização torna-se diferenciado de acordo com as características fenológicas da planta.The invertebrate colonization was investigated during 56-day decomposition of two macrophytes species (Eichhornia azurea andPolygonum ferrugineum. The aim was to determine the role of macroinvertebrates in the process of leaf fragmentation. During material analysis, 2096 invertebrates were associated with E.azureaand 6154 were associated with P. ferrugineum, identified in 18 taxons, with predominance of Diptera larvae (Chironomidae family specially, followed by Oligochaeta species and microcrustaceans such as Cladocera and Copepoda. In both macrophytes the macroinvertebratesshowed a significant increase of density through the process of decomposition, which is probably associated with the loss of phenolic compounds. Results suggest that macrophytes specimens show specific associations with their consumers, i.e., the succession process of colonization becomes singular according to the phenolic characteristics of the plant.

  3. Sucessão de invertebrados durante o processo de decomposição de duas plantas aquáticas (Eichhornia azurea e Polygonum ferrugineum - DOI: 10.4025/actascibiolsci.v28i2.1017 Succession of invertebrates during the decomposition process of two aquatic plants (Eichhornia azurea and Polygonum ferrugineum - DOI: 10.4025/actascibiolsci.v28i2.1017

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    Alexandre Monkolski

    2006-03-01

    Full Text Available A colonização de invertebrados durante o período de 56 dias de decomposição de duas espécies de plantas aquáticas (Eichhornia azurea e Polygonum ferrugineum foi investigada para determinar o papel de macroinvertebrados no processo de fragmentação da folha. Durante a análise do material, foi constatado um total de 2096 invertebrados, associados a E.azurea e 6154 invertebrados associados a P. ferrugineum, identificados dentro de 18 táxons, com predominância de larvas de Diptera da família Chironomidae, seguido por espécimes de Oligochaeta, microcrustáceos como Cladocera e Copepoda. Em ambas as plantas, os macroinvertebrados mostraram um aumento significativo de densidade ao longo do processo de decomposição, o que provavelmente está associado à perda de compostos fenólicos. Os resultados sugerem que as espécies de macrófitas apresentam associações específicas com seus consumidores, ou seja, o processo de sucessão da colonização torna-se diferenciado de acordo com as características fenológicas da planta.The invertebrate colonization was investigated during 56-day decomposition of two macrophytes species (Eichhornia azurea and Polygonum ferrugineum. The aim was to determine the role of macroinvertebrates in the process of leaf fragmentation. During material analysis, 2096 invertebrates were associated with E.azurea and 6154 were associated with P. ferrugineum, identified in 18 taxons, with predominance of Diptera larvae (Chironomidae family specially, followed by Oligochaeta species and microcrustaceans such as Cladocera and Copepoda. In both macrophytes the macroinvertebrates showed a significant increase of density through the process of decomposition, which is probably associated with the loss of phenolic compounds. Results suggest that macrophytes specimens show specific associations with their consumers, i.e., the succession process of colonization becomes singular according to the phenolic characteristics of the

  4. Trophic relationships between macroinvertebrates and fish in a pampean lowland stream (Argentina Relaciones tróficas entre los macroinvertebrados y peces en un arroyo de la llanura pampeana (Argentina

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    María V. López van Oosterom

    2013-03-01

    Full Text Available The diet and trophic relationships between the macroinvertebrates Phyllogomphoides joaquini Rodrigues Capítulo, 1992 and Coenagrionidae (Odonata, Chironomidae (Diptera, Diplodon delodontus (Lamarck, 1919 (Bivalvia: Hyriidae, and Pomacea canaliculata (Lamarck, 1822 (Gastropoda: Ampulariidae and the fishes Pimelodella laticeps Eigenmann, 1917 (Heptapteridae and Bryconamericus iheringii (Boulenger, 1887 (Characidae in a temperate lowland lotic system in Argentina were assessed on the basis of gut contents and stable-isotope analyses. The feeding strategies were analyzed by the AMUNDSEN method. Relative food items contribution for the taxa studied indicated a generalist-type trophic strategy. In macroinvertebrates, in general, the values of stable isotope confirmed the result of the analysis of gut contents. With the fish, stable-isotope analysis demonstrated that both species are predators, although B. iheringii exhibited a more omnivorous behaviour. These feeding studies allowed us to determine the trophic relationships among taxa studied. Detritus and diatoms were a principal source of food for all the macroinvertebrates studied. In La Choza stream the particulate organic matter is a major no limited food resource, has a significant influence upon the community.Se evaluó la dieta y las relaciones tróficas entre los macroinvertebrados Phyllogomphoides joaquini Rodrigues Capítulo, 1992 y Coenagrionidae (Odonata, Chironomidae (Diptera, Diplodon delodontus (Lamarck, 1919 (Bivalvia: Hyriidae, Pomacea canaliculata (Lamarck, 1822 (Gastropoda: Ampulariidae y los peces Pimelodella laticeps Eigenmann, 1917 (Heptapteridae y Bryconamericus iheringii (Boulenger, 1887 (Characidae en un ecosistema lótico pampásico, sobre la base del contenido estomacal y el análisis de isótopos estables. La estrategia alimentaria fue analizada mediante el método de AMUNDSEN. La contribución relativa de cada categoría alimenticia para los taxa estudiados indicó que

  5. Effects of carbofuran and metsulfuron-methyl on the benthic macroinvertebrate community in flooded ricefields Efeito do carbofurano e metsulfuron-methyl sobre a comunidade de macroinvertebrados bentônicos de lavoura de arroz irrigado

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    Joele Baumart

    2011-06-01

    Full Text Available AIM: This study evaluated the effect of the insecticide carbofuran and the herbicide metsulfuron-methyl on the abundance and diversity of benthic macroinvertebrates in a paddy ricefield. METHODS: To achieve this goal, two pesticide treatments [the insecticide carbofuran (IC and the herbicide metsulfuron-methyl (HM] and a control (Co treatment with no added pesticide were established in an experimental area of the Plant Science Department of the Federal University of Santa Maria. Soil samples were collected in triplicate from each treatment 30 days before and 1, 10, and 51 days after the pesticide application, for macrofauna identification. RESULTS: Among the 21 taxa identified, Trichoceridae was present only in Co, Hydroptilidae was recorded only in IC, and Corixidae in HM. In Co, the most abundant group was Annelida, while in IC and HM Diptera (Chironomidae was dominant. Significant differences were observed between Co and IC, in the density of Odontoceridae (Control>IC and Hydrophilidae (ControlHM and Hirudinea (ControlOBJETIVO: O objetivo desse estudo foi avaliar o efeito do inseticida carbofurano e do herbicida metsulfuron-methyl na abundância e diversidade de macroinvertebrados bentônicos em campo de arroz irrigado. MÉTODOS: Para isto, dois tratamentos com agrotóxicos [o inseticida carbofurano (IC e o herbicida metsulfuron-methyl (HM] e um controle (Co, tratamento sem pesticida, foram aplicados em uma área experimental no Departamento de Fitotecnia da Universidade Federal de Santa Maria. Amostras de solo foram coletadas em triplicatas em cada tratamento 30 dias antes (DBA e 1, 10 e 51 dias após a aplicação dos pesticidas, posteriormente a macrofauna foi identificada. RESULTADOS: Vinte e um (21 taxa foram identificados, entre esses Trichoceridae esteve presente apenas em Co, enquanto que Hydroptilidae foi coletado apenas em IC, e Corixidae em HM. Em Co e IC, o grupo mais abundante foi Annelida, e em HM foi Diptera (Chironomidae que

  6. 大型底栖无脊椎动物不同分类阶元对水生态评价的影响%Effects of Macroinvertebrate Taxonomic Resolution on Water Ecological Assessment

    Institute of Scientific and Technical Information of China (English)

    吴东浩; 徐兆安; 王备新; 张咏; 厉以强; 沈燕飞

    2012-01-01

    以江苏苏北地区主要河流为研究对象,探讨底栖动物不同分类阶元对水生态评价的影响.结果表明,在仅包括软体动物、摇蚊和寡毛类物种水平和属级水平的nMDS排序图上,样点间的相对距离和位置未发生变化.与物种水平相比,属级水平丢失的信息(<5%)小于科级水平(7%),且分类单元数与物种水平分类单元数呈极显著正相关(r =0.88,P<0.01).鉴定至属级水平较物种级水平不仅可节省大量的人力、物力和时间,而且可降低鉴定错误的概率;鉴定水平的统一能提高不同地区生态评价结果的可比性.因此,建议在长三角河网地区开展水生态评价时,采用鉴定至属级水平的软体动物、摇蚊和寡毛类较为合适.%The effects of different taxonomie resolutions on water ecological assessment was investigated by using data of benthic macroinvertebrate assemblages collected from 49 river sites in northern Jiangsu Province. The results showed that, based only on data of mollusca, chironomidae and oligochaeta, there were no differences in the location and relative distance among sites on the non-metric multidimensional scaling ordinations (nMDS) at the species or genus level. The information loss was less on the genus level ( <5% ) than on the family level (7 % ) , and the genus-level richness was strongly correlated with that of the species level ( r = 0. 88, P < 0. 01). There was no difference in accuracy of ecological condition assessment between coarse taxonomical level and species level. It costs much less to obtain information from family or genus level instead of species level, and identification errors can be reduced. The consistency of taxonomical resolution among different bioassessment programs increases the potential of inter-regional comparison from different ecological conditions. Our results suggested that the use of genus level in the combination of mollusca, chironomidae and oligochaeta was proper in

  7. The effect of the macroconsumer Aegla longirostri (Crustacea, Decapoda on the invertebrate community in a subtropical stream

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    Gláucia Bolzan Cogo

    2014-06-01

    Full Text Available AIM: This study tested whether the macroconsumer Aegla longirostri is able to modify the invertebrate community associated with decomposing leaves. METHODS: The study was performed in a first-order stream located in central Rio Grande do Sul state. Two types of channels containing leaf litter of Ficus luschnathiana were placed in the stream; one type allowed aeglids to access the leaf litter (PA, and the other type did not (AA. Both types allowed aquatic insects to access the leaf litter. In addition, a control treatment (C was established, in which no channel was used. After 3, 7, 11, 15 and 19 days, a litter bag was removed from each replicate of each treatment. RESULTS: A total of 926 organisms belonging to 19 families were identified. The most common taxon in all treatments was Chironomidae, which comprised 71% of the total and was represented by 16 genera. The presence of aeglids decreased the total abundance of organisms by 89% and the taxonomic richness by 35%. The presence of A. longirostri altered the taxonomic composition of the invertebrates and the structure of the trophic groups, causing a decrease in the abundance of all groups, except for shredders and predators. The gathering-collectors trophic group was the most important (65%, in both the presence and absence of A. longirostri. CONCLUSION: Our study showed that A. longirostri, as well as other macroconsumers, was able to modify the structure of the invertebrate community associated with decomposing leaves in the stream.

  8. Carnivory during Ontogeny of the Plagioscion squamosissimus: A Successful Non-Native Fish in a Lentic Environment of the Upper Paraná River Basin

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    Neves, Mayara Pereira; Delariva, Rosilene Luciana; Guimarães, Ana Tereza Bittencourt; Sanches, Paulo Vanderlei

    2015-01-01

    This study evaluated feeding patterns and ontogenetic variations in a non-native fish species (Plagioscion squamosissimus) in an isolated lake in the Upper Paraná River floodplain. Quarterly samplings were performed from April 2005 to February 2006 using plankton nets to capture larvae, seining nets for juveniles, and gill nets and trammel for adults. Stomach contents (n = 378) were examined according to the volumetric method in which the volume of each food item was estimated using graduated test tubes or a glass counting plate. During early development (larval stage), P. squamosissimus consumed mainly Cladocera and Copepoda. Juveniles showed a more diverse diet, including shrimp (Macrobrachium amazonicum), fish, aquatic insects (Trichoptera, Ephemeroptera, Chironomidae and pupae of Diptera) and plants. It was notable the high proportion of cannibalism (23.3%) in this stage. Adults consumed predominantly shrimp and fish. The use of food resources varied significantly between development stages (ANOSIM; r = 0.458; pjuvenile and larval stages, while M. amazonicum and other fishes caused the differences between adults and other ontogenetic stages. These results are confirmed by the relationship between standard length and developmental periods (ANCOVA; r2 = 0.94; p<0.0001). In general, there were low values of trophic niche breadth. The essentially carnivorous habit from the early stages of P. squamosissimus and the predominant use of M. amazonicum by adults have important roles in feeding patterns of the species, suggesting a major contribution to its success and establishment, especially in lentic environments. PMID:26524336

  9. Annual time-series analysis of aqueous eDNA reveals ecologically relevant dynamics of lake ecosystem biodiversity

    Science.gov (United States)

    Bista, Iliana; Carvalho, Gary R.; Walsh, Kerry; Seymour, Mathew; Hajibabaei, Mehrdad; Lallias, Delphine; Christmas, Martin; Creer, Simon

    2017-01-01

    The use of environmental DNA (eDNA) in biodiversity assessments offers a step-change in sensitivity, throughput and simultaneous measures of ecosystem diversity and function. There remains, however, a need to examine eDNA persistence in the wild through simultaneous temporal measures of eDNA and biota. Here, we use metabarcoding of two markers of different lengths, derived from an annual time series of aqueous lake eDNA to examine temporal shifts in ecosystem biodiversity and in an ecologically important group of macroinvertebrates (Diptera: Chironomidae). The analyses allow different levels of detection and validation of taxon richness and community composition (β-diversity) through time, with shorter eDNA fragments dominating the eDNA community. Comparisons between eDNA, community DNA, taxonomy and UK species abundance data further show significant relationships between diversity estimates derived across the disparate methodologies. Our results reveal the temporal dynamics of eDNA and validate the utility of eDNA metabarcoding for tracking seasonal diversity at the ecosystem scale.

  10. Change does not happen overnight: a case study on stream macroinvertebrates

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    Guareschi S.

    2016-01-01

    Full Text Available The influence of day/night conditions on individual animal/plant species has been widely studied, but diel cycle studies of the entire stream macroinvertebrate community are extremely rare. This study explored potential dissimilarities between daytime and nighttime macroinvertebrate assemblages by extensive fieldwork conducted in the Lemme stream, a natural water course of NW Italy. Here numerous structural and functional metrics (richness, abundance, biomass, indicator taxa, composition, biomonitoring values and feeding groups were evaluated at the family level. Small-scale environmental variables were investigated to understand possible differences between macroinvertebrate assemblages in the daytime/nighttime. After collecting and identifying 21 459 organisms of 50 taxa, Chironomidae (Diptera was the most abundant under both day and night conditions. Our findings stressed that similar results and biological information on daytime/nighttime data were obtained. No marked differences could be related to various factors: heterotrophic condition of small-order streams, presence of aquatic predators under night and day conditions, absence of taxa with a specific phototaxis. Of all the environmental variables, velocity was always the most important in both situations, with some differences detected in the importance of the second variable (riverbed substrate diameter. This research, and future studies on different conditions and geographic areas, will contribute knowledge on stream macroinvertebrate diel activity, and provide useful information about efficient sampling strategies.

  11. Influence of a trout farm on macrozoobenthos communities of the Trešnjica river, Serbia

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    Živić Ivana

    2009-01-01

    Full Text Available Trout farming poses an increasing threat to quality of the water of clean highland streams. Research of this problem has focused primarily on changes in physico-chemical composition of the water and structure of the river bottom, and less on the effects on living organisms. In the present work, we investigated influence of the farm with the highest trout production in Serbia, the 'Riboteks' Trout Farm on the Trešnjica River, on its macrozoobenthos communities. Our investigations showed that the 'Riboteks' Trout Farm wastewaters caused a clear and statistically significant change of moderate intensity in all measured parameters describing the composition and structure of macrozoobenthos communities. These changes were most pronounced in the part of the watercourse closest to the influx of waste water (locality III but remained statistically significant even 500 m downstream (locality IV and were lost only about 3.5 km away from the influx of the farm's wastewater (locality V. The most pronounced were changes in the participation in total abundance of the Baetidae, Chironomidae, and Plecoptera. Additionally, results of the present work confirmed that the mass of fish on the trout farm is a parameter that adequately defines the strength of its action, above all the intensity of its influence on structure of the macrozoobenthos community.

  12. A key to larvae of species belonging to the genus Diamesa from Alps and Apennines (Italy

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    Bruno Rossaro

    2015-07-01

    Full Text Available A key to species belonging to the genus Diamesa Meigen, 1835 (Diptera, Chironomidae from the Alps and Apennines (Italy is presented using characters observable in the fourth-instar larva. The larvae are separated on the basis of qualitative and quantitative characters. At present fifteen species from the Italian Alps are described in all three life stages, but only twelve species groups can be separated as larvae. The separation is based on the length and thickness of anal setae, antennal ratio, head capsule color and few other characters of the labrum and mentum. The shape of mental and mandibular teeth is still a valid taxonomic character, but unfortunately these characters can be rarely used because teeth are often excessively worn in samples collected in the field. Quantitative characters show variability within each species, differing according to the duration of larval development and must be used with caution. The species groups which can be separated in the larval stage are: the dampfi group, which includes D. dampfi and D. permacra, the latitarsis group including D. modesta and D. latitarsis, the zernyi group including D. zernyi and D. vaillanti. The species within each of these groups at present cannot be separated. D. starmachi, D. steinboecki, D. goetghebueri, D. bertrami, D. aberrata, D. incallida, D. cinerella, D. tonsa and D. insignipes can be separated from all the other known species in larval stage.

  13. Remobilization and export of cadmium from lake sediments by emerging insects

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    Currie, R.S.; Fairchild, W.L.; Muir, D.C.G. [Dept. of Fisheries and Oceans, Winnipeg, Manitoba (Canada). Freshwater Inst.

    1997-11-01

    Emerging insects including, Diptera, Odonata, Ephemeroptera, and Trichoptera were collected from Lake 382 (L382) in 1991 and 1992 to estimate quantitatively the export of Cd by aquatic insects from a natural system having elevated Cd concentrations in the water and sediment. L382 is a Canadian Shield lake, located within the Experimental Lakes Area in northwestern Ontario, that received experimental additions of Cd from 1987 to 1992. Emerging Diptera (mostly Chironomidae), Odonata, and Ephemeroptera had mean Cd concentrations of 1.41, 0.11, and 0.30 {micro}g/g wet weight, respectively. An estimated 1.32 to 3.90 g of Cd per year were exported from the sediments of L382 depending on the estimate of production rates used for these groups of insects. Approximately 0.05 to 0.17% of the whole-lake Cd load in L382 sediments was exported annually or 0.12 to 0.39% of the epilimnion Cd sediment load. Insect emergence may have resulted in greater Cd export from L382 relative to losses via the outflow. Cadmium exported from the sediments by insects may be remobilized and become more available to aquatic organisms or enter the terrestrial ecosystem and become available to insectivores.

  14. Trophic relationships between macroinvertebrates and fish in a pampean lowland stream (Argentina

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    María V. López van Oosterom

    2013-03-01

    Full Text Available The diet and trophic relationships between the macroinvertebrates Phyllogomphoides joaquini Rodrigues Capítulo, 1992 and Coenagrionidae (Odonata, Chironomidae (Diptera, Diplodon delodontus (Lamarck, 1919 (Bivalvia: Hyriidae, and Pomacea canaliculata (Lamarck, 1822 (Gastropoda: Ampulariidae and the fishes Pimelodella laticeps Eigenmann, 1917 (Heptapteridae and Bryconamericus iheringii (Boulenger, 1887 (Characidae in a temperate lowland lotic system in Argentina were assessed on the basis of gut contents and stable-isotope analyses. The feeding strategies were analyzed by the AMUNDSEN method. Relative food items contribution for the taxa studied indicated a generalist-type trophic strategy. In macroinvertebrates, in general, the values of stable isotope confirmed the result of the analysis of gut contents. With the fish, stable-isotope analysis demonstrated that both species are predators, although B. iheringii exhibited a more omnivorous behaviour. These feeding studies allowed us to determine the trophic relationships among taxa studied. Detritus and diatoms were a principal source of food for all the macroinvertebrates studied. In La Choza stream the particulate organic matter is a major no limited food resource, has a significant influence upon the community.

  15. How are macroinvertebrates of slow flowing lotic systems directly affected by suspended and deposited sediments?

    Energy Technology Data Exchange (ETDEWEB)

    Kefford, Ben J., E-mail: ben.kefford@rmit.edu.a [Biotechnology and Environmental Biology, School of Applied Sciences, RMIT University, PO Box 71, Bundoora, Victoria 3083 (Australia); Zalizniak, Liliana [Biotechnology and Environmental Biology, School of Applied Sciences, RMIT University, PO Box 71, Bundoora, Victoria 3083 (Australia); Dunlop, Jason E. [Department of Environment and Resource Management (DERM), 120 Meiers Rd, Indooroopilly, Queensland 4068 (Australia); Smart Water Research Facility, Griffith University, Queensland (Australia); Nugegoda, Dayanthi [Biotechnology and Environmental Biology, School of Applied Sciences, RMIT University, PO Box 71, Bundoora, Victoria 3083 (Australia); Choy, Satish C. [Department of Environment and Resource Management (DERM), 120 Meiers Rd, Indooroopilly, Queensland 4068 (Australia)

    2010-02-15

    The effects of suspended and deposited sediments on the macroinvertebrates are well documented in upland streams but not in slower flowing lowland rivers. Using species found in lowland lotic environments, we experimentally evaluate mechanisms for sediments to affect macroinvertebrates, and in one experiment whether salinity alters the effect of suspended sediments. Suspended kaolin clay reduced feeding of Ischnura heterosticta (Odonata: Coenagrionidae) at high turbidity (1000-1500 NTU) but had no effects on feeding of Hemianax papuensis (Odonata: Aeshnidae) and Micronecta australiensis (Hemiptera: Corixidae). In freshwater (0.1 mS/cm), survival of Ischnura aurora was poor in clear water, but improved with suspended kaolin. Growth and feeding of I. aurora were unaffected by suspended sediments and salinity. Burial (1-5 mm) of eggs with kaolin or sand reduced hatching in Physa acuta (Gastropoda: Physidae), Gyraulus tasmanica (Gastropoda: Planorbidae) and Chironomus cloacalis (Diptera: Chironomidae). Settling sediments may pose greater risk to lowland lotic invertebrates than suspended sediments. - Sediment deposition may be more directly detrimental to macroinvertebrates of lowland rivers than suspended sediments.

  16. Colonization by benthic macroinvertebrates in two artificial substrate types of a Riparian Forest

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    Lívia Borges dos Santos

    Full Text Available Abstract: Aim To analyze the efficiency of organic and inorganic substrates in samples of benthic macroinvertebrates of riparian forests from the Cerrado. Specific objectives (i characterize the ecological succession and taxonomic richness of benthic macroinvertebrates in stream affluent of a riparian forest; (ii analyze the influence of seasonality on the colonization of macroinvertebrates; and (iii determine the effect of the types of artificial substrates on the richness, composition and abundance of the benthic community. Methods Sampling was carried out in the rainy and dry seasons, and we installed in the watercourse two types of substrates: organic (leaf packs and inorganic (bricks, organized in pairs. Six samples per season were done to verify colonization, succession, richness and abundance of benthic community. The substrates were carefully sorted and the organisms were identified to the lowest possible taxonomic level. Results The ecological succession was clearly observed, with the initial occurrence of Chironomidae and Baetidae (considered early colonizers, and a late occurrence of organisms such as Helotrephidae and Trichoptera (considered late colonizers. No significant difference was found in the richness and abundance among the studied seasons (rainy and dry, but the organic substrate was significantly higher than the inorganic substrate for these parameters. Conclusion Organic artificial substrates are more efficient in characterizing the community of benthic macroinvertebrates in the study area, because they are more similar to the conditions of the substrate found naturally in the environment.

  17. Biodiversity of benthic macroinvertebrates in Air Terjun Asahan, Asahan, Melaka, Malaysia

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    Nurhafizah-Azwa, S.; Ahmad A., K.

    2016-11-01

    A study on benthic macroinvertebrate diversity was conducted at Air Terjun Asahan, Asahan, Melaka. Five stations were selected with distance intervals of approximately 500 metres. Three replicates of benthic macroinvertebrate and water samples were taken. Results classified Air Terjun Asahan in class II, which indicated good water quality based on WQI recommended by the Department of Environment. A total of 1 phylum, 2 classes, 6 order, 30 families, and 2183 individuals were successfully sampled and recorded. The analysis showed that the average value of Shannon Diversity Index, H' (2.19), Pielou Evenness Index, J' (0.30), and Margaleff Richness Index, DMG (3.77) described that Air Terjun Asahan was in moderate condition and the distribution of macroinvertebrates was uniform between stations. Correlation test showed that the WQI had a strong relationship with the diversity indices involved. BMWP, and FBI showed that Air Terjun Asahan was in good water quality. CCA test was conducted to show environmental factors towards benthic macroinvertebrate distribution. The presence of Leptophlebiidae, Baetidae, Heptageniidae and Chironomidae with high abundance of the families showed the potential as biological indicators of a clean ecosystem.

  18. Seasonal variation in Chironomid emergence from coastal pools

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    Alexander T. Egan

    2015-07-01

    Full Text Available Understanding the phenology of emergences can be useful in determining seasonal chironomid life cycle patterns, which are often influenced by ice cover and temperature in cold climates. Lake Superior is the largest lake in North America and with a mean surface temperature of 3.9 °C influences regional climate. Coastal pools at Isle Royale, a wilderness archipelago in the northern part of the lake, occur in dense patches on low-gradient volcanic bedrock between the lakeshore and forest, creating variable microhabitats for Chironomidae. Four sites were sampled monthly from April to October, 2010. Surface-floating pupal exuviae were collected from a series of pools in two zones: a lower zone near the lake influenced by wave splash, and an upper zone near the forest and influenced by upland runoff. We used Jaccard’s and Whittaker’s diversity indexes to test community similarity across months. Temperature loggers in pools collected hourly readings for most of the study. Assemblage emergences were stable in upper pools, with significant similarity across late spring and summer months. Assemblages were seasonally variable in lower pools, with significant dissimilarity across spring, summer, and fall months. Few species in either zone were unique to spring or fall months. However, many summer species in the splash zone had a narrow emergence period occurring during calm weather following distinct increases in mean water temperature. Regardless of input of cold lake water to the lower zone, pools from both zones generally had corresponding temperature trends.

  19. Even more Chironomid species for classifying lake nutrient status

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    Les Ruse

    2015-07-01

    Full Text Available The European Union Water Framework Directive (WFD classifies ecological status of a waterbody by the determination of its natural reference state to provide a measure of perturbation by human impacts based on taxonomic composition and abundance of aquatic species. Ruse (2010; 2011 has provided methods of assessing anthropogenic perturbations to lake ecological status, in terms of nutrient enrichment and acidification, by analysing collections of floating pupal exuviae discarded by emerging adult Chironomidae. The previous nutrient assessment method was derived from chironomid and environmental data collected during 178 lake surveys of all WFD types found in Britain. Canonical Correspondence Analysis provided species optima in relation to phosphate and nitrogen concentrations. Species found in less than three surveys were excluded from analysis in case of spurious association with environmental values. Since Ruse (2010 an additional 72 lakes have been surveyed adding 31 more species for use in nutrient status assessment. These additional scoring species are reported here. The practical application of the Chironomid Pupal Exuvial Technique (CPET to classify WFD lake nutrient status is demonstrated using CPET survey data from lakes in Poland.

  20. Study on Freshwater Macroinvertebrates of Some Tanzanian Rivers as a Basis for Developing Biomonitoring Index for Assessing Pollution in Tropical African Regions

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    Julius D. Elias

    2014-01-01

    Full Text Available Macroinvertebrates and physicochemical parameters were assessed at 15 sites along five rivers in Kilimanjaro region, Tanzania, with the aim of understanding their ecological status and setting a base to the development of a biological index for tropical regions. Investigated rivers that occur within Pangani basin include Karanga, Rau, Lumbanga, Sere, and Umbwe. Sampling sites were categorized according to the level of water and habitat quality as follows: reference or least impacted (4 sites, moderately impacted (5 sites, and highly impacted (6 sites sites. A total of 12,527 macroinvertebrates belonging to 13 orders and 48 families were recorded. The highest total abundance of 4,110 individuals per m2 was found in Karanga river, while Umbwe river had the lowest with 1,203 individuals per m2. Chironomidae was the most abundant family (2,588 individuals per m2 and the least were Hydridae and Thiaridae, each having 5 individuals per m2. High numbers of taxa were noted among the orders: Ephemeroptera (8, Odonata (8, Diptera (7, and Trichoptera (6. In conclusion, orders with greater diversity of macroinvertebrate families offer a wide range of tolerance to pollution and, thus can potentially be used to develop a biomonitoring index for evaluating pollution in tropical African rivers.

  1. Redescription of larva, pupa and imago male of Chironomus (Chironomus) salinarius Kieffer from the saline rivers of the Lake Elton basin (Russia), its karyotype and ecology.

    Science.gov (United States)

    Orel Zorina, Oksana V; Istomina, Albina G; Kiknadze, Iya I; Zinchenko, Tatiana D; Golovatyuk, Larisa V

    2014-07-29

    Cytology and ecology of Chironomus (Chironomus) salinarius Kieffer, 1915 (Diptera, Chironomidae) was examined from material collected in the saline rivers of the Lake Elton basin (Volgograd region, Russia). Larvae of salinarius-type were identified as C. salinarius on the basis of their karyotype. The species is redescribed on the basis of all metamorphic stages. The reared imago and karyotype were obtained from larvae of the same population. The karyotype of C. salinarius, detailed mapping of the 5 chromosome arms A, C, D, E, F and characteristics of chromosome polymorphism are provided. Information on distribution and ecology of C. salinarius from the saline rivers (total mineralization 6.8-31.6 g l-1) of the Lake Elton basin is also given. Chironomus salinarius is a common in the saline rivers and occurs in sediments with high silt content. On the basis of recent samplings C. salinarius appears to be very abundant in saline, mesotrophic as well as in eutrophic rivers. Chironomus salinarius accounted for 49-66% of total abundance of zoobenthos in water with salinity up to 13-31.6 g l-1.

  2. A Benthic Macroinvertebrate Multimetric Index for Assessment of the Ecological Integrity of Northeast Streams, Thailand

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    Nantiya Rattanachan

    2016-07-01

    Full Text Available This study aims to develop a benthic macroinvertebrate multimetric index for assessing the ecological quality of streams in Northeastern Thailand. ANOSIM indicated that the benthic macroinvertebrate assemblage in both of each basin and each season were not significantly different (R = 0.09, p = 0.24 and R = 0.07, p = 0.35, respectively. The efficacy metrics of each basin consisting of the Mekong II, the Chi, and the Mun basins were integrated and calibrated. A total of 255 data sets of water physico-chemical and benthic macroinvertebrates during the dry period (cool and hot seasons were obtained. The stream classification could be divided into three groups: the reference group (48 stations, the stressed group (42 stations, and the intermediate group (165 stations. Twelve out of 56 metrics have been considered as a core metric for the development of a biological index for quality streams in the Northeast, including Total taxa, EPT taxa, Ephemeroptera taxa, Coleoptera taxa, % EPT, % Chironomidae, % Tolerant individuals, % Intolerant individuals, Beck's index, HBI, Predator taxa, and Clinger taxa. Moreover, this metric set covered the structure and function of organisms including the diversity of species, community structure, tolerance/intolerance measures, functional feeding group, and habit. From the efficacy validation of the biological index, the results of stream assessment corresponded to the classification sites with the physico-chemical characteristics.

  3. Seasonal diet pattern of non-native tubenose goby (Proterorhinus semilunaris in a lowland reservoir (Mušov, Czech Republic

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    Adámek Z.

    2010-08-01

    Full Text Available The tubenose goby (Proterorhinus semilunaris is a gobiid species currently extending its area of distribution in Central Europe. The objective of the study was to evaluate the annual pattern of its feeding habits in the newly colonised habitats of the Mušov reservoir on the Dyje River (the Danube basin, Czech Republic with respect to natural food resources. In the reservoir, tubenose goby has established a numerous population, densely colonising stony rip-rap banks. Its diet was exclusively of animal origin with significant dominance of and preference for two food items – chironomid (Chironomidae larvae and waterlouse (Asellus aquaticus, which contributed 40.2 and 27.6%, respectively, to the total food bulk ingested. The index of preponderance for the two items was also very high, amounting to 73.8 and 26.5, respectively. In the annual pattern, a remarkable preference for chironomid larvae was recorded in the summer period whilst waterlouse were consumed predominantly in winter months. The proportion of other food items was rather marginal – only corixids, copepods, ceratopogonids and cladocerans were of certain minor importance with proportions of 5.4, 4.3, 4.1 and 3.9%, respectively. Certain signs of cannibalism were also recorded, with 0.9 and 0.2% of the diet consisting of their own progeny and eggs, respectively.

  4. Diet of four annual killifishes: an intra and interspecific comparison

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    Gabriel Laufer

    Full Text Available We examined the diet of 4 annual fishes, Austrolebias viarius, Austrolebias cheradophilus, Austrolebias luteoflammulatus and Cynopoecilus melanotaenia inhabiting temporal ponds of southeastern Uruguay, by analysis of stomach contents. Fishes were captured from fifty ephemeral ponds of Castillos Lagoon basin, in the region of the Humedales del Este. We identified 13099 individual prey items extracted from 669 stomachs of the four captured species. In the studied system, annual killifishes represents the most abundant and conspicuous top predators. Killifishes are generalist key predators at the ephemeral ponds of the studied system, consuming mostly aquatic items. Zooplancton represented the bulk of the diet in the four analyzed species, followed by eggs, algae and diatoms. Insects are the next group in prey number, as follows: Diptera larvae (especially Chironomidae and Cullicidae, Ephemeroptera (especially Betidae, and coleopteran larvae (especially Dytiscidae. Acari are also important prey in number. The four fish species differ in diet composition and in diet richness. A general pattern of differences in diet richness among killifish species and demographic groups could be related to variations in body sizes. As top predators annual killifishes are an important component of the temporal pond ecosystems. Understanding the natural history of this species and their communities is necessary in order to conserve them.

  5. An integrative approach to detect subtle trophic niche differentiation in the sympatric trawling bat species Myotis dasycneme and Myotis daubentonii.

    Science.gov (United States)

    Krüger, F; Clare, E L; Greif, S; Siemers, B M; Symondson, W O C; Sommer, R S

    2014-08-01

    Bats are well known for species richness and ecological diversity, and thus, they provide a good opportunity to study relationships and interaction between species. To assess interactions, we consider distinct traits that are probably to be triggered by niche shape and evolutionary processes. We present data on the trophic niche differentiation between two sympatric European trawling bat species, Myotis dasycneme and Myotis daubentonii, incorporating a wide spectrum of methodological approaches. We measure morphological traits involved in foraging and prey handling performance including bite force, weightlifting capacity and wing morphology. We then measure resulting prey consumption using both morphological and molecular diet analyses. These species closely resemble each other in morphological traits, however, subtle but significant differences were apparent in bite force and lift capacity, which are related to differences in basic body and head size. Both morphological and molecular diet analyses show strong niche overlap. We detected subtle differences in less frequent prey items, as well as differences in the exploitation of terrestrial and aquatic-based prey groups. Myotis dasycneme feeds more on aquatic prey, like Chironomidae and their pupal stages, or on the aquatic moth Acentria ephemerella. Myotis daubentonii feeds more on terrestrial prey, like Brachycera, or Coleoptera. This suggests that these bats use different microhabitats within the habitat where they co-occur.

  6. Macroinvertebrates associated with bryophyta in a first-order Atlantic Forest stream

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    Beatriz F. J. V. Rosa

    2011-06-01

    Full Text Available This study describes the composition and structure of the benthic community associated with bryophytes in a first-order stream, located in a biological reserve of the Atlantic Forest, during two seasons. During three months of the dry season of 2007 and three months of the rainy season of 2008, samples of bryophytes attached to stones were collected randomly, along a 100 m stream reach. The structure of the community was analyzed through the mean density of individuals, Shannon's diversity index, Pielou's evenness, family richness, dominance index, and the percentage of Ephemeroptera, Plecoptera and Trichoptera (% EPT. Chironomidae larvae were dominant in the two periods of study, followed by Ceratopogonidae in the rainy season, and Naididae in the dry season. The orders EPT contributed 14 families. The results showed that bryophytes constitute suitable habitat which is able to shelter an abundant and diversified benthic fauna in a small extension of the stream. This habitat provides refuge during spates, and thus minimizes downstream transport of the macroinvertebrate fauna.

  7. The influence of urbanisation on macroinvertebrate biodiversity in constructed stormwater wetlands.

    Science.gov (United States)

    Mackintosh, Teresa J; Davis, Jenny A; Thompson, Ross M

    2015-12-01

    The construction of wetlands in urban environments is primarily carried out to assist in the removal of contaminants from wastewaters; however, these wetlands have the added benefit of providing habitat for aquatic invertebrates, fish and waterbirds. Stormwater quantity and quality is directly related to impervious area (roads, sealed areas, roofs) in the catchment. As a consequence, it would be expected that impervious area would be related to contaminant load and biodiversity in receiving waters such as urban wetlands. This study aimed to establish whether the degree of urbanisation and its associated changes to stormwater runoff affected macroinvertebrate richness and abundance within constructed wetlands. Urban wetlands in Melbourne's west and south east were sampled along a gradient of urbanisation. There was a significant negative relationship between total imperviousness (TI) and the abundance of aquatic invertebrates detected for sites in the west, but not in the south east. However macroinvertebrate communities were relatively homogenous both within and between all study wetlands. Chironomidae (non-biting midges) was the most abundant family recorded at the majority of sites. Chironomids are able to tolerate a wide array of environmental conditions, including eutrophic and anoxic conditions. Their prevalence suggests that water quality is impaired in these systems, regardless of degree of urbanisation, although the causal mechanism is unclear. These results show some dependency between receiving wetland condition and the degree of urbanisation of the catchment, but suggest that other factors may be as important in determining the value of urban wetlands as habitat for wildlife.

  8. Fish assemblages in stream stretches occupied by cattail (Typhaceae, Angiospermae stands in Southeast Brazil

    Directory of Open Access Journals (Sweden)

    Fabíola Carla da Rocha

    Full Text Available Macrophytes are a major component of lentic and lotic aquatic ecosystems. As consequences of environmental degradation, species of cattail (genus Typha may become dominant along streams. The purpose of this study was to investigate the structure and feeding of fish assemblages in stream stretches under influence of Typha sp., also addressing the influences of temporal variation on composition, abundance, biomass, diversity, species richness, and feeding of fish. Six streams (labelled S1-S6 in the upper rio Turvo basin, southeast Brazil, with dense stands of Typha sp. in the instream and riparian habitat, were studied in six campaigns during three central months in both of the dry and wet periods, by using a standardized collection effort. Thirty-seven fish species were registered, totaling 4,228 individuals and 3.9 kg of biomass. Abundance, biomass, diversity, and species richness was higher in the wet period, but only the temporal variation in the species richness revealed to be statistically significant. Cluster analyses with composition and abundance showed little temporal similarity, but indicated two groups of streams (S1-S2-S5 and S3-S4-S6, that were corroborated along the axis 1 of the ordination analysis. Resident species was represented by six species, most of them considered tolerant and generalists. Chironomidae aquatic larvae and detritus were the most important items in the fish diet. These results suggest that the fish populations are opportunistic in exploring stream stretches occupied by cattail.

  9. The opportunistic feeding and reproduction strategies of the annual fish Cynopoecilus melanotaenia (Cyprinodontiformes: Rivulidae inhabiting ephemeral habitats on southern Brazil

    Directory of Open Access Journals (Sweden)

    Cristina da Silva Gonçalves

    Full Text Available Most Rivulidae fishes are popularly known as annual fishes which live in ephemeral environments such as pools, that obligatorily dry out seasonally causing the death of adult individuals. They have unique biological characteristics such as small body size, early sexual maturation, continuous reproduction, an elaborated courtship behavior, and a great reproductive capacity among fishes. The rivulids are widely distributed in North, Central and South America. In this study, the diet and reproductive biology of Cynopoecilus melanotaenia was analyzed. A total of 263 specimens were collected and the analysis of 233 gastrointestinal contents revealed an invertivorous diet composed mainly of small crustaceans (Cladocera, Amphipoda, and Ostracoda and immature insects (Chaoboridae, Culicidae, Syrphidae, but mainly Chironomidae larvae. Lepidophagy on male's diet was also registered. Fecundity was estimated by analyzing 59 pairs of mature ovaries and ranged from 2 to 157 oocytes (mean, 19 ± 26[SD]. The species has fractional spawning, a strategy to increase the chance of survival to prolonged depletions. This study is the first to investigate the reproductive biology of C. melanotaenia. The results confirmed the opportunistic character of the rivulid C. melanotaenia and provided unreported reproductive information that may aid conservation of the species.

  10. The larval alimentary canal of the Antarctic insect, Belgica antarctica.

    Science.gov (United States)

    Nardi, James B; Miller, Lou Ann; Bee, Charles Mark; Lee, Richard E; Denlinger, David L

    2009-09-01

    On the Antarctica continent the wingless midge, Belgica antarctica (Diptera, Chironomidae) occurs further south than any other insect. The digestive tract of the larval stage of Belgica that inhabits this extreme environment and feeds in detritus of penguin rookeries has been described for the first time. Ingested food passes through a foregut lumen and into a stomodeal valve representing an intussusception of the foregut into the midgut. A sharp discontinuity in microvillar length occurs at an interface separating relatively long microvilli of the stomodeal midgut region, the site where peritrophic membrane originates, from the midgut epithelium lying posterior to this stomodeal region. Although shapes of cells along the length of this non-stomodeal midgut epithelium are similar, the lengths of their microvilli increase over two orders of magnitude from anterior midgut to posterior midgut. Infoldings of the basal membranes also account for a greatly expanded interface between midgut cells and the hemocoel. The epithelial cells of the hindgut seem to be specialized for exchange of water with their environment, with the anterior two-thirds of the hindgut showing highly convoluted luminal membranes and the posterior third having a highly convoluted basal surface. The lumen of the middle third of the hindgut has a dense population of resident bacteria. Regenerative cells are scattered throughout the larval midgut epithelium. These presumably represent stem cells for the adult midgut, while a ring of cells, marked by a discontinuity in nuclear size at the midgut-hindgut interface, presumably represents stem cells for the adult hindgut.

  11. The protective effect of rapid cold-hardening develops more quickly in frozen versus supercooled larvae of the Antarctic midge, Belgica antarctica.

    Science.gov (United States)

    Kawarasaki, Yuta; Teets, Nicholas M; Denlinger, David L; Lee, Richard E

    2013-10-15

    During the austral summer, larvae of the terrestrial midge Belgica antarctica (Diptera: Chironomidae) experience highly variable and often unpredictable thermal conditions. In addition to remaining freeze tolerant year-round, larvae are capable of swiftly increasing their cold tolerance through the rapid cold-hardening (RCH) response. The present study compared the induction of RCH in frozen versus supercooled larvae. At the same induction temperature, RCH occurred more rapidly and conferred a greater level of cryoprotection in frozen versus supercooled larvae. Furthermore, RCH in frozen larvae could be induced at temperatures as low as -12°C, which is the lowest temperature reported to induce RCH. Remarkably, as little as 15 min at -5°C significantly enhanced larval cold tolerance. Not only is protection from RCH acquired swiftly, but it is also quickly lost after thawing for 2 h at 2°C. Because the primary difference between frozen and supercooled larvae is cellular dehydration caused by freeze concentration of body fluids, we also compared the effects of acclimation in dehydrated versus frozen larvae. Because slow dehydration without chilling significantly increased larval survival to a subsequent cold exposure, we hypothesize that cellular dehydration caused by freeze concentration promotes the rapid acquisition of cold tolerance in frozen larvae.

  12. Fluvial geomorphology and aquatic-to-terrestrial Hg export are weakly coupled in small urban streams of Columbus, Ohio

    Science.gov (United States)

    Sullivan, S. Mažeika P.; Boaz, Lindsey E.; Hossler, Katie

    2016-04-01

    Although mercury (Hg) contamination is common in stream ecosystems, mechanisms governing bioavailability and bioaccumulation in fluvial systems remain poorly resolved as compared to lentic systems. In particular, streams in urbanized catchments are subject to fluvial geomorphic alterations that may contribute to Hg distribution, bioaccumulation, and export across the aquatic-to-terrestrial boundary. In 12 streams of urban Columbus, Ohio, we investigated the influence of fluvial geomorphic characteristics related to channel geometry, streamflow, and sediment size and distribution on (1) Hg concentrations in sediment and body burdens in benthic larval and adult emergent aquatic insects and (2) aquatic-to-terrestrial contaminant transfer to common riparian spiders of the families Pisauridae and Tetragnathidae via changes in aquatic insect Hg body burdens as well as in aquatic insect density and community composition. Hydrogeomorphic characteristics were weakly related to Hg body burdens in emergent insects (channel geometry) and tetragnathid spiders (streamflow), but not to Hg concentrations in sediment or benthic insects. Streamflow characteristics were also related to emergent insect density, while wider channels were associated with benthic insect community shifts toward smaller-bodied and more tolerant taxa (e.g., Chironomidae). Thus, our results provide initial evidence that fluvial geomorphology may influence aquatic-to-terrestrial contaminant Hg transfer through the collective effects on emergent insect body burdens as well as on aquatic insect community composition and abundance.

  13. A Stream Multimetric Macroinvertebrate Index (MMI) for the Sand Hills Ecoregion of the Southeastern Plains, USA

    Science.gov (United States)

    Kosnicki, Ely; Sefick, Stephen A.; Paller, Michael H.; Jerrell, Miller S.; Prusha, Blair A.; Sterrett, Sean C.; Tuberville, Tracey D.; Feminella, Jack W.

    2016-10-01

    A macroinvertebrate multimetric index is an effective tool for assessing the biological integrity of streams. However, data collected under a single protocol may not be available for an entire region. We sampled macroinvertebrates from the full extent of the Sand Hills ecoregion Level IV of the Southeastern Plains with a standard protocol during the summers of 2010-2012. We evaluated the performance of 94 metrics through a series of screening criteria and built 48 macroinvertebrate multimetric indexs with combinations of the best performing metrics, representing richness, habit, functional feeding guild, sensitivity, and community composition. A series of narrative-response tests for each macroinvertebrate multimetric index was used to find the best performing macroinvertebrate multimetric index which we called the Sand Hills macroinvertebrate multimetric index. The Sand Hills macroinvertebrate multimetric index consisted of the measures Biotic Index, % Shredder taxa, Clinger taxa2/total taxa, Plecoptera and Trichoptera richness, and Tanytarsini taxa2/Chironomidae taxa. Comparison of the Sand Hills macroinvertebrate multimetric index with existing assessment tools calculated with our data indicated that the Sand Hills macroinvertebrate multimetric index performs at a high level with regard to identifying degraded sites and in its response to stress gradients.

  14. [Effects of large-area planting water hyacinth on macro-benthos community structure and biomass].

    Science.gov (United States)

    Liu, Guo-Feng; Liu, Hai-Qin; Zhang, Zhi-Yong; Zhang, Ying-Ying; Yan, Shao-Hua; Zhong, Ji-Cheng; Fan, Cheng-Xin

    2010-12-01

    The effects on macro-benthos and benthos environment of planting 200 hm2 water hyacinth (E. crassipens) in Zhushan Bay, Lake Taihu, were studied during 8-10 months consecutive surveys. Results indicated that average densities of mollusca (the main species were Bellamya aeruginosa) in far-planting, near-planting and planting area were 276.67, 371.11 and 440.00 ind/m2, respectively, and biomass were 373.15, 486.57 and 672.54 g/m2, respectively, showed that average density and biomass of planting area's were higher than those of others. However, the average density and biomass of Oligochaeta (the main species was Limodrilus hoffmeisteri) and Chironomidae in planting area were lower than that of outside planting area. The density and biomass of three dominant species of benthic animal increased quickly during 8-9 months, decreased quickly in October inside and outside water hyacinth planting area. The reason of this phenomenon could be possible that lots of cyanobacteria cells died and consumed dissolve oxygen in proceed decomposing. Algae cells released lots of phosphorus and nitrogen simultaneously, so macro-benthos died in this environment. The indexes of Shannon-Weaver and Simpson indicated that water environment was in moderate polluted state. On the basis of the survey results, the large-area and high-density planting water hyacinth haven't demonstrated a great impact on macrobenthos and benthos environment in short planting time (about 6 months planting time).

  15. Habitat, biota, and sediment characteristics at selected stations in the lower Illinois River Basin, Illinois, 1996-98

    Science.gov (United States)

    Adolphson, Debbie L.; Fazio, David J.; Harris, Mitchell A.

    2001-01-01

    Data collection for the lower Illinois River Basin (LIRB) National Water-Quality Assessment (NAWQA) program began in 1996. Data on habitat, fish, benthic macroinvertebrates, and sediment were collected at eight stations on six streams in the basin--Illinois River, Panther Creek, Mackinaw River, Indian Creek, Sangamon River, and La Moine River. These streams typically flow through agricultural lands with very low gradients. Substrates typically are clay to gravel with areas of cobble. Banks are high, steep, and sparsely vegetated. Topographic surveys provide illustrations of the geometry that promote understanding of channel geometry and a data set that, in the future, can be used by others to assess stream changes. Suspended-sediment particle size, woody debris, and stream velocity are important to fish and benthic macroinvertebrate communities. Fine particles (silts and clays) were abundant in suspended sediment and stream banks, and fish insectivorous cyprinid community composition increased with decreases in the concentration of these suspended fines. Suckers were prevalent in stream reaches with abundant woody-snag cover, whereas sunfish communities were most abundant in areas with slow water velocities. Hydropsychidae, Chironomidae, and Baetidae were the most abundant benthic macroinvertebrate families collected throughout the region, but stream size and water velocity were important to benthic macroinvertebrate community composition. Tricorythodes mayflies and Elmidae had higher relative abundance at sites in small- and moderate-size drainage basins, and Baetidae density was greatest in reaches with highest water velocity.

  16. Effects of summer drawdown on the fishes and larval chironomids in Beulah Reservoir, Oregon

    Science.gov (United States)

    Rose, Brien P.; Mesa, Matthew G.

    2013-01-01

    Summer drawdown of Beulah Reservoir, Oregon, could adversely affect fish and invertebrate production, limit sport fishing opportunities, and hinder the recovery of threatened species. To assess the impacts of drawdown, we sampled fish and Chironomidae larvae in Beulah Reservoir in the springs of 2006 to 2008. The reservoir was reduced to 68% of full pool in 2006 and to run-of-river level in 2007. From spring 2006 to spring 2007, the catch per unit effort (CPUE) of fyke nets decreased significantly for dace [Rhinichthys spp.] and northern pikeminnow [Ptychocheilus oregonensis], increased significantly for suckers [Catastomus spp.] and white crappies [Pomoxis nigromaculatus], and was similar for redside shiners [Richardsonius balteatus]. CPUE of gillnets either increased significantly or remained similar depending on genera, and the size structure of redside shiners, suckers, and white crappies changed appreciably. From 2007 to 2008, the CPUE of northern pikeminnow, redside shiners, suckers, and white crappies decreased significantly depending on gear and the size structure of most fishes changed. Springtime densities of chironomid larvae in the water column were significantly higher in 2006 than in 2008, but other comparisons were similar. The densities of benthic chironomids were significantly lower in substrates that were frequently dewatered compared to areas that were partially or usually not dewatered. Individuals from frequently dewatered areas were significantly smaller than those from other areas and the densities of benthic chironomids in 2008 were significantly lower than other years. Summer drawdown can reduce the catch and alter the size structure of fishes and chironomid larvae in Beulah Reservoir.

  17. Effects of engineered application of Eichhornia crassipes on the benthic macroinvertebrate diversity in Lake Dianchi, an ultra-eutrophic lake in China.

    Science.gov (United States)

    Zhang, Zhiyong; Wang, Zhi; Zhang, Zhenghua; Zhang, Junqian; Guo, Junyao; Li, Enhua; Wang, Xuelei; Liu, Haiqin; Yan, Shaohua

    2016-05-01

    An ecological engineering project with confined growth of 1.5 km(2) of Eichhornia crassipes was implemented to remove pollutants in Lake Dianchi. To assess the ecological effects of this project on benthic macroinvertebrate assemblages, a 1-year investigation at the areas inside and outside E. crassipes mats was conducted from May 2013 to May 2014. All the 10 sampling sites in the areas were grouped into two statistically significant clusters mainly corresponding to inside and outside E. crassipes mat areas (EMAs), by clustering analysis. E. crassipes reduced the densities of pollution indicator taxa (e.g., Oligochaeta and Chironomidae larvae); thus, the total densities of benthic macroinvertebrates at the area inside EMAs (mean 328.2 ind./m(2)) were slightly lower than that at the area outside EMAs (mean 505.6 ind./m(2)). Four functional feeding groups including 38 species of benthic macroinvertebrates were collected at the area inside EMAs, while only three functional feeding groups containing 17 species were collected at the area outside EMAs. The biodiversity indices (Shannon-Weiner, Margalef, Simpson, and Peilou indices) and K-dominance curves also showed higher diversity of benthic macroinvertebrates at the area inside EMAs than at the area outside EMAs. These results suggested that a certain scale of engineering application of E. crassipes was beneficial to benthic macroinvertebrate communities in the ultra-eutrophic Lake Dianchi and it could be used as a pioneer species in ultra-eutrophic lake for pollutant removal.

  18. Adaptation to metals in benthic macrofauna

    Energy Technology Data Exchange (ETDEWEB)

    Klerks, P.L.

    1987-01-01

    This research investigated the occurrence of resistance to metals (a combination of cadmium, nickel and cobalt) in Tanypus neopunctipennis (Insecta: Chironomidae) and Limnodrilus hoffmeisteri (Annelida: Oligochaeta) inhabiting a freshwater tidal cove with elevated levels of these metals in the sediment. Genetic and physiological aspects of the resistance were investigated for the oligochaete. Metal resistance of populations from the polluted area was compared to that in conspecifics from a control area. The resistance of offspring of oligochaetes from the polluted area was determined to assess the genetic component of resistance differences. Cadmium accumulation was determined in an attempt to relate the degree of resistance to differences in metal uptake. Cytosolic metal distributions were determined by gel permeation chromatography, to assess if differences in the induction of metal-binding proteins may account for differences in resistance. Electron probe microanalysis was employed to determine if sequestration of Cd in granules contributes to the resistance. A selection experiment and a determination of the heritability of resistance were performed for additional insight into the evolutionary aspects of the resistance.

  19. Benthic macroinvertebrate based indices for assessing the ecological status of freshwaters on oceanic islands

    Directory of Open Access Journals (Sweden)

    PEDRO M. RAPOSEIRO

    2009-01-01

    Full Text Available Following the Water Framework Directive (2000/60/EC, macroinvertebrates are required biological elements for monitoring European aquatic ecosystems. Several efforts have been made towards establishing a biomonitoring programme for the Azores freshwater systems using benthic macroinvertebrates. However, little was previously known concerning Azorean freshwater macroinvertebrate fauna. Data from a major ongoing survey of macroinvertebrate freshwater fauna for two islands are presented and the use ofmacroinvertebrates as water quality indicators for the Azorean streams is evaluated. The upper, middle and lower reaches of streams longer than 10 km from São Miguel (10 and Santa Maria (1 were surveyed (a total of 33 samples. A total of 21 taxa were collected;Diptera, in particular chironomidae, were dominant; chironomids were collected from all sampling sites. The Azorean lotic fauna is characterized by low levels of abundance and the absence of macroinvertebrate groups commonly associated with continental systems.Traditional biotic indices, used to classify ecological quality, yielded poor to bad classifications despite little or no environmental impacts at the sampling sites. The paucityof macroinvertebrate fauna is probably due to the result of geological and physicochemical processes, the oceanic character of the islands, their volcanic origin, small size and geological youth and climate related factors such as seasonal peaks in rainfall. Considering these constraints, we demonstrate that watershed age plays a determinant role in shaping Azorean macroinvertebrate freshwater communities which can confound the water quality classification via the use of traditional biotic indices.

  20. Ruffe (Gymnocephalus Cernuus L. Growth and Diet in Lake Dusia (Southern Lithuania

    Directory of Open Access Journals (Sweden)

    Pilinkovskij Andrej

    2014-07-01

    Full Text Available The ruffe, Gymnocephalus cernuus (L., is considered to be a food competitor with many commercially valuable fishes such as bream, Abramis brama (L., roach, Rutilus rutilus (L., pikeperch, Sander lucioperca (L., and perch, Perca fluviatilis L. This paper presents the results of an investigation into the fish community structure of Lake Dusia and the population parameters (morphometry, age, growth, diet of ruffe as one of the prevailing fish species in the lake. The fish community of Lake Dusia was dominated by ruffe, perch, and roach. The ruffe population constituted 64.1% of the fish community of the lake in relative abundance and 36.8% in biomass. An analysis of the ruffe diet revealed that Gammaridae and Chironomidae were the principal components in all age-classes. The ruffe population was comprised mainly of individuals 3+ and 4+ years of age. The mean total length (TL of ruffe was 13.39 ± 1.79 cm (minimum-maximum: 6.12-19.93 cm. The growth in length calculated using the von Bertalanffy equation was Lt = 21.3[1-e-a161(t-0,335]. Ruffe growth rates were found to slow as the fish aged. Ruffe growth variations were linked to population density, fish community structure in the water body, abundance of invertebrates (zooplankton and zoobenthos, and type of water body.

  1. Occurrence of polycyclic aromatic hydrocarbons below coal-tar-sealed parking lots and effects on stream benthic macroinvertebrate communities

    Energy Technology Data Exchange (ETDEWEB)

    Scoggins, M.; McClintock, N.L.; Gosselink, L.; Bryer, P. [City Austin, Austin, TX (United States)

    2007-12-15

    Parking-lot pavement sealants recently have been recognized as a major source of polycyclic aromatic hydrocarbons (PAHs) in urban stream sediments in Austin, Texas. Laboratory and field studies have shown that PAHs in sediments can be toxic to aquatic organisms and can degrade aquatic communities. After identifying increases in concentrations of PAHs in sediments below seal-coated parking lots, we investigated whether the increases had significant effects on stream biota in 5 Austin streams. We sampled sediment chemistry and biological communities above and below the point at which stormwater runoff from the parking lots discharged into the streams, thus providing 5 upstream reference sites and 5 downstream treatment sites. Differences between upstream and downstream concentrations of total PAH ranged from 3.9 to 32 mg/kg. Analysis of the species occurrence data from pool and riffle habitats indicated a significant decrease in community health at the downstream sites, including decreases in richness, intolerant taxa, Diptera taxa, and density. In pool sediments, Chironomidae density was negatively correlated with PAH concentrations, whereas Oligochaeta density responded positively to PAH concentrations. In general, pool taxa responded more strongly than riffle taxa to PAHs, but riffle taxa responded more broadly than pool taxa. Increases in PAH sediment-toxicity units between upstream and downstream sites explained decreases in taxon richness and density in pools between upstream and downstream sites.

  2. Survey of arthropod assemblages responding to live yeasts in an organic apple orchard

    Directory of Open Access Journals (Sweden)

    Stefanos S Andreadis

    2015-10-01

    Full Text Available Associations between yeasts and insect herbivores are widespread, and these inter-kingdom interactions play a crucial role in yeast and insect ecology and evolution. We report a survey of insect attraction to live yeast from a community ecology perspective. In the summer of 2013 we screened live yeast cultures of Metschnikowia pulcherrima, M. andauensis, M. hawaiiensis, M. lopburiensis, and Cryptococcus tephrensis in an organic apple orchard. More than 3,000 arthropods from 3 classes, 15 orders, and 93 species were trapped; ca. 79% of the trapped specimens were dipterans, of which 43% were hoverflies (Syrphidae, followed by Sarcophagidae, Phoridae, Lauxaniidae, Cecidomyidae, Drosophilidae, and Chironomidae. Traps baited with M. pulcherrima, M. andauensis, and C. tephrensis captured typically 2.4 times more specimens than control traps; traps baited with M. pulcherrima, M. hawaiiensis, M. andauensis, M. lopburiensis and C. tephrensis were more species-rich than unbaited control traps. We conclude that traps baited with live yeasts of the genera Metschnikowia and Cryprococcus are effective attractants and therefore of potential value for pest control. Yeast-based monitoring or attract-and-kill techniques could target pest insects or enhance the assemblage of beneficial insects. Manipulation of insect behavior through live yeast cultures should be further explored for the development of novel plant protection techniques.

  3. Spatial uniformity in depth optima of midges: evidence from sedimentary archives of shallow Alpine and boreal lakes

    Directory of Open Access Journals (Sweden)

    Tomi P. Luoto

    2012-01-01

    Full Text Available In this study, water depth optima, i.e. habitat preferences within a depth gradient, were estimated for mutual midge (Diptera: Nematocera; Ceratopogonidae, Chironomidae taxa in surface sediment intralake data sets from eastern Finland and Austrian Alps and in a regional data set across Finland. The aim was to investigate how the optima and tolerances differ in these data sets and to discuss whether the possible causal factor for deviance is related to local adaptation, taxa representativeness, or some other factor. A total of 20 mutual taxa were found from the data sets and the estimated optima and tolerances were highly similar, with the exception of three taxa, which had deviating optima in the Austrian lake. The reason for these differences was most likely that the optima were poorly estimated in the Austrian lake due to low abundances and number of occurrences of these taxa. No evidence for intraspecific niche separation or local habitat adaptation was found between the Austrian and Finnish sites, although, interspecific variation in habitats was evident. Therefore, water depth optima estimated from representative number of specimens may be applicable for various ecological, limnological, and paleolimnological purposes. However, when the optima are applied outside the data set’s coverage, the results should be interpreted with caution. In addition, the given optima are not applicable in sites deeper than the sites in the data sets.

  4. The influence of water-level fluctuation on the drift of Simulium chutteri Lewis, 1965 (Diptera, Nematocera) in the Orange River, South Africa.

    Science.gov (United States)

    Car, M

    1983-09-01

    In July 1982, the invertebrate drift at Marksdrift comprised 98, 7% Simulium chutteri; 0, 75% Chironomidae; 0, 3% Ephemeroptera; 0, 15% Copepoda, and 0, 1% Trichoptera. Simuliid eggs were found in only 6 out of 75 samples. A single water-level reduction of 57 cm (54%) resulted in a more than sixfold increase of S. chutteri larvae in the drift and a more than 50% decrease of 1st and 2nd instar larvae in the drift after the water had returned to its original level. Larvae found lying in pools after the water-level had dropped belonged mainly to instars 5-7, 70% of them showing symptoms of starvation after 3 days when the river had risen again. The drift of simuliid head capsules decreased when the larval drift increased, as fewer simuliid larvae moulted when they had been disturbed. The low drift of eggs and the presence of very few pupae and adults indicated that most of the S. chutteri population was in the larval stage and that July was therefore an ideal month for water-level manipulation. Its main effect was achieved by irritating larger larvae and thus preventing them from resettling.

  5. Laboratory and field trials with two Bacillus thuringiensis var. israelensis products for Simulium(Diptera: Nematocera) control in a small polluted river in South Africa.

    Science.gov (United States)

    Car, M

    1984-06-01

    The effects on Simulium adersi and S. hargreavesi larvae of 2 Bacillus thuringiensis var. israelensis products, the liquid formulation "Teknar" (Sandoz) and a powder formulation produced by the Ben Gurion University, Israel, were compared in the laboratory and in the Pienaars River. This river was heavily polluted with effluent from a nearby sewage works and contained 77 mg/l chloride. In the laboratory S. adersi and S. hargreavesi larvae showed 26; 48; 95 and 100% mortality 6 hours after a 10-minute application of 0,8; 1,6; 3,2 and 16 ppm "Teknar" in rain water. The powder formulation applied at 0,2; 1,0; 2,0 and 30 ppm resulted in a 7; 17; 35 and 100% mortality. In polluted river-water the mortality was 85% with 16 ppm "Teknar" and 80% with 30 ppm B. thuringiensis powder. In the field trials "Teknar" at 1,6 ppm and B. thuringiensis powder at 3 ppm did not cause any larval mortality at flow rates of 3 060 l/min and 2 040 l/min, respectively. However, 24 hours after application of the powder formulation, numbers of S. hargreavesi decreased significantly (P = 0,05) 20 m below the application point. A further 24 hours later, after "Teknar" had been applied, the numbers of S. adersi decreased and those of Chironomidae increased significantly. There was a significant increase in S. hargreavesi 200 m downstream after treatment with "Teknar".

  6. Macroinvertebrate Richness Importance in Coastal Tropical Streams of Esmeraldas (Ecuador and Its Use and Implications in Environmental Management Procedures

    Directory of Open Access Journals (Sweden)

    Carlos Martínez-Sanz

    2014-01-01

    Full Text Available This study was aimed at determining the performance of some indices and community attributes frequently used to assess river quality and test the role of macroinvertebrate taxa richness as element of bioindication in several coastal tropical streams of western Esmeraldas (Ecuador. In addition, a macroinvertebrate taxon list of this region was provided for the first time. Thirteen sampled points distributed across nine streams were selected for this study and nineteen parameters and attributes of bioindication were tested. The differences between nonimpact and impact places were evaluated mainly using one-way analysis of variance. Jackknife 2 and Clench were used to estimate the regional richness and the quality of the inventory, respectively. Seventy taxa (principally genus and family of the main groups of macroinvertebrates were collected. Measured richness and family richness were the best metric followed by Biological Monitoring Working Party/Colombia (BMWP/Col, Odonata richness, Shannon-Weiner, and EPT richness (Ephemeroptera + Plecoptera + Trichoptera indices. Only a slight right trend (Ephemeroptera, Trichoptera, and Chironomidae attributes or incorrect performances (Average Score Per Taxon (ASPT and % EPT were showed by frequently used metrics. Finally, several recommendations were made about taxonomic level used, the ranks of quality of taxa richness, and the effort-results relationship in the field of bioindication.

  7. Benthic communities on hard substrates covered by Limnoperna fortunei Dunker (Bivalvia, Mytilidae at an estuarine beach (Río de la Plata, Argentina

    Directory of Open Access Journals (Sweden)

    Fernando G. Spaccesi

    2012-01-01

    Full Text Available The structure and composition of benthic communities on hard substrates covered by the nonindigenous bivalve Limnoperna fortunei Dunker, the golden mussel, were quantified in the middle zone of the Río de la Plata Estuary (Argentina from April 2001 through March 2002. A total of 26 taxa were recorded. L. fortunei and Nematoda were the central and dominant groups, with a prodigious abundance of over 80%. The prevalence of L. fortunei, rather than the environmental variables, regulated the dynamics of the associated invertebrate fauna. The golden mussel alters both the structure and function of benthic native communities on hard substrates, allows a higher surface available for colonization and refuge, and provides food source to deposit-feeding organisms in the form of organic or residual material. The mussel also increases the abundance and diversity of taxa on hard substrata - such as Oligochaeta, Hirudinea, Tardigrada, Chironomidae, Copepoda, Tanaidacea, and Hydrachnidia. Similarities and nonparametric multidimensional-scaling analyses indicated that the benthic composition had a seasonal variation. L. fortunei has an environmental impact, an ability to invade new freshwater ambiences worldwide and ecological characteristic comparable to those of Dreissena polymorpha Pallas (the zebra mussel of North America and Europe.

  8. [Food habits and winter diet of Charadrius melodus (Charadriiformes: Charadriidae) in Boca Ciega, Tamaulipas, Mexico].

    Science.gov (United States)

    Banda-Villanueva, Iris; Contreras-Lozano, Jorge; Garcia-Salas, Juan; González-Páez, Hugo

    2013-06-01

    The Piping Plover (Charadrius melodus) is a migratory endangered species that arrives, along with a great number of other winter migratory birds, to Boca Ciega every year. In spite of the importance of this ecosystem, these species, are threatened by the current habitat change caused by the dredging activities in the area. With the aim to generate new information about the importance of this area during winter, we studied C melodus activities during the winter season in Laguna Madre, from December 2009 to March 2010. Our objectives were: 1) determine the importance of the area during winter, 2) describe C. melodus ethology, feeding substrate preferences and food items, 3) to analyze and describe the sympatric diversity associated with C melodus. A total of ninety nine individuals were observed during the monitoring. The Cochran and Kendall test showed a high significance of the species with the substrate and signs tests using a binomial distribution that indicated a high preference for algal type of substrate. The highest activity recorded for this species during this winter season was feeding. The principal food items found in sediments were larvae of Diptera: Chironomidae and Ephydridae. The sympatric species of C. melodus were two families of Charadriiforms: Scolopacidae (nine species) and Charadriidae (two species). We concluded that this is an important area for feeding, protection and rest sites for this species, and its protection and management is recommended.

  9. What you need is what you eat? Prey selection by the bat Myotis daubentonii.

    Science.gov (United States)

    Vesterinen, Eero J; Ruokolainen, Lasse; Wahlberg, Niklas; Peña, Carlos; Roslin, Tomas; Laine, Veronika N; Vasko, Ville; Sääksjärvi, Ilari E; Norrdahl, Kai; Lilley, Thomas M

    2016-04-01

    Optimal foraging theory predicts that predators are selective when faced with abundant prey, but become less picky when prey gets sparse. Insectivorous bats in temperate regions are faced with the challenge of building up fat reserves vital for hibernation during a period of decreasing arthropod abundances. According to optimal foraging theory, prehibernating bats should adopt a less selective feeding behavior--yet empirical studies have revealed many apparently generalized species to be composed of specialist individuals. Targeting the diet of the bat Myotis daubentonii, we used a combination of molecular techniques to test for seasonal changes in prey selectivity and individual-level variation in prey preferences. DNA metabarcoding was used to characterize both the prey contents of bat droppings and the insect community available as prey. To test for dietary differences among M. daubentonii individuals, we used ten microsatellite loci to assign droppings to individual bats. The comparison between consumed and available prey revealed a preference for certain prey items regardless of availability. Nonbiting midges (Chironomidae) remained the most highly consumed prey at all times, despite a significant increase in the availability of black flies (Simuliidae) towards the end of the season. The bats sampled showed no evidence of individual specialization in dietary preferences. Overall, our approach offers little support for optimal foraging theory. Thus, it shows how novel combinations of genetic markers can be used to test general theory, targeting patterns at both the level of prey communities and individual predators.

  10. Development and evaluation of the Lake Multi-biotic Integrity Index for Dongting Lake, China

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    Xing Wang

    2015-06-01

    Full Text Available A Lake Multi-biotic Integrity Index (LMII for the China’s second largest interior lake (Dongting Lake was developed to assess the water quality status using algal and macroinvertebrate metrics. Algae and benthic macroinvertebrate assemblages were sampled at 10 sections across 3 subregions of Dongting Lake. We used a stepwise process to evaluate properties of candidate metrics and selected ten for the LMII: Pampean diatom index, diatom quotient, trophic diatom index, relative abundance diatoms, Margalef index of algae, percent sensitive diatoms, % facultative individuals, % Chironomidae individuals, % predators individuals, and total number of macroinvertebrate taxa. We then tested the accuracy and feasibility of the LMII by comparing the correlation with physical-chemical parameters. Evaluation of the LMII showed that it discriminated well between reference and impaired sections and was strongly related to the major chemical and physical stressors (r = 0.766, P<0.001. The re-scored results from the 10 sections showed that the water quality of western Dongting Lake was good, while that of southern Dongting Lake was relatively good and whereas that of eastern Dongting Lake was poor. The discriminatory biocriteria of the LMII are suitable for the assessment of the water quality of Dongting Lake. Additionally, more metrics belonging to habitat, hydrology, physics and chemistry should be considered into the LMII, so as to establish comprehensive assessment system which can reflect the community structure of aquatic organisms, physical and chemical characteristics of water environment, human activities, and so on.

  11. High quality draft genome sequence of Leucobacter chironomi strain MM2LB(T) (DSM 19883(T)) isolated from a Chironomus sp. egg mass.

    Science.gov (United States)

    Laviad, Sivan; Lapidus, Alla; Copeland, Alex; Reddy, Tbk; Huntemann, Marcel; Pati, Amrita; Ivanova, Natalia N; Markowitz, Victor M; Pukall, Rüdiger; Klenk, Hans-Peter; Woyke, Tanja; Kyrpides, Nikos C; Halpern, Malka

    2015-01-01

    Leucobacter chironomi strain MM2LB(T) (Halpern et al., Int J Syst Evol Microbiol 59:665-70 2009) is a Gram-positive, rod shaped, non-motile, aerobic, chemoorganotroph bacterium. L. chironomi belongs to the family Microbacteriaceae, a family within the class Actinobacteria. Strain MM2LB(T) was isolated from a chironomid (Diptera; Chironomidae) egg mass that was sampled from a waste stabilization pond in northern Israel. In a phylogenetic tree based on 16S rRNA gene sequences, strain MM2LB(T) formed a distinct branch within the radiation encompassing the genus Leucobacter. Here we describe the features of this organism, together with the complete genome sequence and annotation. The DNA GC content is 69.90%. The chromosome length is 2,964,712 bp. It encodes 2,690 proteins and 61 RNA genes. L. chironomi genome is part of the Genomic Encyclopedia of Type Strains, Phase I: the one thousand microbial genomes (KMG) project.

  12. Effect of land use on the composition, diversity and abundance of insects drifting in neotropical streams.

    Science.gov (United States)

    Gimenez, B C G; Lansac-Tôha, F A; Higuti, J

    2015-11-01

    Streams may exhibit differences in community structure of invertebrate drift, which may be a reflex of variation in environmental factors, able to change in conditions of anthropogenic interventions. The aim of this study was to analyze the composition, diversity and abundance of insects drifting in two neotropical streams under different land use and to identify the environmental factors involved in determining such patterns. 54 taxa of aquatic insects were identified in urban and rural streams. The results indicated significant differences in species composition due to the replacement of specialist species by generalist species in the urban stream. Higher diversity of taxa was recorded in the rural stream, with high levels of dissolved oxygen and high water flow, which favored the occurrence of sensitive groups to environmental disturbances, such as Ephemeroptera, Plecoptera, Trichoptera and Coleoptera taxa, that living mainly in clean and well oxygenated waters. On the other hand, a higher density of insects drifting, especially Chironomidae, was observed in the urban stream, where high values of pH, electrical conductivity and nitrogen were observed. These larvae are able to explore a wide range of environmental conditions, owing to their great capacity for physiological adaptation. Despite observing the expected patterns, there were no significant differences between streams for the diversity and abundance of species. Thus, the species composition can be considered as the best predictor of impacts on the drifting insect community.

  13. Contaminants as habitat disturbers: PAH-driven drift by Andean paramo stream insects.

    Science.gov (United States)

    Araújo, Cristiano V M; Moreira-Santos, Matilde; Sousa, José P; Ochoa-Herrera, Valeria; Encalada, Andrea C; Ribeiro, Rui

    2014-10-01

    Contaminants can behave as toxicants, when toxic effects are observed in organisms, as well as habitat disturbers and fragmentors, by triggering avoidance responses and generating less- or uninhabited zones. Drift by stream insects has long been considered a mechanism to avoid contamination by moving to most favorable habitats. Given that exploration and transportation of crude oil represent a threat for surrounding ecosystems, the key goal of the present study was to assess the ability of autochthonous groups of aquatic insects from the Ecuadorian paramo streams to avoid by drift different concentrations of polycyclic aromatic hydrocarbons (PAH) contained in the soluble fraction of locally transported crude oil. In the laboratory, different groups of insects were exposed to PAH for 12h. Three different assays, which varied in taxa and origin of the organisms, concentrations of PAH (0.6-38.8µgL(-1)), and environment settings (different levels of refuge and flow) were performed. For Anomalocosmoecus palugillensis (Limnephilidae), drift was a major cause of population decline in low concentration treatments but at higher concentrations mortality dominated. PAH was highly lethal, even at lower concentrations, for Chironomidae, Grypopterygidae (Claudioperla sp.) and Hydrobiosidae (Atopsyche sp.), and, therefore, no conclusion about drift can be drawn for these insects. Contamination by PAH showed to be a threat for benthic aquatic insects from Ecuadorian paramo streams as it can cause a population decline due to avoidance by drift and mortality.

  14. Differences found in the macroinvertebrate community composition in the presence or absence of the invasive alien crayfish, Orconectes hylas

    Science.gov (United States)

    Freeland-Riggert, Brandye T.; Cairns, Stefan H.; Poulton, Barry C.; Riggert, Chris M.

    2016-01-01

    Introductions of alien species into aquatic ecosystems have been well documented, including invasions of crayfish species; however, little is known about the effects of these introductions on macroinvertebrate communities. The woodland crayfish (Orconectes hylas (Faxon)) has been introduced into the St. Francis River watershed in southeast Missouri and has displaced populations of native crayfish. The effects of O. hylas on macroinvertebrate community composition were investigated in a fourth-order Ozark stream at two locations, one with the presence of O. hylas and one without. Significant differences between sites and across four sampling periods and two habitats were found in five categories of benthic macroinvertebrate metrics: species richness, percent/composition, dominance/diversity, functional feeding groups, and biotic indices. In most seasons and habitat combinations, the invaded site had significantly higher relative abundance of riffle beetles (Coleoptera: Elmidae), and significantly lower Missouri biotic index values, total taxa richness, and both richness and relative abundance of midges (Diptera: Chironomidae). Overall study results indicate that some macroinvertebrate community differences due to the O. hylas invasion were not consistent between seasons and habitats, suggesting that further research on spatial and temporal habitat use and feeding ecology of Ozark crayfish species is needed to improve our understanding of the effects of these invasions on aquatic communities.

  15. Total Selenium and Selenium Species in Irrigation Drain Inflows to the Salton Sea, California, April and July 2008

    Science.gov (United States)

    May, Thomas W.; Walther, Michael J.; Saiki, Michael K.; Brumbaugh, William G.

    2009-01-01

    This report presents the results for two sampling periods (April 2008 and July 2008) during a 4-year monitoring program to characterize selenium concentrations in selected irrigation drains flowing into the Salton Sea, California. Total selenium, selenium species (dissolved selenite, selenate, organoselenium), and total suspended solids were determined in water samples and total selenium was determined in water column particulates and in sediment, detritus, and biota that included algae, plankton, midge larvae (family, Chironomidae), and two fish species - western mosquitofish (Gambusia affinis) and sailfin molly (Poecilia latipinna). In addition, sediments were analyzed for percent total organic carbon and particle size. Mean total selenium concentrations in water for both sampling periods ranged from 1.93 to 44.2 micrograms per liter, predominately as selenate, which is typical of waters where selenium is leached out of selenium-containing marine shales and associated soils under alkaline and oxidizing conditions. Total selenium concentrations (micrograms per gram dry weight) ranged as follows: algae, 0.75 to 3.39; plankton, 0.88 to 4.03; midges, 2.52 to 44.3; fish, 3.37 to 18.9; detritus, 1.11 to 13.6; sediment, 0.11 to 8.93.

  16. Total Selenium and Selenium Species in Irrigation Drain Inflows to the Salton Sea, California, October 2008 and January 2009

    Science.gov (United States)

    May, Thomas W.; Walther, Michael J.; Saiki, Michael K.; Brumbaugh, William G.

    2009-01-01

    This report presents the results for two sampling periods (October 2008 and January 2009) during a 4-year monitoring program to characterize selenium concentrations in selected irrigation drains flowing into the Salton Sea, California. Total selenium, selenium species (dissolved selenite, selenate, organoselenium), and total suspended solids were determined in water samples. Total selenium also was determined in water column particulates and in sediment, detritus, and biota that included algae, plankton, midge larvae (family, Chironomidae), and two fish species (western mosquitofish, Gambusia affinis, and sailfin molly, Poecilia latipinna). In addition, sediments were analyzed for percent total organic carbon and particle size. Mean total selenium concentrations in water for both sampling periods ranged from 1.00 to 33.6 micrograms per liter, predominately as selenate, which is typical of waters where selenium is leached out of selenium-containing marine shales and associated soils under alkaline and oxidizing conditions. Total selenium concentrations (micrograms per gram dry weight) ranged as follows: algae, 1.52 to 8.26; plankton, 0.79 to 3.66; midges, 2.68 to 50.6; fish, 3.09 to 30.4; detritus, 1.78 to 58.0; and sediment, 0.42 to 10.0.

  17. Total Selenium and Selenium Species in Irrigation Drain Inflows to the Salton Sea, California, October 2007 and January 2008

    Science.gov (United States)

    May, Thomas W.; Walther, Michael J.; Saiki, Michael K.; Brumbaugh, William G.

    2008-01-01

    This report presents the results for two sampling periods (October 2007 and January 2008) during a 4-year monitoring program to characterize selenium concentrations in selected irrigation drains flowing into the Salton Sea, California. Total selenium, selenium species (selenite, selenate, organoselenium), and total suspended solids were determined in water samples, and total selenium was determined in sediment, detritus, and biota that included algae, plankton, midge larvae (family, Chironomidae), and two fish species?western mosquitofish (Gambusia affinis) and sailfin molly (Poecilia latipinna). In addition, sediments were analyzed for percent total organic carbon and particle size. Mean total selenium concentrations in water for both sampling periods ranged from 0.97 to 64.5 micrograms per liter, predominately as selenate, which is typical of waters where selenium is leached out of selenium-containing marine shales and associated soils under alkaline and oxidizing conditions. Total selenium concentrations (micrograms per gram dry weight) ranged as follows: algae, 0.95 to 5.99; plankton, 0.15 to 19.3; midges, 1.39 to 15.4; fish, 3.71 to 25.1; detritus, 0.85 to 21.7; sediment, 0.32 to 7.28.

  18. Total Selenium and Selenium Species in Irrigation Drain Inflows to the Salton Sea, California, April and July 2007

    Science.gov (United States)

    May, Thomas W.; Walther, Michael J.; Saiki, Michael K.; Brumbaugh, William G.

    2007-01-01

    This report presents the results for two sampling periods during a 4-year monitoring survey to provide a characterization of selenium concentrations in selected irrigation drains flowing into the Salton Sea, California. Total selenium, selenium species, and total suspended solids were determined in water samples, and total selenium was determined in sediment, detritus, and biota that included algae, plankton, midge larvae (family, Chironomidae), and two fish species-western mosquitofish (Gambusia affinis), and sailfin molly (Poecilia latipinna). In addition, sediments were analyzed for percent total organic carbon and particle size. Total selenium concentrations in water for both sampling periods ranged from 1.43 to 47.1 micrograms per liter, predominately as selenate, which is typical of waters leached out of selenium-contaminated marine shales under alkaline and oxidizing conditions. Total selenium concentrations ranged from 0.88 to 20.2 micrograms per gram in biota, and from 0.15 to 28.9 micrograms per gram in detritus and sediment.

  19. Application of biological measures for stream integrity assessment in south-east Brazil.

    Science.gov (United States)

    Silveira, M P; Baptista, D F; Buss, D F; Nessimian, J L; Egler, M

    2005-02-01

    The sensitivity of eleven metrics using macroinvertebrate assemblages were evaluated in an environmental gradient in a tropical river in south-east Brazil. Eight sites were sampled in an altitudinal range of 160-650 m.a.s.l. during 1999 (April and August) and 2000 (February). Four substrates were sampled at each site: riffle litter, pool litter, stony substrates and sediment. Correspondence Analysis indicated that assemblages were primarily more influenced by physical changes (like deforestation and erosion processes) than the water chemistry. The sensitivity of each metric was evaluated through the application of box-and-whisker plot method by its power to assess impairment (metrics should be able to discriminate reference sites from impaired sites) and natural variability (metrics should not discriminate two reference sites). Metrics that failed in at least one of the above premises were not considered as sensitive. In this study, the most sensitive metrics were Shannon index, BMWP-ASPT, %_EPT, and relative abundance of EPT to Chironomidae.

  20. Bioassessment using benthic macroinvertebrates of the water quality in the Tigreiro river, Jacuí Basin - doi: 10.4025/actascibiolsci.v35i4.18934

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Copatti

    2013-07-01

    Full Text Available This study aimed to evaluate the water quality in the Tigreiro river, Jacuí river Basin, using different approaches. Benthic macroinvertebrates were sampled in July 2010 (winter and February 2011 (summer at five sites. In this study were analyzed: microbiological, physical and chemical variables, benthic macroinvertebrates richness and diversity, rapid ecological assessment protocol and benthic biotic indices (% EPT, BMWP’-IAP, ASPT, SOMI. A total of 5,852 individuals were collected belonging to 31 taxa of three Phyla: Annelida, Mollusca and Arthropoda. Chironomidae was the most abundant taxon (63.70%. A reduction in richness, diversity H’ and evenness J’ was observed from the initial stretches to the end stretches of Tigreiro river. The use of different approaches showed that sites in the rural area were less altered. The Tigreiro river was strongly impacted, mainly due to discharge of domestic effluents in the urban area, and the combination of different metrics was useful to detect impacted sites and the consequence for the water quality.

  1. Colonização de macroinvertebrados bentônicos em detritos foliares em um riacho de primeira ordem na Floresta Atlântica do nordeste brasileiro

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    Iris Gabrielly Arruda dos Santos

    2015-03-01

    Full Text Available O objetivo do estudo foi avaliar a colonização de macroinvertebrados bentônicos em detritos foliares de Inga ingoides (Leguminosae em experimentos de campo em um riacho de primeira ordem da Mata Atlântica do Estado de Pernambuco no nordeste do Brasil. Um total de 270 bolsas de folhiço, distribuídas em três trechos do riacho com características similares em relação à morfologia e parâmetros físicos e químicos da água foram submersas, entre fevereiro a julho de 2013 e retiradas após 7, 30, 60, 90 e 120 dias. Dois tratamentos foram utilizados: colonização e exclusão da macrofauna. O percentual de biomassa remanescente final (%R foi maior para bolsas de colonização do que para as de exclusão, evidenciando a efetiva participação dos macroinvertebrados no processo de decomposição. Os fragmentadores apresentaram menor participação no processo de decomposição foliar de I. ingoides, sendo Tripletides (Trichoptera: Leptoceridae, Polypedillum e Stenochironomus (Diptera, Chironomidae os táxons predominantes na macrofauna. Filtrador foi o grupo trófico funcional predominante (45,6%, seguido por predador (31,2%, coletor (11,8%, raspador (6,7% e fragmentador (4,8%.

  2. Assessing the performance of macroinvertebrate metrics in the Challhuaco-Ñireco System (Northern Patagonia, Argentina

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    Melina Mauad

    2015-09-01

    Full Text Available ABSTRACT Seven sites were examined in the Challhuaco-Ñireco system, located in the reserve of the Nahuel Huapi National Park, however part of the catchment is urbanized, being San Carlos de Bariloche (150,000 inhabitants placed in the lower part of the basin. Physico-chemical variables were measured and benthic macroinvertebrates were collected during three consecutive years at seven sites from the headwater to the river outlet. Sites near the source of the river were characterised by Plecoptera, Ephemeroptera, Trichoptera and Diptera, whereas sites close to the river mouth were dominated by Diptera, Oligochaeta and Mollusca. Regarding functional feeding groups, collector-gatherers were dominant at all sites and this pattern was consistent among years. Ordination Analysis (RDA revealed that species assemblages distribution responded to the climatic and topographic gradient (temperature and elevation, but also were associated with variables related to human impact (conductivity, nitrate and phosphate contents. Species assemblages at headwaters were mostly represented by sensitive insects, whereas tolerant taxa such as Tubificidae, Lumbriculidae, Chironomidae and crustacean Aegla sp. were dominant at urbanised sites. Regarding macroinvertebrate metrics employed, total richness, EPT taxa, Shannon diversity index and Biotic Monitoring Patagonian Stream index resulted fairly consistent and evidenced different levels of disturbances at the stream, meaning that this measures are suitable for evaluation of the status of Patagonian mountain streams.

  3. A Multimetric Benthic Macroinvertebrate Index for the Assessment of Stream Biotic Integrity in Korea

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    Soon-Jin Hwang

    2012-10-01

    Full Text Available At a time when anthropogenic activities are increasingly disturbing the overall ecological integrity of freshwater ecosystems, monitoring of biological communities is central to assessing the health and function of streams. This study aimed to use a large nation-wide database to develop a multimetric index (the Korean Benthic macroinvertebrate Index of Biological Integrity—KB-IBI applicable to the biological assessment of Korean streams. Reference and impaired conditions were determined based on watershed, chemical and physical criteria. Eight of an initial 34 candidate metrics were selected using a stepwise procedure that evaluated metric variability, redundancy, sensitivity and responsiveness to environmental gradients. The selected metrics were number of taxa, percent Ephemeroptera-Plecoptera-Trichoptera (EPT individuals, percent of a dominant taxon, percent taxa abundance without Chironomidae, Shannon’s diversity index, percent gatherer individuals, ratio of filterers and scrapers, and the Korean saprobic index. Our multimetric index successfully distinguished reference from impaired conditions. A scoring system was established for each core metric using its quartile range and response to anthropogenic disturbances. The multimetric index was classified by aggregating the individual metric ..scores and the value range was quadrisected to provide a narrative criterion (Poor, Fair, Good and Excellent to describe the biological integrity of the streams in the study. A validation procedure showed that the index is an effective method for evaluating stream conditions, and thus is appropriate for use in future studies measuring the long-term status of streams, and the effectiveness of restoration methods.

  4. Acute toxicity of cadmium, lead, zinc, and their mixtures to stream-resident fish and invertebrates.

    Science.gov (United States)

    Mebane, Christopher A; Dillon, Frank S; Hennessy, Daniel P

    2012-06-01

    The authors conducted 150 tests of the acute toxicity of resident fish and invertebrates to Cd, Pb, and Zn, separately and in mixtures, in waters from the South Fork Coeur d'Alene River watershed, Idaho, USA. Field-collected shorthead sculpin (Cottus confusus), westslope cutthroat trout (Oncorhynchus clarkii lewisi), two mayflies (Baetis tricaudatus and Rhithrogena sp.), a stonefly (Sweltsa sp.), a caddisfly (Arctopsyche sp.), a snail (Gyraulus sp.), and hatchery rainbow trout (Oncorhynchus mykiss), were tested with all three metals. With Pb, the mayflies (Drunella sp., Epeorus sp., and Leptophlebiidae), a Simuliidae black fly, a Chironomidae midge, a Tipula sp. crane fly, a Dytiscidae beetle, and another snail (Physa sp.), were also tested. Adult westslope cutthroat trout were captured to establish a broodstock to provide fry of known ages for testing. With Cd, the range of 96-h median effect concentrations (EC50s) was 0.4 to >5,329 µg/L, and the relative resistances of taxa were westslope cutthroat trout ≈ rainbow trout ≈ sculpin fish size was observed. In metal mixtures, the toxicities of the three metals were less than additive on a concentration-addition basis.

  5. Impact of Stream and Floodplain Rehabilitation on Macroinvertebrate Community Structure and Diversity on the Hammer Creek in Lancaster County, PA

    Science.gov (United States)

    Reppert, J. C.; Kondikof, B.; Wallace, J. R.

    2005-05-01

    Naturally occurring floodplains act as a barrier to adverse effects from anthropogenic sources, while retaining aquatic organism diversity and potentially increasing stream productivity. The purpose of the study is to examine macroinvertebrate communities in response to stream and floodplain rehabilitation. This is an on-going study initiated with pre-restoration sampling conducted in July/August 2001. Post-rehabilitation sampling began in December 2001 and is continuing until the present. Long-term monitoring is being conducted among five sampling sites: above the restored area (control site), two sites within the restored section of the stream, and two sites 100 and 2500 meters below the impacted reach. Macroinvertebrates were sampled from the sites using a modified Hess sampler (n=6 replicates samples/ site). Macroinvertebrates were identified to generic level and analyzed using several metrics such as, Shannon and Simpson biodiversity indices, percent EPT, Functional feeding group analyses, ratio of scrapers to collector-filterers, and ratio of EPT abundance to Chironomidae. We found that stream restoration "traumatized" the macroinvertebrate community and diversity exhibited a lag-time in recovery. Because of an increase in riffle habitat, a modification of flow regime, and potential for preservation of habitat heterogeneity within these riffle zones, macroinvertebrate diversity may respond according to this improvement in habitat.

  6. Coexistence of fish species in a large lowland river: food niche partitioning between small-sized percids, cyprinids and sticklebacks in submersed macrophytes.

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    Małgorzata Dukowska

    Full Text Available In the spring and summer of each year, large patches of submersed aquatic macrophytes overgrow the bottom of the alluvial Warta River downstream of a large dam reservoir owing to water management practices. Environmental variables, macroinvertebrates (zoobenthos and epiphytic fauna, zooplankton and fish abundance and biomass were assessed at this biologically productive habitat to learn intraseasonal dynamics of food types, and their occurrence in the gut contents of small-sized roach, dace, perch, ruffe and three-spined stickleback. Gut fullness coefficient, niche breadth and niche overlap indicated how the fishes coexist in the macrophytes. Chironomidae dominated in the diet of the percids. However, ruffe consumed mostly benthic chironomids, while perch epiphytic chironomids and zooplankton. The diet of dace resembled that in fast flowing water although this rheophilic species occurred at unusual density there. The generalist roach displayed the lowest gut fullness coefficient values and widest niche breadth; consequently, intraspecific rather than interspecific competition decided the fate of roach. Three-spined stickleback differed from the other fishes by consuming epiphytic simuliids and fish eggs. The diet overlap between fishes reaching higher gut fullness coefficient values was rather low when the food associated with the submersed aquatic macrophytes was most abundant; this is congruent with the niche overlap hypothesis that maximal tolerable niche overlap can be higher in less intensely competitive conditions.

  7. Coexistence of fish species in a large lowland river: food niche partitioning between small-sized percids, cyprinids and sticklebacks in submersed macrophytes.

    Science.gov (United States)

    Dukowska, Małgorzata; Grzybkowska, Maria

    2014-01-01

    In the spring and summer of each year, large patches of submersed aquatic macrophytes overgrow the bottom of the alluvial Warta River downstream of a large dam reservoir owing to water management practices. Environmental variables, macroinvertebrates (zoobenthos and epiphytic fauna, zooplankton) and fish abundance and biomass were assessed at this biologically productive habitat to learn intraseasonal dynamics of food types, and their occurrence in the gut contents of small-sized roach, dace, perch, ruffe and three-spined stickleback. Gut fullness coefficient, niche breadth and niche overlap indicated how the fishes coexist in the macrophytes. Chironomidae dominated in the diet of the percids. However, ruffe consumed mostly benthic chironomids, while perch epiphytic chironomids and zooplankton. The diet of dace resembled that in fast flowing water although this rheophilic species occurred at unusual density there. The generalist roach displayed the lowest gut fullness coefficient values and widest niche breadth; consequently, intraspecific rather than interspecific competition decided the fate of roach. Three-spined stickleback differed from the other fishes by consuming epiphytic simuliids and fish eggs. The diet overlap between fishes reaching higher gut fullness coefficient values was rather low when the food associated with the submersed aquatic macrophytes was most abundant; this is congruent with the niche overlap hypothesis that maximal tolerable niche overlap can be higher in less intensely competitive conditions.

  8. Acute toxicity of cadmium, lead, zinc, and their mixtures to stream-resident fish and invertebrates

    Science.gov (United States)

    Mebane, Christopher A.; Dillon, Frank S.; Hennessy, Daniel P.

    2012-01-01

    The authors conducted 150 tests of the acute toxicity of resident fish and invertebrates to Cd, Pb, and Zn, separately and in mixtures, in waters from the South Fork Coeur d'Alene River watershed, Idaho, USA. Field-collected shorthead sculpin (Cottus confusus), westslope cutthroat trout (Oncorhynchus clarkii lewisi), two mayflies (Baetis tricaudatus and Rhithrogena sp.), a stonefly (Sweltsa sp.), a caddisfly (Arctopsyche sp.), a snail (Gyraulus sp.), and hatchery rainbow trout (Oncorhynchus mykiss), were tested with all three metals. With Pb, the mayflies (Drunella sp., Epeorus sp., and Leptophlebiidae), a Simuliidae black fly, a Chironomidae midge, a Tipula sp. crane fly, a Dytiscidae beetle, and another snail (Physa sp.), were also tested. Adult westslope cutthroat trout were captured to establish a broodstock to provide fry of known ages for testing. With Cd, the range of 96-h median effect concentrations (EC50s) was 0.4 to >5,329μg/L, and the relative resistances of taxa were westslope cutthroat trout ≈ rainbow trout ≈ sculpin toxicities of the three metals were less than additive on a concentration-addition basis.

  9. PREIMAGINAL STAGES OF COENAGRION PUELLA L. 1758 (ODONATA

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    L. Sh. Amhaeva

    2013-01-01

    Full Text Available Abstract. Aim. Ages and stages of dragonfly larvae Coenagrion puella L., 1758 with a wide area of distribution throughout Russia were determined in the laboratory. Morphological and morphometric characteristics of larvae instars are described.Location. Zoological laboratory of Kabardino-Balkarian State University (Russia.Methods. Common methods of entomological research were used. In experimental conditions, the development stage (F of 260 ex. of Coenagrion puella were studied. Eggs of Coenagrion puella were taken from natural reservoirs and incubated at 22–24 °C. Larvae were fed once a day by Cladocera, Copepoda, Ostracoda, Chironomidae, Oligochaeta.Results and conclusions. Larvae of Coenagrion puella L., 1758 are hatched from eggs after 24–26 days at the temperature 22–24 °C. Time diapason between exuviations is increased with age of larvae: 1–5 stages exuviate by 3–4 days, 6–7 stages by 5–6 days, 8–9 by 6–18 days, 10th by 9–12 days. Morphometric parameters of the larvae are changed with each molting. Main morphological changes indicate a stages of development and are due with change of mask (including its distal margin, lateral lobe, external lamellae (gill plates, antennae and tarsi. The results can be used in ecological monitoring, micropopulation studies. These data can help to determine the variability of dragonflies in mountain ecosystems.

  10. Numerical Response of Migratory Shorebirds to Prey Distribution in a Large Temperate Arid Wetland, China

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    Yamian Zhang

    2016-01-01

    Full Text Available Wuliangsuhai Lake provides important breeding and stopover habitats for shorebirds. The health of this wetland ecosystem is rapidly deteriorating due to eutrophication and water pollution and environmental management is urgently needed. To explore the connections among ecosystem health, prey density, and shorebird populations, we conducted surveys of both the benthic macroinvertebrates and shorebirds in the shorebird habitat of the wetland during the 2011 autumn migration season. The abundance of both shorebirds and benthic macroinvertebrates varied significantly in both space and time. Our data showed a clear association between shorebird populations and the density of benthic macroinvertebrates, which explained 53.63% of the variation in shorebird abundance. The prey density was strongly affected by environmental factors, including water and sediment quality. Chironomidae were mainly found at sites with higher total phosphorus, but with lower sediment concentrations of Cu. Lymnaeidae were mainly found at sites with a higher pH, lower salinity, and lower concentrations of total phosphorus and Cu. Habitats with very high concentrations of total phosphorus, heavy metals, or salinity were not suitable for benthic macroinvertebrates. Our findings suggest that the reductions of nutrient and heavy metal loadings are crucial in maintaining the ecological function of Wuliangsuhai as a stopover habitat for migratory shorebirds.

  11. Fauna fitotelmata en las bromelias Aechmea fendleri André y Aechmea fendleri y Aechmea fendler del Parque Nacional San Esteban, Venezuela stellata S c h u l t d e l P a r q u e N a c i o n a l S a n E s t e b a n , V

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    Jonathan Liria

    2013-04-01

    Full Text Available El presente trabajo caracteriza la asociación de mosquitos y otros invertebrados sobre bromelias del Parque Nacional San Esteban del Estado Carabobo, Venezuela. Se estudiaron 18 plantas de Aechmea fendleri (11 Aechmea fendleri (1 1 Aechmea fendleri y Hohenbergia stellata (7 durante las épocas lluvia (Septiembre 2004 y sequía (Marzo 2005. Fueron colectados un total de 2020 macroinvertebrados. Los taxa más importantes fueron las Familias Chironomidae (43%, Culicidae (25% y Chaoboridae (6% del Orden Diptera, y Scyrtidae (5% del Orden Coleoptera. En Culicidae las especies más abundan- tes fueron: Culex consolador (31%, Cx. neglectus (27% y Wyeomyia celaenocephala (17%. La mayor abundancia y riqueza se encontró en la época de sequía, con el aumento de diversidad en Culicidae. La diversidad y equitabilidad de macroinvertebrados fue mayor H. stellata , pero similares entre estaciones para las comunidades de A. fendleri y A. fendleri y A. fendleri H. stellata .

  12. [Feeding of two amphibian species (Anura: Hylidae) during the low temperatures season and its relationship with energy storage in Santa Fe, Argentina].

    Science.gov (United States)

    Antoniazzi, Carolina Elizabet; López, Javier Alejandro; Duré, Marta; Falico, Diego Alejandro

    2013-06-01

    Feeding of two amphibian species (Anura: Hylidae) during the low temperatures season and its relationship with energy storage in Santa Fe, Argentina. In environments with thermal and pluvial seasonality such as those of the Middle Paraná River floodplain (Province of Santa Fe, Argentina), most amphibian species reproduce during the warm season and drastically diminish their activity during winter. Even though, a few species remain active during the cold season, such as Hypsiboas pulchellus that has its reproductive peak during the autumn-winter period (and the consequent energy demand). The objective of this study was to analyze and compare the feeding and development of fat bodies during the low temperature season for H. pulchellus and Dendropsophus nanus. We analyzed entire gastrointestinal tract contents of both species (H. pulchellus = 110 specimens; D. nanus = 114 specimens) and applied an index (IRI%) that combines prey abundance, volume and frequency to describe frogs diets; we used fat bodies weights as indicators of stored energy reserves. We compared diet between species with a niche overlap index (Ojk: 0-1) and used null models to ascribe statistical significance to evaluate overlap; and we analyzed variation in empty guts proportions through months and between species. Also, using ANCOVAs we explored differences in fat bodies, number and volume of prey consumed along months, between species and sexes. The most important preys in H. pulchellus diet during the cold season were Araneae (IRI% = 34.96), Chironomidae (IRI% = 33.08), Tipulidae (IRI% = 11.44) and Gryllidae (IR1% = 7.31); while for D. nanus, Chironomidae (IR1% = 48.14), Tipulidae (IRI% = 18.41), Psychodidae (IRI% = 7.44) and Araneae (IRI% = 7.34). Diet overlap between species was elevated (Ojk=0.78) and higher than expected by chance (mean simulated indices: Ojk = 0.04; p[observed > or = expected]<0.01; p[observed < or = expected] = 1). In H. pulchellus there was a monthly variation in number

  13. Delineation of level III aquatic ecological function regionalization in the Taihu Lake basin%太湖流域水生态功能三级分区

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    高永年; 高俊峰; 陈垌烽; 许妍; 赵家虎

    2012-01-01

    Aquatic ecoregions have been used as spatial units for aquatic ecosystem management at the watershed scale. According to the protection requirements and characteristics of aquatic ecosystems in the Taihu Lake basin, the main purpose and the principles of level III aquatic ecological function regionalization delineation in this basin were proposed. Then the indicators for delineating level III aquatic ecological function regionalization were established based on regionalization objective and principles. The indicators for delineating level Ili aquatic ecological function regionalization in the non-Taihu Lake area included benthic Shannon-Wiener diversity index, chlorophyll content, water habitat types and benthic indicator species types (including Ephemera, Bivalvia, snail, Chironomidae and Oligochaeta), and the regionalization indicators for delineating level III aquatic ecological function regionalization in the Taihu Lake area included benthic Shannon-Wiener diversity index, chlorophyll content, water flow velocity and benthic indicator species (including Oligochaeta, Chironomidae class, Bivalvia, snail and others) ratio. With the aid of GIS technology, the spatial distribution of the indicators for level III aquatic ecological function regionalization delineation was identified based on the raster data from 1106 aquatic ecoregion function units in the non-Taihu Lake area and 3568 aquatic ecoregion function units in the Taihu Lake area, respectively. Two-step spatial clustering analysis approach and manual-assisted method were used to delineate level III aquatic ecological function zones. Then the Taihu Lake basin was divided into 21 level III aquatic ecological function zones. Moreover, the characteristics of the 21 zones were summarized, showing that there were significant differences in the aspects such as topography, soil type, water quality and aquatic ecology. The results of quantitative comparison of aquatic life also indicated that the benthic dominant

  14. Alimentação e fator de condição de peixes characidiíneos no sistema do Ribeirão Grande, Sudeste do Brasil - DOI: 10.4025/actascibiolsci.v27i3.1336 Feeding and condition factor of characidiin fish in Ribeirão Grande system, Southeastern Brazil - DOI: 10.4025/actascibiolsci.v27i3.1336

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    Francisco Manoel de Souza Braga

    2005-03-01

    Full Text Available Os peixes foram amostrados quatro vezes em cada local, de julho de 2001 a abril de 2002: inverno (julho de 2001, primavera (outubro de 2001, verão (fevereiro de 2002 e outono (abril de 2002. Foram amostrados segmentos de cinco riachos no sistema do Ribeirão Grande (22o 47’ 08’’ S, 45o 28’ 17’’W. Coletas quantitativas foram feitas com um aparelho de pesca-elétrica ligado a um gerador com capacidade máxima de 1.500 V e 8,7 A de 600 Hz de corrente alternada. Alimentação, mudanças na gordura visceral e fator de condição foram comparados em duas espécies de characidiíneos, Characidium lauroi e C. Alipioi do sistema do Ribeirão Grande, sudeste do Brasil. Nas dietas das duas espécies ninfas de Ephemeroptera, foram registradas larvas de Diptera (Chironomidae, Simuliidae, ninfas de Plecoptera, larvas de Trichoptera (Hydroptilidae, Psychoyiidae, insetos terrestres (Coleoptera, Isoptera, Hemiptera [Heteroptera, Homoptera], larvas de Megaloptera (Corydalidae, Arachnida, Ostracoda e restos vegetais. A gordura visceral decresceu em fevereiro, coincidindo com o declínio do fator de condição em ambas as espécies. O aumento da atividade alimentar durante o verão proporciona o acúmulo de gordura. Durante as estações seguintes, esses peixes devem utilizar as reservas de gordura visceral para manutenção e reproduçãoFeeding, seasonal changes in visceral fat and condition factor were compared in two species of characidiin fishes, Characidium lauroi and C. alipioi from Ribeirão Grande system, southeastern Brazil. Five streams of Ribeirão Grande system were sampled (22o 47’ 08’’ S, 45o 28’ 17’’W. The samples were taken four times per site, from July, 2001 to April, 2002: winter (July 2001, spring (October 2001, summer (February 2002 and autumn (April 2002. Quantitative collections were made with an electro-fishing device powered by a generator with maximum capacity of 1,500 V and 8.7 A of 60 Hz alternating current

  15. The opportunistic feeding and reproduction strategies of the annual fish Cynopoecilus melanotaenia (Cyprinodontiformes: Rivulidae inhabiting ephemeral habitats on southern Brazil

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    Cristina da Silva Gonçalves

    2011-03-01

    Full Text Available Most Rivulidae fishes are popularly known as annual fishes which live in ephemeral environments such as pools, that obligatorily dry out seasonally causing the death of adult individuals. They have unique biological characteristics such as small body size, early sexual maturation, continuous reproduction, an elaborated courtship behavior, and a great reproductive capacity among fishes. The rivulids are widely distributed in North, Central and South America. In this study, the diet and reproductive biology of Cynopoecilus melanotaenia was analyzed. A total of 263 specimens were collected and the analysis of 233 gastrointestinal contents revealed an invertivorous diet composed mainly of small crustaceans (Cladocera, Amphipoda, and Ostracoda and immature insects (Chaoboridae, Culicidae, Syrphidae, but mainly Chironomidae larvae. Lepidophagy on male's diet was also registered. Fecundity was estimated by analyzing 59 pairs of mature ovaries and ranged from 2 to 157 oocytes (mean, 19 ± 26[SD]. The species has fractional spawning, a strategy to increase the chance of survival to prolonged depletions. This study is the first to investigate the reproductive biology of C. melanotaenia. The results confirmed the opportunistic character of the rivulid C. melanotaenia and provided unreported reproductive information that may aid conservation of the species.A maioria dos peixes da família Rivulidae são popularmente conhecidos como anuais por completarem todo seu ciclo biológico em pequenos corpos de água temporários que secam obrigatoriamente em determinados períodos do ano causando a morte dos indivíduos adultos. Possuem características biológicas peculiares como pequeno porte, maturação sexual precoce, reprodução contínua, um elaborado padrão de corte e uma grande capacidade reprodutiva entre os peixes. Os rivulídeos se encontram amplamente distribuídos nas Américas do Norte, Central e Sul. Este trabalho analisou a dieta e a biologia

  16. Diet of four annual killifishes: an intra and interspecific comparison

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    Gabriel Laufer

    2009-03-01

    Full Text Available We examined the diet of 4 annual fishes, Austrolebias viarius, Austrolebias cheradophilus, Austrolebias luteoflammulatus and Cynopoecilus melanotaenia inhabiting temporal ponds of southeastern Uruguay, by analysis of stomach contents. Fishes were captured from fifty ephemeral ponds of Castillos Lagoon basin, in the region of the Humedales del Este. We identified 13099 individual prey items extracted from 669 stomachs of the four captured species. In the studied system, annual killifishes represents the most abundant and conspicuous top predators. Killifishes are generalist key predators at the ephemeral ponds of the studied system, consuming mostly aquatic items. Zooplancton represented the bulk of the diet in the four analyzed species, followed by eggs, algae and diatoms. Insects are the next group in prey number, as follows: Diptera larvae (especially Chironomidae and Cullicidae, Ephemeroptera (especially Betidae, and coleopteran larvae (especially Dytiscidae. Acari are also important prey in number. The four fish species differ in diet composition and in diet richness. A general pattern of differences in diet richness among killifish species and demographic groups could be related to variations in body sizes. As top predators annual killifishes are an important component of the temporal pond ecosystems. Understanding the natural history of this species and their communities is necessary in order to conserve them.Nós examinamos a dieta de 4 peixes anuais, Austrolebias viarius, Austrolebias cheradophilus, Austrolebias luteoflammulatus e Cynopoecilus melanotaenia, que habitam poças temporárias do sudeste do Uruguai, através da análise de conteúdo estomacal. Os peixes foram capturados em cinco poças temporárias da bacia da lagoa Castillos, na região de Humedales del Este. Nós identificamos 13099 itens de presas estraídos de 669 estômagos das quatro espécies. No sistema estudado, peixes anuais representam os predadores de topo mais

  17. Los macroinvertebrados bentónicos de pozo azul (Cuenca del río Gaira, Colombia y su relación con la calidad del agua The Benthonic Macroinvertebrates of Pozo Azul (Gaira River Basin, Colombia and their Relationship with Water Quality

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    Manjarrés-Hernández Ana

    2003-12-01

    Full Text Available En julio de 2002 se realizó el estudio de algunos parámetros fisicoquímicos y la estructura de la comunidad de macroinvertebrados bentónicos asociados a cuatro coriotipos (piedra, hojarasca, sedimento y macrófitas en el sector de Pozo Azul sobre la cuenca del río Gaira (Magdalena, Colombia. Se discute la relación entre la estructura de la comunidad y la calidad del agua del sector. Los parámetros fisicoquímicos estuvieron determinados en gran medida por las características geográficas del sistema. El agua se caracterizó por estar saturada de oxígeno y por la ausencia de compuestos intermedios de la estabilización de la materia orgánica como nitritos y amonio. Se colectaron 588 individuos distribuidos en 11 órdenes y 38 familias. Los órdenes más representativos fueron Trichoptera, Coleoptera, Diptera y Ephemeroptera, siendo el último de ellos el más abundante. Las familias más representativas fueron Baetidae, Simullidae, Perlidae, Chironomidae e Hydropsychidae, en ese mismo orden de abundancia. Para la relación de la estructura de la comunidad con la calidad del agua se calculó el índice BMWP, adaptado por la Universidad del Valle, Cali, Colombia, que estableció para este caso un agua de óptima calidad y oligosapróbita, según la ecología sapróbita, estado alcanzado luego de la estabilización frente a pequeñas alteraciones inducidas por las actividades del cultivo del café en la zona.On July 2002, a study of some physicochemical parameters and their relationship with the benthonic macroinvertebrates community structure on four coriotypes: stone, trash, silt and macrophytes, was carried out in Pozo Azul (Gaira River basin, Magdalena, Colombia. The physicochemical parameters were determined, to a considerable extent, by the geographic characteristics of the system. The water was found to be oxygen saturated, and intermediate compounds of the organic matter stabilization, such as nitrites and ammonium, there were

  18. DISTRIBUTION AND OCCURRENCE OF BENTHIC MACROINVERTEBRATES IN RIVERS WITH RICE CULTURE AREA IN ITAJAÍ VALLEY - SC = DISTRIBUIÇÃO E OCORRÊNCIA DE MACROINVERTEBRADOS BENTÔNICOS EM RIOS NAS ÁREAS COM CULTURA ORIZÍCOLA NO VALE DO ITAJAÍ-SC

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    Joseline Molozzi

    2009-01-01

    Full Text Available Rice is one of the main cereals grown in Brazil. The handling of the rice culture may impact in the river downstream of the farming. The main goal of this research was to evaluate the distribution and occurrence of benthic macroinvertebrates in rivers with rice plantations. This research was developed in the cities of Gaspar and Agrolândia, in Itajaí River Basin, Santa Catarina, Brazil. In Gaspar City, macroinvertebrate data and environmental information were collected quarterly, in August/04, November/04 and February/05. In Agrolândia City, they were also collected quarterly in October/04, January/05 and April/05. Benthic macroinvertebrates samples were collected using Surber sampler. The macroinvertebrates were identified at family level. Diversity was estimated using Shannon, Margalef and Evenness Indices. To compare the diversity among these sites, T Student Test was used. Richness and Dominance were also determinated. 21.831 organisms were collected at the six sites. 73% were Diptera with predominance of Chironomidae family with 14.956 individuals. Site 4 had the lowest diversity and the highest dominance. In rivers under influence of the rice culture it is observed predominance of taxons resistant to pollution. Taxons more sensitive to pollution were hardly found at the six sites, demonstrating the inappropriate conditions for their development. = O arroz é um dos principais cereais cultivados no Brasil. No manejo desta cultura é possível que ocorra um impacto no corpo hídrico à jusante das lavouras. Este trabalho teve por objetivo estudar a distribuição e ocorrência de macroinvertebrados bentônicos em rios nas áreas com cultura orizícola. O estudo foi desenvolvido nos municípios de Gaspar e Agrolândia, localizados na bacia do Itajaí, SC. As coletas foram realizadas trimestralmente, em agosto e novembro de 2004 e fevereiro de 2005 em Gaspar, outubro de 2004, janeiro e abril de 2005 em Agrolândia. As amostras de

  19. A biodiversidade bentônica em lagoa marginal ao rio Paranapanema na zona de sua desembocadura, na represa de Jurumirim - DOI: 10.4025/actascibiolsci.v28i4.166 The benthic biodiversity in a lake marginal to the Paranapanema river in its mouth zone into Jurumirim reservoir- DOI: 10.4025/actascibiolsci.166

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    Rosemary Cristina Souza Davanso

    2007-11-01

    Full Text Available O presente trabalho teve como objetivo principal verificar a biodiversidade bentônica em áreas do fundo da lagoa do Coqueiral, zona de desembocadura do rio Paranapanema, na represa de Jurumirim, Estado de São Paulo. Foram selecionados dezoito pontos de amostragem, englobando áreas rasas e áreas profundas. As coletas foram feitas em intervalos trimestrais ao longo de um ano; também foram analisadas as variáveis físicas e químicas da água (nível, transparência, temperatura, oxigênio dissolvido, pH e condutividade elétrica. Amostras do sedimento, para análise da fauna e de fatores abióticos (granulometria e conteúdo orgânico, foram recolhidas em tréplicas, utilizando como coletor a draga de Petersen. O material foi triado e analisado sob microscópio estereoscópico. Contagem e identificação dos organismos foram realizadas, e densidade, abundância relativa, riqueza taxonômica e índice de dominância foram calculados. A análise revelou uma fauna com baixa diversidade e a dominância de Chironomidae e Ephemeroptera. Domínio de Ephemeroptera, constituído por Campsurus, ocorreu no período mais quente do ano e com baixa profundidade da lagoa. A distribuição dos organismos teve como principais fatores determinantes profundidade, transparência, pH e temperatura da água. Na comparação feita entre áreas rasas e profundas, foi observada uma menor densidade de organismos nas regiões profundas.Coqueiral lake is a marginal lake located at the southeast São Paulo State, in the mouth zone of the Paranapanema river into Jurumirim Reservoir and it has high connectivity with the Paranapanema river. This work aimed to verify the benthic biodiversity in areas of the lake bottom. 18 sampling sites in the lake were selected, including shallow and deep areas. The samples were taken every three months during one year. Physical and chemical water variables (level, transparency, dissolved oxygen, pH, and electric conductivity were

  20. Effect of acute exposure to cadmium on the expression of heat-shock and hormone-nuclear receptor genes in the aquatic midge Chironomus riparius

    Energy Technology Data Exchange (ETDEWEB)

    Planello, R.; Martinez-Guitarte, J.L. [Grupo de Biologia y Toxicologia Ambiental, Facultad de Ciencias, Universidad Nacional de Educacion a Distancia, UNED, Senda del Rey 9, 28040 Madrid (Spain); Morcillo, G., E-mail: gmorcillo@ccia.uned.es [Grupo de Biologia y Toxicologia Ambiental, Facultad de Ciencias, Universidad Nacional de Educacion a Distancia, UNED, Senda del Rey 9, 28040 Madrid (Spain)

    2010-03-01

    Cadmium is a widespread and highly toxic pollutant of particular ecotoxicological relevance for aquatic ecosystems where it accumulates. To identify biomarkers for ecotoxicity monitoring, the effect of cadmium on the expression of different genes related to the stress response as well as to the ecdysone hormone-signalling pathway was studied in the aquatic larvae of Chironomus riparius (Diptera, Chironomidae), a standard test organism in aquatic toxicology testing. Reverse Transcription Polymerase Chain Reaction (RT-PCR) was used to evaluate the effects of acute and short-term cadmium exposures (10 mM CdCl{sub 2}, 12 h and 24 h) on the expression of hsp70, hsc70, hsp90 and hsp40 genes, as well as on that of the ecdysone hormonal-receptor genes (EcR and usp). A significant 3-fold increase in the level of hsp70 gene transcripts was induced by the treatment, whereas neither the other stress genes tested (hsp90 and hsp40) nor the constitutive form of hsp70, hsc70, was affected in the larvae exposed to cadmium. These results show that hsp70 is differentially activated to other environmentally regulated heat-shock genes, and constitutes a biomarker of exposure to this toxic metal. In addition, we also found that cadmium is able to alter the expression of the ecdysone receptor gene (EcR), whose mRNA level is significantly increased whereas usp levels remained unaltered. This finding, evidenced for the first time in invertebrates, supports the view that cadmium has the ability to mimic the effect of the hormone by the activation of the ecdysone nuclear receptor, which may partly explain the endocrine disruption capability that has been previously suggested for this toxic metal. Our research adds to the growing evidence implicating heavy metals, and cadmium in particular, as potential endocrine disruptive agents and may have significant implications for ecological risk assessment of endocrine-disrupting compounds in invertebrates.

  1. Hypoxia and anoxia effects on alcohol dehydrogenase activity and hemoglobin content in Chironomus riparius Meigen, 1804

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    Valentina Grazioli

    2016-02-01

    Full Text Available The metabolic effects of low oxygen content on alcohol-dehydrogenase (ADH activity and hemoglobin (Hb concentration were investigated in IV-instar larvae of Chironomus riparius (Diptera: Chironomidae from an Italian stream. Two series of short-term (48 h experiments were carried out: exposure to (1 progressive hypoxia (95 to 5% of oxygen saturation and (2 anoxia (at <5% of oxygen saturation. In (1, Hb amount increased with increasing oxygen depletion up to a critical value of oxygenation (about 70% of oxygen saturation. Below this percentage, the Hb amount declined to values comparable with those present in the control. The respiration rate (R remained almost constant at oxygen saturation >50% and decreased significantly only after 48 h of treatment (= <5% of oxygen saturation reaching values <100 mmolO2 gAFDW-1 h-1. ADH activity showed two phases of growth, within the first 14 h and over 18 h of exposure. Overall, we inferred that i Hb might function as short-term oxygen storage, enabling animals to delay the on-set of anaerobiosis; and ii alcoholic fermentation co-occurs for a short time with aerobic respiration, becoming the prevalent metabolic pathway below 5% of oxygen saturation (<1 mg L-1. These considerations were supported also by results from anoxia exposure (2. In such condition, larvae were visibly stressed, becoming immobile after few minutes of incubation, and ADH reached higher values than in the hypoxia treatment (2.03±0.15 UADH mg prot-1. Overall, this study showed a shift from aerobic to anaerobic activity in C. riparius larvae exposed to poorly oxygenated water with an associated alteration of ADH activity and the Hb amount. Such metabolites might be valid candidate biomarkers for the environmental monitoring of running waters.

  2. Trace DNA from insect skins: a comparison of five extraction protocols and direct PCR on chironomid pupal exuviae.

    Science.gov (United States)

    Kranzfelder, Petra; Ekrem, Torbjørn; Stur, Elisabeth

    2016-01-01

    Insect skins (exuviae) are of extracellular origin and shed during moulting. The skins do not contain cells or DNA themselves, but epithelial cells and other cell-based structures might accidentally attach as they are shed. This source of trace DNA can be sufficient for PCR amplification and sequencing of target genes and aid in species identification through DNA barcoding or association of unknown life stages. Species identification is essential for biomonitoring programs, as species vary in sensitivities to environmental factors. However, it requires a DNA isolation protocol that optimizes the output of target DNA. Here, we compare the relative effectiveness of five different DNA extraction protocols and direct PCR in isolation of DNA from chironomid pupal exuviae. Chironomidae (Diptera) is a species-rich group of aquatic macroinvertebrates widely distributed in freshwater environments and considered a valuable bioindicator of water quality. Genomic DNA was extracted from 61.2% of 570 sampled pupal exuviae. There were significant differences in the methods with regard to cost, handling time, DNA quantity, PCR success, sequence success and the ability to sequence target taxa. The NucleoSpin(®) Tissue XS Kit, DNeasy(®) Blood and Tissue kit, and QuickExtract(™) DNA Extraction Solution provided the best results in isolating DNA from single pupal exuviae. Direct PCR and DTAB/CTAB methods gave poor results. While the observed differences in DNA isolation methods on trace DNA will be relevant to research that focuses on aquatic macroinvertebrate ecology, taxonomy and systematics, they should also be of interest for studies using environmental barcoding and metabarcoding of aquatic environments.

  3. Aquatic insects as the main food resource of fish the community in a Neotropical reservoir

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    Ana Paula Vidotto-Magnoni

    Full Text Available We evaluated the feeding of fish species of the Nova Avanhandava Reservoir, low Tietê River, São Paulo State, Brazil. Fishes were collected in two stretches of the reservoir: Santa Bárbara (14 samples and Bonito (two samples between September 2002 and March 2004, using gill and seining nets. The results of stomach contents analysis were expressed with the frequency of occurrence and gravimetric method, combined in the Alimentary Index (AI. The 20 species studied consumed 52 food items, grouped in 10 food categories: aquatic insects, terrestrial insects, crustaceans, fish, macroinvertebrates, microcrustaceans, algae, vegetal matter, detritus/sediment and scales. The aquatic insects (mainly Chironomidae, Odonata and Ephemeroptera were the most common food resources, consumed by 18 species. The diet composition of the community (species grouped indicated that the dominant food category in the diet of fishes was aquatic insects (AI = 77.6%, followed by crustaceans (AI = 7.1%. Four trophic guilds were identified according a cluster analysis (Pearson distance: insectivorous (10 species, omnivorous (4 species, detritivorous (3 species and piscivorous/carcinophagous (3 species. Despite the highest number of species, the insectivorous guild was responsible for more than 80% in captures in number and biomass (CPUEn and CPUEb. The low values of niche breadth presented by all species, along with the low values of diet overlap between species pairs indicate a high degree of food resources partitioning among species. The aquatic insects, despite being the main food resource of insectivorous fishes, also complemented the diet of other species, which demonstrate the importance of this food resource for the fish community, sustaining a high diversity, abundance and biomass of fishes.

  4. Impact of urbanization on the ecology of Mukuvisi River, Harare, Zimbabwe

    Science.gov (United States)

    Moyo, N. A. G.; Rapatsa, M. M.

    2016-04-01

    The main objective in this study was to compare the physico-chemical characteristics and biota of a river (Mukuvisi) passing through an urban area to that of a non-urbanised river (Gwebi). Five sites in the Mukuvisi River and five sites in the Gwebi River were sampled for water physico-chemical parameters (pH, conductivity, DO, BOD, TDS, ammonia, Cl, SO42-, PO42-, NO33-, F-, Pb, Cu, Fe, Mn, Zn and Cr) once every month between August, 2012-August, 2013. Cluster analysis based on the physico-chemical parameters grouped the sites into two groups. Mukuvisi River sites formed their own grouping except for one site which was grouped with Gwebi River sites. Principal Component Analysis (PCA) was used to extract the physico-chemical parameters that account for most variations in water quality in the Mukuvisi and Gwebi Rivers. PCA identified sulphate, chloride, fluoride, iron, manganese and zinc as the major factors contributing to the variability of Mukuvisi River water quality. In the Gwebi river, sulphate, nitrate, fluoride and copper accounted for most of the variation in water quality. Canonical Correspondence Analysis (CCA) was used to explore the relationship between physico-chemical parameters and macroinvertebrate communities. CCA plots in both Mukuvisi and Gwebi Rivers showed significant relationships between macroinvertebrate communities and water quality variables. Phosphate, ammonia and nitrates were correlated with Chironomidae and Simulidae. Gwebi River had higher (P Clarias gariepinus from the Mukuvisi River had high liver histological lesions and low AChE activity and this led to lower growth rates in this river.

  5. Non-native western tubenose gobies Proterorhinus semilunaris show distinct site, sex and age-related differences in diet

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    Všetičková L.

    2014-01-01

    Full Text Available The tubenose goby, Proterorhinus semilunaris, has expanded its range throughout Europe. Comprehensive studies to identify its impact on native riverine ecosystems, however, are relatively scarce. Here, we evaluate dietary preferences of P. semilunaris on a non-native river to reveal any such impacts. Fish were sampled monthly over 2011–2012 from three sites along the River Dyje (Czech Republic; Danube basin with differing population levels and food availability. Both the amount of food consumed and dietary composition varied seasonally, with site having a strong effect. Food consumed differed between males and females, but not dietary composition; while diet differed between age classes, but not food consumed. In general, Trichoptera, Chironomidae and zooplankton dominated the diet at all sites, with Trichoptera taken more often earlier in the year and zooplankton later. Mussels were always avoided, despite high abundance, while less preferred prey were occasionally taken in high numbers in response to increased availability or energy demand (e.g. spawning. Fish eggs and fry (all P. semilunaris were only taken in high numbers at one site, being related to high population level and fry drift from a reservoir. Male feeding declined over the breeding season, presumably due to nest guarding, while female feeding declined over winter, possibly resulting in high mortality. Proterorhinus semilunaris is a feeding opportunist, which may facilitate colonisation in habitats with poor prey availability. No predation pressure on native species was observed through consumption of eggs or fry, though small/young indigenous fish may be affected through diet competition.

  6. Trends in Benthic macroinvertebrate community Biomass and Energy Budgets in Lake Sevan, 1928-2004

    Science.gov (United States)

    Stapanian, Martin A.; Jenderedjian, K.; Hakobyan, S.

    2012-01-01

    Water levels of Lake Sevan (Armenia) were artificially lowered by nearly 20 m between 1949 and 1997. Lowered water levels, combined with increased eutrophication, were associated with seasonally anoxic conditions (lasting 1–4 months) near the bottom of the profundal zone each year during 1976–2004. In addition, the extents of the macrophyte zone and of certain substrate types were severely reduced following drawdown. Maximal depth of occurrence decreased by 2–44 m for at least for 50 species of benthic macroinvertebrates between 1982 and 2004 compared to 1937–1961. Species richness of benthic macroinvertebrates declined from 25 to three species at depths where seasonal anoxia occurred. Total biomass increased by a factor of 10 from the period 1928–1948 to 1976–1979 then declined by a factor of 3 to 4 between 1987 and 2004. Energy flow through detritivores was more than tripled during 1976–2004 compared to 1928–1971, a result of increased plankton primary production. In contrast, energy flow through herbivorous benthic macroinvertebrates decreased by a factor of nearly 5, due to reduced areal coverage of macrophytes. Energy flow through filter feeders did not change over the time period examined, but energy flow through the entire zoobenthos community was nearly tripled. The biomasses of Oligochaeta, Chironomidae, and total zoobenthos showed a delayed response to changes in primary production of 7–9, 2, and 2–4 years, respectively. These patterns may provide a basis to predict results of restoration efforts based on the abundance of the zoobenthos in future years as the level of the lake is restored and water quality improves.

  7. Environmental factors associated with the distribution of Anopheles arabiensis and Culex quinquefasciatus in a rice agro-ecosystem in Mwea, Kenya.

    Science.gov (United States)

    Muturi, Ephantus J; Mwangangi, Joseph; Shililu, Josephat; Jacob, Benjamin G; Mbogo, Charles; Githure, John; Novak, Robert J

    2008-06-01

    Studies were conducted between May and June, 2006 to investigate the environmental factors affecting the distribution of An. arabiensis Patton and Culex quinquefasciatus Say in Mwea, Kenya. The sampling unit comprised all non-paddy aquatic habitats and ten randomly selected paddies and canals located within a 200 m radius from the periphery of the study site. Thirteen physico-chemical variables were recorded for each sampling site in each sampling occasion and a sample of mosquito larvae and other aquatic invertebrates collected. The non-paddy aquatic habitats identified included pools and marshes. Morphological identification of 1,974 mosquito larvae yielded four species dominated by Cx. quinquefasciatus (73.2%) and An. arabiensis (25.0%). Pools were associated with significantly higher Cx. quinquefasciatus larval abundance and less diversity of other aquatic invertebrates compared with other habitat types. In contrast, the abundance of An. arabiensis did not differ significantly among habitat types. Culex quinquefasciatus habitats had higher water conductivity and exhibited a higher abundance of other aquatic invertebrates than An. arabiensis habitats. Chi-square analysis indicated that the two species were more likely to coexist in the same habitats than would be expected by chance alone. Anopheles arabiensis larvae were positively associated with dissolved oxygen and adults of family Haliplidae and negatively associated with emergent vegetation and Heptageniidae larvae. Culex quinquefasciatus larvae were positively associated with dissolved oxygen, total dissolved solids, Chironomidae larvae, and Microvelidae adults and negatively associated with emergent vegetation. These findings suggest that both biotic and abiotic factors play a significant role in niche partitioning among Cx. quinquefasciatus and An. arabiensis, a factor that should be considered when designing an integrated vector control program.

  8. Cross-ecosystem fluxes: Export of polyunsaturated fatty acids from aquatic to terrestrial ecosystems via emerging insects.

    Science.gov (United States)

    Martin-Creuzburg, Dominik; Kowarik, Carmen; Straile, Dietmar

    2017-01-15

    Cross-ecosystem fluxes can crucially influence the productivity of adjacent habitats. Emerging aquatic insects represent one important pathway through which freshwater-derived organic matter can enter terrestrial food webs. Aquatic insects may be of superior food quality for terrestrial consumers because they contain high concentrations of essential polyunsaturated fatty acids (PUFA). We quantified the export of PUFA via emerging insects from a midsize, mesotrophic lake. Insects were collected using emergence traps installed above different water depths and subjected to fatty acid analyses. Insect emergence from different depth zones and seasonal mean fatty acid concentrations in different insect groups were used to estimate PUFA fluxes. In total, 80.5mg PUFA m(-2)yr(-1) were exported, of which 32.8mgm(-2)yr(-1) were eicosapentaenoic acid (EPA), 7.8mgm(-2)yr(-1) were arachidonic acid (ARA), and 2.6mgm(-2)yr(-1) were docosahexaenoic acid (DHA). While Chironomidae contributed most to insect biomass and total PUFA export, Chaoborus flavicans contributed most to the export of EPA, ARA, and especially DHA. The export of total insect biomass from one square meter declined with depth and the timing at which 50% of total insect biomass emerged was correlated with the water depths over which the traps were installed, suggesting that insect-mediated PUFA fluxes are strongly affected by lake morphometry. Applying a conceptual model developed to assess insect deposition rates on land to our insect-mediated PUFA export data revealed an average total PUFA deposition rate of 150mgm(-2)yr(-1) within 100m inland from the shore. We propose that PUFA export can be reliably estimated using taxon-specific information on emergent insect biomass and seasonal mean body PUFA concentrations of adult insects provided here. Our data indicate that insect-mediated PUFA fluxes from lakes are substantial, implying that freshwater-derived PUFA can crucially influence food web processes in adjacent

  9. Estudo da dieta natural da ictiofauna de um reservatório centenário, São Paulo, Brasil

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    Amanda R. Ribeiro

    2014-12-01

    Full Text Available Este estudo teve como objetivo caracterizar e comparar a alimentação de 13 espécies de peixes em três zonas (zona de influência fluvial, zona de transição e zona lacustre do reservatório de Itupararanga. Foram analisados 436 estômagos, sendo encontrados 17 recursos alimentares, todos de origem autóctone. As dietas predominantes das espécies foram: peixe, inseto, material vegetal e detritos na zona de influência fluvial, peixe, sedimento e material vegetal na zona de transição e inseto, escama e peixe na zona lacustre. Através do Índice Alimentar, as espécies foram categorizadas nas guildas: piscívora, insetívora, detritívora e carcinófaga. O Cluster indicou separação da guilda insetívora em espécies generalistas (insetos diversos e especialista (Chironomidae o que aumenta para cinco guildas. Na zona fluvial foram verificadas quatro guildas; na zona de transição três guildas e na zona lacustre duas guildas. Observou-se ainda uma dominância de espécies piscívoras que pode estar relacionada à idade do reservatório. Este estudo ampliou o conhecimento dos hábitos alimentares dos peixes em reservatórios antigos e suas diferenças, comparando as zonas existentes.

  10. Composição da fauna cavernícola brasileira, com uma análise preliminar da distribuição dos taxons

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    Eleonora Trajano

    1990-01-01

    Full Text Available New data on Brazilian cave fauna are added to previous surveys and the relative abundance and distribution of the cavernicolous taxa is discussed. Terrestrial representatives of several arthropod families and genera are common in both tropical and subtropical Brazilian caves: Endecous and Eidmanacris crickets, Reduviidae heteropterans, Carabidae, Catopinae and Ptilodactylidae beetles, dipterans such as the Chironomidae, Keroplatidae, Phoridae and Drosophilidae, Hydropsychidae trichopterans, Pseudonnanolenidae and Chelodesnidae millipedes, Plato, Ctenus, Loxosceles and Blechroscelis spiders, Pachylinae opilionids, Chernetidae pseudoscorpions and acarians such as the Macrochelidae and Uropodidae. Other taxa are mainly or exclusively tropical Blattelidae, Blattidae and BlaberidaE cockroaches, Histeridae beetles, Noctuoidea moths, social insects as termites and ants, Styloniscidae isopods, Migalomorpha spiders, Amblypigi On the other hand, Psauridae spiders, Goniosoma and Tricommatinae opilionids, Elmidae beetles, and Philosciidae isopods seems to be mainly subtropical. Brazilian aquatic cave fauna seems to be less diversified than the terrestrial one. Siluriform fishes such as pimelodids, trichomycterids and loricariids predominate throughout the country, besides decapod (Macrobrachium shrimps, Potamidae crabs, Aegla anomurans, the latter exclusive of subtropical caves and amphipod (Spelaeogammarus, in tropical caves, and Hyalella crustaceans. Insect larvae (e.g. Elmidae coleopterans, Nematocera dipterans, trichopterans and adults (e.g. Veliidae and Naucoridae heteropterans, Dytiscidae coleopterans, oligochaetes and gastropods such as the Hydrobiidae, are also relatively common. Blechroscelis spiders, Goniosoma opilionids, Zelurus heteropterans, Eidmanacris crickets, Keroplatidae dipterans and Macrobrachium shrimps, among others, live next to the entrance zone in the majority of the caves. But, these animals become troglofiles under certain

  11. Baseline assessment of fish communities, benthic macroinvertebrate communities, and stream habitat and land use, Big Thicket National Preserve, Texas, 1999-2001

    Science.gov (United States)

    Moring, J. Bruce

    2003-01-01

    The Big Thicket National Preserve comprises 39,300 hectares in the form of nine preserve units connected by four stream corridor units (with two more corridor units proposed) distributed over the lower Neches and Trinity River Basins of southeastern Texas. Fish and benthic macroinvertebrate data were collected at 15 stream sites (reaches) in the preserve during 1999–2001 for a baseline assessment and a comparison of communities among stream reaches. The fish communities in the preserve were dominated by minnows (family Cyprinidae) and sunfishes (family Centrarchidae). Reaches with smaller channel sizes generally had higher fish species richness than the larger reaches in the Neches River and Pine Island Bayou units of the preserve. Fish communities in geographically adjacent reaches were most similar in overall community structure. The blue sucker, listed by the State as a threatened species, was collected in only one reach—a Neches River reach a few miles downstream from the Steinhagen Lake Dam. Riffle beetles (family Elmidae) and midges (family Chironomidae) dominated the aquatic insect communities at the 14 reaches sampled for aquatic insects in the preserve. The Ephemeroptera, Plecoptera and Trichoptera (EPT) Index, an index sensitive to water-quality degradation, was smallest at the Little Pine Island Bayou near Beaumont reach that is in a State 303(d)-listed stream segment on Little Pine Island Bayou. Trophic structure of the aquatic insect communities is consistent with the river continuum concept with shredder and scraper insect taxa more abundant in reaches with smaller stream channels and filter feeders more abundant in reaches with larger channels. Aquatic insect community metrics were not significantly correlated to any of the stream-habitat or land-use explanatory variables. The percentage of 1990s urban land use in the drainage areas upstream from 12 bioassessment reaches were negatively correlated to the reach structure index, which indicates

  12. The effect of sewage effluent on the physico-chemical and biological characteristics of the Sand River, Limpopo, South Africa

    Science.gov (United States)

    Seanego, K. G.; Moyo, N. A. G.

    Population growth in urban areas is putting pressure on sewage treatment plants. The improper treatment of sewage entering the aquatic ecosystems causes deterioration of the water quality of the receiving water body. The effect of sewage effluent on the Sand River was assessed. Eight sampling sites were selected, site 1 and 2 were upstream of the sewage treatment plant along the urbanised area of Polokwane, whilst sites 3, 4, 5, 6, 7 and 8 were downstream. The physico-chemical parameters and coliform counts in the water samples were determined. The suitability of the water for irrigation was also determined. Hierarchical average linkage cluster analysis produced two clusters, grouping two sites above the sewage treatment works and six sites downstream of the sewage effluent discharge point. Principal component analysis (PCA) identified total nitrogen, total phosphorus, conductivity and salinity as the major factors contributing to the variability of the Sand River water quality. These factors are strongly associated with the downstream sites. Canonial correspondence analysis (CCA) indicated the macroinvertebrates, Chironomidae, Belastomatidae, Chaoborus and Hirudinea being strongly associated with nitrogen, phosphorus, conductivity and temperature. Escherichia coli levels in the Polokwane wastewater treatment works maturation ponds, could potentially lead to contamination of the Polokwane aquifer. The Sodium Adsorption Ratio was between 1.5 and 3.0 and residual sodium carbonate was below 1.24 Meq/l, indicating that the Sand River water is still suitable for irrigation. The total phosphorus concentrations fluctuated across the different site. Total nitrogen concentrations showed a gradual decrease downstream from the point of discharge. This shows that the river still has a good self-purification capacity.

  13. Characterization of benthic communities and physical habitat in the Stanislaus, Tuolumne, and Merced Rivers, California.

    Science.gov (United States)

    Hall, Lenwood W; Killen, William D; Anderson, Ronald D

    2006-04-01

    The primary goal of this study was to characterize physical habitat and benthic communities (macroinvertebrates) in the Stanislaus, Tuolumne and Merced Rivers in California's San Joaquin Valley in 2003. These rivers have been listed as impaired water bodies (303 (d) list) by the State of California due to the presence of organophosphate (OP) insecticides chlorpyrifos and diazinon, Group A pesticides (i.e., organochlorine pesticides), mercury, or unknown toxicity. Based on 10 instream and riparian physical habitat metrics, total physical habitat scores in the Stanislaus River ranged from 124 to 188 (maximum possible total score is 200). The highest total habitat score was reported at the upstream site. Tuolumne River physical habitat scores ranged from 86 to 167. Various Tuolumne River physical habitat metrics, including total habitat score, increased from downstream to upstream in this river. Merced River physical habitat scores ranged from 121 to 170 with a significant increase in various physical habitat metrics, including total habitat score, reported from downstream to upstream. Channel flow (an instream metric) and bank stability (a riparian metric) were the most important physical habitat metrics influencing the various benthic metrics for all three rivers. Abundance measures of benthic macroinvertebrates (5,100 to 5,400 individuals) were similar among the three rivers in the San Joaquin watershed. Benthic communities in all three rivers were generally dominated by: (1) Baetidae species (mayflies) which are a component of EPT taxa generally considered sensitive to environmental degradation; (2) Chironomidae (midges) which can be either tolerant or sensitive to environmental stressors depending on the species; (3) Ephemerellidae (mayflies) which are considered sensitive to pollution stress; and (4) Naididae (aquatic worms) which are generally considered tolerant to environmental stressors. The presence of 117 taxa in the Stanislaus River, 114 taxa in the

  14. The response of Vaal River drift and benthos to Simulium (Diptera: Nematocera) control using Bacillus thuringiensis var. israelensis (H-14).

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    Car, M; De Moor, F C

    1984-09-01

    Two trials to test the efficacy of Bacillus thuringiensis Berliner var. israelensis de Barjac (serotype H-14) against target simuliid and non-target aquatic invertebrates were undertaken in the Vaal River near Warrenton in South Africa. In the 1st trail an application of 1,6 ppm/10 min of B. thuringiensis resulted in a significant (P less than 0,05) reduction of simuliid larvae in rapids 70 m below the treatment point 40 hours after its application. Further downstream the larvicide was ineffectual because the low flow of the river (6 m3/s) allowed the Bacillus pores to settle out in calmer stretches. The 2nd trial was carried out upstream of small rapids with a calculated flow of 0,5 m3/s at a spore concentration of 2,3 ppm/7 min. The effect of B. thuringiensis on the benthic population density and drift activity of the benthos was recorded. A high mortality of simuliid larvae and Ephemeroptera was observed 35 m below the application point 9 hours after the application of the larvicide. The mortality in Ephemeroptera was partially due to the handling of these animals. Population densities of simuliid larvae in the treated rapids decreased 18 hours after application of the larvicide, but small simuliid larvae showed a numerical increase again after 72 hours, indicating rapid recolonization from drifting larvae. Tanytarsine Chironomidae decreased after the application of B. thuringiensis, but most other fauna either increased or did not decrease significantly (P greater than 0,05). Within 43 minutes after treatment of the rapids with the larvicide, simuliid drift increased more than sixtyfold, revealing the immediate irritating effect of the product on the target organisms.(ABSTRACT TRUNCATED AT 250 WORDS)

  15. Bioindicación de la calidad del agua con lógica difusa Sugeno y macroinvertebrados acuáticos de la Sabana de Bogotá Bioindication of water quality in the Bogota Sabana using fuzzy logic Sugeno and aquatic microinvertebrates

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    Ospina Rodulfo

    2002-11-01

    Full Text Available

    Se presenta una implementación de la metodología de lógica difusa Sugeno que permite el cálculo de la calidad biológica del agua en la Sabana de Bogotá, Colombia. Se emplearon un total de 28 sitios correspondientes a 9 subcuencas de la Sabana de Bogotá. Los organismos utilizados para la implementación del modelo de lógica Sugeno fueron: Leptoceridae e Hydrobiosidae como indicadores de aguas limpias, Planariidae y Amphipoda como indicadores aguas contaminadas y como indicadores de aguas muy contaminadas se seleccionaron Psychodidae y Syrphidae. Adicionalmente se incluyo la familia Chironomidae. Los resultados obtenidos con la aplicación de la lógica Sugeno fueron confrontados con los valores del índice fisicoquímico (Cfq para comprobar el nivel de confiabilidad de la metodología de 1ógica Sugeno, observándose una correlación altamente significativa.

    An application of the Sugeno-rype fuzzy logic to calculate biological water quality in Bogota, Colombia is presented 28 sites corresponding to 9 watersheds in the Bogota area were used. The organisms selected were: Leptoceridae and Hidrobiosidae as indicators of dean waters, Planariidae and Amphipoda as indicators of polluted waters and Psychodida and Syrphidae as indicators of highly polluted waters Chironomids were also included. In order to prove the degree of reliability of Sugeno-type fuzzy logic, the results obtained were compared with values for the Cfq index, and a highly significant correlation was obtained.

  16. Group-specific multiplex PCR detection systems for the identification of flying insect prey.

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    Daniela Sint

    Full Text Available The applicability of species-specific primers to study feeding interactions is restricted to those ecosystems where the targeted prey species occur. Therefore, group-specific primer pairs, targeting higher taxonomic levels, are often desired to investigate interactions in a range of habitats that do not share the same species but the same groups of prey. Such primers are also valuable to study the diet of generalist predators when next generation sequencing approaches cannot be applied beneficially. Moreover, due to the large range of prey consumed by generalists, it is impossible to investigate the breadth of their diet with species-specific primers, even if multiplexing them. However, only few group-specific primers are available to date and important groups of prey such as flying insects have rarely been targeted. Our aim was to fill this gap and develop group-specific primers suitable to detect and identify the DNA of common taxa of flying insects. The primers were combined in two multiplex PCR systems, which allow a time- and cost-effective screening of samples for DNA of the dipteran subsection Calyptratae (including Anthomyiidae, Calliphoridae, Muscidae, other common dipteran families (Phoridae, Syrphidae, Bibionidae, Chironomidae, Sciaridae, Tipulidae, three orders of flying insects (Hymenoptera, Lepidoptera, Plecoptera and coniferous aphids within the genus Cinara. The two PCR assays were highly specific and sensitive and their suitability to detect prey was confirmed by testing field-collected dietary samples from arthropods and vertebrates. The PCR assays presented here allow targeting prey at higher taxonomic levels such as family or order and therefore improve our ability to assess (trophic interactions with flying insects in terrestrial and aquatic habitats.

  17. Indirect effects of bioinsecticides on the nontarget fauna: The Camargue experiment calls for future research

    Science.gov (United States)

    Poulin, Brigitte

    2012-10-01

    Following its high selectivity and low toxicity to nontarget organisms, Bacillus thuringiensis var. israelensis (Bti) has become the most commonly used microbial agent to control mosquitoes worldwide. Considered non-toxic to mammals, birds, fish, plants and most aquatic organisms, Bti direct effects on the nontarget fauna are largely limited to non-biting midges (Chironomidae). Studies addressing the indirect effects of Bti through food web perturbations are scanty and showed no significant results. Mosquito-control in southern France was implemented in 1965 using various insecticides over 400 km of coast. In spite of a high mosquito nuisance, the Camargue wetlands were excluded from this control programme to preserve biodiversity. The expanding use of Bti has prompted the implementation of an experimental mosquito control in 2006 involving 2500 of the 25,000 ha of larval biotopes of the Camargue, accompanied by impact studies on the nontarget fauna. Using birds from natural and human-inhabited areas as model species, we assessed trophic perturbations caused by three years of Bti applications. The preliminary results of this 5-yr programme revealed significant effects of Bti spraying on abundance of reed-dwelling invertebrates serving as food to passerines, as well as on the diet and breeding success of house martins nesting in rural estates and small towns. Very few studies (if any) have provided such compelling evidence of an insecticide affecting vertebrate populations, putting into question the environmental-friendly character of Bti, at least in some areas. The significance of these results are discussed within a wider context and completed with an analysis of the current Bti bibliography to highlight and orient priorities for future research on this topic.

  18. Results of Macroinvertebrate Sampling Conducted at 33 SRS Stream Locations, July--August 1993

    Energy Technology Data Exchange (ETDEWEB)

    Specht, W.L.

    1994-12-01

    In order to assess the health of the macroinvertebrate communities of SRS streams, the macroinvertebrate communities at 30 stream locations on SRS were sampled during the summer of 1993, using Hester-Dendy multiplate samplers. In addition, three off-site locations in the Upper Three Runs drainage were sampled in order to assess the potential for impact from off-site activities. In interpreting the data, it is important to recognize that these data were from a single set of collections. Macroinvertebrate communities often undergo considerable temporal variation, and are also greatly influenced by such factors as water depth, water velocity, and available habitat. These stations were selected with the intent of developing an on-going sampling program at a smaller number of stations, with the selection of the stations to be based largely upon the results of this preliminary sampling program. When stations within a given stream showed similar results, fewer stations would be sampled in the future. Similarly, if a stream appeared to be perturbed, additional stations or chemical analyses might be added so that the source of the perturbation could be identified. In general, unperturbed streams will contain more taxa than perturbed streams, and the distribution of taxa among orders or families will differ. Some groups of macroinvertebrates, such as Ephemeroptera (mayflies), Plecoptera (stoneflies) and Trichoptera (caddisflies), which are collectively called EPT taxa, are considered to be relatively sensitive to most kinds of stream perturbation; therefore a reduced number of EPT taxa generally indicates that the stream has been subject to chemical or physical stressors. In coastal plain streams, EPT taxa are generally less dominant than in streams with rocky substrates, while Chironomidae (midges) are more abundant. (Abstract Truncated)

  19. Benthic Macro-Fauna Composition and Abundance in Sombreiro River, Niger Delta, Nigeria

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    E.N. Ezekiel

    2011-04-01

    Full Text Available The benthic macro-fauna composition and abundance in sombreiro was studied for a period of two years (August 2007 - July2009. A total of twenty-eight species belonging to fourteen (14 families, six (6 classes and three (3 phyla were recorded in Sombreiro River. The phylum Annelida dominated with two classes (Oligochaeta and Polychaeta. Oligochaeta was represented by two families (Naididae and Lumbricidae and seven species having 25% by composition. Polychaeta was represented by seven families (Nereidae, Nepthyidae, Capitellidae, Eucinidae, Glyceridae, Arenicolidae and Syllidae and thirteen species having 46.4% by composition. The Phylum arthropoda was represented by two classes (Crustacea and inseita. Two families (Gammaridae and Penaidae having two species consisting of 7.2% were recorded, for the class crustacea. The class insecta was represented by one family (Chironomidae with one species consisting of 3.6%. The phylum Mollusca was represented by two classes (Gastropoda and Bivalvia. Gastropoda had two species with 7.2% composition and Bivalvia has three species with10.7% composition. Oligochaeta was the highest and constituted 62.0%. The others were Polychaeta (23.9%, Insecta (6.7%, Gastropoda (3.9%, Bivalvia (2.2% and Crustacea (1.3%. The mean diversity(S ranged between 11 species. Mean abundance of individuals (N was 985. Mean Margalef index (d value was 1.339. The mean value for Shannon-Wienner (H was 0.956. Mean Pielou’s index of relative density or evenness index (E was 0.986. Mean SimpsIn’s Dominance index (C was 0.623.

  20. Taphonomy of the fossil insects of the middle Eocene Kishenehn Formation

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    Dale E. Greenwalt

    2015-12-01

    Full Text Available The lacustrine oil shales of the Coal Creek Member of the Kishenehn Formation in northwestern Montana comprise a relatively unstudied middle Eocene fossil insect locality. Herein, we detail the stratigraphic position of the fossiliferous unit, describe the insect fauna of the Coal Creek locality and document its bias towards very small but remarkably pre-served insects. In addition, the depositional environment is examined and the mineral constituents of the laminations that comprise the varves of the Kishenehn oil shale are defined. Fifteen orders of insects have been recorded with the majority of all insects identified as aquatic with the families Chironomidae (Diptera and Corixidae (Hemiptera dominant. The presence of small aquatic insects, many of which are immature, the intact nature of >90% of the fossil insects and the presence of Daphnia ephippia, all indicate that the depositional environment was the shallow margin of a large freshwater lake. The fossil insects occur within fossilized microbial mat layers that comprise the bedding planes of the oil shale. Unlike the fossiliferous shales of the Florissant and Okanagan Highlands, the mats are not a product of diatomaceous algae nor are diatom frustules a component of the sediments or the varve structure. Instead, the varves are composed of very fine eolian siliciclastic silt grains overlaid with non-diatomaceous, possibly cyanobacteria-derived microbial mats which contain distinct traces of polyaromatic hydrocarbons. A distinct third layer composed of essentially pure calcite is present in the shale of some exposures and is presumably derived from the seasonal warming-induced precipitation of carbonate from the lake’s waters. The Coal Creek locality presents a unique opportunity to study both very small middle Eocene insects not often preserved as compression fossils in most Konservat-Lagerstätte and the processes that led to their preservation.

  1. Selenium in aquatic biota inhabiting agricultural drains in the Salton Sea Basin, California

    Science.gov (United States)

    Saiki, Michael K.; Martin, Barbara A.; May, Thomas W.

    2012-01-01

    Resource managers are concerned that water conservation practices in irrigated farmlands along the southern border of the Salton Sea, Imperial County, California, could increase selenium concentrations in agricultural drainwater and harm the desert pupfish (Cyprinodon macularius), a federally protected endangered species. As part of a broader attempt to address this concern, we conducted a 3-year investigation to collect baseline information on selenium concentrations in seven agricultural drains inhabited by pupfish. We collected water, sediment, selected aquatic food-chain taxa (particulate organic detritus, filamentous algae, net plankton, and midge [Chironomidae] larvae), and two poeciliid fishes (western mosquitofish Gambusia affinis and sailfin molly Poecilia latipinna) for selenium determinations. The two fish species served as ecological surrogates for pupfish, which we were not permitted to sacrifice. Dissolved selenium ranged from 0.70 to 32.8 μg/L, with selenate as the major constituent. Total selenium concentrations in other environmental matrices varied widely among drains, with one drain (Trifolium 18) exhibiting especially high concentrations in detritus, 5.98–58.0 μg Se/g; midge larvae, 12.7–50.6 μg Se/g; mosquitofish, 13.2–20.2 μg Se/g; and mollies, 12.8–30.4 μg Se/g (all tissue concentrations are based on dry weights). Although toxic thresholds for selenium in fishes from the Salton Sea are still poorly understood, available evidence suggests that ambient concentrations of this element may not be sufficiently elevated to adversely affect reproductive success and survival in selenium-tolerant poeciliids and pupfish.

  2. Benthic macroinvertebrates as bioindicators of water quality in an Atlantic forest fragment

    Directory of Open Access Journals (Sweden)

    Augusto Oliveira

    2010-12-01

    Full Text Available The objective of this study was to evaluate benthic macroinvertebrate communities as bioindicators of water quality in five streams located in the "Reserva Particular do Patrimônio Natural" (RPPN Mata Samuel de Paula and its surroundings, in the municipality of Nova Lima near the city of Belo Horizonte, Minas Gerais State, southeastern Brazil. This region has been strongly modified by human activities including mining and urbanization. Samples were collected in the field every three months between August 2004 and November 2005, totaling six samplings in the rainy and dry seasons. This assessment identified one area ecologically altered while the other sampling sites were found to be minimally disturbed systems, with well-preserved ecological conditions. However, according to the Biological Monitoring Work Party (BMWP and the Average Score Per Taxon (ASPT indices, all sampling sites had excellent water quality. A total of 14,952 organisms was collected, belonging to 155 taxa (148 Insecta, two Annelida, one Bivalvia, one Decapoda, one Planariidae, one Hydracarina, and one Entognatha. The most abundant benthic groups were Chironomidae (47.9%, Simuliidae (12.3%, Bivalvia (7.5%, Decapoda (6.1%, Oligochaeta (5.2%, Polycentropodidae (3.7%, Hydropsychidae (2.5%, Calamoceratidae (1.8%, Ceratopogonidae (1.7%, and Libellulidae (1.2%. The assessment of the benthic functional feeding groups showed that 34% of the macroinvertebrates were collector-gatherers, 29% predators, 24% collector-filterers, 8% shredders, and 5% scrapers. The RPPN Mata Samuel de Paula comprises diversified freshwater habitats that are of great importance for the conservation of many benthic taxa that are intolerant to organic pollution.

  3. EVALUACIÓN DE COMUNIDADES DE MACROINVERTEBRADOS ASOCIADOS A TRES ESPECIES DE MACRÓFITAS ACUÁTICAS EN LA LAGUNA DE MORONACOCHA, IQUITOS

    Directory of Open Access Journals (Sweden)

    Zoila Perea Saavedra

    2011-12-01

    Full Text Available El objetivo fue evaluar la riqueza y abundancia de macroinvertebrados acuáticos asociados a tres especies de macrófitas acuáticas del Lago Moronacocha. Los muestreos se realizaron entre los meses de mayo y julio del 2009; se realizaron colectas mensuales de 27 muestras de cada macrófita, tomándose adicionalmente medidas de parámetros fisicoquímicos: temperatura, oxígeno y pH. Las muestras de Pistia stratiotes (huama y Echinocloa crassipes (putu putu, fueron colectadas con una red de bentos (20 x 30 cm y 180 µm de abertura de malla, mientras que los ejemplares de Echinocloa polystachya (gramalote fueron colectados manualmente.No se encontraron diferencias estadísticas significativas en cuanto la riqueza y abundancia entre las tres macrófitas  evaluadas (P>0.05. Se encontró una abundancia de 1538 individuos, siendo las familias más abundantes en la colecta: Chironomidae, Noteridae y Haplotaxidae, siendo además Hydrophilidae, Elmidae y Planorbidae abundantes solo para Pistia stratiotes. De las 31 familias reportadas en este estudio, 17 estuvieron presentes en las tres macrófitas evaluadas.  Los valores promedio de T° (26,4 °C y pH (6,7 registrados se encontraron dentro de los límites adecuados. Concluyendo que la composición de macroinvertebrados acuáticos en el Lago Moronacocha, no está influenciada por el tipo de macrófita que existe en ella.

  4. Lake to land subsidies: experimental addition of aquatic insects increases terrestrial arthropod densities.

    Science.gov (United States)

    Hoekman, David; Dreyer, Jamin; Jackson, Randall D; Townsend, Philip A; Gratton, Claudio

    2011-11-01

    Aquatic insects are a common and important subsidy to terrestrial systems, yet little is known about how these inputs affect terrestrial food webs, especially around lakes. Mývatn, a lake in northern Iceland, has extraordinary midge (Chironomidae) emergences that result in large inputs of biomass and nutrients to terrestrial arthropod communities. We simulated this lake-to-land resource pulse by collecting midges from Mývatn and spreading their dried carcasses on 1-m2 plots at a nearby site that receives very little midge deposition. We hypothesized a positive bottom-up response of detritivores that would be transmitted to their predators and would persist into the following year. We sampled the arthropod community once per month for two consecutive summers. Midge addition resulted in significantly different arthropod communities and increased densities of some taxa in both years. Detritivores, specifically Diptera larvae, Collembola, and Acari increased in midge-addition plots, and so did some predators and parasitoids. Arthropod densities were still elevated a year after midge addition, and two years of midge addition further increased the density of higher-order consumers (e.g., Coleoptera and Hymenoptera). Midge addition increased arthropod biomass by 68% after one year and 108% after two years. By manipulating the nutrient pulse delivered by midges we were able to elucidate food web consequences of midge deposition and spatial and temporal dynamics that are difficult to determine based on comparative approaches alone. Resources cross ecosystem boundaries and are assimilated over time because of life-history strategies that connect aquatic and terrestrial food webs and these systems cannot be fully understood in isolation from each other.

  5. Selenium in aquatic biota inhabiting agricultural drains in the Salton Sea Basin, California.

    Science.gov (United States)

    Saiki, Michael K; Martin, Barbara A; May, Thomas W

    2012-09-01

    Resource managers are concerned that water conservation practices in irrigated farmlands along the southern border of the Salton Sea, Imperial County, California, could increase selenium concentrations in agricultural drainwater and harm the desert pupfish (Cyprinodon macularius), a federally protected endangered species. As part of a broader attempt to address this concern, we conducted a 3-year investigation to collect baseline information on selenium concentrations in seven agricultural drains inhabited by pupfish. We collected water, sediment, selected aquatic food-chain taxa (particulate organic detritus, filamentous algae, net plankton, and midge [Chironomidae] larvae), and two poeciliid fishes (western mosquitofish Gambusia affinis and sailfin molly Poecilia latipinna) for selenium determinations. The two fish species served as ecological surrogates for pupfish, which we were not permitted to sacrifice. Dissolved selenium ranged from 0.70 to 32.8 μg/L, with selenate as the major constituent. Total selenium concentrations in other environmental matrices varied widely among drains, with one drain (Trifolium 18) exhibiting especially high concentrations in detritus, 5.98-58.0 μg Se/g; midge larvae, 12.7-50.6 μg Se/g; mosquitofish, 13.2-20.2 μg Se/g; and mollies, 12.8-30.4 μg Se/g (all tissue concentrations are based on dry weights). Although toxic thresholds for selenium in fishes from the Salton Sea are still poorly understood, available evidence suggests that ambient concentrations of this element may not be sufficiently elevated to adversely affect reproductive success and survival in selenium-tolerant poeciliids and pupfish.

  6. 20th century human pressures drive reductions in deepwater oxygen leading to losses of benthic methane-based food webs

    Science.gov (United States)

    Belle, Simon; Millet, Laurent; Verneaux, Valérie; Lami, Andrea; David, Etienne; Murgia, Laurie; Parent, Claire; Musazzi, Simona; Gauthier, Emilie; Bichet, Vincent; Magny, Michel

    2016-04-01

    Freshwater lakes play a key role in the global carbon cycle as sinks (organic carbon sequestration) and sources (greenhouse gas emissions). Understanding the carbon cycle response to environmental changes is becoming a crucial challenge in the context of global warming and the preponderance of human pressures. We reconstructed the long-term (1500 years) evolution of trophic functioning of the benthic food web, based on methanotrophic ancient DNA and chironomid isotope analyses). In addition, human land use is also reconstructed in three different lakes (eastern France, Jura Mountains). Our findings confirm that the benthic food web can be highly dependent on methane-derived carbon (up to 50% of the chironomid biomass) and reveal that the activation of this process can correspond to a natural functioning or be a consequence of anthropic perturbation. The studied lakes also showed a similar temporal evolution over the last century with the disappearance of the profundal aquatic insects (Chironomidae, Diptera), considered as keystone for the whole lake food web (e.g., coupling benthic-pelagic), inducing a potential collapse in the transfer of methane to top consumers. This functional state, also called the dead zone expansion, was caused by the change in human land-use occurring at the beginning of the 20th century. The strong modification of agro-pastoral practices (e.g., fertilization practices, intensive grazing, and sewage effluent) modified the influx of nutrients (by diffuse and/or point-source inputs) and induced a significant increase in the trophic status and organic matter sedimentation to reach unprecedented values. Further studies should be planned to assess dead zone expansion and, according to the regime shift theory, to provide environmental tipping points for sustainable resource management.

  7. Landuse legacies and small streams: Identifying relationships between historical land use and contemporary stream conditions

    Science.gov (United States)

    Maloney, K.O.; Feminella, J.W.; Mitchell, R.M.; Miller, S.A.; Mulholland, P.J.; Houser, J.N.

    2008-01-01

    The concept of landscape legacies has been examined extensively in terrestrial ecosystems and has led to a greater understanding of contemporary ecosystem processes. However, although stream ecosystems are tightly coupled with their catchments and, thus, probably are affected strongly by historical catchment conditions, few studies have directly examined the importance of landuse legacies on streams. We examined relationships between historical land use (1944) and contemporary (2000-2003) stream physical, chemical, and biological conditions after accounting for the influences of contemporary land use (1999) and natural landscape (catchment size) variation in 12 small streams at Fort Benning, Georgia, USA. Most stream variables showed strong relationships with contemporary land use and catchment size; however, after accounting for these factors, residual variation in many variables remained significantly related to historical land use. Residual variation in benthic particulate organic matter, diatom density, % of diatoms in Eunotia spp., fish density in runs, and whole-stream gross primary productivity correlated negatively, whereas streamwater pH correlated positively, with residual variation in fraction of disturbed land in catchments in 1944 (i.e., bare ground and unpaved road cover). Residual variation in % recovering land (i.e., early successional vegetation) in 1944 was correlated positively with residual variation in streambed instability, a macroinvertebrate biotic index, and fish richness, but correlated negatively with residual variation in most benthic macroinvertebrate metrics examined (e.g., Chironomidae and total richness, Shannon diversity). In contrast, residual variation in whole-stream respiration rates was not explained by historical land use. Our results suggest that historical land use continues to influence important physical and chemical variables in these streams, and in turn, probably influences associated biota. Beyond providing insight

  8. Implementation of artificial neural networks (ANNs) to analysis of inter-taxa communities of benthic microorganisms and macroinvertebrates in a polluted stream.

    Science.gov (United States)

    Kim, Byunghyuk; Lee, Se-Eun; Song, Mi-Young; Choi, Jung-Hye; Ahn, Soon-Mo; Lee, Kun-Seop; Cho, Eungchun; Chon, Tae-Soo; Koh, Sung-Cheol

    2008-02-01

    This study was performed to gain an understanding of the structural and functional relationships between inter-taxa communities (macroinvertebrates as consumers, and microbes as decomposers or preys for the invertebrates) in a polluted stream using artificial neural networks techniques. Sediment samples, carrying microorganisms (eubacteria) and macroinvertebrates, were seasonally collected from similar habitats in streams with different levels of pollution. Microbial community taxa and densities were determined using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and 16S rDNA sequence analysis techniques. The identity and density of macroinvertebrates were concurrently determined. In general, differences were observed on grouping by self-organizing map (SOM) in polluted, clean and recovering sites based on the microbial densities, while the community patterns were partly dependent on the sampling period. A Spearman rank order correlation analysis revealed correlations of several eubacterial species with those of macroinvertebrates: a negative correlation was observed between Acidovorax sp. (from polluted sites) and Gammaridae (mostly from the clean site), while Herbaspirillum sp. and Janthinobacterium sp. appeared to have positive correlations with some macroinvertebrate species. The population dynamics of the tolerant texa, Tubificidae and Chironomidae, appeared to be related with changes in the densities of Acidovorax sp. This study revealed community relationships between macroinvertebrates and microorganisms, reflecting the connectivity between the two communities via the food chain. A further physio-ecological and symbiological study on the invertebrate-microorganism relationships will be required to understand the degradation and utilization of detritus in aquatic ecosystems as well as to elucidate the roles of the inter-taxa in the recovery of polluted aquatic environments.

  9. Habitat characteristics for different freshwater snail species as determined biologically through macroinvertebrate information.

    Science.gov (United States)

    El-Khayat, Hanaa M M; Mahmoud, Kadria M A; Mostafa, Bayomy B; Tantawy, Ahmad A; El-Deeb, Fatma A; Ragb, Fawzy M; Ismail, Nahed M; El-Said, Kalil M; Taleb, Hoda M Abu

    2011-12-01

    Macro-invertebrates including freshwater snails collected from 643 sites over 8 successive seasons among the River Nile, branches, main canals and certain drains in eight Egyptian Governorates. Thirteen snail species and one bivalve species were identified. The most distributed were Lanistus carinatus and Physa acuta while the most abundant were Cleopatra bulimoides and Physa acuta during the whole study. The sites that harbored each snail species in all the examined water-courses were grouped seasonally and their biological assessment was determined by their minimum and maximum total point similarity percentage to that of the corresponded reference site and mean of the total points. Habitats for most snail species attained minimum total point's similarity percentage less than 21% (very poor habitat) during autumn and winter then spring while during summer very poor habitat was harbored by only few snail species. P. acuta was the only survived snails in habitat which attained 0 as a minimum total point's similarity percentage during two seasons and L. carinatus and Succinea cleopatra during one season. With respect to medically important snails very poor sites constituted 23% of Biomphalaria alexandrina sites, 14% of Lymnaea natalensis and 9.4% of Bulinus truncatus sites. The studied macroinvertebrate matrices, total number of organisms, taxa richness, the Ephemeroptera, Plecoptera, and Trichoptera (EPT) index, ratio of EPT index to chironomidae, ratio of scraper to filtering collector, contribution of dominant macroinvertebrate major group, comparison revealed descending tolerances from B. alexanrina followed by L. natalensis then B. truncates, but Hilsenhoff Biotic Index (HBI) showed the same tolerance to organic pollution.

  10. Benthic fauna of extremely acidic lakes (pH 2-3)

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, G.G.

    2001-07-01

    The structure of the benthic invertebrate communities were investigated in terms of composition, abundance, and biomass from extremely acidic lakes with pH values from 2 to 3 in areas where coal was intensively mined in the Lusatian region in the eastern region of Germany. Benthic invertebrates colonisation on leaves and the breakdown rate processing of the three deciduous leaf: Betula pendula (birch), Fraxinus excelsior (ash), and Juglans regia (walnut) were investigated. Also, the main key-species of these acidic environments were investigated, in terms of description of pupal exuviae of Chironomus crassimanus and the feeding habit of this acid-resistant species through analysis of their gut content. The benthic food web in extremely acidic mining Lusatian lakes is very short in terms of species richness, trophic relationship, guilds and functional feeding groups. Collector-filters and scraper-grazers were absent in extremely acidic mining lakes (AML 107, AML 111 and AML 117). Shredders as Limnophyes minimus (Diptera, Chironomidae, Orthocladiinae) and Hydrozetes lacustris (Acari, Hydrozetidae) occurred in low abundance in AML 107 and AML 111, and it may be in response to slow leaf breakdown process in these ecosystems, except in AML 117 where the H. lacustris contributed most to ecosystems functioning via the processing of litter. Aquatic insects as Sialis lutaria (Megaloptera, Sialidae), Orectochilus villosus (Coleoptera, Gyrinidae), Coenagrion mercuriale (Odonata, Coenagrionidae), and Phryganeidae (Trichoptera) are the top-predators of these ecosystems. They did not depend on the level of pH in the lakes, but on the availability of food resources. (orig.)

  11. Response of benthic macroinvertebrate communities to highway construction in an Appalachian watershed

    Science.gov (United States)

    Hedrick, Lara B.; Welsh, S.A.; Anderson, James T.; Lin, L.-S.; Chen, Y.; Wei, X.

    2010-01-01

    Highway construction in mountainous areas can result in sedimentation of streams, negatively impacting stream habitat, water quality, and biotic communities. We assessed the impacts of construction of a segment of Corridor H, a four-lane highway, in the Lost River watershed, West Virginia, by monitoring benthic macroinvertebrate communities and water quality, before, during, and after highway construction and prior to highway use at upstream and downstream sites from 1997 through 2007. Data analysis of temporal impacts of highway construction followed a Before-After-Control-Impact (BACI) study design. Highway construction impacts included an increase in stream sedimentation during the construction phase. This was indicated by an increase in turbidity and total suspended solids. Benthic macroinvertebrate metrics indicated a community more tolerant during and after construction than in the period before construction. The percent of Chironomidae and the Hilsenhoff Biotic Index (HBI) increased, while percent of Ephemeroptera, Plecoptera, and Trichoptera (EPT) decreased. Our 10-year study addressed short-term impacts of highway construction and found that impacts were relatively minimal. A recovery of the number of EPT taxa collected after construction indicated that the benthic macroinvertebrate community may be recovering from impacts of highway construction. However, this study only addressed a period of 3 years before, 3 years during, and 4 years post construction. Inferences cannot be made concerning the long-term impacts of the highway, highway traffic, runoff, and other factors associated with highway use. Continual monitoring of the watershed is necessary to determine if the highway has a continual impact on stream habitat, water quality, and biotic integrity. ?? 2010 Springer Science+Business Media B.V.

  12. Copper, cadmium, and zinc concentrations in juvenile Chinook salmon and selected fish-forage organisms (aquatic insects) in the upper Sacramento River, California

    Science.gov (United States)

    Saiki, Michael K.; Martin, Barbara A.; Thompson, Larry D.; Walsh, Daniel

    2001-01-01

    This study assessed the downstream extent andseverity of copper (Cu), cadmium (Cd), and zinc (Zn)contamination from acid mine drainage on juvenile chinook salmon(Oncorhynchus tshawytscha) and aquatic insects over aroughly 270-km reach of the Sacramento River below KeswickReservoir. During April–May 1998, salmon were collected fromfour sites in the river and from a fish hatchery that receiveswater from Battle Creek. Salmon from river sites were examinedfor gut contents to document their consumption of variousinvertebrate taxa, whereas salmon from river sites and thehatchery were used for metal determinations. Midge(Chironomidae) and caddisfly (Trichoptera) larvae and mayfly(Ephemeroptera) nymphs were collected for metal determinationsduring April–June from river sites and from Battle and Buttecreeks. The fish hatchery and Battle and Butte creeks served asreference sites because they had no history of receiving minedrainage. Salmon consumed mostly midge larvae and pupae (44.0%,damp-dry biomass), caddisfly larvae (18.9%), Cladocera (5.8%),and mayfly nymphs (5.7%). These results demonstrated thatinsects selected for metal determinations were important as fishforage. Dry-weight concentrations of Cu, Cd, and Zn weregenerally far higher in salmon and insects from the river thanfrom reference sites. Within the river, high metalconcentrations persisted as far downstream as South Meridian (thelowermost sampling site). Maximum concentrations of Cd (30.7 μg g-1) and Zn (1230 μg g-1),but not Cu (87.4 μg g-1), in insects exceeded amounts that other investigators reported as toxic when fed for prolonged periods to juvenile salmonids.

  13. Hydroclimatic shifts recorded in peat archive from Rąbień mire (Central Poland) - better understanding of past climate changes using multidisciplinary approach

    Science.gov (United States)

    Słowiński, Michał; Marcisz, Katarzyna; Płóciennik, Mateusz; Obremska, Milena; Pawłowski, Dominik; Okupny, Daniel; Słowińska, Sandra; Borówka, Ryszard; Kittel, Piotr; Forysiak, Jacek; Michczyńska, Danuta J.; Lamentowicz, Mariusz

    2016-04-01

    Hydrological changes are main drivers of the processes occurring in the peatland ecosystem, e.g. organic matter accumulation and decomposition. Hydroclimatic changes in mires are caused by various non-climatic factors, such as hydroseral succession or land use changes. Central Europe, namely Poland, is characterized by a transitional climate with influence o both continental and Atlantic air masses, which makes a this region a very sensitive to climate change. Here we explore a potential of multidisciplinary approach in reconstruction of past climate change and particularly hydroclimatic conditions which control in Sphagnum peatland ecosystem. We reconstructed 3300 years (between 3,500 BC and 200 BC) history of development of Rąbień mire using several biotic proxies (pollen, plant macrofossils, testate amoebae, Cladocera, Chironomidae) and geochemistry. Study site - Rąbień mire (area 42 ha) is located in central Poland and it is protected nature reserve. The origin of the mire depression is connected with the development of the thermokarst basin isolated by dunes. Rąbień mire is limnogenic, i.e. formed by the process of terrestrialisation of a water body and thickness of biogenic deposits is 6.2 m (440 cm of lacustrine sediment and 180 cm of peat). Our results demonstrate the high potential of Rąbień peat record for reconstructing the palaeohydrological dynamics. The studied time interval is characterized by two pronounced dry periods: ~2,500 to ~1,700 cal. BC and ~800 to ~600 cal. BC, and two periods of significant increases in water table: ~1,100 to ~800 cal. BC and ~600 to ~250 cal. BC. The timing of the wet shift at 600 cal. BC corresponds to wet periods in different sites from Central and Eastern Europe. Our investigation reveals a complex pattern of proxies, what might be linked to the past atmospheric circulation patterns. Extreme hydroclimatic conditions most possibly had a direct impact on the functioning of peatland ecosystems. What has been

  14. Under siege: Isolated tributaries are threatened by regionally impaired metacommunities

    Energy Technology Data Exchange (ETDEWEB)

    Merriam, Eric R., E-mail: emerriam@mix.wvu.edu; Petty, J. Todd

    2016-08-01

    Pristine streams are often targeted as conservation priorities because of their ability to preserve regional biodiversity. However, isolation within heavily degraded regions likely alters important metapopulation and metacommunity processes (e.g., rescue and mass effects), affecting the ability of in-tact communities to boost regional conditions. To test this hypothesis, we sampled invertebrate communities and physicochemical conditions from 168 streams within the mountaintop removal-valley fill mining region of West Virginia. We used redundancy analysis to first test for significant effects of local (observed physicochemical conditions) and neighborhood (streams within a 5 km buffer) degradation on assemblage structure across all taxa and stress tolerance (low, moderate, high) and dispersal (low, high) categories. We then used generalized linear and hurdle models to characterize changes in community metrics and individual taxa, respectively. Local condition consistently explained the majority of variation (partial R{sup 2} up to 5 × those of neighborhood condition) in community structure and was the only factor affecting sensitive taxa. Neighborhood condition explained significant variation in moderately tolerant taxa with low dispersal capacity and highly tolerant taxa, regardless of dispersal. Decreased occurrence (Baetis) and abundance (Maccaffertium) of key taxa and corresponding metrics (%E, %EPT) suggest decreased dispersal and associated mass and rescue effects within degraded neighborhoods. Decreased neighborhood conditions also resulted in the proliferation of tolerant taxa (Chironomidae, Chimarra, Hemerodromia). Our results suggest communities within even the most pristine streams are at risk when isolated within heavily impacted regions. Consequently, protection of regional species' pools in heavily impacted regions will require more than simply conserving un-impacted streams. - Graphical abstract: In heavily degraded regions, even the most

  15. Drifting algal mats as an alternative habitat for benthic invertebrates: Species specific responses to a transient resource.

    Science.gov (United States)

    Norkko; Bonsdorff; Norkko

    2000-05-18

    Patchy occurrences of benthic drift algae (i.e. loose lying macroalgal mats) may increase habitat complexity on normally bare soft bottoms, but at the same time, extensive amounts of drifting algal mats are known to stress the benthic fauna. This paper presents results of the first detailed study of the fauna associated with drift algal mats in the northern Baltic Sea. In order to assess the importance of drifting algae as an alternative habitat for benthic fauna, benthic drift algal mats were sampled on shallow (2-9 m) sandy soft bottoms in the outer archipelago of the Åland Islands (Finland). Species composition, abundance and biomass of the macrofauna associated with algal mats were recorded. The results show that drifting algae at times can harbour very high abundances of invertebrates (up to 1116 individuals/g algal dryweight), surpassing invertebrate densities recorded in seagrass communities. The algal fauna varied between sites and over time, and factors such as ambient benthic fauna, exposure to wind-wave disturbance, depth, and algal coverage and condition influenced the invertebrate community composition of the algal mats. Abundance increased while individual biomass of the animals decreased over time (summer season; July-October). A series of laboratory experiments were conducted in order to test the ability of a few important benthic species to move up into, and survive in a drifting algal mat. Macoma balthica, Hydrobia spp., Nereis diversicolor and Bathyporeia pilosa were used in the experiments, and significant differences in their survival and mobility within drifting algae were recorded. This study shows that benthic species differ significantly in their ability to utilise the algal mats, with mainly opportunistic and mobile taxa such as Hydrobia spp., Chironomidae and Ostracoda benefiting from the algae, whereas infaunal species such as M. balthica and B. pilosa are negatively affected. The occurrence of eutrophication induced drifting macroalgal

  16. The food spectrum of the cardinal - tetra (Paracheirodon axelrodi, Characidae in its natural habitat Estratégias alimentares do cardinal-tetra (Paracheirodon axelrodi, Characidae em seu ambiente natural

    Directory of Open Access Journals (Sweden)

    Ilse Walker

    2004-01-01

    Full Text Available The cardinal tetra (Paracheirodon axelrodi is the most intensively commercialized ornamental fish from the Rio Negro Basin (Amazonas State, Brasil. Analysis of the stomach and gut contents of fish caught in their natural habitats show conclusively that the cardinal is essentially a predator, feeding on the mesofauna that adheres to submerged litter, roots and waterplants. Microcrustacea and chironomid larvae (Diptera were the most frequently ingested prey, while algae intake was relatively infrequent. It is argued that the relatively small size of the cardinals captured in their natural habitat is due to the annual migrations imposed by the inundation cycles, rather than to resource limitation, because it is known from earlier investigations of similar habitats, that these plant substrates are densely colonized by the aquatic mesofauna. Cardinals raised in captivity are larger and have higher rates of growth.O cardinal (Paracheirodon axelrodi é o peixe ornamental comercializado com maior intensidade na Bacia do Rio Negro (Estado do Amazonas, Brasil. Análise do conteúdo estomacal de peixes capturados nos seus habitats naturais mostra, que o cardinal é essencialmente um predador, alimentando-se da mesofauna que está colonizando a liteira submersa, arbustos submersos, raízes flutuantes e plantas aquáticas. As presas principais são microcrustáceos e larvas de quironomídeos (Chironomidae, Diptera, enquanto ingestão de algas é pouco freqüente. Considera-se que o tamanho relativamente pequeno de cardinais capturados nos ambientes naturais é devido as migrações anuais que acompanham os ciclos anuais de enchente e vazante, e não à falta de recursos; já que é conhecido de ambientes parecidos de outros rios da região, que estes substratos aquáticos são densamente colonizados pela mesofauna. Cardinais criados em cativeiros tem taxas de crescimento mais altas e são de tamanho maiores.

  17. Experimental acidification of two biogeochemically-distinct neotropical streams: Buffering mechanisms and macroinvertebrate drift

    Energy Technology Data Exchange (ETDEWEB)

    Ardón, Marcelo, E-mail: ardonsayaom@ecu.edu [Department of Biology and North Carolina Center for Biodiversity, East Carolina University, Greenville, NC 27858 (United States); Duff, John H. [U.S. Geological Survey, Menlo Park, CA 94025 (United States); Ramírez, Alonso [Department of Environmental Sciences, University of Puerto Rico, San Juan, PR 00931 (Puerto Rico); Small, Gaston E. [Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, MN 55108 (United States); Jackman, Alan P. [University of California, Davis, CA 95616 (United States); Triska, Frank J. [U.S. Geological Survey, Menlo Park, CA 94025 (United States); Pringle, Catherine M. [Odum School of Ecology, University of Georgia, Athens, GA 30602 (United States)

    2013-01-15

    Research into the buffering mechanisms and ecological consequences of acidification in tropical streams is lacking. We have documented seasonal and episodic acidification events in streams draining La Selva Biological Station, Costa Rica. Across this forested landscape, the severity in seasonal and episodic acidification events varies due to interbasin groundwater flow (IGF). Streams that receive IGF have higher concentrations of solutes and more stable pH (∼ 6) than streams that do not receive IGF (pH ∼ 5). To examine the buffering capacity and vulnerability of macroinvertebrates to short-term acidification events, we added hydrochloric acid to acidify a low-solute, poorly buffered (without IGF) and a high-solute, well buffered stream (with IGF). We hypothesized that: 1) protonation of bicarbonate (HCO{sub 3}{sup −}) would neutralize most of the acid added in the high-solute stream, while base cation release from the sediments would be the most important buffering mechanism in the low-solute stream; 2) pH declines would mobilize inorganic aluminum (Ali) from sediments in both streams; and 3) pH declines would increase macroinvertebrate drift in both streams. We found that the high-solute stream neutralized 745 μeq/L (96% of the acid added), while the solute poor stream only neutralized 27.4 μeq/L (40%). Protonation of HCO{sub 3}{sup −} was an important buffering mechanism in both streams. Base cation, Fe{sup 2+}, and Ali release from sediments and protonation of organic acids also provided buffering in the low-solute stream. We measured low concentrations of Ali release in both streams (2-9 μeq/L) in response to acidification, but the low-solute stream released double the amount Ali per 100 μeq of acid added than the high solute stream. Macroinvertebrate drift increased in both streams in response to acidification and was dominated by Ephemeroptera and Chironomidae. Our results elucidate the different buffering mechanisms in tropical streams and

  18. Ribosomal genes as early targets of cadmium-induced toxicity in Chironomus riparius larvae

    Energy Technology Data Exchange (ETDEWEB)

    Planello, R. [Biologia Ambiental, Facultad de Ciencias, Universidad Nacional de Educacion a Distancia, Senda del Rey 9, 28040, Madrid (Spain); Martinez-Guitarte, J.L. [Biologia Ambiental, Facultad de Ciencias, Universidad Nacional de Educacion a Distancia, Senda del Rey 9, 28040, Madrid (Spain); Morcillo, G. [Biologia Ambiental, Facultad de Ciencias, Universidad Nacional de Educacion a Distancia, Senda del Rey 9, 28040, Madrid (Spain)]. E-mail: gmorcillo@ccia.uned.es

    2007-02-01

    Cadmium is a widespread environmental pollutant that causes severe impacts in organisms. Although the effects of cadmium on aquatic insects have been studied in terms of their toxicity and changes in developmental parameters, little is known about its molecular and genetic effects. We have investigated the alterations in the pattern of gene expression provoked by acute exposure to cadmium in Chironomus riparius Mg. (Diptera, Chironomidae), a sentinel organism widely used in aquatic toxicity testing. The early cytotoxic effects were evaluated using immunocytochemistry and specific fluorescent probes in fourth instar larvae after 12 h of 10 mM cadmium treatments; under these conditions no significant effect on larvae mortality was detected until after 36 h of exposure. The changes in the pattern of gene expression were analysed by means of DNA/RNA hybrid antibodies in the polytene chromosomes from salivary gland cells. A decrease in the activity of the nucleolus is especially remarkable, accompanied by a significant reduction in size and the modification in nucleolar architecture, as shown by FISH. The inhibition of rDNA transcription was further evaluated by Northern blot analysis, which showed a marked decrease in the level of preribosomal rRNA (54% 45S 12 h). However, the BR genes, whose products are the giant polypeptides that constitute the silk-like secretion for constructing housing tubes, remain active. Simultaneously, decondensation and activation take place at some chromosomal regions, especially at the centromeres. The changes observed in the pattern of gene expression do not resemble those found after heat shock or other cell stressors. These data provide the first evidence that cadmium interacts with ribosomal genes and results in a drastic impairment of the functional activity of the nucleolus, an essential organelle for cellular survival. Therefore, the depletion of ribosomes would be a long-term effect of Cd-induced cellular damage. These findings may

  19. ASSESSMENT OF THE DEVELOPMЕNT OF POND FORAGE BASE WHEN REARING CARP (CYPRINUS CARPIO CARPIO FISH SEEDS AT FISH FARM «MERKURIY»

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    B. Grishin

    2015-09-01

    Full Text Available Purpose. To assess the development of main components of natural forage base in nursery ponds during the period of rearing the carp fish seeds in monoculture. Methodology. Hydrobiological (bacterioplankton, phytoplankton, zooplankton, zoobenthos and hydrochemical samples have been collected and processes according to generally accepted methods. Findings. Qualitative and quantitative parameters of the development of bacterio-, phyto-, zooplankton and zoobenthos in nursery ponds have been studied when rearing young-of-the-year Lubin few scale carp, Antoninsko-Zozulenets carp and their reciprocal crosses in monoculture (50 thousand fish/ha. General water mineralization in ponds was 292.7–315.7 mg/dm3 and according to O.A. Alekin’s classification, pond water belonged to hydrocarbonate class of calcium group. Water pH was 7.4–7.5. Permanganate values were 12.5–14.9 mgO/dm3. On average, average ammonium nitrogen content, nitrite nitrogen and nitrate nitrogen, mineral phosphorus, total iron did not exceed normative values. Qualitative and quantitative parameters of phyto-, bacterio-, zooplankton of nursery ponds have been studied. The seasonal development of phytoplankton was within 15.96–20.88 mg/dm3 with the predominance of Chlorococcales in the floristic spectrum. The development of bacterioplankton was within 5.08–5.81 mg/dm3. Zooplankton was dominated by cladoceran-copepod complex with average seasonal values of 5.27–17.20 g/m3. Zoobenthos was formed of Diptera larvae (Chironomidae and Chaoboridae with average seasonal biomasses of 0.51–1.8 g/m2. According to saprobic parameters, pond water belonged to β-mesosabrobic zone and corresponded to the water quality class II (“clean enough” category. Fish productivity of nursery ponds was within 617.2–815.2 kg/ha; output of carp young-of-the-year was within 39.82–43.56%, mean weight of young-of-the-year was 31.0–39.3 g. Originality. For the first time we carried out a

  20. The invasive Chinese pond mussel Sinanodonta woodiana (Lea, 1834 as a host for native symbionts in European waters

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    Anna Cichy

    2016-01-01

    Full Text Available Biological invasions are commonly observed in both the natural habitats and those which are altered by human activities. An understanding of the mechanisms involved in the successful introduction, establishment and invasion of exotic taxa is essential in predicting of changes in biodiversity and community structure. Symbiont-mediated interactions between exotic and native hosts are of special interest due to the indirect effects on population dynamics. The aim of this study was to estimate the presence of symbionts in Chinese pond mussel Sinanodonta woodiana (Lea, 1834, an exotic species of mussel in European fresh waters. The number of 340 individuals of S. woodiana was collected from Polish water bodies, including thermally heated lakes and fish ponds with natural thermal regime. The examination of mussels revealed the presence of Rhipidocotyle campanula sporocysts and cercariae (Digenea: Bucephalidae, water mites Unionicola ypsilophora (Acari: Hydracarina, oligochaetes Chaetogaster limnaei limnaei (Oligochaeta: Naididae and chironomids Glyptotendipes sp. (Diptera: Chironomidae. The global prevalence of mussels inhabited by Ch. limnaei limnaei was 7.6%, by water mites and chironomids 3.5%, and by R. campanula cercariae 2.0%. The significant difference in the number of mussels with symbionts was identified between heated lakes and fish ponds (χ2=4.15; df=1, P=0.04, with a higher global prevalence of mussels in fish ponds (22.3% compared to heated lakes (13.7%. R. campanula or U. ypsilophora were only found in mussels collected from thermally polluted lakes or fish ponds, respectively. Chironomid larvae and oligochaetes occurred in both types of water bodies. However, Glyptotendipes sp. inhabited mussels with a higher global prevalence in fish ponds than in thermally polluted lakes, while Ch. limnaei limnaei was observed mainly in hosts from heated lakes, and only from one fish pond that were not drained. Our findings indicate that the alien

  1. 上海苏州河大型底栖动物的研究%A study on macro-invertebrate of the Suzhou River, Shanghai.

    Institute of Scientific and Technical Information of China (English)

    刘国才; 赖伟; 殷浩文; 顾福康

    2001-01-01

    苏州河白鹤至浙江路段6个采样断面大型底栖动物隶属于环节动物门(Annelida)、软体动物门(Mollusca)及节肢动物门(Arthropoda).其中寡毛纲(Oligochaeta)4种、蛭纲(Hirudinea)2种、腹足纲(Gastropoda)5种、双壳纲(Bivalvia)2种及昆虫纲摇蚊科幼虫(Chironomidae)与潜蝇蛹(Agromyzigae)(未定种).随着底质污染的加重,群落结构趋于简化.种类少、高度耐污是存活大型底栖动物的显著特点.从白鹤至华槽断面,高度耐污的霍甫水丝蚓(Limnodrilus hoffmeisteri)数量趋于增加,并在华槽断面形成明显数量高峰;北新泾、武宁路河段底质污染严重,环节动物、软体动物消失;浙江路断面受黄浦江"逆流"影响,寡毛纲动物再度出现,并形成一定数量.%Macro-invertebrate from Annelida, Mollusca and Arthropoda were found in six sections from Baihe to Zhejiang road in the Suzhou River, among which four species were from Oligochaeta, two species from Hirudinea, five species from Gastropoda, two species from Bivalvia and several species from Insecta (unidentified). The community structure of macro-invertebrates became simple with the sediment pollution getting heavier. Limited species with high pollution resistibility were the characteristics of the species survival. The amounts of Limnodrilus hoffmeisteri with high pollution resistibility increased gradually from Baihe to Huacao section, and reached a peak in Huacao section; species from An-nelida, Mollusca were not found in Beixinjing and Wuninglu sections due to heavy sediment pollution; species from Oli-gochaeta were found again and had certain numbers in Zhejiang road section as the result of the effect of courterflow of the Huangpu River.

  2. Avaliação da comunidade de macroinvertebrados aquáticos como ferramenta para o monitoramento de um reservatório na bacia do rio Pitangui, Paraná, Brasil

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    Ivana F Barbola

    2011-06-01

    Full Text Available Os macroinvertebrados bentônicos e nectônicos representam elementos importantes na estrutura e funcionamento dos ecossistemas aquáticos e sua distribuição é influenciada pela natureza química do substrato, composição da vegetação e profundidade da lâmina d'água. O conhecimento desta fauna contribui para a avaliação da qualidade da água e a elaboração de ações visando à conservação da biodiversidade. No presente estudo foram avaliadas diferentes medidas bióticas da comunidade de invertebrados da represa de Alagados, importante manancial da cidade de Ponta Grossa, no Paraná. Em cinco diferentes pontos de amostragem, foram coletados 18.473 exemplares de macroinvertebrados aquáticos ou semi-aquáticos, pertencentes a 46 táxons dos filos Annelida (Hirudinea e Oligochaeta, Mollusca (Gastropoda, Platyhelminthes (Turbellaria, Nematoda e Arthropoda (Arachnida, Crustacea e Insecta. Esta comunidade foi constituída predominantemente por organismos predadores (45,7% dos táxons amostrados, seguidos de coletores e/ou filtradores (23,9%; raspadores (15,2%, fragmentadores (13% e detritívoros (2,2%. De modo geral, os índices de diversidade (H' e equitabilidade (J foram significativamente baixos para os cinco locais investigados, com H' variando de 0,3301 a 1,0396. Quanto à tolerância dos organismos à poluição orgânica, alguns táxons mais sensíveis foram muito raros (Plecoptera ou em baixa frequência (Trichoptera e Ephemeroptera. Entre os grupos mais resistentes a ambientes poluídos estão os Chironomidae e os Hirudinea, ambos bastante comuns nas amostras de Alagados. Este estudo reforça a importância da análise de bioindicadores na avaliação da qualidade de água para consumo humano e também para a conservação de ecossistemas, considerando que um programa de monitoramento ambiental deve integrar medidas físicas, químicas e biológicas.

  3. Avaliação rápida da integridade ecológica em riachos urbanos na bacia do rio Corumbá no Centro-Oeste do Brasil

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    Giovanna Gomes Cordeiro

    2016-06-01

    Full Text Available A urbanização tem ocasionado o lançamento de volumes significativos de efluentes domésticos parcialmente tratados nos corpos hídricos brasileiros causando diversos prejuízos ecológicos para estes ecossistemas. Para avaliar a integridade ecológica de riachos na região de Cerrado do Brasil Central foram selecionados quatro pontos de coleta, considerando o nível de influência antrópica ao qual estão submetidos. Foram analisados parâmetros físicos e químicos da água, o uso da paisagem e a comunidade de macroinvetebrados bentônicos. As coletas foram realizadas em julho de 2015 e foram mensuradas "in situ" as variáveis condutividade elétrica, temperatura da água, pH, oxigênio dissolvido, turbidez, largura e comprimento do riacho e velocidade da correnteza. Em seguida, foram coletadas amostras para o seston, perifíton, macroinvertebrados bentônicos e sedimento depositado. O ponto "Referência" apresentou menor abundância de larvas de Chironomus (Chironomidae: Diptera e maior riqueza taxonômica, além de maior abundância dos grupos taxonômicos Ephemeroptera, Plecoptera e Trichoptera, mostrando ser o sistema mais íntegro dentre os analisados. A sub-bacia delimitada a partir desse ponto mostrou uma maior porcentagem de áreas com vegetação nativa (51%. Os pontos com presença de efluentes domésticos ("ETE" e "Jusante" por sua vez, apresentaram valores mais elevados de condutividade elétrica, turbidez, maior abundância de larvas de Chironomus e menor riqueza de táxons, mostrando elevado impacto em função das atividades antrópicas. A avaliação rápida realizada com a composição da comunidade bentônica e as variáveis físicas e químicas da água foi suficiente na identificação das alterações na integridade ecológica causadas pela influência antrópica na bacia hidrográfica do rio Corumbá.

  4. Insect-Based Holocene (and Last Interglacial?) Paleothermometry from the E and NW Greenland Ice Sheet Margins: A Fly's-Eye View of Warmth on Greenland

    Science.gov (United States)

    Axford, Y.; Bigl, M.; Carrio, C.; Corbett, L. B.; Francis, D. R.; Hall, B. L.; Kelly, M. A.; Levy, L.; Lowell, T. V.; Osterberg, E. C.; Richter, N.; Roy, E.; Schellinger, G. C.

    2013-12-01

    Here we present new paleotemperature reconstructions based upon insect (Chironomidae) assemblages and other proxies from lake sediment cores recovered in east Greenland at ~71° N near Scoresby Sund and in northwest Greenland at ~77° N near Thule/Qaanaaq. In east Greenland, Last Chance Lake (informal name) is a small, non-glacial lake situated ~90 km east of the Greenland Ice Sheet margin. The lake preserves a sedimentary record of the entire Holocene (Levy et al. 2013). Chironomids from Last Chance Lake record cold summer temperatures (and establishment of a cold-climate fauna including abundant Oliveridia and Pseudodiamesa) during the late Holocene, preceded by summer temperatures estimated to have been 3 to 6°C warmer during the first half of the Holocene (when summer insolation forcing was greater than today). In northwest Greenland, Delta Sø and Wax Lips Lake (informal name) both preserve Holocene sediments. Here we discuss the late Holocene chironomid record from Delta Sø, whereas from Wax Lips Lake (a small, non-glacial lake situated ~2 km west of the ice sheet margin) we present a longer sedimentary and biostratigraphic record. The deeper portions of cores from Wax Lips Lake yield pre-Holocene and nonfinite radiocarbon ages, suggesting that this lake preserves sediments predating the Last Glacial Maximum. Abundant chironomids in the pre-glacial sediments appear to record interglacial conditions, and we infer that these sediments may date to the Last Interglacial (Eemian). The preservation of in situ Last Interglacial lacustrine sediments so close to the modern ice sheet margin suggests a minimally erosive glacierization style throughout the last glacial period, like that inferred for other Arctic locales such as on Baffin Island (Briner et al. 2007), ~750 km southwest of our study site. Our study sites are situated nearby key ice core sites (including NEEM, Camp Century, Agassiz and Renland) and very close to the ice sheet margin. These chironomid

  5. Ecosystem ecology meets adaptive management: food web response to a controlled flood on the Colorado River, Glen Canyon

    Science.gov (United States)

    Cross, Wyatt F.; Baxter, Colden V.; Donner, Kevin C.; Rosi-Marshall, Emma J.; Kennedy, Theodore A.; Hall, Robert O.; Wellard Kelly, Holly A.; Rogers, R. Scott

    2011-01-01

    Large dams have been constructed on rivers to meet human demands for water, electricity, navigation, and recreation. As a consequence, flow and temperature regimes have been altered, strongly affecting river food webs and ecosystem processes. Experimental high-flow dam releases, i.e., controlled floods, have been implemented on the Colorado River, USA, in an effort to reestablish pulsed flood events, redistribute sediments, improve conditions for native fishes, and increase understanding of how dam operations affect physical and biological processes. We quantified secondary production and organic matter flows in the food web below Glen Canyon dam for two years prior and one year after an experimental controlled flood in March 2008. Invertebrate biomass and secondary production declined significantly following the flood (total biomass, 55% decline; total production, 56% decline), with most of the decline driven by reductions in two nonnative invertebrate taxa, Potamopyrgus antipodarum and Gammarus lacustris. Diatoms dominated the trophic basis of invertebrate production before and after the controlled flood, and the largest organic matter flows were from diatoms to the three most productive invertebrate taxa (P. antipodarum, G. lacustris, and Tubificida). In contrast to invertebrates, production of rainbow trout (Oncorhynchus mykiss) increased substantially (194%) following the flood, despite the large decline in total secondary production of the invertebrate assemblage. This counterintuitive result is reconciled by a post-flood increase in production and drift concentrations of select invertebrate prey (i.e., Chironomidae and Simuliidae) that supported a large proportion of trout production but had relatively low secondary production. In addition, interaction strengths, measured as species impact values, were strongest between rainbow trout and these two taxa before and after the flood, demonstrating that the dominant consumer—resource interactions were not

  6. Caracterización de la artropofauna terrestre del humedal Jaboque (Bogotá, Colombia

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    Amat García Germán

    2005-07-01

    Full Text Available En el humedal Jaboque, se estudió la diversidad y la estructura trófica de la artropofauna asociada a las comunidades de vegetación Juncus effusus, Juncus effusus-Polygonum punctatum, Schoenoplectus californicus y Typha latifolia. La composición y riqueza asociada a la comunidad Bidens laevis y la composición de los insectos antófilos relacionados a algunas plantas. Se identificaron en total 212 morfoespecies, distribuidas en 48 familias y siete órdenes. A lo largo del estudio se colectaron 8.944 individuos que presentan una biomasa seca de 9757,8 mg. El órden Diptera y sus familias
    Ephydridae, Chironomidae y Muscidae son taxas, con predominio a nivel de riqueza, abundancia y biomasa. Entre las comunidades de vegetación consideradas se aprecia una artropofauna variable en composición, diversidad de morfoespecies y diversidad trófica. Se encontraron seis tipos
    de patrones de distribución, con familias especialistas en cuanto a la selección de hábitats y con valores de abundancia relativa global bajos (0–1% hasta familias generalistas en cuanto a selección de hábitats (4–5 comunidades de vegetación y con valores de abundancia relativa altos
    (>5%. Se encontró un total de 16 morfoespecies de insectos presentando contenido polínico. Estas morfoespecies pertenecen a las familias Muscidae, Syrphidae, Dolichopodidae, Tephritidae, Tipulidae, Sciaridae, Heleomyzidae, Sciomyzidae y Chrysomelidae. Los dípteros y sus familias Muscidae y Syrphidae registraron las mayores riquezas de morfoespecies, abundancias, número de familias vegetales visitadas, además de demostrar una alta capacidad de movilidad. Las compuestas con estrategia de polinización entomófila y las gramíneas con estrategia anemófila presentaron las mayores riquezas de insectos visitantes florales.

  7. Survival strategies of freshwater insects in cold environments

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    Valeria LENCIONI

    2004-09-01

    literature regarding adaptation strategies in aquatic insects is presented, highlighting the scarcity of information on freshwater insects from Alpine regions. Most references are on Diptera Chironomidae from North America and North Europe. Some recent findings on aquatic insects from Italian Alpine streams are also presented.

  8. Macroinvertebrates as tadpole food: importance and body size relationships Macroinvertebrados como alimento de girinos: importância e relações com tamanho de corpo

    Directory of Open Access Journals (Sweden)

    Silvia L. Dutra

    2005-12-01

    Full Text Available Macroinvertebrates as food were recorded for three anurans tadpoles: Hyla saxicola (Bokermann, 1964 (Hylidae, Scinax machadoi (Bokermann & Sazima, 1973 (Hylidae, and Bufo rubescens (Lutz, 1925 (Bufonidae. These species are commonly found in the mountain streams at Serra do Cipó National Park, Minas Gerais State, Brazil. Tadpoles were collected in pools of second-order reach in Mascates stream and third and fourth order reaches of Indaiá stream from March-October, 2003. Biometrical data were recorded before dissecting each individual and a feeding importance index was estimated. Eight taxa of chironomids and three taxa of mayfly exuviae were found in the guts, but no significantly differences were found between tadpole species (ANOVA, p > 0.05. The results support the drift transport hypothesis that predicts that tadpoles commonly ingest suspended matter in lotic ecosystems, are generalist feeders, and macroinvertebrates are probably incidental ingested.A presença de macroinvertebrados como item na dieta de girinos foi estudada para as espécies Hyla saxicola (Bokermann, 1964 (Hylidae, Scinax machadoi (Bokermann & Sazima, 1973 (Hylidae e Bufo rubescens (Lutz, 1925 (Bufonidae. Estas espécies são comumente encontradas nos córregos de altitude no Parque Nacional da Serra do Cipó, Estado de Minas Gerais, Brasil. Os girinos foram coletados em poções em um trecho de segunda ordem no córrego Mascates, e em trechos de terceira e quarta ordens no córrego Indaiá, entre março e outubro de 2003. Medidas biométricas foram mensuradas antes da dessecação de cada indivíduo e foi estimado um índice de importância de alimentação para os macroinvertebrados encontrados. Oito taxa de Chironomidae e três taxa de exúvias de Ephemeroptera foram encontrados, mas não houve diferenças significativas entre os macroinvertebrados encontrados nas espécies de girinos (ANOVA, p > 0,05. Os resultados obtidos corroboram a hipótese de transporte por

  9. A HEALTH ASSESSMENT USING A BENTHIC-INDEX OF BIOTIC INTEGRITY IN GANJIANG RIVER BASIN%基于底栖生物完整性指数的赣江流域河流健康评价

    Institute of Scientific and Technical Information of China (English)

    张方方; 张萌; 刘足根; 陈宏文; 齐述华

    2011-01-01

    底栖生物完整性指数(B-IBI)是最为广泛应用的水生态系统健康评价指数之一.根据2009-2010 年期间赣江流域60 个采样点的底栖动物数据(15 个参照点,45 个受损点),对17 个生物参数进行分布范围、判别能力和Pearson 相关性分析,确定了B-IBI 指数体系由总分类单元数、甲壳和软体动物分类单元数、甲壳和软体动物%和BI 指数构成.采用比值法统一各生物参数量纲,将各个生物参数分值加和得到B-IBI 指数值.根据参照点的B-IBI 值的25%分位数值最终确定赣江流域河流健康评价标准.评价结果表明,赣江流域60个采样点中19 个为健康,19 个为亚健康,14 个为一般,8 个较差.综合来看,赣江流域河流处于健康-亚健康状态:上游各支流中绵水、贡江、上犹江和桃江为健康状态,章水、濂水、梅江和平江为较差状态; 中游各支流健康评价结果多为健康-亚健康状态,而乌江为较差状态; 下游各支流为健康-亚健康状态; 赣江干流上健康评价的结果均为健康.%Benthic index of biotic integrity (B-IBI) is one of the most widely-used aquatic ecosystem health assessment indices. In the present study, benthic macroinvertebrates were sampled and collected from 60 stream sites in Ganjiang River basin during the period of 2009 to 2010, among which 15 sites were considered as reference sites and 45 impaired sites. Seventeen candidate metrics were selected for the establishment of B-IBI system, which were Shannon-Wiener index, Margalef index, Total number of taxa, (Crustacea+Mollusca) taxa, EPT taxa, Chironomidae taxa, Intolerant taxa, Dominant taxon %, Three dominant taxa %, Chironomidae %, Tubifex %, (Crustacea+Mollusca) %, Intolerant taxa %, Tolerant taxa %, Biotic Index, Predators % and Filterers %, respectively. The analyses of index value distribution, discrimination ability and Pearson correlation were then performed on these candidate metrics. After the analyses

  10. Aquatic invertebrate's distribution in a freshwater coastal lagoon of southern Brazil in relation to water and sediment characteristics Distribuição de invertebrados aquáticos em uma lagoa costeira de água doce ao sul do Brasil em relação às características de água e sedimento

    Directory of Open Access Journals (Sweden)

    Leonardo Kleba Lisboa

    2011-06-01

    Full Text Available AIM: The objective of this study was to evaluate the influence of water and sediment characteristics on the abundance, richness and diversity of the benthic invertebrate community in Peri lagoon, a freshwater coastal lagoon located in central coast of Santa Catarina State; METHODS: Samplings were performed in April, May and June 2009, in five different sites of Peri lagoon. The samples were taken with an Eckman-Birge drag, totalizing 60 for the invertebrate community, and 45 for sediment. Water physicochemical variables were also measured. Environmental influences in benthic community have been measured using a Canonical Correspondence Analysis (CCA. Linear regressions were also plotted for main correlations; RESULTS: A total of 5,535 specimens were collected, identified into 18 taxa. Tanaidacea was the most abundant representing 54% of relative abundance, followed by Diptera (23%, and Ostracoda (17%. The richest family was Chironomidae with 6 taxa. CCA results indicated positive correlation between Chaoborus and Stenocypris with local depth, and negative correlation between Odonata, Gastropoda, Cytheridella and Coleoptera with the finest grains of sediment, as well as between Tanaidacea, Lopescladius, Annelida and Nematoda with both organic matter (OM content in sediment and local depth. Linear regression analysis demonstrated inverse relation of Tanaidacea in response to OM (y = 0.6 - 0.62.OM and sand (y = 0.6 - 0.6.sand, and of Lopescladius in response to OM (y = 0.37 - 0.41.OM and sand (y = 0.37 - 0.46.sand. The fact that Peri lagoon has no marine influence and has Tanaidacea as the most abundant taxa, a group not expected in freshwaters, gives to this lagoon a particular relevance among coastal lagoons. The study concluded that sediment characteristics and local depth are more significant than water variables in determining the benthic community structure in Peri lagoon, which varied in accordance with different local conditions.OBJETIVO: O

  11. Aquatic insects as the main food resource of fish the community in a Neotropical reservoir

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    Ana Paula Vidotto-Magnoni

    2009-01-01

    Full Text Available We evaluated the feeding of fish species of the Nova Avanhandava Reservoir, low Tietê River, São Paulo State, Brazil. Fishes were collected in two stretches of the reservoir: Santa Bárbara (14 samples and Bonito (two samples between September 2002 and March 2004, using gill and seining nets. The results of stomach contents analysis were expressed with the frequency of occurrence and gravimetric method, combined in the Alimentary Index (AI. The 20 species studied consumed 52 food items, grouped in 10 food categories: aquatic insects, terrestrial insects, crustaceans, fish, macroinvertebrates, microcrustaceans, algae, vegetal matter, detritus/sediment and scales. The aquatic insects (mainly Chironomidae, Odonata and Ephemeroptera were the most common food resources, consumed by 18 species. The diet composition of the community (species grouped indicated that the dominant food category in the diet of fishes was aquatic insects (AI = 77.6%, followed by crustaceans (AI = 7.1%. Four trophic guilds were identified according a cluster analysis (Pearson distance: insectivorous (10 species, omnivorous (4 species, detritivorous (3 species and piscivorous/carcinophagous (3 species. Despite the highest number of species, the insectivorous guild was responsible for more than 80% in captures in number and biomass (CPUEn and CPUEb. The low values of niche breadth presented by all species, along with the low values of diet overlap between species pairs indicate a high degree of food resources partitioning among species. The aquatic insects, despite being the main food resource of insectivorous fishes, also complemented the diet of other species, which demonstrate the importance of this food resource for the fish community, sustaining a high diversity, abundance and biomass of fishes.Neste estudo foi avaliada a dieta das espécies de peixes do reservatório de Nova Avanhandava, baixo rio Tietê, Estado de São Paulo, Brasil. Os peixes foram coletados em dois

  12. Influence of environmental factors on benthic macroinvertebrate communities of urban streams in Vereda habitats, Central Brazil Influência de variáveis ambientais na comunidade de macroinvertebrados bentônicos de córregos urbanos de Veredas, Brasil Central

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    Renata de Moura Guimaraes Souto

    2011-09-01

    Full Text Available AIM: Veredas and the aquatic and semi-aquatic communities play a key role in watershed protection in the Cerrado Biome. Information about the effects of physical and chemical variables and habitat integrity on benthic communities has been increased in recent years; however, there is no study evaluating the influence of urbanization on macroinvertebrates of Vereda streams. Thus, improving the knowledge of the relationship between abiotic properties and benthic fauna is very important for understanding the functioning of ecological processes and health of aquatic ecosystems. This study investigated the influence of physical and chemical variables on benthic macroinvertebrate communities along a gradient of anthropogenic disturbance in four Vereda streams in Uberlândia (MG, one in a preserved area and three in the urban area; METHODS: samplings were collected during the dry and rainy seasons; RESULTS: principal component analysis separated the stream in the preserved area from those in the urban area by having lower values of BOD, COD, sediment size, conductivity, detergents, pH, deposited solids and total dissolved solids. Pollution sensitive groups (e.g., Ephemeroptera and Trichoptera were associated to the stream in the preserved area, and more tolerant groups (e.g., Chironomidae and Oligochaeta had greater abundance in the streams of the urban area. Canonical Correspondence Analysis indicated that dissolved oxygen, conductivity, BOD, oil and grease, and turbidity explained 56% of the variance in the distribution and abundance of macroinvertebrates; CONCLUSIONS: Benthic communities of Vereda streams in urban areas in the Cerrado Biome seem to be highly affected by human activities that increase water organic pollution and sedimentation.OBJETIVO: Veredas e comunidades aquáticas e semi-aquáticas desempenham importante papel na proteção das bacias hidrográficas no Bioma Cerrado. Informações sobre efeitos de variáveis físico-químicas e da

  13. Water quality assessment of fifth-order tributaries of the reservoir at the Marechal Mascarenhas de Morais Hydroelectric Power Station in the Rio Grande watershed (State of Minas Gerais, Brazil Avaliação da qualidade da água dos afluentes de quinta ordem do reservatório da Usina Hidrelétrica de Marechal Mascarenhas de Morais na bacia hidrográfica do médio rio Grande (Minas Gerais, Brasil

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    Douglas de Pádua Andrade

    2012-09-01

    Full Text Available Aim: This study assessed the water quality from the springs and river mouths of the fifth-order tributaries which compose the reservoir of Marechal Mascarenhas de Morais HPS in the middle Rio Grande watershed, Minas Gerais, Brazil. Methods: It has been studied 14 tributaries distributed in the reservoir, two points for tributary - spring and river mouth. Eighteen limnological variables added to the Rapid Assessment Protocol and Trophic Level Index were evaluated. The benthic macroinvertebrates had been collected by the use of a granulometric sieve and a Petersen-type sampler. Results: The cluster analysis of limnological data revealed the existence of two tributary groups. Group I consisted of eutrophic tributaries degraded by human activities, while group II exhibited good water quality and well-preserved environments. Group I was divided into two subgroups, Ia tributaries were characterized by being altered by human activities, while the Ib subgroup was composed of highly impacted tributaries. By ordering the PCA, it can be observed spatial segregation of groups, where the most polluted tributaries were separated from those which are better preserved. A total of 8,987 individuals belonging to 36 families of macroinvertebrates were identified. The family Chironomidae was the most abundant. There was no significant difference in total abundance and the richness of macroinvertebrates taxa inhabiting springs, by those who inhabiting the river mouths. Conclusions: It was noticed that most of the tributaries which supply and composes the reservoir are already degraded and have low quality water. It is observed that the human presence drastically affected water quality and faunal composition of tributaries. Thus, it is necessary a complementary study of the tributaries in working with issues related to reservoirs, as these components have direct influence on the water quality and composition of these lentic environments.Objetivos: O trabalho avaliou

  14. Seafloor mapping at Olkiluoto western coast of Finland

    Energy Technology Data Exchange (ETDEWEB)

    Ilmarinen, K.; Leinikki, J.; Oulasvirta, P. (Alleco Oy, Helsinki (Finland))

    2009-02-15

    the more variable bottom and the more exposed location compared to the corresponding transects 2 and 3, 4 and 5a. The somewhat sheltered transect 5 and the exposed transects 1 and 2 had the highest biomasses of individuals. The biomass was high because of the bivalvia Macoma baltica which is very common in 2-5 meters depth on the sand, silt and mud bottoms. At the transects 1, 2 and 5 were found Oligochaeta which are more common in clear water. These transects had slightly less turbid water than the other transects. The biomass of Polychaeta Marenzelleria (arctia) was high at the transects 3 and 4. This species can tolerate low oxygen levels. Transect 5a is extremely shallow and located in a flad - an enclosed bay in a land uplift region that still receives sea water regularly. High biomass of chironomids (Chironomidae) were found at the transect 5a and especially the species Chironomus f. l. plumosus, which was only found at this transect, indicates high eutrofication. Depth mapping by echo sounding was carried out at a transect interval of 50 meters in the sea area that was estimated to be less than 2 meters deep. The mapping area also included a few kilometers of the lower parts of the rivers Eurajoki and Lapinjoki. The mapping material was handed to the Geological Survey of Finland for creating a depth model. It was not a surprise to the survey team that much of the measured area was deeper than 2 meters, as the depth information printed on nautical charts aims primarily at maritime safety. (orig.)

  15. Stream ecosystem health assessment of inflow rivers in Lake Dianchi catchment by using Benthic Integrity Biotic Index (B-IBI)%应用底栖动物完整性指数评价滇池流域入湖河流生态系统健康

    Institute of Scientific and Technical Information of China (English)

    苏玉; 曹晓峰; 黄艺

    2013-01-01

    Benthic Integrity Biotic Index (B-IBI) was used to evaluate the health of inflow rivers in Lake Dianchi of Yunnan Province , China. Macroinvertebrate assemblages were collected from 38 sampling sites in Lake Dianchi, including 9 sites that were undisturbed or less disturbed and 29 sites that were disturbed in wet season of July - Aug. 2009 and dry season of Jan. - Feb. 2010. The range of index value distribution, spearman correlation and judgment ability were analyzed for the 19 biological parameters, including Shannon-Wiener index; total number of taxa; total density; taxa numbers of Crustacea + Mollusca, Hirudinea, and Mollus-ca taxa; percentage of Crustacea + Mollusca, Hirudinea, Mollusca, Oligochaeta, Limnodrilushoffmeisteri, Chironomidae, Oli-gochaeta/Hirudinea, Gatherers, Predator, Omnivore, and Scrapers; percentage of tolerant taxa; and Goodnight index. Ratio scoring method for B-IBI index was used to get a uniform score. By using the each 20 percentiles of B-IBI as a criteria to evaluate the aquatic ecosystem health, the results showed that, health criteria when B-IBI > 1. 62 , sub-health when 1. 03 - 1. 62, good-fair when 0.31 -1.03, fair when 0. 10-0.31, and poor when B-IBl<0. 10. The B-IBI index was positive correlation to NO3--N and water temperature-, but not significantly correlation to other factors.%采用底栖动物完整性指数(B-IBI)评价滇池流域入湖河流健康状况.根据滇池流域38个样点(9个参照点,29个干扰点)于2009年丰水期和2010年平水期采得的大型底栖动物数据,对19个生物参数进行分布范围、Spearman相关性和判别能力分析,确定构成滇池流域底栖动物生物完整性的指数为甲壳动物+软体动物分类单元数、集食者%、捕食者%和耐污类群%.用比值法统一量纲,计算各个生物参数的值,并将所得的值相加即得到B-IBI指数值.根据B-IBI指数值的25%分位数确定健康等级标准,并对小于25%分位数的值进行四等分,

  16. Effect of some environmental factors on arthropod communities in bat guano

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    Watanasit, S.

    2002-01-01

    Full Text Available Data are presented on the taxonomic composition of arthropod fauna found in bat guano in 6 limestone caves of southern Thailand, collected by Berlese's funnel type trap. There were 2 sampling periods; the first from 29 April to 7 May 1996 and the second from 1 to 4 August 1996. Combined samples of bat guano comprised 4,430 individuals of 32 families of the following : 13 orders (2 classes ; Arachnida and Hexapoda Araneae, Acari, Pseudoscorpiones, Collembola, Blattaria, Hemiptera, Thysanoptera, Psocoptera, Neuroptera, Diptera, Coleoptera, Lepidoptera and Hymenoptera. The relationships between arthropods and physical factors such as cave temperature, relative humi-dity of the cave, moisture in guano, pH of guano, total nitrogen in guano and organic matters in guano were explored. The results showed that the number of individuals of Leptonetidae (P<0.05, Araneae (P<0.05 and Psocoptera (P<0.05 positively correlated with total nitrogen in guano but numbers of Blattellidae (P<0.05 and Blattaria (P<0.05 negatively correlated with total nitrogen in guano. The total numbers of families of arthropods (P<0.05 and the number of individuals of Leptonetidae (P<0.05, Sphaeropsocidae (P<0.05, Liposcelidae (P<0.05, Alleculidae (P<0.01, Chironomidae (P<0.05, Formicidae (P<0.05, Araneae (P<0.05, Psocoptera (P<0.01 and Hymenoptera (P<0.05 positively correlated with organic matters in guano. None of all arthropods correlated with cave temperature, relative humidity of the cave, moisture in guano and pH of guano. Study on the effect of type of bat guano (insectivore or frugivore bat guano and the light factor (light or dark zone on arthropods showed that type of bat guano has an effect on total numbers of families (P<0.05 and the number of individuals of Leptonetidae (P<0.01, Laelapidae (P<0.05, Blattellidae (P<0.05, Sphaeropsocidae (P<0.01, Liposcelidae (P<0.05, Dermestidae (P<0.01, Staphylinidae (P<0.01, Tineidae (P<0.05, Araneae (P<0.01, Blattaria (P<0

  17. The early to mid-Miocene environment of Antarctica

    Science.gov (United States)

    Ashworth, A. C.; Lewis, A.

    2012-12-01

    Paleoecological studies in the Transantarctic Mountains of the McMurdo region provide evidence that the climate was both warmer and wetter in the early to mid-Miocene than it was during the late Miocene. The climate change was accompanied by a shift from wet- to cold-based glaciation in the TAM and the probable growth of the polar ice sheet. Terrestrial and freshwater aquatic fossil assemblages from the Friis Hills (77°S) and the Olympus Range (77°S), with endpoint 40Ar/39Ar ages on tephras of 19.76 Ma and 14.07 Ma, respectively, indicate climatic cooling during the interval. At c.14 Ma, the temperature dropped below the threshold required to support the plants and insects of a tundra biome, and they became extinct. This interpretation is supported by pollen studies from Ross Sea cores. The extinction of the tundra biota on the continent appears to have been time-transgressive, occurring at 12.8 Ma on the Antarctic Peninsula. Evidence of climatic cooling from early to mid-Miocene is based on a decrease in biodiversity. During interglacial phases of the early Miocene, the poorly drained valley of the Friis Hills supported a sexually-reproducing moss community dominated by Campylium cf. polygamum, which today grows on the margins of lakes and in soil between boulders. Wood and leaves of Nothofagus (Southern Beech), and the seeds of at least five other angiosperm species are preserved as fossils. In addition, there are abundant megaspores and spiny, curved leaves of the aquatic lycopod Isoetes (Quillwort), as well as chitinous remains of curculionid beetles and Chironomidae (midges). During glacial phases, the only fossils found are Nothofagus leaves of a species which appears to be different than that associated with the interglacial phases. Pollen supports the interpretation that there was more than one species of Nothofagus in the vegetation. The types and numbers of species indicate that the vegetation was a shrub tundra. The closest modern analog for the fossil

  18. Long-term macroinvertebrate response to flow abstraction at Alpine water intakes

    Science.gov (United States)

    Gabbud, Chrystelle; Savioz, Amélie; Lane, Stuart

    2016-04-01

    The natural flow hydrological characteristics of Alpine streams, dominated by snowmelt and glacier melt, have been established for many years. More recently, the ecosystems that they sustain have been described and explained, following the hydrological, biochemical, morphodynamic, and biotic elements specific to Alpine streams. However, natural Alpine flow regimes may be strongly modified by hydroelectric power production, which impacts upon both river discharge and sediment transfer, and hence on downstream flora and fauna. These kinds of impacts are well studied where river are regulated by dams, with sediments retained behind walls, but they are much less focus on water intakes, whose storage capacity is very smaller and thus have to flush flow and sediment regularly. Here we focus on the impacts of flow abstraction on macroinvertebrates, the most widely ecological group used in freshwater biomonitoring as they act typically as indicators of environmental health. Some key generalizations can be made. For instance, in European glacially fed river systems, Plecoptera, Chironomidae, Ephemeroptera, Simuliidae, and Diptera are the main taxa found in spring as they are better adapted to cold conditions. Petts and Bickerton (1994) published macroinvertebrate samples from the upper part of the glacial stream system the Borgne d'Arolla (Valais, Switzerland), highlighting that: (1) taxa variability and productivity decline in the river because of flow abstraction, (2) 60 % of the communities were provided by tributaries, (3) there is migration upstream of the species in response to the passage from a dominant ice-melt to a snow-melt regime, (4) the colonisation is difficult because of a significant modification of the habitat in the river by sediment transport, until it becomes warmer, clearer and more stable further downstream. In order to establish the long-term impacts of flow abstraction upon instream ecology where sediment delivery is maintained but transport

  19. 伊比利亚河共生的当年生鳟和埃布罗河鳟的夏季摄食关系%Summer feeding relationships of the co-occurring hatchling brown trout Salmo trutta and Ebro minnows Phoxinus bigrri in an Iberian river

    Institute of Scientific and Technical Information of China (English)

    Javier OSCOZ; Pedro M.LEUNDA; María C.ESCALA; Rafael MIRANDA

    2008-01-01

    The stomach content composition of 306 Ebro minnows and 185 hatchling brown trout captured in August (1996-1998) in the Larraun River (Ebro River Basin, Northern Spain) is described and compared in order to determine interspecific dietary overlap. Both species fed mainly on aquatic invertebrates. Feeding strategy plots showed that both species are generalist feeders with a heterogeneous diet. Additionally, the comparison between the stomach content and the benthic macroinvertebrate community revealed that both hatchling brown trout and Ebro minnows avoided Elmidae, Gammaridae, Caenidae, Baetidae and Leuctridae, instead showing a preference for Chironomidae, Heptageniidae and Trichoptera. Even though a two species was significant in the Larraun River, differential habitat use and diet plasticity could be minimizing the interspecific competition in river reaches where both species were co-dominant, allowing co-occurrence of these species in relatively high numbers. However, this adaptability and plasticity in Ebro minnows could be a threat to allopatric brown trout populations in rivers with limited trophic resources and limited habitat availability%1996-1998年8月在Larraun河(埃布罗河流域,西班牙北部)共捕获306尾埃布罗河(鱼岁)和185尾0龄的鳟,分析比较了胃含物组成,并测定了种间的食物重叠.食物的个数百分比组成表明两种都主要摄食水生无脊椎动物.摄食策略图显示两种都是摄食不同食物 种类的广食性种类.另外,比较胃含物和底栖大型无脊椎动物群落表明,0龄的鳟和埃布罗河(鱼岁)不摄食光螺科、钩虾科、细蜉科、 四节蜉科和卷襀科的物种,而喜食摇蚊科、五节蜉科和毛翅目物种.尽管简化的Morisitas指数表明Larraun河中这两种鱼之间的食物重叠是显著的,但由于栖息地不同和摄食的可塑性可以降低种间的竞争,使得该水域的这两种鱼能以相对较大的数量共存.然而,在食物资源和

  20. Benthic processes affecting contaminant transport in Upper Klamath Lake, Oregon

    Science.gov (United States)

    Kuwabara, James S.; Topping, Brent R.; Carter, James L.; Carlson, Rick A; Parchaso, Francis; Fend, Steven V.; Stauffer-Olsen, Natalie; Manning, Andrew J.; Land, Jennie M.

    2016-09-30

    summers of 2013 and 2014. However, consistently detectable concentrations for all four solutes provide no evidence that they consistently serve as the limiting nutrient for primary production in the lake. In contrast to the four solutes (SRP, ammonia, Fe, and Mn), benthic fluxes of dissolved arsenic (As) were both negative and positive (that is, the lakebed currently serves as both a source and a sink for dissolved As, depending on season). In a further contrast with SRP, ammonia, dissolved Fe, and Mn, dissolved-As riverine loads to UKL were of similar magnitude to benthic loads. A negative relationship between dissolved-As flux and water-column As over the 2014 temporal study provides a potential advantage for the management of water-quality in contrast to solutes, like SRP or ammonia, with consistently positive flux. The mean total benthic invertebrate density during 2013 was 12,610 individuals per square meter (n=63). Although benthic invertebrate density did not change over the study period, it was higher in littoral habitats than open-lake or trench habitats and higher in the northern region compared to the central or southern regions of UKL. Mean total benthic invertebrate density during 2014 was 19,726 individuals m−2 (n=27). Density during the pre-bloom and bloom periods of April 15 to August 13, 2014 (the first two thirds of the 2014 sampling period), were similar to 2013. However, benthic invertebrate density more than doubled during the latter one-third of the study, that is, the post-bloom period between August 20 to October 16, 2014. Oligochaeta, Chironomidae and Hirudinea represented well over 90 percent of the benthic fauna; Oligochaeta were twice as abundant as Chironomidae or Hirudinea, the latter two of which were similar in density. Benthic invertebrates may enhance dissolved-nutrient (or toxicant) transport across the sediment-water interface by (1) modifying diffusion-layer thicknesses and permeability through bioturbation, (2) enhancing advective

  1. 水葫芦生态净化工程对竺山湖底栖动物群落结构变化的影响%Effects of Ecological Purification Engineering of Planting Water Hyacinth on Macro-Benthos Community Structure

    Institute of Scientific and Technical Information of China (English)

    刘国锋; 韩士群; 何俊; 严少华; 周庆

    2014-01-01

    , which has the wide adaptability, large biomass, strong purification ability, especially the eutrophication water, after solving the mechanized harvesting, recycling use of terminal processing. The conventional ecological engineering practice is mainly in small water body or inland rivers, which has the obvious purification effects for no wind disturbance. But controlled planting the aquatic plants in large water body to purify the polluted water is still rare now. According to the instruction and requirements of Jiangsu Province, the ecological effects of planting 67 hectares water hyacinth (E. crassipens) in Zhushan Bay, Lake Taihu, which is one of the polluted lake water purification measures in Jiangsu Province and mainly planted by Jiangsu Academic Agricultural Science, on macro-benthos population and structure and benthos environment, were studied during 4~11 month in 2011 with consecutive surveys. Results indicated that average density mollusca (the main species were Bellamya aeruginosa) in far-planting, near-planting and planting area was 15.13、15.63、22.63 ind·m-2,respectively, and biomass was 17.00、17.60、25.50 g·m-2,respectively, showed that benthos biomass in planting area was higher than that the others. However, the average density and biomass of Oligochaeta (the main species were Limodrilus hoffmeisteri) and Chironomidae in planting area were lower than that outside of planting area, and it demonstrated that the benthic environment gradually improved after controlled planting the floating plants. It indicated that the ecological engineering management through planting water hyacinth couldn’t show the obvious purification effects of polluted water in a short time, especially in a shallow, wind disturbance of large lake, and it need long-term, lasting approached to reach the purifying goals. The index of Shannon-Weaver and Simpson indicated that water environment was severe polluted state. On the basis of the survey results, the large-area and high

  2. Plancto e hidrobiologia sanitária de tanques tropicais com dáfnias e rotíferos

    Directory of Open Access Journals (Sweden)

    Lejeune P. H. de Oliveira

    1967-01-01

    phases is merely to satisfy an easy explanation thus the first phase that of exudation of concrete. We consider the 2nd. phase formation of bacterian and cyanophycean thin pellicel. 3rd. phase - dilution by rains, and fertilisation by birds; the 4th phase - plankton flora and fauna established. The biological material arrived with the air, the rains, and also with contaminations by dusts; with big portion of sand, of earth, and leaves of trees resulted of the SW wind actions in the storming days (See - Est. I, fig. 3, G. - the mangrove trees of the Pinheiro Island. Many birds set down and rest upon the pillar structure, its faeces which are good fertilizers fall into the ponds. Some birds were commonly pigeons, black ravens, swallows, sparrows and other sea mews, moor hens, and a few sea birds of comparatively rare occurence. We get only some examples of tropical dust contaminated helioplankton, of which incipient observations were been done sparcely. See the systematic list of the species of plankters. Phytoplankters - Cyanophyta algae as a basic part for food of zooplankters, represented chiefly by rotiferse, water-fleas Moinodaphnia and other Crustacea: Ostracoda Copepoda and Insecta: Chironomidae and Culicidae larvae. The polysaprobic of septic irruptions have not been done only by heating in summer, and, a good reason of that, for example: when the fifth pond was in polysaprobic phase as the same time an alike septic phase do not happened into the 3rd. pond, therefore, both were in the same conditions of temperature, but with unlike contaminations. Among the most important aquatic organisms used as indicatiors of pollution - and microorganisms of real importance in the field of sanitary science, by authorities of renown, for instance: PALMER, PRESCOTT, INGRAM, LIEBMANN, we choose following microalgae: a The cosmopolite algae Scenedesmus quadricuada, a common indicator in mesosaprobio waters, which lives between pH 7,0 and it is assimilative of NO[3 subscripted] and