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Sample records for chironomus riparius meigen

  1. Accumulation of mercury in larvae and adults, Chironomus riparius (Meigen)

    SciTech Connect

    Not Available

    1986-09-01

    Among benthic aquatic insects there are taxa that grow abundant in sediments polluted with organic matter. Some of them also tolerate high levels of heavy metals. In this research short exposure and partial life cycle tests were carried out to evaluate the accumulation of mercury in Chironomus riparius Meigen larvae, pupal exuviae and adults from water enriched with HgCl/sub 2/. Their abundance in heavily polluted waters and the fact that it is easy to rear them suggested the use of this species for the toxicity tests considered in our present research. Short exposure tests were carried out to evaluate the LC/sub 50/ of HgCl/sub 2/ for the 4th instar larva of C. riparius Meigen.

  2. Proteomic evaluation of cadmium toxicity on the midge Chironomus riparius Meigen larvae.

    PubMed

    Lee, Sung-Eun; Yoo, Dong-hun; Son, Jino; Cho, Kijong

    2006-02-01

    Heavy-metal pollution of aquatic ecosystems is a widespread phenomenon after industrial consumption. Whether aquatic organisms are adapted to the heavy-metal pollutants or not, such environmental stress causes changes in physiological responses. In this study, the aquatic midge, Chironomus riparius Meigen, was used to find changes of expression of proteins in relation to cadmium exposure. Dose-response relationships between cadmium concentrations and mortality of 3rd instar midge larvae were observed and the protein levels were compared using PD-Quest after 2-DE. Comparing the intensity of protein spots, 21 proteins decreased and 18 proteins increased in response to cadmium treatment. With increased proteins, three enzymes such as S-adenosylmethionine decarboxylase, O-methyltransferase, and aspartokinase were involved in the glutathione biosynthesis and a key enzyme regulating fatty acid biosynthesis, oleyl-acyl carrier protein thioesterase was also identified. According to the functional classification of decreased levels of proteins, they were involved in energy production, protein fate, nucleotide biosynthesis, cell division, transport and binding, signal transduction, and fatty acid and phospholipid metabolism in the cell. In addition, phenol hydroxylase, thioesterase, zinc metalloprotease, and aspartate kinase were newly expressed after cadmium exposure at the concentration of the LC(10 )value. Therefore, these proteins seem to be potential biomarkers for cadmium exposure in the aquatic ecosystems. PMID:16372273

  3. Characterization of Heterochromatin in the Salivary Gland Chromosomes of Chironomus riparius Meigen and Chironomuspiger Strenzke (Diptera, Chironomidae) by Differential and Fluorochrome Staining.

    PubMed

    Michailova, Paraskeva; Ilkova, Julia; Maryańska-Nadachowska, Anna; Warchałowska-Śliwa, Elżbieta

    2015-01-01

    The constitutive heterochromatin of two homosequential sibling species, Chironomus riparius and Chironomus piger, was studied. The salivary gland chromosomes of both species were analyzed using three staining methods: orcein and C band staining combined with DAPI and CMA3 fluorochrome staining. Both species have the chromosome set 2n = 8, with the same banding pattern and chromosome arm combinations: AB, CD, EF, G, but they differed in number and distribution of heterochromatic bands, AT-rich sequences (DAPI+) and GC-rich sequences (CMA3+). In the polytene chromosomes of C. piger, C-bands were found in centromeres only. They contain two types of repetitive DNA sequences: DAPI+ (very weak) and CMA3+ sequences. However, the polytene chromosomes of C. riparius have many interstitial heterochromatic bands in addition to the centromeric heterochromatin. Some of these bands contain both AT-rich and GC-rich sequences, while others are either AT-rich (DAPI+) or GC-rich (CMA3+). Therefore, these closely related species differ both in the content and localization of constitutive heterochromatin. The species-specific organization of the constitutive heterochromatin can be used as an additional cytogenetic marker for species differentiation. PMID:26255462

  4. Responses of the aquatic midge Chironomus riparius to DEET exposure.

    PubMed

    Campos, Diana; Gravato, Carlos; Quintaneiro, Carla; Soares, Amadeu M V M; Pestana, João L T

    2016-03-01

    N,N-diethyl-3-methylbenzamide (DEET) is the active ingredient of many commercial insect repellents. Despite being detected worldwide in effluents, surface water and groundwater, there is still limited information on DEET's toxicity toward non-target aquatic invertebrates. Thus, our main objective was to assess the effects of DEET in the life cycle of Chironomus riparius and assess its biochemical effects. Laboratory assays showed that DEET reduced developmental rates (reduced larval growth, delayed emergence) of C. riparius larvae and also caused a decrease in the size of adult midges. Concerning the biochemical responses, a short exposure to DEET caused no effects in lipid peroxidation, despite the significant inhibition of catalase and glutathione-S-transferase activities and of total glutathione contents. Moreover, inhibition of acetylcholinesterase activity was also observed showing neurotoxic effects. Environmental risk assessment of insect repellents is needed. Our results showed moderate toxicity of DEET toward C. riparius, however, due to their mode of action, indirect ecological effects of DEET and of other insect repellents cannot be excluded and should be evaluated. PMID:26773354

  5. The Use of the Developmental Rate of the Aquatic Midge Chironomus riparius (Diptera, Chironomidae) in the Assessment of the Postsubmersion Interval.

    PubMed

    González Medina, Alejandro; Soriano Hernando, Óscar; Jiménez Ríos, Gilberto

    2015-05-01

    Nonbiting midges (Diptera, Chironomidae) are the most abundant members of the fauna associated with submerged carcasses, but their use in the medicolegal context is very restricted because of their complex ontogeny. In this case, the corpse of a woman was recovered in late spring from a river in Granada (Iberian Peninsula). It showed obvious signs of long permanence in the aquatic environment and, along with pulmonary and microscopical analyses, led to the conclusion that the cause of death was drowning. Several larvae-like specimens were sampled from the scalp and later identified by morphological external features as IV instar larvae of Chironomus riparius Meigen, 1804 (Diptera, Chironomidae). Sequencing of cytochrome oxidase subunit I was performed to confirm the identification. The knowledge of the biology of C. riparius at low temperatures was critical to assess a postsubmersion interval of 16-17 days. PMID:25613586

  6. Effects of inbreeding on mouthpart deformities of Chironomus riparius under sublethal pesticide exposure.

    PubMed

    Vogt, Christian; Langer-Jaesrich, Miriam; Elsässer, Oliver; Schmitt, Claudia; Van Dongen, Stefan; Köhler, Heinz-R; Oehlmann, Jörg; Nowak, Carsten

    2013-02-01

    Mouthpart deformities in chironomids have been reported to indicate adverse effects of environmental pollutants. The authors assessed rates of mouthpart deformities in tributyltin-exposed, inbred, and outcrossed Chironomus riparius larvae over multiple generations. The authors found that the occurrence of mouthpart deformities was significantly correlated with inbreeding, whereas no correlation was found with the tributyltin exposure. The present study confirms the strong effect of high inbreeding rates on developmental deformities in chironomids. PMID:23161736

  7. Dynamics and recovery of a sediment-exposed Chironomus riparius population: A modelling approach.

    PubMed

    Diepens, Noël J; Beltman, Wim H J; Koelmans, Albert A; Van den Brink, Paul J; Baveco, Johannes M

    2016-06-01

    Models can be used to assess long-term risks of sediment-bound contaminants at the population level. However, these models usually lack the coupling between chemical fate in the sediment, toxicokinetic-toxicodynamic processes in individuals and propagation of individual-level effects to the population. We developed a population model that includes all these processes, and used it to assess the importance of chemical uptake routes on a Chironomus riparius population after pulsed exposure to the pesticide chlorpyrifos. We show that particle ingestion is an important additional exposure pathway affecting C. riparius population dynamics and recovery. Models ignoring particle ingestion underestimate the impact and the required recovery times, which implies that they underestimate risks of sediment-bound chemicals. Additional scenario studies showed the importance of selecting the biologically relevant sediment layer and showed population effects in the long term. PMID:27031571

  8. Assessing the risk of metal mixtures in contaminated sediments on Chironomus riparius based on cytosolic accumulation.

    PubMed

    Péry, Alexandre R R; Geffard, Alain; Conrad, Arnaud; Mons, Raphaël; Garric, Jeanne

    2008-11-01

    Sediments usually contain mixtures of trace metals introduced via natural geochemical processes and anthropogenic activities. Kinetics and effects of these metals are strongly dependent both on the composition of the mixture and on the physico-chemical characteristics of the sediment. Relating effects to metal concentration may consequently be advised. However, total accumulation may be a poor predictor of metal toxicity for Chironomus riparius exposed to contaminated field sediments. As an alternative, we proposed to relate effects on Chironomus growth with cytosolic metal accumulation, measured in larvae after a short exposure period. Dose-response relationships were derived for zinc, copper, and cadmium through single-metal exposure data analysed with toxicokinetics and toxicodynamics models. They permitted, on the basis of cytosolic accumulation measures, to predict successfully the effects of mixtures of cadmium, zinc, and copper on the growth of larvae exposed to spiked sediments, as well as to field sediments in which zinc and copper were assumed to be predominant. PMID:18514899

  9. Biochemical and morphological responses in Chironomus riparius (Diptera, Chironomidae) larvae exposed to lead-spiked sediment.

    PubMed

    Arambourou, Helene; Gismondi, Eric; Branchu, Philippe; Beisel, Jean-Nicolas

    2013-11-01

    The aim of the present study was to assess the potential use of biochemical markers and mentum deformities as indicators of long-term exposure to lead (Pb) in Chironomus riparius larvae. To do this, the authors measured 3 biochemical markers (i.e., malondialdehyde level, metallothionein concentration, and energy reserve content) as well as larval growth and mentum deformities after 16-d exposure to sediment containing Pb. The concentrations studied ranged from 3.5 mg/kg to 505.5 mg/kg dry weight. Despite the bioaccumulation of Pb in C. riparius bodies, frequencies of both mentum deformities and the dry weight were not significantly different between the control and stressed groups. On the contrary, Pb exposure caused a significant increase of both malondialdehyde level and metallothionein concentration. The increase of body Pb concentrations did not significantly modify body copper and zinc concentrations. Moreover, we observed a decrease of total lipid content and an increase of glycogen content as a function of a dose-response relationship, while no variation in protein concentrations was observed. Despite the adverse effects observed at the biochemical level, larval development was not affected. These results suggested that measurements of malondialdehyde level, metallothionein concentration, and energy reserve content can be used as relevant biomarkers of long-term sublethal exposure to Pb in C. riparius larvae. PMID:23893569

  10. The effect of temperature gradients on endocrine signaling and antioxidant gene expression during Chironomus riparius development.

    PubMed

    Park, Kiyun; Kwak, Ihn-Sil

    2014-02-01

    Temperature is one of the most important environmental factors affecting the biological processes of aquatic species. To investigate the potential effects of temperature on the developmental processes of aquatic invertebrates, we analyzed biological and molecular transcriptional responses during Chironomus riparius development, including five stages spanning from embryo to adult stages. We assessed the temperature change-induced reduction of survival rate, changes in biological development including the male:female ratio in emerged adults, the success rates of pupation and emergence, and the developmental timing of pupation and emergence. The increased temperature induced expression of endocrine signaling genes, such as the ecdysone receptor, ultraspiracle (ortholog of the RXR), and the estrogen-related receptor in the fourth-instar larval and pupal stages of C. riparius development. Altered temperature also affected the activity of antioxidant genes, including catalase, peroxidase, glutathione peroxidase, and superoxide dismutase during the fourth-instar larval to adult stages of C. riparius development, as a result of altered development. Increased temperature during the fourth-instar larval stage increased oxidative stress in pupae and adults. Responses of antioxidant genes to increased temperature occurred in a developmental stage-dependent manner. However, reduced temperature did not induce the expression of antioxidant genes in a developmental stage-dependent manner, although it did induce oxidative stress during C. riparius development. Increased temperature also caused greater toxicity of di-ethylhexyl phthalate (DEHP) in fourth-instar larvae. Our findings suggest that altered temperatures may disturb the invertebrate hormone system and developmental processes by inducing oxidative stress in aquatic environments. PMID:24239821

  11. Standardization of a chronic sediment toxicity test with Chironomus riparius -- An EU collaboration

    SciTech Connect

    Fleming, R.; Grootelaar, L.; Guchte, C. van de |

    1995-12-31

    Because of the need for sensitive measures of low level contaminants in European sediments, a chronic sediment toxicity test method, using Chironomus riparius has been developed as part of a collaborative program for the European Commission. The protocol is a partial life cycle test exposing the animals from egg stage to pre-emergence in sediment-water systems. In 1995 the protocol was ring tested in several laboratories in Europe, the US and Canada using the moth-proofer permethrin as a model substance. This was spiked into a natural sediment using a spiking protocol also developed in this program. Results of the ring test and details of the protocols will be presented.

  12. Effect of cadmium on oviposition and egg viability in Chironomus riparius (diptera: chironomidae)

    SciTech Connect

    Williams, K.A.; Green, D.W.J.; Pascoe, D.; Gower, D.E.

    1987-01-01

    Although the importance of toxicity data on freshwater macroinvertebrates for establishing water quality criteria is now well recognized few attempts have been made to determine the relative sensitivities of different life stages or ages within a species. Previous work with insects has suggested that earlier life stages may be more sensitive than later ones although toxicant effects on the egg itself have been virtually ignored. The selection of water of a suitable quality for egg-laying has been demonstrated in mosquitoes. However, there is virtually no information available on oviposition behavior in relation to toxicant stress or water quality although some authors have speculated on the presence of chemo-receptors in insect antennae and their possible involvement in testing water quality prior to oviposition. The present study aimed to investigate the extent of selection by Chironomus riparius females between a range of cadmium solutions as sites for oviposition and the effect of cadmium on egg hatching.

  13. Ecotoxicological assessment of grey water treatment systems with Daphnia magna and Chironomus riparius.

    PubMed

    Hernández Leal, L; Soeter, A M; Kools, S A E; Kraak, M H S; Parsons, J R; Temmink, H; Zeeman, G; Buisman, C J N

    2012-03-15

    In order to meet environmental quality criteria, grey water was treated in four different ways: 1) aerobic 2) anaerobic+aerobic 3) aerobic+activated carbon 4) aerobic+ozone. Since each treatment has its own specific advantages and disadvantages, the aim of this study was to compare the ecotoxicity of differently treated grey water using Chironomus riparius (96 h test) and Daphnia magna (48 h and 21d test) as test organisms. Grey water exhibited acute toxicity to both test organisms. The aerobic and combined anaerobic+aerobic treatment eliminated mortality in the acute tests, but growth of C. riparius was still affected by these two effluents. Post-treatment by ozone and activated carbon completely removed the acute toxicity from grey water. In the chronic toxicity test the combined anaerobic+aerobic treatment strongly affected D. magna population growth rate (47%), while the aerobic treatment had a small (9%) but significant effect. Hence, aerobic treatment is the best option for biological treatment of grey water, removing most of the toxic effects of grey water. If advanced treatment is required, the treatment with either ozone or GAC were shown to be very effective in complete removal of toxicity from grey water. PMID:22197265

  14. Effects of activated carbon amended sediment on biological responses in Chironomus riparius multi-generation testing.

    PubMed

    Nybom, Inna; Abel, Sebastian; Mäenpää, Kimmo; Akkanen, Jarkko

    2016-11-15

    The biological effects of activated carbon (AC) amendments in sediments were studied with the midge Chironomus riparius. The effects on larvae growth were studied using three different AC particles sizes (PAC: 90% <63μm, MAC: ø 63-200μm and GAC: ø 420-1700μm). The long- term effects of MAC were studied in an emergence experiment over two generations (P, F1), together with larvae growth experiment over three generations (P, F1, F2). Retarded growth and development of the larvae were observed in the two smallest particle sizes (PAC and MAC), as well as morphological changes in the gut wall microvilli layer studied from transmission electron micrographs. In addition, at high AC treatments the larvae reaching fourth instar stage were of a smaller size compared to the controls. With PAC treatment AC amendment dosages higher than 1% of sediment dry weight induced mortality. In the emergence experiment there was an indication of a delay in F1 generation emergence. Male dry weight (dw) in P generation was significantly reduced in the 2.5% MAC treatment. The effects of AC amendments were more obvious in the C. riparius larvae compared to the effects seen in emerging adults exposed to AC-amended sediment during the larval stage. PMID:27450330

  15. Ecotoxicity of bare and coated silver nanoparticles in the aquatic midge, Chironomus riparius.

    PubMed

    Park, Sun-Young; Chung, Jiwoong; Colman, Benjamin P; Matson, Cole W; Kim, Younghun; Lee, Byung-Cheon; Kim, Phil-Je; Choi, Kyunghee; Choi, Jinhee

    2015-09-01

    Although sediment is generally considered to be the major sink for nanomaterials in aquatic environments, few studies have addressed the ecotoxicity of nanomaterials in the presence of sediment. In the present study, the ecotoxicity of silver nanoparticles (AgNPs) with a range of organic coatings was examined in a freshwater sediment-dwelling organism, Chironomus riparius, using acute and chronic ecotoxicity endpoints, including molecular indicators. The toxicity of AgNPs coated with different organic materials, such as polyvinylpyrrolidone, gum arabic, and citrate, to C. riparius was compared with that of bare-AgNPs and AgNO3 (ionic silver). Total silver concentration was also measured to monitor the behavior of the AgNPs in water and sediment and to determine how ion dissolution affects the toxicity of all AgNPs. The coated- and bare-AgNPs caused DNA damage and oxidative stress-related gene expression. In addition, the bare-AgNPs and AgNO3 had a significant effect on development and reproduction. The surface coatings generally mitigated the toxicity of AgNPs to C. riparius, which can be explained by the reduced number of ions released from coated-AgNPs. Citrate-AgNPs caused the most significant alteration at the molecular level, but this did not translate to higher-level effects. Finally, comparing previously conducted studies on AgNP-induced gene expression without sediments, the authors show that the presence of sediment appears to mitigate the toxicity of AgNPs. PMID:25892495

  16. In situ bioassay using Chironomus riparius: An intermediate between laboratory and field sediment quality assessments

    SciTech Connect

    Guchte, C. van de; Grootelaar, L.; Naber, A.

    1995-12-31

    Benthic macroinvertebrates like chironomid larvae are important indicators for sediment quality. Both in field surveys and laboratory bioassays effect parameters like abundance, survival, growth, larval development and morphological abnormalities of chironomids are recommended biological endpoints to assess the impact of sediment associated contaminants. Now and then results from field surveys on contaminated sites appeared to differ from results in laboratory bioassays on sediment field samples from the same sites. The impact of so-called modifying factors like temperature, oxygen levels and the availability of food could be studied in the laboratory. However, these factors could not fully explain the observed differences. In situ bioassays have been developed to bridge the gap between laboratory and field derived data with respect to the exposure of cultured Chironomus riparius larvae versus field collected Chironomus sp. larvae. Control survival in the in situ bioassays was within acceptable limits (> 80%). Effects observed during the caged exposure of laboratory cultured first instar larvae at contaminated sites were in agreement with the hypothesis that adequate in-field bioassessment reduces uncertainties inherent in the use of standardized laboratory bioassays. Although relative risk ranking of chemicals or contaminated sites can rely upon standard testing protocols, in situ bioassays can give a better insight in exposure-effect relationships under actual field conditions.

  17. Patterns of Fluctuating Asymmetry and Shape Variation in Chironomus riparius (Diptera, Chironomidae) Exposed to Nonylphenol or Lead

    PubMed Central

    Arambourou, Hélène; Beisel, Jean-Nicolas; Branchu, Philippe; Debat, Vincent

    2012-01-01

    Deformities and fluctuating asymmetry in chironomid larvae have been proposed as sensitive indicators of biological stress and are commonly used to assess the ecological impact of human activities. In particular, they have been associated in Chironomus riparius, the most commonly used species, with heavy metal and pesticide river pollution. In this study, the effect of lead and 4-nonylphenol on mouthpart morphological variation of Chironomus riparius larvae was investigated by traditional and geometric morphometrics. For this purpose, first to fourth instar larvae were exposed to sediment spiked with lead (from 3.0 to 456.9 mg/kg dry weight) or 4-NP (from 0.1 to 198.8 mg/kg dry weight). Mentum phenotypic response to pollutants was assessed by four parameters: (1) the frequency of deformities, (2) fluctuating asymmetry of mentum length, (3) fluctuating asymmetry of mentum shape and (4) the mentum mean shape changes. Despite the bioaccumulation of pollutants in the chironomid’s body, no significant differences between control and stressed groups were found for mouthpart deformities and fluctuating asymmetry of mentum length. Slight effects on mentum shape fluctuating asymmetry were observed for two stressed groups. Significant mean shape changes, consisting of tooth size increase and tooth closing, were detected for lead and 4-NP exposure respectively. Those variations, however, were negligible in comparison to mentum shape changes due to genetic effects. These results suggest that the use of mentum variation as an indicator of toxic stress in Chironomus riparius should be considered cautiously. PMID:23133660

  18. Combination effects of pyrethroids and neonicotinoids on development and survival of Chironomus riparius.

    PubMed

    Kunce, Warren; Josefsson, Sarah; Örberg, Jan; Johansson, Frank

    2015-12-01

    Standard ecotoxicological risk assessments are conducted on individual substances, however monitoring of streams in agricultural areas has shown that pesticides are rarely present alone. In fact, brief but intense pulse events such as storm water runoff and spray drift during application subject freshwater environments to complex mixtures of pesticides at high concentrations. This study investigates the potential risks to non-target aquatic organisms exposed to a brief but intense mixture of the neonicotinoid pesticides imidacloprid and thiacloprid and the pyrethroid pesticides deltamethrin and esfenvalerate, compared to single substance exposure. All four of these pesticides have been detected in surface waters at concentrations higher than benchmark values and both classes of pesticides are known to exert adverse effects on non-target aquatic organisms under single substance exposure scenarios. First instar midge larvae of the non-target aquatic organism, Chironomus riparius, were exposed to combinations of these four pesticides at 50% of their LC50 (96 h) values in a 1h pulse. They were then reared to adulthood in uncontaminated conditions and assessed for survival, development time and fecundity. Our results show that the risk of disruption to survival and development of non-target aquatic organisms under this scenario is not negligible on account of the significant increases in mortality of C. riparius found in the majority of the pesticide exposures and the delays in development after pyrethroid exposure. While none of the deleterious effects appear to be amplified by combination of the pesticides, there is some evidence for antagonism. No effects on fecundity by any of the pesticide treatments were observed. PMID:26379201

  19. Effects of Activated Carbon on PCB Bioaccumulation and Biological Responses of Chironomus riparius in Full Life Cycle Test.

    PubMed

    Nybom, Inna; Abel, Sebastian; Waissi, Greta; Väänänen, Kristiina; Mäenpää, Kimmo; Leppänen, Matti T; Kukkonen, Jussi V K; Akkanen, Jarkko

    2016-05-17

    The nonbiting midge Chironomus riparius was used to study the remediation potential and secondary effects of activated carbon (AC, ø 63-200 μm) in PCB contaminated sediments. AC amendments efficiently reduced PCB bioavailability determined by Chironomus riparius bioaccumulation tests and passive samplers. PCBs were shown to transfer from larvae to adults. Lower PCB concentrations were observed in adult midges emerging from AC amended compared to unamended sediments. Increased reproduction, survival, larval growth and gut wall microvilli length were observed with low AC dose (0.5% sediment dw) compared to unamended sediment, indicating an improved success of larvae in the sediment with low organic carbon content. On the other hand, higher AC doses (2.5% sediment dw) caused adverse effects on emergence and larval development. In addition, morphological changes in the gut wall microvilli layer were observed. This study showed that the secondary effects of AC amendments are dependent on the dose and the sediment characteristics. Metamorphic species, such as C. riparius, may act as a vector for organic pollutants from aquatic to terrestrial ecosystems and according to this study the AC amendments may reduce this transport. PMID:27100921

  20. Effects of extracellular polymeric and humic substances on chlorpyrifos bioavailability to Chironomus riparius.

    PubMed

    Lundqvist, Anna; Bertilsson, Stefan; Goedkoop, Willem

    2010-04-01

    The role of sediment organic matter quality and quantity for chlorpyrifos bioavailability was studied in experiments with Chironomus riparius larvae and with four types of organic matter; (1) commercially available extracellular polymeric substances (EPS), (2) EPS produced by sediment microbes, (3) commercially available humic substances and, (4) humic substances extracted from a boreal lake. The effects of each type of organic matter were assessed at three concentrations. We used a (14)C-tracer approach to quantify uptake of chlorpyrifos in the larvae, and the partitioning of the insecticide within the microcosm. Carbon-normalised larval uptake was reduced both by EPS and humic substances. However, the reduction in uptake was much greater for EPS than for humic substances: uptake was reduced by 94 and 88% for commercial and complex EPS, and by 59 and 57% for commercial and complex humic substances, respectively. We also found differences in chlorpyrifos uptake, and sediment concentrations between treatments with commercially available and complex polymers, suggesting that minor differences in the quality of relatively simple organic molecules can affect contaminant behaviour in ecotoxicological studies. Passive uptake in dead controls was 40% of that in living larvae. Therefore, both passive and digestive uptake were important processes for chlorpyrifos uptake by larvae. Our results show that both EPS and humic substances affect chlorpyrifos bioavailability to sediment biota negatively and contribute to the understanding of the processes that regulate organic contaminant bioavailability in aquatic environments. PMID:19851864

  1. Comprehensive sediment toxicity assessment of Hessian surface waters using Lumbriculus variegatus and Chironomus riparius.

    PubMed

    Galluba, Simone; Oetken, Matthias; Oehlmann, Jörg

    2012-01-01

    The objective of this study was a sediment assessment of predominantly small rivers in the German federal state of Hesse. For this purpose, sediment samples were taken at 50 study sites with different contamination levels. The benthic invertebrates Chironomus riparius (Diptera) and Lumbriculus variegatus (Oligochaeta) were used as test species and exposed to whole sediments in chronic laboratory experiments. The bioassays were carried out on the basis of OECD guidelines 218 and 225 for the testing of chemicals. For about 50 % of the study sites chemical analytical data for pollutants from environmentally important substance classes like metals, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and organotin compounds were available. These data were used to analyze correlations between effects in the bioassays and measured chemical contaminations at sampling sites. For 22 % of the sediments ecologically relevant adverse effects were observed. In the majority of these cases effects occurred in only one of the biotests, and only one sediment sample exerted a negative effect on both test organisms. There was no significant correlation between biological responses and chemical data considering substance classes. However, there was a weak positive correlation between arsenic concentration and both worm number and worm biomass as well as a weak positive correlation between single PAHs and worm biomass. In some sediment tests elevated ammonia concentrations occurred in the overlying water so that an influence of these partially toxic concentrations on the test results cannot be ruled out. PMID:22375534

  2. A Determination of Metallothionein in Larvae of Freshwater Midges (Chironomus riparius) Using Brdicka Reaction

    PubMed Central

    Fabrik, Ivo; Ruferova, Zuzana; Hilscherova, Klara; Adam, Vojtech; Trnkova, Libuse; Kizek, Rene

    2008-01-01

    Among wide spectrum of biomolecules induced by various stress factors low molecular mass protein called metallothionein (MT) is suitable for assessment of the heavy metal environmental pollution. The aim of this work was to determine the metallothionein and total thiols content in larvae of freshwater midges (Chironomus riparius) sampled from laboratory exposure to cadmium(II) ions and from field studies using differential pulse voltammetry Brdicka reaction. Unique electrochemical instrument, stationary electrochemical analyser Autolab coupled with autosampler, was utilized for the analysis of the samples. The detection limit for MT was evaluated as 5 nM. The larvae exposed to two doses (50 ng/g or 50 μg/g) of cadmium(II) ions for fifteen days under laboratory controlled conditions were at the end of the exposure killed, homogenized and analysed. MT content in control samples was 1.2 μM, in larvae exposed to 50 ng Cd/g it was 2.0 μM and in larvae exposed to 50 μg Cd/g 2.9 μM. Moreover at field study chironomid larvae as well as sediment samples have been collected from eight field sites with different levels of pollution by heavy. The metals content (chromium, nickel, copper, zinc, arsenic, molybdenum, cadmium, tin and lead) in the sediment and or MT content in the chironomid larvae were determined by inductively coupled plasma mass spectrometry or Brdicka reaction, respectively.

  3. Metallothionein modulation in relation to cadmium bioaccumulation and age-dependent sensitivity of Chironomus riparius larvae.

    PubMed

    Toušová, Zuzana; Kuta, Jan; Hynek, David; Adam, Vojtěch; Kizek, René; Bláha, Luděk; Hilscherová, Klára

    2016-06-01

    The goal of this study was to contribute to understanding of the mechanisms behind sensitivity differences between early and late instar larvae of Chironomus riparius and to address the influence of the differences in standard testing approaches on the toxicity evaluation. A 10-day contact sediment toxicity test was carried out to assess sensitivity to cadmium exposure in relation to different age and laboratory culture line origin of test organisms. Chironomid larvae of early (OECD 218 method) and late instar (US-EPA600/R-99/064 method) differed substantially in sensitivity of traditional endpoints (OECD: LOEC 50 and 10 μg Cd/g dry weight (dw); US-EPA: LOEC > 1000 and 100 μg Cd/g dw for survival and growth, respectively). Bioaccumulated cadmium and metallothioneins (MTs) concentrations were analyzed to investigate the role of MTs in reduced sensitivity to cadmium in late instar larvae. Metallothioneins were induced after treatment to greater Cd concentrations, but their levels in relation to cadmium body burdens did not fully explain low sensitivity of late instars to cadmium, which indicates some other effective way of detoxification in late instars. This study brings new information related to the role of MTs in age-dependent toxicant sensitivity and discusses the implications of divergence in data generated by chironomid sediment toxicity tests by standardized methods using different instars. PMID:26957427

  4. Assessment of potential biomarkers, metallothionein and vitellogenin mRNA expressions in various chemically exposed benthic Chironomus riparius larvae

    NASA Astrophysics Data System (ADS)

    Park, Kiyun; Kwak, Inn-Sil

    2012-12-01

    The objective of this study was conducted to identify the possibility of using Chironomus metallothionein (MT) and vitellogenin (VTG) as biomarkers of stress caused by endocrinedisrupting chemicals (EDCs), heavy metals, herbicides and veterinary antibiotics. We characterized the MT and VTG cDNA in Chironomus riparius and evaluated their mRNA expression profiles following exposure to different environmental pollutants. The gene expression analysis showed that the MT mRNA levels increased significantly after long-term exposure to cadmium (Cd), copper (Cu), Lead (Pb), di(2-ethylhexyl) phthalate (DEHP), and 2,4-dichlorophenoxyacetic acid (2,4-D). Moreover, the VTG mRNA expression increased significantly in C. riparius larvae exposed to BPA, NP, DEHP, Cd, 2,4-D and fenbendazole. Evaluation of the long-term effects of environmental pollutants revealed up regulation of Chironomus MT mRNA in response to DEHP exposure among EDCs, and the level of the VTG mRNA was increased significantly following treatment with Cd and herbicide 2,4-D at all concentrations in a dose-dependent manner. These results indicate that VTG could be used as a potential biomarker of herbicide and Cd as well as EDCs, while MT was a potential biomarker of heavy metals such as Cd, Cu, and Pb in aquatic environments.

  5. Bioconcentration of 5,5',6-trichlorobiphenyl and pentachlorophenol in the midge, Chironomus riparius, as measured by a pharmacokinetic model

    USGS Publications Warehouse

    Lydy, M.J.; Hayton, W.L.; Staubus, A.E.; Fisher, S.W.

    1994-01-01

    A two compartment pharmacokinetic model was developed which describes the uptake and elimination of 5,5',6-trichlorobiphenyl (TCB) and pentachlorophenol (PCP) in the midge, Chironomus riparius. C. riparius were exposed to nominal TCB (2 ??g L-1) and PCP (9 ??g L-1) concentrations during a 16 h static uptake phase. Depuration was determined over approximately 45 h using a flowthrough system without feeding. The uptake clearance (P) was 330 ?? 61 ml g-1 midge h-1 for TCB and 55 ?? 4 ml g-1 midge h-1 for PCP, while measured bioconcentration factors (BCF) were 35,900 and 458 for TCB and PCP, respectively. Overall, the clearance-volume- based pharmacokinetic model predicted BCF values that were consistent with published values as well as with BCF values obtained from the octanol-water partition coefficient (K(ow)).

  6. Effects of pH on the toxicity and uptake of (14C)lindane in the midge, Chironomus riparius

    SciTech Connect

    Fisher, S.W.

    1985-10-01

    The toxicity of the insecticide, lindane, was measured in the midge, Chironomus riparius, at pH 4, 6, and 8 with the finding that lindane is significantly more toxic at pH 6 than at pH 4 and 8. The higher toxicity of lindane at pH 6 is a product of two factors. First the penetration of the compound into the midge is lower at pH 4 than at pH 6 and 8. Second, a greater percentage of total radioactivity is contributed by parent compound at pH 6.

  7. Effect of sulfidation and dissolved organic matters on toxicity of silver nanoparticles in sediment dwelling organism, Chironomus riparius.

    PubMed

    Lee, Si-Won; Park, Sun-Young; Kim, Younghun; Im, Hosub; Choi, Jinhee

    2016-05-15

    The properties, fate, and toxicity of silver nanoparticles (AgNPs) are readily modified in the environment. Thus, in order to predict the environmental impact of AgNPs, the toxicity test should be conducted to assess the interactions of AgNPs with environmental matrices. Dissolved organic matter (DOM) is known to mitigate AgNPs toxicity in natural systems, and it is also known that silver binds strongly to sulfur. Little is known, however, about the effect of sulfidation and to what extent it could compete with DOM in the sediment. We therefore investigated the effect of sulfide on a sediment dwelling organism, Chironomus riparius using ecotoxicity endpoints. We then investigated how sulfide and a combination of sulfide and DOM affect the toxicity of AgNPs in C. riparius. We also monitored the concentrations of silver in the water and sediment compartments, as well as in C. riparius tissue, in the presence and absence of sulfide. Finally, in order to investigate how sulfide and DOM affect the release of ions from AgNPs, we also monitored released Ag(+) in each treatment. In the presence of sulfide, AgNPs were found to be less toxic to C. riparius in acute and chronic endpoints than AgNPs alone, whereas DOM treatment did not modulate the toxicity of AgNPs. Sulfide treatment reduced the release of Ag(+) from AgNPs. Water-spiked AgNPs with sulfide were found to be more slowly incorporated into both sediment and larvae as compared to the AgNP alone. Overall, the results suggest that the presence of sulfide in sediment mitigates the ecotoxicity of AgNPs in C. riparius. PMID:26938319

  8. Critical body residues for lethal and sublethal effects of membrane narcotics in the midge, Chironomus riparius

    SciTech Connect

    Fisher, S.W.; Hwang, H.; Landrum, P.F.

    1995-12-31

    The concept of the critical body residue (CBR) offers a compelling new way to evaluate hazard posed by persistent contaminants such as PCBs. The authors tested the utility of using CBRs for PCBs in an invertebrate species, Chironomus riparius. Acute toxicity (< 10 d) tests were performed with 2nd instar larvae by adding trace amounts of {sup 14}C-labeled PCBs to unlabeled PCBs in amounts sufficient to generate a dose-responsive mortality curve. Because of the limited water solubility of the PCBs tested, it was not possible to produce a toxic tissue concentration via aqueous exposure. This difficulty was overcome by allowing the midges to feed upon contaminated algae (Chlorella vulgaris) which could be loaded with much higher levels of PCBs than would dissolve in water. CBRs for acute toxicity were measured for 3 PCBs; an average CBR of about 1 mmol/kg was determined. If the midge CBRs are lipid normalized, they fall into the range of values that have previously been determined for vertebrates. The authors also evaluated CBRs in midges for a variety of sublethal impairments including development time within a stadium, larval weight and fecundity. A CBR of 1.09 {micro}mol/kg resulted in a significant increase in larval development time and decrease in larval weight for second instar larvae. Tissue residues declined in the third and fourth instars, despite continuing exposure suggesting that the animals developed attenuating mechanisms or that contaminant loss at ecdysis is significant. Despite declining tissue residues throughout the larval instars, fecundity was reduced from 284 eggs/female in controls to 244 eggs/female in animals exposed to the highest sublethal concentration.

  9. Mercury tissue residue approach in Chironomus riparius: Involvement of toxicokinetics and comparison of subcellular fractionation methods.

    PubMed

    Gimbert, Frédéric; Geffard, Alain; Guédron, Stéphane; Dominik, Janusz; Ferrari, Benoit J D

    2016-02-01

    Along with the growing body of evidence that total internal concentration is not a good indicator of toxicity, the Critical Body Residue (CBR) approach recently evolved into the Tissue Residue Approach (TRA) which considers the biologically active portion of metal that is available to contribute to the toxicity at sites of toxic action. For that purpose, we examined total mercury (Hg) bioaccumulation and subcellular fractionation kinetics in fourth stage larvae of the midge Chironomus riparius during a four-day laboratory exposure to Hg-spiked sediments and water. The debris (including exoskeleton, gut contents and cellular debris), granule and organelle fractions accounted only for about 10% of the Hg taken up, whereas Hg concentrations in the entire cytosolic fraction rapidly increased to approach steady-state. Within this fraction, Hg compartmentalization to metallothionein-like proteins (MTLP) and heat-sensitive proteins (HSP), consisting mostly of enzymes, was assessed in a comparative manner by two methodologies based on heat-treatment and centrifugation (HT&C method) or size exclusion chromatography separation (SECS method). The low Hg recoveries obtained with the HT&C method prevented accurate analysis of the cytosolic Hg fractionation by this approach. According to the SECS methodology, the Hg-bound MTLP fraction increased linearly over the exposure duration and sequestered a third of the Hg flux entering the cytosol. In contrast, the HSP fraction progressively saturated leading to Hg excretion and physiological impairments. This work highlights several methodological and biological aspects to improve our understanding of Hg toxicological bioavailability in aquatic invertebrates. PMID:26688328

  10. The effects of binary UV filter mixtures on the midge Chironomus riparius.

    PubMed

    Ozáez, Irene; Morcillo, Gloria; Martínez-Guitarte, José-Luis

    2016-06-15

    Organic ultraviolet (UV) filters are used in a wide variety of products, including cosmetics, to prevent damage from UV light in tissues and industrial materials. Their extensive use has raised concerns about potential adverse effects in human health and aquatic ecosystems that accumulate these pollutants. To increase sun radiation protection, UV filters are commonly used in mixtures. Here, we studied the toxicity of binary mixtures of 4-methylbenzylidene camphor (4MBC), octyl-methoxycinnamate (OMC), and benzophenone-3 (BP-3), by evaluating the larval mortality of Chironomus riparius. Also molecular endpoints have been analyzed, including alterations in the expression levels of a gene related with the endocrine system (EcR, ecdysone receptor) and a gene related with the stress response (hsp70, heat shock protein 70). The results showed that the mortality caused by binary mixtures was similar to that observed for each compound alone; however, some differences in LC50 were observed between groups. Gene expression analysis showed that EcR mRNA levels increased in the presence of 0.1mg/L 4MBC but returned to normal levels after exposure to mixtures of 4MBC with 0.1, 1, and 10mg/L of BP-3 or OMC. In contrast, the hsp70 mRNA levels increased after exposure to the combinations tested of 4MBC and BP-3 or OMC mixtures. These data suggest that 4MBC, BP-3, and OMC may have antagonist effects on EcR gene transcription and a synergistic effect on hsp70 gene activation. This is the first experimental study to show the complex patterned effects of UV filter mixtures on invertebrates. The data suggest that the interactions within these chemicals mixtures are complex and show diverse effects on various endpoints. PMID:26971216

  11. UV filters induce transcriptional changes of different hormonal receptors in Chironomus riparius embryos and larvae.

    PubMed

    Ozáez, Irene; Aquilino, Mónica; Morcillo, Gloria; Martínez-Guitarte, José-Luis

    2016-07-01

    Organic ultraviolet (UV) filters are emerging contaminants that are ubiquitous in fresh and marine aquatic systems due to their extensive use in cosmetics, plastics, paints, textiles, and many other industrial products. The estrogenic effects of organic UV filters have been long demonstrated in vertebrates, and other hormonal activities may be altered, according to more recent reports. The impact of UV filters on the endocrine system of invertebrates is largely unknown. We have previously reported that some UV filters may affect ecdysone-related genes in the aquatic insect Chironomus riparius, an ecotoxicologically important model organism. To further analyze other possible effects on endocrine pathways, we first characterized four pivotal genes related with hormonal pathways in insects; thereafter, these genes were assessed for alterations in transcriptional activity after exposure to 4-methylbenzylidene camphor (4MBC) or benzophenone-3 (BP-3), two extensively used sunscreens. We found that both chemicals disturbed the expression of all four genes analyzed: hormonal receptor 38 (HR38), methoprene-tolerant (Met), membrane-associate progesterone receptor (MAPR) and insulin-like receptor (INSR), measured by changes in mRNA levels by real-time PCR. An upregulatory effect at the genomic level was detected in different developmental stages. Interestingly, embryos appeared to be more sensitive to the action of the UV filters than larvae. Our results suggest that the risk of disruption through different endocrine routes is not negligible, considering the significant effects of UV filters on key hormonal receptor and regulatory genes. Further effort is needed to develop environmental risk assessment studies on these pollutants, particularly for aquatic invertebrate model organisms. PMID:27089421

  12. Vinclozolin alters the expression of hormonal and stress genes in the midge Chironomus riparius.

    PubMed

    Aquilino, Mónica; Sánchez-Argüello, Paloma; Martínez-Guitarte, José-Luis

    2016-05-01

    Vinclozolin is a fungicide used in agriculture that can reach aquatic ecosystems and affect the organisms living there. Its effects have been intensively studied in vertebrates, where it acts as an antiandrogen, but there is a lack of information about its mechanistic effects on invertebrates. In this work, we analyzed the response of genes related to the endocrine system, the stress response, and the detoxification mechanisms of Chironomus riparius fourth instar larvae after 24h and 48h exposures to 20 (69.9nM), 200 (699nM), and 2000μg/L (6.99μM) of Vinclozolin. Survival analysis showed that this compound has low toxicity, as it was not lethal for this organism at the concentrations used. However, this fungicide was shown to modify the transcriptional activity of the ecdysone response pathway genes EcR, E74, and Kr-h1 by increasing their mRNA levels. While no changes were observed in disembodied, a gene related with the ecdysone synthesis metabolic pathway, Cyp18A1, which is involved in the inactivation of the active form of ecdysone, was upregulated. Additionally, the expression of two genes related to other hormones, FOXO and MAPR, did not show any changes when Vinclozolin was present. The analysis of stress response genes showed significant changes in the mRNA levels of Hsp70, Hsp24, and Gp93, indicating that Vinclozolin activates the cellular stress mechanisms. Finally, the expressions of the genes Cyp4G and GstD3, which encode enzymes involved in phase I and phase II detoxification, respectively, were analyzed. It was found that their mRNA levels were altered by Vinclozolin, suggesting their involvement in the degradation of this compound. For the first time, these results show evidence that Vinclozolin can modulate gene expression, leading to possible significant endocrine alterations of the insect endocrine system. These results also offer new clues about the mode of action of this compound in invertebrates. PMID:26966872

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

    PubMed

    Lagauzère, S; Pischedda, L; Cuny, P; Gilbert, F; Stora, G; Bonzom, J-M

    2009-04-01

    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 72h, 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. PMID:19121883

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

    PubMed

    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. PMID:26044750

  15. Fullerenes(nC60) affect the growth and development of the sediment-dwelling invertebrate Chironomus riparius larvae.

    PubMed

    Waissi-Leinonen, Greta C; Nybom, Inna; Pakarinen, Kukka; Akkanen, Jarkko; Leppänen, Matti T; Kukkonen, Jussi V K

    2015-11-01

    The possible toxicity of nanoparticles (NPs) to aquatic organisms needs to be investigated for chronic effects at low concentrations. Chronic effects of carbon NPs, fullerenesC60, on the midges of Chironomus riparius at different life stages on larvae and adult midges were investigated. Sediment associated fullerenesC60 were studied by 10-day growth and 42-day emergence tests with artificial sediment at nominal concentration ranges 0.0004-80 mg/kg dry weight. The body length decreased in the lower tested concentrations (0.0025-20 mg/kg), but the effect vanished with higher concentrations. Delayed emergence rate observed at 0.5 mg/kg. The observed effects correlated with analyzed sediment particle sizes indicating that small agglomerates of fullerene have more significant effects on C. riparius than larger agglomerates observed with higher C60 doses. The results reveal that fullerene may pose risks to benthic organisms, emerging as changes in the ecotoxic parameters studied here which inflects by the survival of the population. PMID:26142746

  16. Efficient shedding of accumulated metals during metamorphosis in metal-adapted populations of the midge Chironomus riparius

    SciTech Connect

    Groenendijk, D.; Kraak, M.H.S.; Admiraal, W. . Dept. of Aquatic Ecology and Ecotoxicology)

    1999-06-01

    Metal accumulation and loss during metamorphosis were investigated in Chironomus riparius populations in a metal contaminated lowland river. Cadmium and zinc levels were measured in imagoes and larvae at reference and metal-exposed sites. It was hypothesized that the relationship between metal concentrations in biota and environmental compartments would be influenced by the presence of metal-adapted chironomids. In contrast to the large interpopulation differences in larval body burdens of cadmium, body burdens in imagoes vanished to background levels for all midge populations. This indicated that any cadmium accumulated in larval stages was lost during metamorphosis. This nearly 100% efficiency in shedding of cadmium is most likely caused by an increased metal handling capacity present in exposed midges. In agreement with the cadmium measurements, larval body burdens of zinc showed also highly significant interpopulation differences. In contrast with the cadmium values, however, body burdens of zinc in imagoes showed highly significant interpopulation differences and differences were even recorded between the two exposed sites, indicating interpopulation differences in shedding capacity for zinc. It is concluded that the highly efficient shedding of accumulated metals reflected the metal adaptation recorded in earlier studies of metal-exposed C. riparius populations from the River Dommel. Based on the differences in metal accumulation and the differences found in shedding of metals between the two exposed midge populations, it was concluded that population differentiation due to metal stress is a gradual process rather than an all-or-nothing situation.

  17. Alteration in the expression of antioxidant and detoxification genes in Chironomus riparius exposed to zinc oxide nanoparticles.

    PubMed

    Gopalakrishnan Nair, Prakash M; Chung, Ill Min

    2015-12-01

    Zinc oxide nanoparticles (ZnONPs) are widely used in several commercial products due to their unique physicochemical properties. However, their release into the aquatic environments through various anthropogenic activities will lead to toxic effect in aquatic organisms. Although several investigations have been reported on the effect of ZnONPs in aquatic organisms using traditional end points such as survival, growth, and reproduction, the molecular level end points are faster and sensitive. In this study, the expression of different genes involved in oxidative stress response, detoxification, and cellular defense was studied in an ecotoxicologically important bio-monitoring organism Chironomus riparius in order to understand the subcellular effects of ZnONPs. The fourth instar larvae were exposed to 0, 0.2, 2, 10, and 20 mg/L of ZnONPs and Zn ions (in the form of ZnSO4.7H2O) for 24 and 48 h period. The expression of CuZn superoxide dismutase, manganese superoxide dismutase, catalase, phospholipid hydroperoxide glutathione peroxidase, thioredoxin reductase 1 and delta-3, sigma-4 and epsilon-1 classes of glutathione S-transferases, cytochrome p4509AT2, and heat shock protein 70 were studied using real-time polymerase chain reaction method. Gene expression results showed that the expression of genes related to oxidative stress response was more pronounced as a result of ZnONPs exposure as compared to Zn ions. The mRNA expression of genes involved in detoxification and cellular protection was also modulated. Significantly higher expression levels of oxidative stress-related genes shows that oxidative stress is an important mechanism of toxicity as a result of ZnONPs exposure in C. riparius. PMID:26278375

  18. Effects of exposure to high concentrations of waterborne Tl on K and Tl concentrations in Chironomus riparius larvae.

    PubMed

    Belowitz, Ryan; Leonard, Erin M; O'Donnell, Michael J

    2014-11-01

    Thallium (Tl) is a non-essential metal which is released into the environment primarily as the result of anthropogenic activities such as fossil fuel burning and smelting of ores. The ionic radius of monovalent Tl⁺ is similar to that of K⁺ and Tl⁺ may thus interfere with K⁺-dependent processes. We determined that the acute (48 h) lethal concentration where 50% of the organisms do not survive (LC₅₀) of Tl for 4th instar Chironomus riparius larvae was 723 μmol L⁻¹. Accumulation of Tl by the whole animal was saturable, with a maximum accumulation (Jmax) of 4637 μmol kg⁻¹ wet mass, and K(D) of 670 μmol Tl l⁻¹. Tl accumulation by the gut appeared saturable at the lowest four Tl concentrations, with a Jmax of 2560 μmol kg⁻¹ wet mass and a K(D) of 54.5 μmol Tl l⁻¹. The saturable accumulation at the gut may be indicative of a limited capacity for intracellular detoxification, such as storage in lysosomes or complexation with metal-binding proteins. Tl accumulation by the hemolymph was found to be linear and Tl concentrations in the hemolymph were ~75% of the exposure concentration at Tl exposures >26.9 μmol L⁻¹. There was not a significant decrease in whole animal, gut or hemolymph K during exposure to waterborne Tl at any of the concentrations tested (up to 1500 μmol L⁻¹). The avoidance of hypokalemia by C. riparius larvae may contribute to survival during acute waterborne exposures to Tl. PMID:25046737

  19. Exposure to sediments from polluted rivers has limited phenotypic effects on larvae and adults of Chironomus riparius.

    PubMed

    Arambourou, Hélène; Beisel, Jean-Nicolas; Branchu, Philippe; Debat, Vincent

    2014-06-15

    Laboratory studies have sometimes failed to detect a relationship between toxic stress and morphological defects in invertebrates. Several hypotheses have been proposed to account for this lack of effect. (1) It was suggested that only a combination of stressful conditions - rather than a single one - would affect the phenotype. (2) Phenotypic defects should be detected on adult individuals, rather than on juveniles. (3) Phenotypic abnormalities might mostly affect the progeny of the exposed individuals, some contaminants exhibiting trans-generational effects. In the present study, we test those three hypotheses. We first examined the effects of a multiple exposure by using laboratory Chironomus riparius larvae cultured on two sediments sampled in contaminated rivers and those containing a mixture of mineral and organic compounds. On the larvae, we investigated mentum phenotypes: the frequency of phenodeviants, the shape fluctuating asymmetry and the mean shape. To test whether adult's morphology was more sensitive than the larval's, we also measured asymmetry and mean shape of the adult wings. Finally, to test for a trans-generational phenotypic effect, we measured mentum shape variations in the offspring derived from the measured adults. Overall, our results point out a very limited phenotypic response to contaminated sediments, suggesting that a multiple exposure is not necessarily sufficient to generate phenotypic defects. Adult traits were no more affected than larval traits, discarding the hypothesis that adult phenotypes would be more sensitive biomarkers. Finally, no effect was detected on the offspring generation, suggesting that no trans-generational effect occurs. This general lack of effect suggests that the use of phenotypic defects in C. riparius as an indicator of sediment contamination should be considered cautiously. PMID:24691209

  20. Fluctuating asymmetry and mentum gaps in populations of the midge Chironomus riparius (Diptera: Chironomidae) from a metal-contaminated River

    SciTech Connect

    Groenendijk, D.; Zeinstra, L.W.M.; Postma, J.F.

    1998-10-01

    The developmental stability of both metal-exposed and nonexposed Chironomus riparius populations from the lowland River Dommel was investigated using fluctuating asymmetry (FA) and the incidence of mentum gaps. It was hypothesized that larval development was affected by the influx of Cd, Zn, Fe, Cu, and Pb directly by chemical stress, as well as through inbreeding of metal-adapted and nonadapted specimens. Morphological para/meters were therefore assessed in field-collected larvae and in clean, laboratory-cultured, first-generation (F1) larvae. Fluctuating asymmetry values and mentum gap incidence at contaminated field sites were significantly higher than at clean, upstream locations. Furthermore, FA values of clean, laboratory-cultured F1 larvae generally fell to reference values, indicating the direct effect of metal pollution on developmental aberrations. Mentum gaps were not observed in clean F1 cultures. Slightly elevated FA values were, however, still observed in clean F1 larvae from polluted locations downstream from the metal input. This residual disturbance was thought to reflect genetic stress emerging from interbreeding between metal-adapted and nonadapted specimens. Fluctuating asymmetry and mentum gaps together serve as a useful ecotoxicological marker for metal stress and, when combined with in situ studies and F1 cultures, allow for analysis of the response of animal populations to spatial and temporal gradients in metal exposure.

  1. Support for the evolutionary speed hypothesis from intraspecific population genetic data in the non-biting midge Chironomus riparius.

    PubMed

    Oppold, Ann-Marie; Pedrosa, João A M; Bálint, Miklós; Diogo, João B; Ilkova, Julia; Pestana, João L T; Pfenninger, Markus

    2016-02-24

    The evolutionary speed hypothesis (ESH) proposes a causal mechanism for the latitudinal diversity gradient. The central idea of the ESH is that warmer temperatures lead to shorter generation times and increased mutation rates. On an absolute time scale, both should lead to an acceleration of selection and drift. Based on the ESH, we developed predictions regarding the distribution of intraspecific genetic diversity: populations of ectothermic species with more generations per year owing to warmer ambient temperatures should be more differentiated from each other, accumulate more mutations and show evidence for increased mutation rates compared with populations in colder regions. We used the multivoltine insect species Chironomus riparius to test these predictions with cytochrome oxidase I (COI) sequence data and found that populations from warmer regions are indeed significantly more differentiated and have significantly more derived haplotypes than populations from colder regions. We also found a significant correlation of the annual mean temperature with the population mutation parameter θ that serves as a proxy for the per generation mutation rate under certain assumptions. This pattern could be corroborated with two nuclear loci. Overall, our results support the ESH and indicate that the thermal regime experienced may be crucially driving the evolution of ectotherms and may thus ultimately govern their speciation rate. PMID:26888029

  2. Transcriptional profiling induced by pesticides employed in organic agriculture in a wild population of Chironomus riparius under laboratory conditions.

    PubMed

    Lencioni, Valeria; Grazioli, Valentina; Rossaro, Bruno; Bernabò, Paola

    2016-07-01

    Copper (Cu) and azadirachtin (AZA-A+B) are pesticides allowed in organic agriculture whose environmental risk and toxicity for aquatic wildlife is only partially known. Reverse Transcription Polymerase Chain Reaction was used to assess the molecular effect of acute and short-term exposure (3, 24h) of Cu (0.01, 0.05, 1, 10, 25mgl(-1)) and AZA-A+B (0.2, 0.3, 0.4, 0.5, 1mgl(-1)) on the expression of five candidate genes (hsp70, hsc70, hsp40, hsp10 and cyP450) in a non-target species, Chironomus riparius. Fourth-instar larvae were collected from a mountain stream polluted by agricultural land run-off. All genes were responsive to both pesticides but each gene had a specific response to the different experimental concentrations and exposure times. A few similarities in transcriptional profiling were observed, such as a linear concentration-dependent response of hsp70 after 24h of exposure (at ≥1mgl(-1) of Cu and ≥0.2mgl(-1) of AZA-A+B) and an up-regulation regardless of the concentration of hsc70 after 24h of exposure (at ≥0mgl(-1) of Cu and ≥0.2mgl(-1) of AZA-A+B and the up-regulation of hsp70 after 3h of exposure at ~LC50 (Cu-LC50=26.1±2.5mgl(-1), AZA-A+B-LC50=1.1±0.2mgl(-1)). According to the results, hsp40, hsp10 and cyP450 may be defined as pesticide-dependent (i.e., hsp40 and hsp10 seemed to responded mainly to AZA-A+B and cyP450 to Cu), while hsc70 as time-dependent regardless of the pesticide (i.e., hsc70 responded only after 24h of treatment with Cu and AZA-A+B). This study gives new insights on the potential role of the C. riparius's hsps and cyP450 genes as sensitive biomarkers for freshwater monitoring. PMID:26994805

  3. The ribosome biogenesis pathway as an early target of benzyl butyl phthalate (BBP) toxicity in Chironomus riparius larvae.

    PubMed

    Herrero, Óscar; Planelló, Rosario; Morcillo, Gloria

    2016-02-01

    Butyl benzyl phthalate (BBP) is a ubiquitous contaminant whose presence in the environment is expected for decades, since it has been extensively used worldwide as a plasticizer in the polyvinyl chloride (PVC) industry and the manufacturing of many other products. In the present study, the interaction of BBP with the ribosome biogenesis pathway and the general transcriptional profile of Chironomus riparius aquatic larvae were investigated by means of changes in the rDNA activity (through the study of the internal transcribed spacer 2, ITS2) and variations in the expression profile of ribosomal protein genes (rpL4, rpL11, and rpL13) after acute 24-h and 48-h exposures to a wide range of BBP doses. Furthermore, cytogenetic assays were conducted to evaluate the transcriptional activity of polytene chromosomes from salivary gland cells, with special attention to the nucleolus and the Balbiani rings (BRs) of chromosome IV. BBP caused a dose and time-dependent toxicity in most of the selected biomarkers, with a general depletion in the gene expression levels and the activity of BR2 after 48-h treatments. At the same time, decondensation and activation of some centromeres took place, while the activity of nucleolus remained unaltered. Withdrawal of the xenobiotic allowed the larvae to reach control levels in the case of rpL4 and rpL13 genes, which were previously slightly downregulated in 24-h tests. These data provide the first evidence on the interaction of BBP with the ribosome synthesis pathways, which results in a significant impairment of the functional activity of ribosomal protein genes. Thus, the depletion of ribosomes would be a long-term effect of BBP-induced cellular damage. These findings may have important implications for understanding the adverse biological effects of BBP in C. riparius, since they provide new sensitive biomarkers of BBP exposure and highlight the suitability of this organism for ecotoxicological risk assessment, especially in aquatic

  4. Transcriptional responses, metabolic activity and mouthpart deformities in natural populations of Chironomus riparius larvae exposed to environmental pollutants.

    PubMed

    Planelló, Rosario; Servia, María J; Gómez-Sande, Pablo; Herrero, Óscar; Cobo, Fernando; Morcillo, Gloria

    2015-04-01

    Biomarkers are an important tool in laboratory assays that link exposure or effect of specific toxicants to key molecular and cellular events, but they have not been widely used in invertebrate populations exposed to complex mixtures of environmental contaminants in their natural habitats. The present study focused on a battery of biomarkers and their comparative analysis in natural populations of the benthic larvae of Chironomus riparius (Diptera), sampled in three differentially polluted rivers (the Con, Sar, and Louro in Galicia, Spain). In our study, some parameters were identified, such as hsp70 gene activity, GST enzymatic activity, total glycogen content and mouthpart deformities, which showed significant differences among populations from the three rivers that differed in the levels and types of sedimentary contaminants analyzed (metals, organic-chlorine pesticides, alkylphenols, pharmaceutical, and personal care products). In contrast to these sensitive biomarkers, other parameters showed no significant differences (hsc70 gene, EcR gene, P450 gene, RNA:DNA ratio, total protein content), and were stable even when comparing field and nonexposed laboratory populations. The hsp70 gene seems to be particularly sensitive to conditions of pollutant exposure, while its constitutive counterpart hsc70 showed invariable expression, suggesting that the hsc70/hsp70 ratio may be a potential indicator of polluted environments. Although further studies are required to understand the correlation between molecular responses and the ecological effects of pollutants on natural populations, the results provide new data about the biological responses to multiple-stressor environments. This field study adds new molecular endpoints, including gene expression, as suitable tools that, complementing other ecotoxicological parameters, may help to improve the methodologies of freshwater monitoring under the increasing burden of xenobiotics. PMID:23893657

  5. Assessing the toxicity of dodecylbenzene sulfonate to the midge Chironomus riparius using body residues as the dose metric.

    PubMed

    Hwang, Haejo; Fisher, Susan W; Kim, Kyeok; Landrum, Peter F; Larson, Robert J; Versteeg, Donald J

    2003-02-01

    Dodecylbenzene sulfonate (DBS) is a component of linear alkylbenzene sulfonate (LAS), an anionic surfactant, mainly used in household detergents. Due to the large quantity of DBS in use, there is concern over adverse environmental effects. This work examined the toxicokinetics and toxicity of the 2-phenyl isomer of dodecylbenzene sulfonate in 4-d, 10-d, and partial life-cycle tests on the midge, Chironomus riparius, exposed to aqueous solutions. Toxicokinetics were determined in 10-d uptake and 5-d elimination tests. The toxicokinetics were based on parent compound concentration in water and yielded an uptake coefficient (ku) of 17.5 (14.87-20.20) ml/g/h, an elimination rate constant (ke) of 0.073 (0.062-0.085) per h, a bioconcentration factor (BCF) of 56 to 240, and a half-life (t 1/2) of 9.5 (8.0-11.0) h. Biotransformation measurements did not reveal evidence for DBS metabolism. Thus, body residues, determined in the toxicity study, represent parent compound. In toxicity tests, 4- and 10-d LR50s (the body residue required to cause 50% mortality) in live midges were 0.72 (0.65-0.79) and 0.18 (0.08-0.42) mmol/kg, respectively. Thirty-day LR50s were 0.18 (0.09-1.64) and 0.21 (0.15-0.39) mmol/kg in duplicate studies. Of the sublethal endpoints, only developmental time increase was significant, with the lowest-observed-effect residues of 0.085 (0.067-0.105) and 0.100 (0.087-0.114) mmol/kg for male and female midges, respectively. Deformities in surviving larvae were also observed as chronic responses for body residues exceeding the 30-d LR50. The body residues required for mortality suggest that DBS acts like a polar narcotic in the midge. PMID:12558161

  6. Ultraviolet filters differentially impact the expression of key endocrine and stress genes in embryos and larvae of Chironomus riparius.

    PubMed

    Ozáez, Irene; Morcillo, Gloria; Martínez-Guitarte, José-Luis

    2016-07-01

    Several organic UV filters have hormonal activity in vertebrates, as demonstrated in fishes, rodents and human cells. Despite the accumulation of filter contaminants in aquatic systems, research on their effects on the endocrine systems of freshwaters invertebrates is scarce. In this work, the effects of five frequently used UV filters were investigated in embryos and larvae of Chironomus riparius, which is a reference organism in ecotoxicology. LC50 values for larvae as well as the percentage of eclosion of eggs were determined following exposures to: octyl-p-methoxycinnamate (OMC) also known as 2-ethylhexyl-4-methoxycinnamate (EHMC); 4-methylbenzylidene camphor (4MBC); 4-hydroxybenzophenone (4HB); octocrylene (OC); and octyldimethyl-p-aminobenzoate (OD-PABA). To assess sublethal effects, expression levels of the genes coding for the ecdysone receptor (EcR) and heat shock protein HSP70 were investigated as biomarkers for endocrine and stress effects at the cellular level. Life-stage-dependent sensitivity was found. In embryos, all of the UV filters provoked a significant overexpression of EcR at 24h after exposure. OC, 4MBC and OD-PABA also triggered transcriptional activation of the hsp70 stress gene in embryos. In contrast, in larvae, only 4MBC and OMC/EHMC increased EcR and hsp70 mRNA levels and OD-PABA upregulated only the EcR gene. These results revealed that embryos are particularly sensitive to UV filters, which affect endocrine regulation during development. Most UV filters also triggered the cellular stress response, and thus exhibit proteotoxic effects. The differences observed between embryos and larvae and the higher sensitivity of embryos highlight the importance of considering different life stages when evaluating the environmental risks of pollutants, particularly when analyzing endocrine effects. PMID:26994811

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

    PubMed

    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. PMID:25146235

  8. Ecdysone-Related Biomarkers of Toxicity in the Model Organism Chironomus riparius: Stage and Sex-Dependent Variations in Gene Expression Profiles

    PubMed Central

    Gómez-Sande, Pablo; Ozáez, Irene; Cobo, Fernando; Servia, María J.

    2015-01-01

    Despite being considered a model organism in toxicity studies, particularly in assessing the environmental impact of endocrine disrupting compounds (EDCs) and other chemicals, the molecular basis of development is largely unknown in Chironomus riparius. We have characterized the expression patterns of important genes involved in the ecdysone pathway from embryos to pupa, but specially during the different phases of C. riparius fourth larval instar, according to the development of genital and thoracic imaginal discs. Real-Time PCR was used to analyze: EcR and usp, two genes encoding the two dimerizing partners of the functional ecdysone receptor; E74, an early response gene induced by ecdysteroids; vg (vitellogenin), an effector gene; hsp70 and hsc70, two heat-shock genes involved in the correct folding of the ecdysone receptor; and rpL13, as a part of the ribosomal machinery. Our results show for the first time stage and sex-dependent variations in ecdysone-responsive genes, specially during the late larval stage of C. riparius. The induction in the expression of EcR and usp during the VII-VIII phase of the fourth instar is concomitant with a coordinated response in the activity of the other genes analyzed, suggesting the moment where larvae prepare for pupation. This work is particularly relevant given that most of the analyzed genes have been proposed previously in this species as sensitive biomarkers for the toxicological evaluation of aquatic ecosystems. Identifying the natural regulation of these molecular endpoints throughout the Chironomus development will contribute to a more in-depth and accurate evaluation of the disrupting effects of EDCs in ecotoxicological studies. PMID:26448051

  9. Ecdysone-Related Biomarkers of Toxicity in the Model Organism Chironomus riparius: Stage and Sex-Dependent Variations in Gene Expression Profiles.

    PubMed

    Planelló, Rosario; Herrero, Óscar; Gómez-Sande, Pablo; Ozáez, Irene; Cobo, Fernando; Servia, María J

    2015-01-01

    Despite being considered a model organism in toxicity studies, particularly in assessing the environmental impact of endocrine disrupting compounds (EDCs) and other chemicals, the molecular basis of development is largely unknown in Chironomus riparius. We have characterized the expression patterns of important genes involved in the ecdysone pathway from embryos to pupa, but specially during the different phases of C. riparius fourth larval instar, according to the development of genital and thoracic imaginal discs. Real-Time PCR was used to analyze: EcR and usp, two genes encoding the two dimerizing partners of the functional ecdysone receptor; E74, an early response gene induced by ecdysteroids; vg (vitellogenin), an effector gene; hsp70 and hsc70, two heat-shock genes involved in the correct folding of the ecdysone receptor; and rpL13, as a part of the ribosomal machinery. Our results show for the first time stage and sex-dependent variations in ecdysone-responsive genes, specially during the late larval stage of C. riparius. The induction in the expression of EcR and usp during the VII-VIII phase of the fourth instar is concomitant with a coordinated response in the activity of the other genes analyzed, suggesting the moment where larvae prepare for pupation. This work is particularly relevant given that most of the analyzed genes have been proposed previously in this species as sensitive biomarkers for the toxicological evaluation of aquatic ecosystems. Identifying the natural regulation of these molecular endpoints throughout the Chironomus development will contribute to a more in-depth and accurate evaluation of the disrupting effects of EDCs in ecotoxicological studies. PMID:26448051

  10. The plasticizer benzyl butyl phthalate (BBP) alters the ecdysone hormone pathway, the cellular response to stress, the energy metabolism, and several detoxication mechanisms in Chironomus riparius larvae.

    PubMed

    Herrero, Óscar; Planelló, Rosario; Morcillo, Gloria

    2015-06-01

    Butyl benzyl phthalate (BBP) has been extensively used worldwide as a plasticizer in the polyvinyl chloride (PVC) industry and the manufacturing of many other products, and its presence in the aquatic environment is expected for decades. In the present study, the toxicity of BBP was investigated in Chironomus riparius aquatic larvae. The effects of acute 24-h and 48-h exposures to a wide range of BBP doses were evaluated at the molecular level by analysing changes in genes related to the stress response, the endocrine system, the energy metabolism, and detoxication pathways, as well as in the enzyme activity of glutathione S-transferase. BBP caused a dose and time-dependent toxicity in most of the selected biomarkers. 24-h exposures to high doses affected larval survival and lead to a significant response of several heat-shock genes (hsp70, hsp40, and hsp27), and to a clear endocrine disrupting effect by upregulating the ecdysone receptor gene (EcR). Longer treatments with low doses triggered a general repression of transcription and GST activity. Furthermore, delayed toxicity studies were specially relevant, since they allowed us to detect unpredictable toxic effects, not immediately manifested after contact with the phthalate. This study provides novel and interesting results on the toxic effects of BBP in C. riparius and highlights the suitability of this organism for ecotoxicological risk assessment, especially in aquatic ecosystems. PMID:25725395

  11. Effects of uranium-contaminated sediments on the bioturbation activity of Chironomus riparius larvae (Insecta, Diptera) and Tubifex tubifex worms (Annelida, Tubificidae).

    PubMed

    Lagauzère, S; Boyer, P; Stora, G; Bonzom, J-M

    2009-07-01

    Freshwater sediments represent a compartment for accumulation of toxic substances, notably of metallic pollutants such as uranium. However, they also constitute a privileged habitat for many benthic macro-invertebrate species with important roles in the functioning of these ecosystems, particularly through their bioturbation activities. Uranium accumulation in sediments can thus have harmful effects on these organisms (e.g., developmental delay, malformations, mortality). The present study aimed to evaluate the consequences of these effects on the bioturbation activity of Chironomus riparius larvae and Tubifex tubifex worms. These two species, which are widespread in freshwater ecosystems, are characteristic of two different modes of bioturbation: bioirrigation and upward bioconveying, respectively. By quantifying the burial and redistribution of fluorescent particulate tracers (microspheres), sediment reworking induced by these macro-invertebrates was measured after 12d of exposure. Biodiffusion D(b) and bioadvection W rates, as well as several other parameters, were estimated to assess and compare the bioturbation activity of the two species, separately and in combination, between uncontaminated and uranium-spiked sediments. The results reveal that C. riparius larvae were more sensitive to uranium, but their bioturbation activity, even under uncontaminated conditions, had little effect on sediment reworking. Particle mixing was mainly induced by T. tubifex worms, which were only affected by uranium at high concentrations in the sediment. Finally, bioturbation by T. tubifex led to a high degree of uranium release from sediment to the overlying water, which highlights the crucial role of this mostly dominant species on uranium biogeochemical cycles at concentrations existing in naturally contaminated sites. PMID:19403158

  12. Additive effects of predator cues and dimethoate on different levels of biological organisation in the non-biting midge Chironomus riparius.

    PubMed

    Van Praet, Nander; De Jonge, Maarten; Stoks, Robby; Bervoets, Lieven

    2014-10-01

    The combined effects of a pesticide and predation risk on sublethal endpoints in the midge Chironomus riparius were investigated using a combination of predator-release kairomones from common carp (Cyprinus carpio) and alarm substances from conspecifics together with the pesticide dimethoate. Midge larvae were exposed for 30 days to three sublethal dimethoate concentrations (0.01, 0.1 and 0.25 mg L(-1)) in the presence or absence of predator cues. Sublethal endpoints were analysed at different levels of biological organisation. Available energy reserves, enzyme biomarkers, feeding rate and life history endpoints were investigated. Three endpoints were significantly affected by the two highest dimethoate concentrations, i.e. AChE activity, age at emergence and emergence success, with a significant decrease in response after exposure to 0.25, 0.1 and 0.01 mg L(-1) dimethoate, respectively. Four sublethal endpoints were significantly affected by predator stress: Total protein content, GST activity and biomass decreased only in the presence of the predation risk, while AChE activity further decreased significantly in the presence of predation cues and effects on AChE of combined exposure were additive. From this study we can conclude that sublethal life history characteristics should be included in ecotoxicity testing as well as natural environmental stressors such as predator stress, which might act additively with pollutants on fitness related endpoints. PMID:25063887

  13. Characterization of six small HSP genes from Chironomus riparius (Diptera, Chironomidae): Differential expression under conditions of normal growth and heat-induced stress.

    PubMed

    Martín-Folgar, Raquel; de la Fuente, Mercedes; Morcillo, Gloria; Martínez-Guitarte, José-Luis

    2015-10-01

    Small heat shock proteins (sHSPs) comprise the most numerous, structurally diverse, and functionally uncharacterized family of heat shock proteins. Several Hsp genes (Hsp 90, 70, 40, and 27) from the insect Chironomus riparius are widely used in aquatic toxicology as biomarkers for environmental toxins. Here, we conducted a comparative study and characterized secondary structure of the six newly identified sHsp genes Hsp17, Hsp21, Hsp22, Hsp23, Hsp24, and Hsp34. A characteristic α-crystallin domain is predicted in all the new proteins. Phylogenetic analysis suggests a strong relation to other sHSPs from insects and interesting evidence regarding evolutionary origin and duplication events. Comparative analysis of transcription profiles for Hsp27, Hsp70, and the six newly identified genes revealed that Hsp17, Hsp21, and Hsp22 are constitutively expressed under normal conditions, while under two different heat shock conditions these genes are either not activated or are even repressed (Hsp22). In contrast, Hsp23, Hsp24, and Hsp34 are significantly activated along with Hsp27 and Hsp70 during heat stress. These results strongly suggest functional differentiation within the small HSP subfamily and provide new data to help understand the coping mechanisms induced by stressful environmental stimuli. PMID:26129721

  14. Effects of in vivo exposure to UV filters (4-MBC, OMC, BP-3, 4-HB, OC, OD-PABA) on endocrine signaling genes in the insect Chironomus riparius.

    PubMed

    Ozáez, Irene; Martínez-Guitarte, José Luis; Morcillo, Gloria

    2013-07-01

    There is increasing evidence indicating that several UV filters might have endocrine disruptive effects. Numerous studies have evaluated hormonal effects in vertebrates, mainly reporting estrogenic and androgenic activities in mammals and fishes. There is only limited knowledge about potential endocrine activity in invertebrate hormonal systems. In this work, the effects on endocrine signaling genes of six frequently used UV filters were investigated in Chironomus riparius, a reference organism in aquatic toxicology. The UV filters studied were: octyl-p-methoxycinnamate (OMC) also called 2-ethylhexyl-4-methoxycinnamate (EHMC); 4-methylbenzylidene camphor (4-MBC); benzophenone-3 (BP-3); 4-hidroxybenzophenone (4-HB); octocrylene (OC); and octyldimethyl-p-aminobenzoate (OD-PABA). After in vivo exposure at different dosages, expression levels of the genes coding for the ecdysone receptor (EcR), the ultraspiracle (usp, ortholog of the RXR) and the estrogen-related receptor (ERR) were quantified by Real Time PCR. The EcR gene was significantly upregulated by 4-MBC, OMC/EHMC and OD-PABA, with a dose-related response following 24h exposure. In contrast, the benzophenones, BP-3 and 4-HB, as well as OC did not alter this gene at the same exposure conditions. The transcription profiles of the usp and ERR genes were not significantly affected, except for BP-3 that inhibited the usp gene at the highest concentration. To our knowledge, this is the first experimental evidence in invertebrates of a direct effect of UV filters on endocrine-related genes, and is consistent with the known effects on vertebrate hormonal receptor genes. The capability of 4-MBC, OMC/EHMC and OD-PABA to stimulate the expression of the ecdysone receptor, a key transcription factor for the ecdysone-genomic response in arthropods, suggests the possibility of a broad and long-term effect on this hormonal pathway. These findings strengthen the need for further research about the ecotoxicological implications

  15. Relative acute effects of low pH and high iron on the hatching and survival of the water mite (Arrenurus manubriator) and the aquatic insect (Chironomus riparius)

    SciTech Connect

    Rousch, J.M.; Simmons, T.W.; Kerans, B.L.; Smith, B.P.

    1997-10-01

    The authors investigated the relative effects of low pH and high iron on a water mite, Arrenurus manubriator and an aquatic insect, Chironomus riparius. Eggs and active stages were exposed in static renewal toxicity tests to pH 6, 5, 4, 3, and 2, made by adding sulfuric acid to reconstituted soft water, or to iron levels of 200, 400, 600, 800, and 1,000 mg/L, made by adding ferrous sulfate to soft water at pH 4. Experiments were conducted at 22 C with a 16:8-h photoperiod, and treatments were replicated three times with at least nine individuals per treatment. Data were analyzed with a logistic response function and one-way ANOVA for pH and iron tests, respectively. Egg hatching was reduced at pH 2 for midges and at pH 3 for mites. Iron had no effect on hatching for either species. Survival of midge larvae was partially reduced at pH 4, and survival of mite deutonymphs, larvae, female and male adults was reduced at pH 3. Survival of midge larvae, and mite deutonymphs and male adults was reduced at 400, 200, and 1,000 mg Fe/L, respectively. Mite female adults and larvae were unaffected by iron. Higher metabolic requirements of unfed immature stages, the gelatinous covering of mite and insect eggs, the longer incubation period of mite eggs, and the greater osmoregulatory potential of adult mites may have contributed to the differences observed.

  16. Uptake and metabolism of benzo(a)pyrene absorbed to sediment by the freshwater invertebrate species Chironomus riparius and Sphaerium corneum

    SciTech Connect

    Borchert, J.; Karbe, L.; Westendorf, J.

    1997-01-01

    The polyaromatic hydrocarbon (PAH) Benzo(a)pyrene (BP) is a widespread contaminant, which is known to be carcinogenic in mammals after ic activation. BP is released into the environment and the water as a by-product of combustion of fossil and recent material (fuel, wood) in industry, traffic and households and is also released by natural sources. Most of the PAHs are highly lipophilic and therefore bound to humic substances, dissolved macromolecules and particulate matter which are at least deposited in the aquatic sediments. The BP concentrations in sediments of pristine waters do normally not exceed 1 {mu}g/g dry weight (dw). In polluted waters of industrial areas, the BP concentration may increase up to 100 {mu}g/g dw. The risk for environmental health caused by such sediment bound PAHs can be assessed by using BP as a model substance. One aim of this study was to investigate if the sediment bound BP is bioavailable to sediment dwelling organisms. For this purpose we examined the uptake of sediment bound BP. The metabolism of PAHs in insects has been investigated, however, only little is known about the Phase I and Phase II metabolism in clams, especially in freshwater species. The organisms choosen were two sediment inhabiting invertebrates, the larvae of the midge Chironomus riparius and the European fingernail clam Sphaerium corneum. Also investigated was the question of whether the BP taken up by the test organisms undergoes metabolic activation, since the toxicity of BP is modulated by metabolism. 11 refs., 3 figs., 4 tabs.

  17. Effects of carbamazepine and two of its metabolites on the non-biting midge Chironomus riparius in a sediment full life cycle toxicity test.

    PubMed

    Heye, Katharina; Becker, Dennis; Lütke Eversloh, Christian; Durmaz, Vedat; Ternes, Thomas A; Oetken, Matthias; Oehlmann, Jörg

    2016-07-01

    The antiepileptic drug carbamazepine (CBZ) and its main metabolites carbamazepine-10,11-epoxide (EP-CBZ) and 10,11-dihydro-10,11-dihydroxy-carbamazepine (DiOH-CBZ) were chosen as test substances to assess chronic toxicity on the non-biting midge Chironomus riparius. All the three substances were tested in a 40-day sediment full life cycle test (according to OECD 233) in which mortality, emergence, fertility, and clutch size were evaluated. In addition, these parameters were considered to calculate the population growth rate which represents an integrated measure to assess population relevant effects. With an LC50 of 0.20 mg/kg (time-weighted mean), the metabolite EP-CBZ was significantly more toxic than the parent substance CBZ (LC50: 1.1 mg/kg). Especially mortality, emergence, and fertility showed to be sensitive parameters under the exposure to CBZ and EP-CBZ. By using classical molecular dynamics (MD) simulations, the binding of CBZ to the ecdysone receptor was investigated as one possible mode of action (MoA) but appeared to be unlikely. The second metabolite DiOH-CBZ did not cause any effects within the tested concentration rage (0.17-1.2 mg/kg). Even though CBZ was less toxic compared to EP-CBZ, CBZ is found in the environment at much higher concentrations and therefore causes a higher potential risk for sediment dwelling organisms compared to its metabolites. Nevertheless, the current study illustrates the importance of including commonly found metabolites into the risk assessment of parent substances. PMID:27064208

  18. Roles of uptake, biotransformation, and target site sensitivity in determining the differential toxicity of chlorpyrifos to second to fourth instar Chironomous riparius (Meigen)

    USGS Publications Warehouse

    Buchwalter, D.B.; Sandahl, J.F.; Jenkins, J.J.; Curtis, L.R.

    2004-01-01

    Early life stages of aquatic organisms tend to be more sensitive to various chemical contaminants than later life stages. This research attempted to identify the key biological factors that determined sensitivity differences among life stages of the aquatic insect Chironomous riparius. Specifically, second to fourth instar larvae were exposed in vivo to both low and high waterborne concentrations of chlorpyrifos to examine differences in accumulation rates, chlorpyrifos biotransformation, and overall sensitivity among instars. In vitro acetylcholinesterase (AChE) assays were performed with chlorpyrifos and the metabolite, chlorpyrifos-oxon, to investigate potential target site sensitivity differences among instars. Earlier instars accumulated chlorpyrifos more rapidly than later instars. There were no major differences among instars in the biotransformation rates of chlorpyrifos to the more polar metabolites, chlorpyrifos-oxon, and chlorpyridinol (TCP). Homogenate AChE activities from second to fourth instar larvae were refractory to chlorpyrifos, even at high concentrations. In contrast, homogenate AChE activities were responsive in a dose-dependent manner to chlorpyrifos-oxon. In general, it appeared that chlorpyrifos sensitivity differences among second to fourth instar C. riparius were largely determined by differences in uptake rates. In terms of AChE depression, fourth instar homogenates were more sensitive to chlorpyrifos and chlorpyrifos-oxon than earlier instars. However, basal AChE activity in fourth instar larvae was significantly higher than basal AChE activity in second to third instar larvae, which could potentially offset the apparent increased sensitivity to the oxon. ?? 2003 Elsevier B.V. All rights reserved.

  19. Allatostatin A-like immunoreactivity in the nervous system and gut of the larval midge Chironomus riparius: modulation of hindgut motility, rectal K+ transport and implications for exposure to salinity.

    PubMed

    Robertson, Lisa; Chasiotis, Helen; Galperin, Vladimir; Donini, Andrew

    2014-11-01

    Evidence for the presence of allatostatin (AST) A-like neuropeptides in the larval midge Chironomus riparius is reported. Immunohistochemical studies on the nervous system and gut revealed the presence of AST A-like immunoreactive (AST-IR) cells and processes. The nerve cord contained AST-IR processes that originated from cells in the brain and travelled the length of nerve cord to the terminal ganglion. Within each ganglion, these processes gave rise to varicosities, suggesting that they formed synapses with neurons in the ganglia. Endocrine cells containing AST-IR were present in three regions of the midgut: near the attachment of the Malpighian tubules, between the anterior and posterior midgut, and in the vicinity of the gastric caecae. The terminal ganglion also contained four AST-IR cells that gave rise to axons that projected onto the hindgut and posterior midgut. Application of a cockroach AST to the semi-isolated hindgut of larval C. riparius led to dose-dependent inhibition of muscle contractions with an EC50 of ~10 nmol l(-1) and a decrease in rectal K(+) reabsorption resulting from reduced rectal Na(+)/K(+)-ATPase and vacuolar type H(+)-ATPase activities. The results suggest the presence of endogenous AST-like neuropeptides in larval C. riparius, where these factors play a role in the function of the gut. Furthermore, regulation of ion reabsorption by ASTs at the rectum could serve as an ideal mechanism of ion regulation in the face of abrupt and acute elevated salt levels. PMID:25214489

  20. A cysteine-clamp gene drives embryo polarity in the midge Chironomus*

    PubMed Central

    Klomp, Jeff; Athy, Derek; Kwan, Chun Wai; Bloch, Natasha I.; Sandmann, Thomas; Lemke, Steffen; Schmidt-Ott, Urs

    2015-01-01

    In the common fruit fly Drosophila, head formation is driven by a single gene, bicoid, which generates head-to-tail polarity of the main embryonic axis. Bicoid deficiency results in embryos with tail-to-tail polarity and no head. However, most insects lack bicoid, and the molecular mechanism for establishing head-to-tail polarity is poorly understood. We have identified a gene that establishes head-to-tail polarity of the mosquito-like midge, Chironomus riparius. This gene, named panish, encodes a cysteine-clamp DNA binding domain and operates through a different mechanism than bicoid. This finding, combined with the observation that the phylogenetic distributions of panish and bicoid are limited to specific families of flies, reveals frequent evolutionary changes of body axis determinants and a remarkable opportunity to study gene regulatory network evolution. PMID:25953821

  1. Embryo development. A cysteine-clamp gene drives embryo polarity in the midge Chironomus.

    PubMed

    Klomp, Jeff; Athy, Derek; Kwan, Chun Wai; Bloch, Natasha I; Sandmann, Thomas; Lemke, Steffen; Schmidt-Ott, Urs

    2015-05-29

    In the fruit fly Drosophila, head formation is driven by a single gene, bicoid, which generates head-to-tail polarity of the main embryonic axis. Bicoid deficiency results in embryos with tail-to-tail polarity and no head. However, most insects lack bicoid, and the molecular mechanism for establishing head-to-tail polarity is poorly understood. We have identified a gene that establishes head-to-tail polarity of the mosquito-like midge, Chironomus riparius. This gene, named panish, encodes a cysteine-clamp DNA binding domain and operates through a different mechanism than bicoid. This finding, combined with the observation that the phylogenetic distributions of panish and bicoid are limited to specific families of flies, reveals frequent evolutionary changes of body axis determinants and a remarkable opportunity to study gene regulatory network evolution. PMID:25953821

  2. Differential sensitivity of Chironomus and human hemoglobin to gamma radiation.

    PubMed

    Gaikwad, Pallavi S; Panicker, Lata; Mohole, Madhura; Sawant, Sangeeta; Mukhopadhyaya, Rita; Nath, Bimalendu B

    2016-08-01

    Chironomus ramosus is known to tolerate high doses of gamma radiation exposure. Larvae of this insect possess more than 95% of hemoglobin (Hb) in its circulatory hemolymph. This is a comparative study to see effect of gamma radiation on Hb of Chironomus and humans, two evolutionarily diverse organisms one having extracellular and the other intracellular Hb respectively. Stability and integrity of Chironomus and human Hb to gamma radiation was compared using biophysical techniques like Dynamic Light Scattering (DLS), UV-visible spectroscopy, fluorescence spectrometry and CD spectroscopy after exposure of whole larvae, larval hemolymph, human peripheral blood, purified Chironomus and human Hb. Sequence- and structure-based bioinformatics methods were used to analyze the sequence and structural similarities or differences in the heme pockets of respective Hbs. Resistivity of Chironomus Hb to gamma radiation is remarkably higher than human Hb. Human Hb exhibited loss of heme iron at a relatively low dose of gamma radiation exposure as compared to Chironomus Hb. Unlike human Hb, the heme pocket of Chironomus Hb is rich in aromatic amino acids. Higher hydophobicity around heme pocket confers stability of Chironomus Hb compared to human Hb. Previously reported gamma radiation tolerance of Chironomus can be largely attributed to its evolutionarily ancient form of extracellular Hb as evident from the present study. PMID:27237970

  3. Rearing and Maintaining Midge Cultures (Chironomus tentans) for Laboratory Studies.

    ERIC Educational Resources Information Center

    Hein, John; Mahadeva, Madhu N.

    1992-01-01

    The life history of the Chironomus tentans can be observed in easily established and maintained laboratory cultures. Projects for the classroom include observing hydration of an egg mass; embryonic development, hatching and larval feeding; larval activity; and mating activity. (MDH)

  4. New data on poorly known species of the genus Leia Meigen (Diptera, Mycetophilidae) from the Palaearctic region.

    PubMed

    Polevoi, Alexei; Salmela, Jukka

    2016-01-01

    New data on four poorly known species of the genus Leia Meigen (L. nigricornis van Duzee, L. flavipennis Laštovka & Matile, L. iturupensis Zaitzev and L. rufiptera Ostroverkhova) are presented. Detailed redescriptions and terminalia figures are provided. Leia nigricornis is reported for the first time from the Palaearctic region and L. automnala Ostroverkhova & Grishina is found to be a junior synonym of L. flavipennis. A variation in the male terminalia of L. bimaculata Meigen is illustrated, based on specimens from several European countries. PMID:27394752

  5. Chironomus group classification according to the mapping of polytene chromosomes

    NASA Astrophysics Data System (ADS)

    Salleh, Syafinaz; Kutty, Ahmad Abas

    2013-11-01

    Chironomus is one of the important genera in Chironomidae family since they are widely diverse and abundance in aquatic ecosystem. Since Chironomus is very diverse, taxonomic work on this genus is very difficult and incomplete. Objective of this study is to form group classification of Chironomus according to the polytene chromosome mapping. The specific characteristics of polytene chromosomes in the salivary gland appeared to be particularly promising for taxonomic diagnosis of chironomid species. Chironomid larvae were collected from pristine sites at Sg. Langat and cultured in laboratory to reach fourth instar stage. The salivary glands were removed from larvae and chromosomes were stained with aceto orcein. Results showed that polytene chromosomes of Chironomus comprise of three long metacentric or submetacentric arms (BF, CD and AE arms) and one short acrocentric (G arm). In regards to nucleolar organizing region (NOR), Balbiani ring (BR), puffings and chromosome rearrangement, a number of four groups of different banding patterns were found. Two groups called as G group A and B have common NOR on arm BF and BR on arm G. However, group A has rearrangement pattern on arm CD and not in group B. This makes group B separated from group A. Another two groups called as groups C and D do not have common NOR on arm BF and also BR on arm G. Groups C and D were separated using arms G and arm AE. At arm G, only group C rearrangement pattern at unit 23c whereas group D was found to have large NOR at arm G and as well as arm AE, only group D has rearrangement pattern at unit 12c. This study indicates that chromosome arrangement could aid in revealing Chironomus diversity.

  6. Karyotype and C-Banding Patterns of Mitotic Chromosomes in Meadow Bromegrass (Bromus riparius Rehm)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chromosomes of meadow bromegrass, Bromus riparius, are mainly median and similar in morphology. C-bands were located at telomeric regions of the chromosomes. Majority of the chromosomes had telomeric bands either in one or both arms. Approximately 10 chromosomes had no C-bands. Karyotype of meadow b...

  7. Chromosome analysis of Endochironomus albipennis Meigen, 1830 and morphologically similar Endochironomus sp. (Diptera, Chironomidae) from water bodies of the Volga region, Russia

    PubMed Central

    Durnova, Natalya; Sigareva, Ludmila; Sinichkina, Olga

    2015-01-01

    Abstract Based upon the detailed chromosome map of polytene chromosomes of the eurybiont species Endochironomus albipennis Meigen, 1830, the localization of the centromere regions using a C-banding technique is defined. Chromosomal polymorphism in populations from two water bodies in the Volga region has been studied, 17 sequences are described. Polytene chromosomes of Endochironomus sp. (2n=6), having larvae morphologically similar to those of Endochironomus albipennis Meigen, 1830 (2n=6) are described for the first time. PMID:26752268

  8. A new species of the genus Ctenophora Meigen (Diptera: Tipuloidea: Tipulidae) from China, with a key to the world species.

    PubMed

    Men, Qiu-Lei; Huang, Min-Yi

    2014-01-01

    One new species of the genus Ctenophora Meigen, 1803, C. fumosa Men, sp. nov. (southern China: Anhui) is described and illustrated. A key to known species along with a checklist of known species of the genus Ctenophora are provided. The type specimens of the new species are deposited in the animal specimen room, School of Life Science, Anqing Normal University, Anqing, Anhui Province, China.  PMID:25082059

  9. New data on the genus Hybos Meigen (Diptera: Hybotidae) from the Palaearctic Region.

    PubMed

    Shamshev, Igor; Grootaert, Patrick; Kustov, Semen

    2015-01-01

    The taxonomy and distribution of the genus Hybos Meigen in the Palaearctic Region is reviewed with a special reference to the European fauna. Twenty-three species have been recorded from the Palaearctic, of which only four species are known from Europe. We describe two new species, H. andradei sp. nov. (Portugal) and H. mediasiaticus sp. nov. (Middle Asia). The status of two previously considered doubtful species of Hybos are validated: H. striatellus Villeneuve, 1913 (Algeria) and H. vagans Loew, 1874 (the Caucasus). Both species are re-described, and the lectotype of H. striatellus is designated. A key to species of Hybos from the western Palaearctic is compiled. Numerous new data on distributions of H. culiciformis (Fabricius, 1775), H. femoratus (Müller, 1776), H. grossipes (Linné, 1767) and H. vagans are given. Hybos culiciformis is recorded for the first time from Algeria, Byelorussia, Croatia, Cyprus, Lebanon, and Portugal; H. femoratus-from Estonia, Georgia (including Abkhazia), Kazakhstan, Mongolia and Ukraine; H. grossipes-from Byelorussia, Estonia, Kazakhstan, Latvia, Mongolia, Ukraine; H. vagans-from Armenia, Azerbaijan, Georgia (including Abkhazia), Russia, Turkey. The variation of some characters in H. culiciformis is discussed and is confirmed for Portugese specimens by COI barcoding. Female postabdominal structures are examined and described for H. andradei sp. nov., H. culiciformis, H. femoratus, H. grossipes, H. mediasiaticus sp. nov., and H. striatellus. Possible relationships of the West-Palaearctic species are discussed. A check-list of Hybos from the Palaearctic Realm is provided. PMID:25947449

  10. Antennal sensilla of the green bottle fly, Lucilia sericata (Meigen) (Diptera: Calliphoridae).

    PubMed

    Zhang, D; Liu, X H; Li, X Y; Zhang, M; Li, K

    2013-11-01

    Lucilia sericata (Meigen) is a cosmopolitan synanthropic fly of forensic and medical importance, which can work as a mechanic vector of pathogens or cause myiasis of both human and sheep. As essential olfactory organs, antennae of adult L. sericata were examined with stereoscopic microscope, scanning electron microscope, and laser scanning confocal microscope. On antennal scape and pedicel, both microtirchiae and several bristles are detected, while another two structures, setiferous plaques and pedicellar buttons, are also found on the antennal pedicel. Seven subtypes of antennal sensilla are observed on antennal funiculus including one subtype of trichoid sensilla, two subtypes of basiconic sensilla, two subtypes of coeloconic sensilla, and two subtypes of sensory pits. Size and density of the former four types of sensilla on antennal funiculus are measured. Three distinctive sensillar characters of L. sericata are detected, which may contribute to greater olfactory sensitivity of this species and their wide distribution throughout the world. Unlike the common poreless pedicellar button with mechanoreceptor function, every pedicellar button in L. sericata is perforated by three pores, which might indicate potential chemoreceptor function of this structure. Besides, another unique feature is greater number of setiferous plaques in genus Lucilia than calliphorids of other genera. Expect for the common sensory pits with basiconic or basiconic-like sensilla in them, sensory pits filled with rarely described coeloconic-like sensilla are founded in L. sericata as well. After comparison with previous equivalent findings, the functions of these specific structures are discussed according to the life history of this calliphorid. PMID:23955594

  11. Revision of the Nearctic species of Callomyia Meigen (Diptera: Platypezidae) and phylogeny of the genus.

    PubMed

    Cumming, Heather J; Wheeler, Terry A

    2016-01-01

    The Nearctic fauna of the genus Callomyia Meigen is revised and a phylogeny of the world species, based on morphological characters, is presented. Although morphological data are used primarily to delimit species, molecular sequence data (DNA barcodes) are used where possible, to help determine species boundaries and associate sexes. Species descriptions, diagnoses, and distribution maps are presented, along with illustrations of habitus, male terminalia, and additional important diagnostic characters. A key to the Nearctic species is provided. Ten species are recorded from the Nearctic Region including three new species: C. argentea Cumming sp. nov., C. arnaudi Cumming sp. nov., C. bertae Kessel, C. browni Cumming sp. nov., C. calla Kessel, C. corvina Kessel, C. gilloglyorum Kessel, C. proxima Johnson, C. velutina Johnson, and C. venusta Snow. The female of C. velutina is described, and three new synonyms are proposed: C. cleta Kessel is a junior synonym of C. calla syn. nov.; C. clara Kessel is a junior synonym of C. corvina syn. nov.; and C. liardia Kessel & Buegler is a junior synonym of C. proxima syn. nov. Phylogenetic relationships within the genus are reconstructed. The genus is monophyletic based primarily on the setulose R1 wing vein, female antennal size and three larval characters. The Nearctic species do not form a monophyletic group with respect to the Old World species. PMID:27395101

  12. Ethmolaimus riparius sp. n. and Paramononchus major sp. n. (Nematoda) from Lake Baikal, Russia.

    PubMed

    Gagarin, Vladimir G; Naumova, Tatyana V

    2016-01-01

    Two new nematode species found in Lake Baikal (Russia) are described and illustrated. Ethmolaimus riparius sp. n. is morphologically close to E. pilosus Shoshin, 1998 and E. lanatus Shoshin, 1998. The new species differs from E. pilosus by the longer and thinner body (L = 1228-1501 µm, a = 26-34 vs L = 720-1070 µm, a = 19-23), larger stoma (26-32 µm long vs 19-24 µm long), longer spicules and gubernaculum (45-50 µm long and 21-25 µm long vs accordingly 32-37 µm long and 8 µm long). E. riparius sp. n. differs from E. lanatus by the longer body (L = 1228-1501 µm vs L = 680-1180), shorter cephalic setae (its length is equal 1.1-1.4 labial region diameter vs 1.6-2.1 labial region diameter) and longer spicules and gubernaculum (45-50 µm long and 21-25 µm long vs accordingly 25-30 µm long and 7-8 µm long). Paramononchus major sp. n is close to P. orientalis Gagarin & Naumova, 2012, but differs from it by the longer body (L = 5926-7820 µm vs L = 3081-3778 µm), longer spicules (410-475 µm long vs 208-238 µm long) and larger number of precloacal supplements (52-61 vs 21-24). Keys for the identification of valid species of the genera Ethmolaimus and Paramononchus are given. PMID:27394603

  13. The first report of Telomerina flavipes (Meigen, 1830) (Diptera, Sphaeroceridae) in a forensic case, with redescription of its pupa.

    PubMed

    Arnaldos, María-Isabel; Ubero-Pascal, Nicolás; García, Rafael; Carles-Tolrá, Miguel; Presa, Juan-José; García, María-Dolores

    2014-09-01

    This paper presents a forensic investigation that took place in the city of Murcia (SE Spain) and shows how the entomological specimens collected at the scene were extremely helpful for estimating the minimum post-mortem interval (PMImin). The occurrence of Telomerina flavipes (Meigen, 1830) (Diptera: Sphaeroceridae) is reported here for the first time in a forensic case. Additionally, the importance of other entomological evidence in this case is discussed. The first known images of the puparium are provided, as well as its redescription and that of the cephalopharyngeal skeleton recovered from the puparium. PMID:25128390

  14. [Synergistic effect of physical and Chironomus plumosus combined disturbance on regeneration and transformation of internal phosphorus].

    PubMed

    Shi, Xiao-Dan; Li, Da-Peng; Wang, Ren; Huang, Yong

    2015-03-01

    To explain the synergistic effect of physical and Chironomus plumosus combined disturbance on the regeneration and transformation of internal phosphorus, laboratory static incubation experiments were carried out with the sediments and overlying water from a eutrophic river in Suzhou. Rhizon samplers were used to acquire the pore water. In the experiment, we compared the variation of different phosphorus forms in the overlying water, the pore water and sediments under the Chironomus plumosus disturbance and the combined disturbance. The results indicated that the amount of different forms of phosphorus (TP, PP, DTP, DIP) in the overlying water under combined disturbance was higher than that under Chironomus plumosus combination disturbance. It was attributed to the significant increase of the microbial activity in the sediments. Compared with Chironomus plumosus disturbance, the amount of DIP and ferrous decreased with the greater magnitude and range. It was attributed to the superposition effect of the physical and benthos disturbance on the penetration depth of the dissolved oxygen. In addition, the amount of NH4C1-P decreased remarkably in the 0-2 cm sediment while Fe/Al-P increased obviously. Furthermore, the variation magnitude of NH4Cl-P and Fe/Al-P was higher under combined disturbance than that under Chironomus plumosus disturbance, which suggested the superposition effect of the physical and benthos disturbance on the regeneration and migration of phosphorus. PMID:25929063

  15. Growth of immature Chironomus calligraphus in laboratory conditions.

    PubMed

    Canteiro, Rita de Cássia S A; Albertoni, Edélti F

    2011-12-01

    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 < 0.001). The Dyar’s Rule showed a constant growth rate, r = 1.5. Our results demonstrated that C. calligraphus is a species with short life cycle, low mortality rate, food adaptability, fast larval growth and easily maintained at laboratory, factors that allowed the use of this native species as a tool for ecotoxicological tests. PMID:21971596

  16. Centromeric polymerase III transcription units in Chironomus pallidivittatus.

    PubMed Central

    Rovira, C; Edström, J E

    1996-01-01

    Cp1 is a polymorphic short interspersed repeat (SINE) which is distributed over the whole genome of the dipteran Chironomus pallidivittatus, and is particularly abundant in the centromeres. It contains two different sequence modules, one of which, the B module, has a polymerase III internal control region (ICR) typical for tRNA genes (A and B box). Such sequence motifs are common in SINEs and assumed to function in RNA-mediated transposition. In the present case, however, several structural features speak for another role. An investigation of the transcription of the B module shows that it encodes a 99 nt RNA species in vivo, Cp1-RNA, terminating within the module. The transcription unit is likely to have evolved from a pre-tRNA gene and the transcript has sequence similarities to non-processed pre-tRNA. Most of the in vitro transcription is eliminated by deletion or substitution mutation of an upstream TATA box, present within the B module, as well as by changing either the A or B box. The properties of the transcript suggest that it does not have a role in transposition but may have some other function, perhaps in the centromere. PMID:8649983

  17. Review of the longipalpus-Group of Chrysotus Meigen (Diptera: Dolichopodidae), with Description of Four New Species.

    PubMed

    Capellari, R S

    2015-02-01

    The longipalpus-group of Chrysotus Meigen is reviewed and comprises eight species: Chrysotus coquitos n. sp. (Mexico), Chrysotus crosbyi Van Duzee (Eastern US, Bermuda, Cuba, Puerto Rico and Brazil; introduced in Australasian Region), Chrysotus longipalpus Aldrich (=Chrysotus sagittarius Van Duzee, n. syn.; Eastern US, Saint Vincent, Grenadas and Brazil; introduced in the Afrotropical, Australasian, Oriental and Palaearctic regions), Chrysotus miripalpus Parent (Costa Rica and Brazil), Chrysotus neopedionomus n. sp. (Brazil), Chrysotus pachystoma n. sp. (Belize), Chrysotus xiphostoma Robinson (Dominica and Saint Lucia), and Chrysotus zumbadoi n. sp. (Costa Rica). Lectotype and paralectotypes are designated for Chrysotus pallidipalpus Van Duzee, and a neotype for C. miripalpus. Illustrations of the hypopygium and ovipositor, photos of the male palpus and a key to species of the group are provided. PMID:26013012

  18. A new record of Chironomus (Chironomus) acidophilus Keyl (Diptera, Chironomidae) from the Uzon volcanic caldera (Kronotsky Reserve, Kamchatka Peninsula, Russia), its karyotype, ecology and biology.

    PubMed

    Orel, Oksana V; Lobkova, Ludmila E; Zhirov, Sergey V; Petrova, Ninel A

    2015-01-01

    Morphology, cytology, ecology and biology of Holarctic Chironomus (Chironomus) acidophilus Keyl, 1960 (Diptera, Chironomidae) was examined from material collected in the geothermal Vosmerka Lake (pH=2.0-2.5). An illustrated redescription of C. acidophilus is given on the basis of adult males reared from field-collected pupae, and of simultaneously collected larvae. Additional larvae belonging to the pseudothummi-complex were identified as C. acidophilus on the basis of their karyotype. The karyotype of C. acidophilus (2n=8) and detailed mapping of the 4 chromosome arms A, E, D and F are provided. The population of C. acidophilus from Kamchatka was found to be karyologically monomorphic. Information on distribution and ecology of C. acidophilus from Vosmerka Lake (total mineralization 1583.5 mg/l) is also given. Chironomus acidophilus is the only species of aquatic insects recorded in this lake. Lack of competition and a richness of food resources contribute to the high abundance (35161 ind./m2) and biomass (11.342 g/m2) of the larvae of C. acidophilus in Vosmerka Lake. PMID:26249988

  19. OBSERVATIONS ON THE 10-DAY CHIRONOMUS TENTANS SURVIVAL AND GROWTH BIOASSAY IN EVALUATING GREAT LAKES SEDIMENTS

    EPA Science Inventory

    A 10-day bioassay with larval chironomids (Chironomus tentans) was used to evaluate sediment samples from harbors at Michigan City, IN, St. Joseph, MI, Grand Haven, MI and Toledo, OH for toxicity, based on the endpoints of survival, dry weight, and growth. Larval responses in se...

  20. What Food and Feeding Rates are Optimum for the Chironomus dilutus Sediment Toxicity Test Method?

    EPA Science Inventory

    Laboratory tests with benthic macroinvertebrates are commonly used to assess the toxicity of both contaminated sediments and individual chemicals. Among the standard procedures for benthic macroinvertebrates are 10-d, 20-d, and life cycle exposures using the midge, Chironomus ...

  1. Method refinements for the midge life-cycle, Chironomus dilutus test

    EPA Science Inventory

    Larval stages of non-biting midges can be found in almost any freshwater ecosystem, and one of the commonly tested midges is Chironomus dilutus (Chironomidae, Diptera) which is used for toxicity testing and ecological risk assessment of freshwater contaminants. USEPA, ASTM, Envir...

  2. INTERLABORATORY STUDY OF PRECISION: HYALELLA AZTECA AND CHIRONOMUS TENTANS FRESHWATER SEDIMENT TOXICITY ASSAYS

    EPA Science Inventory

    Standard 10-d whole sediment toxicity test methods have recently been developed by the U.S. Environmental Protection Agency (EPA) for the amphipod Hyalella azteca and the midge Chironomus tentans. An interlaboratory evaluation of method precision was performed using a group of se...

  3. Cloning and expression of an atrazine inducible cytochrome P450 from Chironomus tentans (Diptera: Chironomidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previous studies performed in our lab have measured the effect of atrazine exposure on cytochrome P450-dependent monooxygenase activity and have found increased activity in midge larvae (Chironomus tentans) as a result of atrazine exposure (1-10 ppm). Here we report the cloning and expression of a ...

  4. TOXICITY OF VERTICAL SEDIMENTS IN THE TRENTON CHANNEL, DETROIT RIVER, MICHIGAN, TO CHIRONOMUS TENTANS (INSECTA: CHIRONOMIDAE)

    EPA Science Inventory

    The objective of this study was to determine the effects of sediment from various sediment core depths on survival and weight gain of larvae of the dipteran midge, Chironomus tentans, during 10-d laboratory exposures. ediment cores were collected from 12 sites in the Trenton Chan...

  5. Mineral Deposition in Bacteria-Filled and Bacteria-Free Calcium Bodies in the Crustacean Hyloniscus riparius (Isopoda: Oniscidea)

    PubMed Central

    Vittori, Miloš; Rozman, Alenka; Grdadolnik, Jože; Novak, Urban; Štrus, Jasna

    2013-01-01

    Crustacean calcium bodies are epithelial sacs which contain a mineralized matrix. The objectives of this study were to describe the microscopic anatomy of calcium bodies in the terrestrial isopod Hyloniscus riparius and to establish whether they undergo molt-related structural changes. We performed 3D reconstruction of the calcium bodies from paraffin sections and analyzed their structure with light and electron microscopy. In addition, we analyzed the chemical composition of their mineralized matrices with micro-Raman spectroscopy. Two pairs of these organs are present in H. riparius. One pair is filled with bacteria while the other pair is not. In non-molting animals, the bacteria-filled calcium bodies contain apatite crystals and the bacteria-free calcium bodies enclose CaCO3-containing concretions with little organic matrix. During preparation for molt, an additional matrix layer is deposited in both pairs of calcium bodies. In the bacteria-filled calcium bodies it contains a mixture of calcium carbonate and calcium phosphate, whereas only calcium carbonate is present in bacteria-free calcium bodies. After ecdysis, all mineral components in bacteria-free calcium bodies and the additional matrix layer in bacteria-filled calcium bodies are completely resorbed. During calcium resorption, the apical surface of the calcium body epithelium is deeply folded and electron dense granules are present in spaces between epithelial cells. Our results indicate that the presence of bacteria might be linked to calcium phosphate mineralization. Calcium bodies likely provide a source of calcium and potentially phosphate for the mineralization of the new cuticle after molt. Unlike other terrestrial isopods, H. riparius does not form sternal CaCO3 deposits and the bacteria-free calcium bodies might functionally replace them in this species. PMID:23554963

  6. Chronic effects of contaminated sediment on Daphnia magna and Chironomus tentans (journal version)

    SciTech Connect

    Nebeker, A.V.; Onjukka, S.T.; Cairns, M.A.

    1988-01-01

    Chronic tests were conducted with Daphnia magna (cladoceran) and Chironomus tentans (midge) to determine their usefulness as test organisms for chronic sediment assays, and to estimate the potential long-term impact of contaminated freshwater sediments and contaminated Superfund-site soils on freshwater invertebrates. These two species were used successfully in acute sediment tests and were shown to be useful in chronic tests in water.

  7. Chronic effects of contaminated sediment on Daphnia magna and Chironomus tentans

    SciTech Connect

    Nebeker, A.V.; Onjukka, S.T.; Cairns, M.A.

    1988-10-01

    Chronic tests were conducted with Daphnia magna (cladoceran) and Chironomus tentans (midge) to determine their usefulness as test organisms for chronic sediment assays, and to estimate the potential long-term impact of contaminated freshwater sediments and contaminated Superfund site soils on freshwater invertebrates. These two species have been used successfully in acute sediment tests, and have been shown to be useful in chronic tests in water--only bioassays.

  8. A new case of an Holarctic element in the Colombian Andes: first record of Cordyla Meigen (Diptera, Mycetophilidae) from the Neotropical region.

    PubMed

    Kurina, Olavi; Oliveira, Sarah Siqueira

    2015-01-01

    Three new species of Mycetophilidae - Cordyla monticola sp. n., Cordyla pseudopusilla sp. n. and Cordyla reducta sp. n. - are described from the Colombian Andes, representing the first described species of Cordyla Meigen from the Neotropical region. Colour photos of their habitus, wing and terminalia are provided. The morphological affinities of male terminalia are discussed in a worldwide context. The distributional pattern of the genus clearly indicates a case of northern elements reaching the north-western region of the Neotropics that corresponds to a secondary extension of a Holarctic clade to the south. PMID:26445929

  9. A new case of an Holarctic element in the Colombian Andes: first record of Cordyla Meigen (Diptera, Mycetophilidae) from the Neotropical region

    PubMed Central

    Kurina, Olavi; Oliveira, Sarah Siqueira

    2015-01-01

    Abstract Three new species of Mycetophilidae – Cordyla monticola sp. n., Cordyla pseudopusilla sp. n. and Cordyla reducta sp. n. – are described from the Colombian Andes, representing the first described species of Cordyla Meigen from the Neotropical region. Colour photos of their habitus, wing and terminalia are provided. The morphological affinities of male terminalia are discussed in a worldwide context. The distributional pattern of the genus clearly indicates a case of northern elements reaching the north-western region of the Neotropics that corresponds to a secondary extension of a Holarctic clade to the south. PMID:26445929

  10. Induction of morphological deformities in Chironomus tentans exposed to zinc- and lead-spiked sediments.

    PubMed

    Martinez, A; Moore, B C; Schaumloffel, J; Dasgupta, N

    2001-11-01

    Laboratory experiments were used to assess morphological responses of Chironomus tentans larvae exposed to three levels of zinc and lead. Chironomus tentans egg masses were placed into triplicate control and metal-spiked aquaria containing the measured concentrations 1,442, 3,383, and 5,562 microg/g Pb dry weight and 1,723, 3,743, and 5,252 microg/g Zn dry weight. Larvae were collected at 10-d intervals after egg masses were placed in aquaria until final emergence. Larvae were screened for mouthpart deformities and metal body burdens. Deformities increased with time of exposure in both Zn and Pb tanks. Deformity rates between the three Zn concentrations differed statistically, with low and medium Zn levels containing the highest overall deformity rates of 12%. Deformity rates for larvae held in the Pb aquaria were found to differ significantly. Larvae in the low-Pb tanks had a deformity rate of 9%. Larvae and water from both the Zn and Pb aquaria had increasing metal concentrations with increasing sediment metal concentration. Results demonstrate that Zn and Pb each induce chironomid mouthpart deformities at various concentrations. However, a clear dose-related response was not demonstrated. Our research provides more support for the potential use of chironomid deformities as a tool for the assessment of heavy metal pollution in aquatic systems. PMID:11699772

  11. Isolation of a homozygous X-linked translocation stock with two additional sex-chromosomes in the onion fly Hylemya antiqua Meigen.

    PubMed

    van Heemert, K

    1977-05-01

    The onion fly, Hylemya antiqua Meigen, was subjected to irradiation and selection based on observations of fertility and cytogenetics, in order to isolate structural chromosome mutations which might be used for genetic control of this species. To the present time, only a "simple" X-linked translocation could be obtained as a homozygous stock. Sibcrossing was carried out using translocation trisomics (TN + X) obtained from test-crossed translocation heterozygous females (TN) showing numerical nondisjunction. A homozygous stock was obtained with two additional sex-chromosomes. This is a unique case because normally an X-linked translocation can not be made homozygous in the male sex, which normally only carries one X-chromosome. PMID:24407169

  12. Refining methods for conducting long-term sediment and water toxicity tests with Chironomus dilutus: Formation of a midge chronic testing work group

    EPA Science Inventory

    Standard methods have been established by USEPA, ASTM International, Environment Canada and Organization for Economic Cooperation and Development for conducting sediment toxicity tests with various species of midges including Chironomus dilutus. Short-term 10-day exposures are ty...

  13. Effects of sediment bioturbation by Chironomus tentans on toxicity of heavy metals to Ceriodaphnia dubia

    SciTech Connect

    Pearson, M.S.; Clements, W.H.

    1994-12-31

    A laboratory study was conducted to examine the toxicological significance of bioturbation by Chironomus tentans (Diptera: Chironomidae) exposed to mixtures of heavy metals (Cd, Cu, Pb and Zn) in sediment. Overlying water was collected from beakers with and without chironomids. Overlying water samples from beakers with chironomids showed significantly higher levels of total zinc (p = 0.0088), copper (p < 0.0001) and lead (p = 0.0485) compared to beakers without chironomids. Ceriodaphnia dubia chronic toxicity tests were used to evaluate toxicity of the overlying water. Overlying water from beakers without chironomids was not toxic to C. dubia. In contrast, overlying water from beakers with chironomids was acutely toxic to C. dubia at dilutions > 50%. Dilutions of 6.25%, 12.5% and 25% had a reproductive effect on C. dubia. Results of this laboratory experiment indicate that benthic invertebrates may be responsible for increased toxicity of overlying waters.

  14. Lethal effects of abamectin on the aquatic organisms Daphnia similis, Chironomus xanthus and Danio rerio.

    PubMed

    Novelli, Andréa; Vieira, Bruna Horvath; Cordeiro, Daniela; Cappelini, Luciana Teresa Dias; Vieira, Eny Maria; Espíndola, Evaldo Luiz Gaeta

    2012-01-01

    Abamectin is used as an acaricide and insecticide for fruits, vegetables and ornamental plants, as well as a parasiticide for animals. One of the major problems of applying pesticides to crops is the likelihood of contaminating aquatic ecosystems by drift or runoff. Therefore, toxicity tests in the laboratory are important tools to predict the effects of chemical substances in aquatic ecosystems. The aim of this study was to assess the potential hazards of abamectin to the freshwater biota and consequently the possible losses of ecological services in contaminated water bodies. For this purpose, we identified the toxicity of abamectin on daphnids, insects and fish. Abamectin was highly toxic, with an EC(50) 48 h for Daphnia similis of 5.1 ng L(-1), LC(50) 96 h for Chironomus xanthus of 2.67 μg L(-1) and LC(50) 48 h for Danio rerio of 33 μg L(-1). PMID:21955349

  15. Sensitivity of midge larvae of Chironomus tentans Fabricius (Diptera Chironomidae) to heavy metals

    SciTech Connect

    Khangarot, B.S.; Ray, P.K.

    1989-03-01

    The discharge of heavy metals into the natural waters has numerous obvious impacts on physical, chemical and biological parameters of aquatic ecosystem. Bioassay tests are important steps in establishing appropriate water quality criteria and standards for diverse use of ponds, lakes, streams and river waters. Therefore, the acute toxicities of various heavy metals to water flea Daphnia magna, and snail Lymnaea acuminata, and toad tadpoles Bufo mentanostictus have been reported from the authors' laboratory. Chironomid larvae might be particularly useful as indicators of water quality because they are widely distributed in freshwater systems and often from diverse communities within particular habitat. The aim of this study was to determine the acute toxicity of ten heavy metals to the midge larvae Chironomus tentans Fabricius, which forms an important link in aquatic food chain(s).

  16. Polytene chromosomes and phylogenetic relationships of Chironomus atrella (Diptera: Chironomidae) in North America.

    PubMed

    Martin, Jon; Andreeva, Eugenia N; Kiknadze, Iya I; Wülker, Wolfgang F

    2006-11-01

    The identity of Chironomus atrella Townes has been confusing because the name has been used for at least 2 quite different species. This situation is clarified karyosystematically by describing the banding patterns and chromosomal polymorphisms from a number of locations in Canada and the US. Most populations show only moderate levels of polymorphism (average heterozygosity, 0.36), although in some samples from shallow waters, the level of polymorphism is much higher (average heterozygosity, up to 0.92). The banding patterns of the polytene chromosomes are either identical or closely related to those found in Holarctic species with a northern distribution. These patterns and the distribution of inversions in the C. atrella populations are consistent with a progenitor that colonized North America across the Bering Strait and spread down the Rocky Mountain chain; at the same time, new gene combinations developed that allowed it to spread eastward over the majority of the continent. PMID:17426753

  17. Teratogenic and genotoxic responses of larval Chironomus (Diptera) to contaminated sediments

    SciTech Connect

    Hudson, L.A.; Muir, K.; Ciborowski, J.J.H.

    1994-12-31

    Sediment-associated contaminants can produce developmental or genotoxic stresses independently of their cytotoxic effects. In the laboratory, the authors exposed Chironomus larvae to mixtures of polluted (either Detroit R., MI, or cadmium or benzo-[a]-pyrene-spiked) sediment diluted with uncontaminated, formulated sediment. Second-instar Chironomus nr. salinarius were grown to 4th star in water filled 1-L jars containing 300 mL of contaminated:formulated sediment mixture in ratios of 1:0, 1:1, 1:3, 1:7, 1:15 or 0:1. Surviving larvae were preserved in Carnoy`s solution. Each larva`s head was slide-mounted and examined for deformities of the mentum. Polytene chromosome preparations were made from salivary glands of the same animals using acid fuschin staining and examined for reduced relative size of the nuclear organizer (NO) indicative of inhibition of RNA synthesis activity. Incidence of chironomid deformities from control (0:1) sediments ({plus_minus}I SE) was 7.9 {plus_minus} 1.6% (N = 268): 4.0 {plus_minus} 1.5% of 178 control larvae examined displayed NO reduction. Incidence of mentum deformities and of NO reduction increased linearly with each doubling of Detroit R. concentration at 1:0 for deformities; 12.2 {plus_minus} 3.5% (N = 149) for NO reductions. Reduction of NO in a larva was unrelated to mentum condition, indicating that these are independent responses to contaminant stress. Equivalent results were obtained for exposure to single-compound sediments. This is the first documentation of controlled dose-response effects of contaminants on chironomid deformities.

  18. Brachyopa minima (Diptera: Syrphidae), a new species from Greece with notes on the biodiversity and conservation of the genus Brachyopa Meigen in the Northern Aegean Islands.

    PubMed

    Pérez-Bañón, Celeste; Radenković, Snezana; Vujić, Ante; Petanidou, Theodora

    2016-01-01

    An on-going study of the hoverfly fauna of the Northern Aegean Islands (Greece) has revealed the presence of four species of the genus Brachyopa Meigen. During the survey the following species were found: B. bicolor (Fallén), B. quadrimaculosa Thompson in Kaplan & Thompson, B. minima Vujić & Pérez-Bañón sp. nov. and an unidentified species very close to B. pilosa (Collin). Morphological characters and mitochondrial COI barcodes were used to link different life stages of B. minima, and to identify a larval specimen of B. bicolor. In this study adult and larval morphology and habitat preferences for B. minima are described. The description of larval morphology of B. bicolor and Brachyopa sp. aff. pilosa is amended too. An identification key to the adults of the B. quadrimaculosa group sensu Kassebeer (2002) in the Eastern Mediterranean (Greece, Israel and Turkey) is provided. The importance of specific microhabitats for the continued existence of these taxa is discussed. PMID:27395920

  19. Species of Coenosia Meigen (Diptera, Muscidae) described by Fritz van Emden from the British Museum Ruwenzori Expedition of 1934-1935.

    PubMed

    Couri, Márcia; Pont, Adrian

    2016-01-01

    All the species of Coenosia Meigen (Diptera, Muscidae) described by Fritz van Emden from the British Museum (Natural History) Ruwenzori Expedition of 1934-1935 (Emden 1940), supplemented by species from the Entomological Expedition to Abyssinia of 1926-1927 (Emden 1941), were studied, a total of 51 species. All types are deposited in the Natural History Museum, London, UK. For each species, a diagnosis is given and photographs of the 10 holotypes and of their labels are presented. Dissections and illustrations of the male terminalia were made when paratypes or identified specimens were available; all terminalia are described for the first time. One new synonym is proposed: C. kilembana (Emden, 1940) as a junior synonym of C. rebmanni Speiser, 1924; and three subspecies had their status revised and were elevated to species rank: C. brunneigena Emden, 1940, previously a subspecies of C. heterocnemis Emden, 1940; and C. albisquama (Emden, 1940) and C. argentescens (Emden, 1940), both previously subspecies of C. niveifrons (Stein, 1913). PMID:27470872

  20. Similarity analysis of PAH and PCB bioaccumulation patterns in sediment-exposed Chironomus tentans larvae

    SciTech Connect

    Wood, L.W.; O`Keefe, P.; Bush, B.

    1997-02-01

    Larvae of the aquatic insect Chironomus tentans were exposed at the third or fourth instar stage to sediments collected near the outfalls of two aluminum foundries and an aluminum fabrication plant. Biota and sediment bioaccumulation factors (BFs), based on wet tissue weights and dry sediment weights, ranged from 0.07 to 0.27 for polycyclic aromatic hydrocarbons (PAHs) and from 0.22 to 1.42 for polychlorinated biphenyls (PCBs). A higher rate of metabolism of PAHs compared with PCBs could explain the differences in BF values for the two groups of chemicals. It was found, using community similarity procedures from the field of ecology, that the congener patterns for PAHs and PCBs bioaccumulated by the larvae differed from the pattern of the same compounds in the sediments to which they were exposed. Affinity analysis indicated that the larvae favored the higher molecular weight PAH and PCB congeners. Preferential ingestion of sediments with defined particle size ranges, metabolism, and octanol/water partition coefficients (log K{sub ow}) are factors that may have influenced the bioaccumulation patterns. However, no single factor could adequately account for the differences between the larval and sediment patterns.

  1. Toxicity and Affecting Factors of Bacillus thuringiensis var. Israelensis on Chironomus kiiensis Larvae

    PubMed Central

    Cao, Chuan-Wang; Sun, Li-Li; Wen, Rong-Rong; Li, Xiao-Peng; Wu, Hong-Qu; Wang, Zhi-Ying

    2012-01-01

    Bacillus thuringiensis var. israelensis (Bti) is a suitable agent for controlling Chironomus kiiensis, a major pest polluting water. In this study, laboratory bioassays were used to study toxicity and affecting factors of Bti on C. kiiensis larvae. Tests were conducted using three commercial Bti formulations (oil miscible suspension, 1,200 ITU/mL; wettable power, 1,200 ITU/mg; technical material, 5,000 ITU/mg) of Bti. The toxicity of Bti formulations to third and fourth instar C. kiiensis larvae was in decreasing order of technical material, oil miscible suspension, and wettable powder, based on the 12 and 24 hour LC50 values. Increasing larval densities (from 10 to 30 per bioassay cup) increased the LC50 values for fourth instar C. kiiensis larvae. The LC50 values for fourth instar larvae reared in sand substrate were higher than those from soil substrate, and autoclaved substrates significantly increased the LC50 values. The technical material of Bti at 12 and 24 hours responded similarly to changes in temperature between 30° C and 15° C, but the LC50 values at a range of tested temperatures showed distinct differences in time points. PMID:23465075

  2. Evaluation of short-term chronic in situ testing with Hyalella azteca and Chironomus tentans

    SciTech Connect

    Chappie, D.J.; Burton, G.A. Jr.

    1995-12-31

    Traditional toxicity testing of simple grab samples is limited by uncertainties arising from extrapolations of laboratory results to field situations. Long term testing in lakes and streams measured the effects of intermittent storm events and contamination from sediments. Aquatic organisms are enclosed in plastic containers with 149 um mesh openings. These chambers were anchored to the bottom allowing continual water exchange and association with sediments to occur. This study was designed to evaluate the effectiveness of chronic in situ testing (one to four weeks of exposure) with Chironomus tentans and Hyalella azteca. With the addition of 0.01 g of rabbit pellets per chamber as a food source, H. azteca survival was greater than 80% after four weeks of exposure. Testing with H. azteca was limited by cold water temperatures (< 12 C). The midge C. tentans required a silica sand or shredded paper towel substrate added to the chambers. C. tentans were more sensitive to handling stress and stream flow than H. azteca. maximizing the usefulness of in situ testing with chronic exposures allows lethal, sub-lethal, and bioaccumulation effects to be measured.

  3. Joint toxicity of triazine herbicides and organophosphate insecticides to the midge Chironomus tentans.

    PubMed

    Schuler, L J; Trimble, A J; Belden, J B; Lydy, M J

    2005-08-01

    A series of recent studies demonstrated that the triazine herbicide atrazine, although not itself acutely toxic, potentiated the toxicity of certain organophosphate insecticides (OPs) to the midge Chironomus tentans. In the current study, a series of triazine herbicides and triazine herbicide degradation products were tested to determine if other triazines potentiate OP toxicity to midges. Chlorpyrifos and diazinon were the OPs tested. Toxicity tests were conducted using a factorial design and analysis of variance to statistically determine if each triazine had an effect on expected toxicity. Log-probit procedures were also used to evaluate the magnitude of change in median effective concentration (EC50) values during coexposure with each triazine. All of the triazine herbicides tested (atrazine, simazine, cyanazine, and hexazinone) were capable of potentiating the toxicity of the OPs, whereas the degradation products (s-triazine, deethylatrazine, and deisopropylatrazine) had less effect. In most cases, a triazine concentration of 100 microg/L was necessary to significantly increase OP toxicity, and higher concentrations of triazine caused a greater degree of potentiation. Changes in EC50 values ranged from no change to a 2.5-fold increase in toxicity. Generally, EC50 values changed by less than a factor of 2, indicating that the effect may be of limited concern in regard to future risk assessments of OPs. PMID:15988628

  4. [Development of Sediment Micro-Interface Under Physical and Chironomus plumosus Combination Disturbance].

    PubMed

    Wang, Ren; Li, Da-peng; Huang, Yong; Liu, Yan-jian; Chen, Jun

    2015-11-01

    Synergistic effect of physical and Chironomus plumosus combination disturbance on the characteristics of the micro-environment and micro-interface was investigated by the Rhizon samplers and Unisense micro sensor system. The results showed that the oxygen penetration depth (OPD), total oxygen exchange (TOE), water content and total microbial activity increased under the combination disturbance and bioturbation and were kept at the higher level, compared with the control. These parameters increased with the physical intensity under combination disturbance. However, the content of Fe2+ decreased under the combination disturbance and bioturbation and the decrease was more obvious than that in the control. The changes of the Fe2+, the water content and the total microbial activity were large at 0-4 cm depth in the sediments. Therefore, the area might be the active area for the transformation of internal sedimentary phosphorus forms. The curve fitting was used for the OPD, TOE, the content of Fe2+, the water content and the total microbial activity with the physical intensity under combination disturbance. It was observed that the second-order polynomial equation was suitable for the curve fitting. In addition, jump type synergistic effect was presented in the above mentioned parameters under combination disturbance when the physical intensity was higher than 34 r x min(-1). The remodeling on the sediment micro-interface and micro-environment might be the main inducing mechanism for the transformation of internal phosphorus. PMID:26910997

  5. Assessment of the effect of nanomaterials on sediment-dwelling invertebrate Chironomus tentans larvae.

    PubMed

    Oberholster, P J; Musee, N; Botha, A-M; Chelule, P K; Focke, W W; Ashton, P J

    2011-03-01

    Studies were conducted to determine the effects of a panel of seven nanomaterials (NMs), namely: α-alumina, γ-alumina, precipitated silica; silica fume, calcined silica fume, colloidal antimony pentoxide (Sb(2)O(5)), and superfine amorphous ferric oxide (Fe(2)O(3)), on sediment dwelling invertebrates Chironomus tentans under controlled laboratory conditions. Percentage survival, enzyme activities, growth development, and DNA fragmentation parameters were studied as acute, biochemical, and physiological toxicities of NMs, respectively. Quantitation of catalase and peroxidase enzyme activity demonstrated that toxicant stress of the NMs increased enzyme activity in a concentration dependent fashion across all treatments. The percentage growth length of the test specimens exposed to different NMs was significantly reduced compared to the negative control while only five concentrations were not in the toxic range, namely; Fe(2)O(3) (5 μg/kg); silica fume (5 μg/kg, 50 μg/kg); Sb(2)O(5) (5 μg/kg) and calcined silica fume (5 μg/kg). Genotoxic stress assessed by use of DNA laddering showed complementary findings to the other ecotoxicological endpoints tested in this study--the percentage survival and growth length inhibition. PMID:21216008

  6. Interlaboratory study of precision: Hyalella azteca and Chironomus tentans freshwater sediment toxicity assays

    USGS Publications Warehouse

    Burton, G.A., Jr.; Norberg-King, T. J.; Ingersoll, C.G.; Benoit, D.A.; Ankley, G.T.; Winger, P.V.; Kubitz, J.; Lazorchak, J.M.; Smith, M.E.; Greer, E.; Dwyer, F.J.; Call, D.J.; Day, K.E.; Kennedy, P.; Stinson, M.

    1996-01-01

    Standard 10-d whole-sediment toxicity test methods have recently been developed by the U.S. Environmental Protection Agency (EPA) for the amphipod Hyalella azteca and the midge Chironomus tentans. An interlaboratory evaluation of method precision was performed using a group of seven to 10 laboratories, representing government, academia, and environmental consulting firms. The test methods followed the EPA protocols for 4-d water-only reference toxicant (KCl) testing (static exposure) and for 10-d whole-sediment testing. Test sediments included control sediment, two copper-containing sediments, and a sediment contaminated primarily with polycyclic aromatic hydrocarbons. Reference toxicant tests resulted in H. azteca and C. tentans median lethal concentration (LC50) values with coefficents of variation (CVs) of 15.8 and 19.6%, respectively. Whole sediments which were moderately contaminated provided the best estimates of precision using CVs. Hyalella azteca and C. tentans tests in moderately contaminated sediments exhibited LC50 CVs of 38.9 and 13.5%, respectively. The CV for C. tentans growth was 31.9%. Only 3% (1 of 28) of samples exceeded acceptable interlaboratory precision limits for the H. azteca survival tests. No samples exceeded the intralaboratory precision limit for H. azteca or C. tentans survival tests. However, intralaboratory variability limits for C. tentans growth were exceeded by 80 and 100% of the laboratories for a moderately toxic and control sample, respectively. Interlaboratory variability limits for C. tentans survival were not exceeded by any laboratory. The results showed these test methods to have relatively low variance and acceptable levels of precision in interlaboratory comparisons.

  7. Toxicity of sediment-associated pesticides to Chironomus dilutus and Hyalella azteca.

    PubMed

    Ding, Yuping; Weston, Donald P; You, Jing; Rothert, Amanda K; Lydy, Michael J

    2011-07-01

    Two hundred sediment samples were collected and their toxicity evaluated to aquatic species in a previous study in the agriculturally dominated Central Valley of California, United States. Pyrethroid insecticides were the main contributors to the observed toxicity. However, mortality in approximately one third of the toxic samples could not be explained solely by the presence of pyrethroids in the matrices. Hundreds of pesticides are currently used in the Central Valley of California, but only a few dozen are analyzed in standard environmental monitoring. A significant amount of unexplained sediment toxicity may be due to pesticides that are in widespread use that but have not been routinely monitored in the environment, and even if some of them were, the concentrations harmful to aquatic organisms are unknown. In this study, toxicity thresholds for nine sediment-associated pesticides including abamectin, diazinon, dicofol, fenpropathrin, indoxacarb, methyl parathion, oxyfluorfen, propargite, and pyraclostrobin were established for two aquatic species, the midge Chironomus dilutus and the amphipod Hyalella azteca. For midges, the median lethal concentration (LC₅₀) of the pesticides ranged from 0.18 to 964 μg/g organic carbon (OC), with abamectin being the most toxic and propargite being the least toxic pesticide. A sublethal growth endpoint using average individual ash-free dry mass was also measured for the midges. The no-observable effect concentration values for growth ranged from 0.10 to 633 μg/g OC for the nine pesticides. For the amphipods, fenpropathrin was the most toxic, with an LC₅₀ of 1-2 μg/g OC. Abamectin, diazinon, and methyl parathion were all moderately toxic (LC₅₀s 2.8-26 μg/g OC). Dicofol, indoxacarb, oxyfluorfen, propargite, and pyraclostrobin were all relatively nontoxic, with LC₅₀s greater than the highest concentrations tested. The toxicity information collected in the present study will be helpful in decreasing the

  8. Potential impact of Chironomus plumosus larvae on hypolimnetic oxygen in the central basin of Lake Erie

    USGS Publications Warehouse

    Soster, Frederick M.; Matisoff, Gerald; Schloesser, Donald W.; Edwards, William J.

    2015-01-01

    Previous studies have indicated that burrow-irrigating infauna can increase sediment oxygen demand (SOD) and impact hypolimnetic oxygen in stratified lakes. We conducted laboratory microcosm experiments and computer simulations with larvae of the burrowing benthic midge Chironomus plumosus to quantify burrow oxygen uptake rates and subsequent contribution to sediment oxygen demand in central Lake Erie. Burrow oxygen uptake and water flow velocities through burrows were measured using oxygen microelectrodes and hot film anemometry, respectively. Burrow oxygen consumption averaged 2.66 × 10− 10 (SE = ± 7.82 × 10− 11) mol O2/burrow/s at 24 °C and 9.64 × 10− 10 (SE = ± 4.86 × 10− 10) mol O2/burrow/s at 15 °C. In sealed microcosm experiments, larvae increased SOD 500% at 24 °C (density = 1508/m2) and 375% at 15 °C (density = 864/m2). To further evaluate effects of densities of C. plumosus burrows on SOD we developed a 3-D transport reaction model of the process. Using experimental data and chironomid abundance data in faunal surveys in 2009 and 2010, we estimated that bioirrigation by a population of 140 larvae/m2 could account for between 2.54 × 10− 11 mol/L/s (model results) and 5.58 × 10− 11 mol/L/s (experimental results) of the average 4.22 × 10− 11 mol/L/s oxygen depletion rate between 1970 and 2003, which could have accounted for 60–132% of the oxygen decline. At present, it appears that the population density of this species may be an important factor in development of hypoxic or anoxic conditions in central Lake Erie.

  9. Influence of pH on the toxicity of ammonia to Chironomus tentans and Lumbriculus variegatus

    SciTech Connect

    Schubauer-Berigan, M.K.; Monson, P.D.; West, C.W.; Ankley, G.T.

    1995-04-01

    The US Environmental Protection Agency water-quality criteria establish permissible levels of ammonia in the nation`s fresh waters. These criteria are based on accumulated research suggesting that, for most aquatic species (primarily fishes), the toxicity of un-ionized ammonia predominates over that of the ammonium ion. The development of a sediment-quality criterion for ammonia requires evaluation of the relative toxicity of the two ammonia forms to benthic and epibenthic macroinvertebrates to determine whether the water-quality toxicity model can be applied to sediments. Flow-through ammonia toxicity tests were conducted over 10 d with the oligochaete Lumbriculus variegatus and the larval midge Chironomus tentans at four pH values (6.3, 7.2, 7.8, and 8.6) using a unique pH control system. Total ammonia was more toxic at elevated than at low pH to both species, suggesting that un-ionized ammonia (more prevalent at high pH) is important in determining the toxicity of ammonia to these two species. Hardness or alkalinity differences in the range of 30 to 200 mg/kg (as CaCO{sub 3}) did not appear to affect the toxicity of ammonia to the two species in separate 4-d tests. Based on results of the 10-d tests, the joint toxicity/pH model that establishes the water-quality criterion value for ammonia appears to be sufficiently protective of L. variegatus and C. tentans, by factors of at least 3 and 10, respectively. However, this study did not address potential differences in exposure of benthic organisms to ammonia in sediments vs. that in the water column; nor were the chronic effects of ammonia on these species measured in this study.

  10. Sediment properties influencing the bioavailability of uranium to Chironomus dilutus larvae in spiked field sediments.

    PubMed

    Crawford, Sarah E; Liber, Karsten

    2016-04-01

    The partitioning of metals between dissolved and solid phases directly affects metal bioavailability to benthic invertebrates and is influenced by metal-binding properties of sediment phases. Little research has been done examining the effects of sediment properties on the bioavailability of uranium (U) to freshwater benthic invertebrates. In the present study, 18 field sediments with a wide range of properties (total organic carbon, fine fraction, cation exchange capacity, and iron content) were amended with the same concentrations of U to characterize the effects of these sediment properties on U bioavailability to freshwater midge, Chironomus dilutus. Bioaccumulation of U by C. dilutus larvae varied by over an order of magnitude when exposed to sediments spiked with 50 mg U kg(-1) d.w. (5-69 mg U kg(-1) d.w.) and 500 mg U kg(-1) d.w. (20-452 mg U kg(-1) d.w.), depending on the type of sediment. Variance in U bioaccumulation was best explained by differences in the cation exchange capacity, fine fraction (≤50 μm particle size), and Fe content of U-spiked sediment, with generated regression equations predicting observed bioaccumulation within a factor of two. The presented regression equations offer an easy-to-apply method for accounting for the influence of sediment properties on U bioavailability in freshwater sediment, with fine fraction being the single most practical variable. This research strongly supports that risk assessments and guidelines for U-contaminated sediments should not ignore the influence of sediment properties that can result in substantial differences in the bioaccumulation of U in benthic invertebrates. PMID:26802266

  11. Transcriptome Profiling of Chironomus kiinensis under Phenol Stress Using Solexa Sequencing Technology

    PubMed Central

    Cao, Chuanwang; Wang, Zhiying; Niu, Changying; Desneux, Nicolas; Gao, Xiwu

    2013-01-01

    Phenol is a major pollutant in aquatic ecosystems due to its chemical stability, water solubility and environmental mobility. To date, little is known about the molecular modifications of invertebrates under phenol stress. In the present study, we used Solexa sequencing technology to investigate the transcriptome and differentially expressed genes (DEGs) of midges (Chironomus kiinensis) in response to phenol stress. A total of 51,518,972 and 51,150,832 clean reads in the phenol-treated and control libraries, respectively, were obtained and assembled into 51,014 non-redundant (Nr) consensus sequences. A total of 6,032 unigenes were classified by Gene Ontology (GO), and 18,366 unigenes were categorized into 238 Kyoto Encyclopedia of Genes and Genomes (KEGG) categories. These genes included representatives from almost all functional categories. A total of 10,724 differentially expressed genes (P value <0.05) were detected in a comparative analysis of the expression profiles between phenol-treated and control C. kiinensis including 8,390 upregulated and 2,334 downregulated genes. The expression levels of 20 differentially expressed genes were confirmed by real-time RT-PCR, and the trends in gene expression that were observed matched the Solexa expression profiles, although the magnitude of the variations was different. Through pathway enrichment analysis, significantly enriched pathways were identified for the DEGs, including metabolic pathways, aryl hydrocarbon receptor (AhR), pancreatic secretion and neuroactive ligand-receptor interaction pathways, which may be associated with the phenol responses of C. kiinensis. Using Solexa sequencing technology, we identified several groups of key candidate genes as well as important biological pathways involved in the molecular modifications of chironomids under phenol stress. PMID:23527048

  12. Sediment organic matter content as a confounding factor in toxicity tests with Chironomus tentans

    SciTech Connect

    Lacey, R.; Watzin, M.C.; McIntosh, A.W.

    1999-02-01

    Physicochemical characteristics of sediment unrelated to contaminant levels and bioavailability may influence the outcome of toxicity tests. In particular, sediment organic matter content has the potential to be a confounding factor in toxicity tests using the midge larva Chironomus tentans because the larvae are infaunal and feed on organic matter in the sediments. To examine the possibility, the authors conducted a series of tests using formulated sediments with varying organic matter contents following the standard US Environmental Protection Agency (US EPA) 10-day C. tentans growth and survival protocol. Formulated sediments made with peat moss, {alpha}-cellulose, and maple leaves were tested. An organic-rich natural sediment diluted with formulated sediment to achieve a range of organic matter contents was also examined. In a final experiment, sediments containing each of the four organic matter sources at the same concentration were tested against one another. Survival was not greatly affected by concentration of organic matter, except at the lowest concentrations in natural sediment, where survival dipped below 70%. In experiments using peat moss, {alpha}-cellulose, and maple leaves, significant differences in C. tentans growth were found at different organic matter concentrations. In contrast, concentration of organic matter in the natural sediment dilution series had little effect on growth, perhaps because much of this material was highly refractory. In the comparison experiment, growth differed significantly among the four sediments, with best growth achieved with {alpha}-cellulose and leaves. These results suggest that both organic matter quantity and quality can be confounding factors in toxicity tests using C. tentans.

  13. Bioavailability-based toxicity endpoints of bifenthrin for Hyalella azteca and Chironomus dilutus.

    PubMed

    Harwood, Amanda D; Landrum, Peter F; Lydy, Michael J

    2013-01-01

    Recent studies have determined that techniques, such as solid phase microextraction (SPME) fibers and Tenax beads, can predict bioaccumulation and potentially could predict toxicity for several compounds and species. Toxicity of bifenthrin was determined using two standard sediment toxicity tests with the benthic species Hyalella azteca and Chironomus dilutus in three reference sediments with different characteristics. The objectives of the current study were to establish bioavailability-based median lethal concentrations (LC50) and median effect concentrations (EC50) of the pyrethroid insecticide bifenthrin, compare their ability to assess toxicity to the use of whole sediment concentrations, as well as to make comparisons of the concentrations derived using each method in order to make assessments of accuracy and extrapolation potential. Four metrics were compared including SPME fiber concentration, pore water concentration derived using SPMEs, 6 h Tenax extractable concentration, and 24 h Tenax extractable concentration. The variation among the LC50s and EC50s in each sediment derived using bioavailability-based methods was comparable to variation among organic carbon normalized sediment concentrations, but improved over whole sediment concentrations. There was a significant linear relationship between SPME or Tenax and organic carbon normalized sediment concentrations. Additionally, there was a significant relationship between the SPME and Tenax concentrations across sediments. The significant linear relationship between SPME and Tenax concentrations further demonstrates that these bioavailability-based endpoints are interrelated. This study derived bioavailability-based benchmarks that may prove to be more accurate than sediment-based ones in predicting toxicity across sediment types. PMID:23084260

  14. Bioavailability-based chronic toxicity measurements of permethrin to Chironomus dilutus.

    PubMed

    Du, Juan; Pang, Junxiao; You, Jing

    2013-06-01

    Compared with acute toxicity, chronic exposures to low levels of contaminants are more environmentally relevant, but fewer data are available. In the present study, sediment toxicity of the pyrethoid permethrin to Chironomus dilutus was determined. The whole-life-cycle toxicity testing was conducted with the endpoints covering survival, growth, emergence, and reproduction. Permethrin caused 50% lethality in C. dilutus at 1.83 ± 1.13 µg/g organic carbon (OC) and 1.20 ± 0.55 µg/g OC after exposures of 20 d (before pupation) and 58 d (the end of the testing), respectively. The 5% and median effect concentrations (EC5 and EC50) represented the marginal and toxic levels of the sublethal effects, respectively, and effect data were all normalized to the controls before Probit analysis. The EC5s for growth, emergence, and reproduction were 0.034 ± 0.006 µg/g OC, 0.016 ± 0.008 µg/g OC, and 0.009 ± 0.008 µg/g OC, respectively; the respective EC50s were 1.09 ± 0.56 µg/g OC, 0.838 ± 0.077 µg/g OC, and 0.039 ± 0.105 µg/g OC. In addition, a 24-h Tenax extraction was employed to better assess permethrin bioavailability. Ultimately, response spectra with a series of endpoints were developed for permethrin using either OC-normalized bulk sediment concentrations or bioavailability-based Tenax extractable concentrations as the dose metric. The development of bioavailability-based chronic toxicity endpoints for sediment-associated permethrin would provide valuable benchmarks for evaluating ecological risk of this contaminant and contributing to improve sediment management policies. PMID:23424028

  15. [Response of Sediment Micro Environment and Micro Interface to Physical Disturbance Intensity Under the Disturbance of Chironomus plumosus].

    PubMed

    Shi, Xiao-dan; Li, Yong; Li, Da-peng; Wang, Ren; Deng, Meng; Huang, Yong

    2015-05-01

    The response of sediment micro environment and micro intertace to physical disturbance intensity under the physical and Chironomus plumosus disturbance was investigated by means of sediment Rhizon samplers and Unisense micro sensor system. The sediment and overlying water were taken from Meiliang bay of Taihu Lake. The results showed that the OPD reached up to 12.1 mm under the high intensity (240 r · min(-1)), while it was higher than 3. 8. mm under low intensity (60 r · min(-1)). The TOE, the difference of TOE and DOE, OPD, ORP and the difference of DO spatial distribution were all positively correlated with the physical disturbance intensity. The increasing magnitude and range of pH as well as the decreasing magnitude and range of ferrous followed the same response tendency. Within the 0-6 cm sediment, the water content and porosity as well as the microbial activity at the same depth increased with the increase of physical disturbance intensity. In addition, the degree of response of the above parameters to the physical disturbance intensity was weakened with the increase of sediment depth. It was suggested that Chironomus plumosus dug more and deeper galleries under high intensity physical disturbance. Therefore, the sediment micro environment and micro interface were transformed in the vertical direction of the sediment. PMID:26314108

  16. Using artificial streams to assess the effects of metal-mining effluent on the life cycle of the freshwater midge (Chironomus tentans) in situ.

    PubMed

    Hruska, Kimberly A; Dubé, Monique G

    2004-11-01

    In 2002, we developed an in situ life-cycle bioassay with Chironomus tentans in artificial streams to evaluate the effects of a complex metal mine effluent under ambient environmental conditions. The bioassay was tested in the field using effluent from the Copper Cliff Waste Water Treatment Plant at INCO (Sudbury, ON, Canada). Chironomus tentans were exposed throughout the life cycle to 45% Copper Cliff effluent, which is the average effluent concentration measured in Junction Creek (ON, Canada), the natural receiving environment. Chironomus tentans in the effluent treatment exhibited reduced survival (p = 0.001), reduced total emergence (p = 0.001), increased time-to-emergence (p = 0.001), and reduced hatching success (p = 0.001) relative to animals in the reference water treatment. Chironomus tentans in the effluent treatment were not significantly different from the reference in terms of growth, sex ratio, number of egg cases/female, and number of eggs/egg case. This research showed how a life-cycle bioassay could be used in situ to assess metal mine effluent effects on a benthic invertebrate. PMID:15559287

  17. [Identification of Ca2+ release channels in salivary glands secretory cells of Chironomus plumosus L].

    PubMed

    Man'ko, V V; Bychkova, S V; Klevets', M Iu

    2004-01-01

    The presence of two types of well-characterised Ca2+ release channels, namely IP3-receptors (Ins(1,4,5)P3Rs) and ryanodine-receptors (RyRs), was detected in the salivary glands secretory cells of Chironomus plumosus L. For this aim different blockators and activators of these Ca2+ -transport systems were used. The conditions for permeabilization of these cells by saponine were experimentally chosen for their more intensive action. It was shown that IP3 decreased calcium content in saponine-treated gland tissue by (41.14 +/- 11.75)%. The effect of IP3 was not observed under condition of heparin and eosin Y presence in the incubation medium, but heparin alone did not cause any action on calcium content in saponine-treated gland tissue. The observed effects of IP3 are supposed to be the evidences of Ins (1,4,5)P3Rs presence in the intracellular membrane of this object. It was also shown that calcium content in intact gland tissue increased by (67.12 +/- 22.60)% in presence of heparin (500 mkg/ml) in the incubation medium. This effect of heparin was also observed with presence of verapamil (100 mkM) and eosin Y (5, 20 mkM) in incubation medium. So, this effect is not connected with function of voltage-gated Ca2+ -channels and Ca2+ -pumps. Ryanodine in concentration of 5nM decreased calcium content in saponine-treated gland tissue by (35.18 +/- 3.87)% but it caused the increase of calcium content at high concentration (500 nM) by (40.72 +/- 12.52)%. It improved the presence of RyRs in intracellular membrane of secretory cells of this object. Besides, these channels, perhaps, belong to "non-sensitive" to caffeine, because caffeine did not affect calcium content in the gland tissue neither in presence nor with absence of eosin Y. PMID:15909419

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

    PubMed

    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. PMID:25966582

  19. An inducible HSP70 gene from the midge Chironomus dilutus: Characterization and transcription profile under environmental stress

    USGS Publications Warehouse

    Karouna-Renier, N. K.; Rao, K.R.

    2009-01-01

    In the present study, we identified and characterized an inducible heat shock protein 70 (HSP70) from the midge Chironomus dilutus and investigated the transcriptional profile of the gene under baseline and environmentally stressful conditions. Using real-time quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR), we observed increased expression of CD-HSP70-1 in response to both heat shock and copper stress. We also investigated the expression of this gene during midge development. All C. dilutus developmental stages expressed CD-HSP70-1 under normal conditions, although at extremely low levels. Phylogenetic analysis of the amino acid sequence demonstrated distinct clustering of this gene with inducible HSP70s from other insect species. ?? 2008 The Authors.

  20. Utility of DNA taxonomy and barcoding for the inference of larval community structure in morphologically cryptic Chironomus (Diptera) species.

    PubMed

    Pfenninger, Markus; Nowak, Carsten; Kley, Christoph; Steinke, Dirk; Streit, Bruno

    2007-05-01

    Biodiversity studies require species level analyses for the accurate assessment of community structures. However, while specialized taxonomic knowledge is only rarely available for routine identifications, DNA taxonomy and DNA barcoding could provide the taxonomic basis for ecological inferences. In this study, we assessed the community structure of sediment dwelling, morphologically cryptic Chironomus larvae in the Rhine-valley plain/Germany, comparing larval type classification, cytotaxonomy, DNA taxonomy and barcoding. While larval type classification performed poorly, cytotaxonomy and DNA-based methods yielded comparable results: detrended correspondence analysis and permutation analyses indicated that the assemblages are not randomly but competitively structured. However, DNA taxonomy identified an additional species that could not be resolved by the traditional method. We argue that DNA-based identification methods such as DNA barcoding can be a valuable tool to increase accuracy, objectivity and comparability of the taxonomic assessment in biodiversity and community ecology studies. PMID:17444904

  1. 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.

    PubMed

    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. PMID:20697808

  2. Karyotype characteristics and polymorphism peculiarities of Chironomus bernensis Wülker & Klötzli, 1973 (Diptera, Chironomidae) from the Central Caucasus and Ciscaucasia

    PubMed Central

    Karmokov, Mukhamed Kh.; Polukonova, Natalia V.; Sinichkina, Olga V.

    2015-01-01

    Abstract Data about the karyotype characteristics, features of chromosomal polymorphism and larval morphology of populations of Chironomus bernensis Wülker & Klötzli, 1973 (Diptera, Chironomidae) from the Central Caucasus (the northern macroslope) and Ciscaucasia are presented. The characteristics of the pericentromeric regions of the long chromosomes of this species from Caucasian populations were very similar to the ones from some European populations (from Poland and Italy), but differed from Swiss and Siberian populations. In the North Caucasian populations 10 banding sequences were found: two in arms A, C, and E, and one in arms B, D, F, and G. Nine of them were already known for this species, and one, berC2, is described for the first time. Cytogenetic distances between all the studied populations of Chironomus bernensis show that close geographical location of all studied populations from the Central Caucasus and Ciscaucasia is reflected in their similar cytogenetic structure, but on the other hand, that they are more closely related to populations from Europe than to populations from Western Siberia. At the same time, all studied larvae from Caucasian populations have a four-bladed premandible, instead of a two-bladed one, as in the description of Chironomus bernensis from Switzerland (Wülker and Klötzli 1973, Polukonova 2005c). These peculiarities may indicate the relative isolation of the Caucasus from the viewpoint of microevolution. Further research on karyological and morphological characteristics of Chironomus bernensis from geographically distant regions is necessary as there is a possibility that the presently known species is actually polytypic and consists of several sibling species. PMID:26312128

  3. Effects of TFM and Bayer 73 on in vivo oxygen consumption of the aquatic midge Chironomus tentans

    USGS Publications Warehouse

    Kawatski, J.A.; Dawson, V.K.; Reuvers, J.L.

    1974-01-01

    Exposure of fourth instar larvae of Chironomus tentans to 2.0-8.0 mg/liter of TFM (3-trifluormethyl-4-nitrophenol) for 6 hr at 22 A? 0.5 C in soft water resulted in a significantly increased rate of larval oxygen consumption compared to that of control larvae, as measured with the Warburg respirometer. Maximum stimulation of oxygen consumption occurred with 8.0 mg/liter of TFM, and 1.0 mg/liter of TFM had no measurable effect on basal respiration. When hardness of exposure water was progressively increased, the effect of TFM on oxygen consumption was diminished. Bayer 73 (5,2'-dichloro-4'-nitrosalicylanilide) stimulated oxygen consumption at 0.75 and 1.0 mg/liter, had no significant effect at concentrations less that 0.75 mg/liter, and inhibited oxygen consumption at concentrations of 1.20 mg/liter or greater. Mixtures of TFM and Bayer 73, in the ratio of 98:2, had no greater effect on oxygen consumption than TFM alone.

  4. Toxicity and bioaccumulation of a mixture of heavy metals in Chironomus tentans (Diptera: Chironomidae) in synthetic sediment

    SciTech Connect

    Harrahy, E.A.; Clements, W.H.

    1997-02-01

    This research investigated toxicity and bioaccumulation of a mixture of Cd, Cu, Pb, and Zn in Chironomus tentans in synthetic sediment, and compared predicted to measured steady-state bioaccumulation factors (BAFs). In a toxicity test, C. tentans were exposed to various dilutions of a base concentration (1.0 X) of a mixture of the four metals (5 {micro}g/g Cd. 10 {micro}g/g Cu. 70 {micro}g/g Pb, and 300 {micro}g/g Zn) in synthetic sediment. Mortality ranged from 17 to 100%. To measure bioaccumulation of the metals, C. tentans were exposed to 0.35 X the base concentration for a period of up to 14 d in two uptake tests. Bioaccumulation of all four metals increased over the 14-d uptake phases. Concentrations of metals in chironomids were significantly correlated with exposure time in the uptake phases. Only concentrations of copper approached background levels after 7 d depuration. Uptake rate coefficients and elimination rate constants were determined for each metal. Bioaccumulation factors were highest for Cd and lowest for Pb. With the exception of Pb, steady-state BAFs were within a factor of about two of those calculated using the first-order kinetic model. The high BAFs calculated may indicate greater bioavailability in synthetic sediment. Studies comparing toxicity and bioaccumulation of natural and synthetic sediments are necessary before the use of synthetic sediments is widely adopted.

  5. Role of ingestion route in the perfluoroalkyl substance bioaccumulation by Chironomus plumosus larvae in sediments amended with carbonaceous materials.

    PubMed

    Zhai, Yawei; Xia, Xinghui; Zhao, Xiuli; Dong, Haiyang; Zhu, Baotong; Xia, Na; Dong, Jianwei

    2016-01-25

    The role of ingestion route in the bioaccumulation of six types of perfluoroalkyl substances (PFASs) by Chironomus plumosus larvae in sediments amended with four types of carbonaceous materials (CMs) was studied. The results showed that the body burden of PFASs decreased in the presence of CMs at mass ratios of 0.2-2%, regardless of ingestion. PFASs accumulated by the larvae with ingestion exposure were higher than those without ingestion, and the role of ingestion route was altered in the presence of CMs. The contribution of ingestion route to PFAS bioaccumulation was 2.7-31.6% without CMs, and it increased to more than 61.4% in the presence of fullerene at mass ratios of 0.2-2%. The enhancement of the ingestion route contribution caused by CMs is due to the fact that the CMs can be ingested and CM-associated PFASs can be partly desorbed in larvae. The maximum desorption efficiency of perfluorooctanoic acid was 20.8% from fullerene by the larval digestive juice. This study suggests that CM-associated PFASs could be accumulated partly by organisms, and the ecological risk of PFASs might increase in some cases with the presence of CMs. This should be considered when applying CMs in PFAS and other hydrophobic organic compound pollution remediation. PMID:26489915

  6. Effectiveness of ozonation treatment in eliminating toxicity of oil sands process-affected water to Chironomus dilutus.

    PubMed

    Anderson, J C; Wiseman, S B; Wang, N; Moustafa, A; Perez-Estrada, L; Gamal El-Din, M; Martin, J W; Liber, K; Giesy, J P

    2012-01-01

    Water soluble organic compounds (OCs), including naphthenic acids (NAs), are potentially toxic constituents of oil sands process-affected water (OSPW) that is generated during extraction of bitumen from Alberta oil sands. Ozonation can decrease concentrations of OCs in OSPW. However, effects of ozonated-OSPW on multicellular organisms are unknown. A 10-day and a chronic exposure of Chironomus dilutus to OSPW were conducted to assess effects on survival, growth, development, and behavior. Two separate batches of OSPW were treated with 30 or 80 mg ozone (O(3))/L. Wet body masses of larvae exposed to OSPW were 64 to 77% less than their respective controls (p < 0.001). However, both levels of ozonation significantly attenuated effects of OSPW on growth. Similarly, chronic exposure to untreated OSPW resulted in significantly less pupation than in the controls, with 31% and 71% less pupation of larvae exposed to the two batches of OSPW (p < 0.05). Emergence was significantly less for larvae exposed to OSPW, with 13% and 8% of larvae emerging, compared to 81% in controls (p < 0.0001). Both levels of ozonation of OSPW attenuated effects on emergence. These results suggest that OCs degraded by ozonation causes toxicity of OSPW toward C. dilutus, and that ozonation attenuates toxicity of OSPW. PMID:21992611

  7. Impact of environmental factors on the toxicity of Bacillus thuringiensis var. israelensis IPS82 to Chironomus kiiensis.

    PubMed

    Lei, Ping; Zhao, Wen-Ming; Yang, Shui-Yun; Zhang, Jin-Song; Liu, Li-Jun

    2005-03-01

    To determine the feasibility of microbiological control of chironomid larvae in water sources for the city of Shenzhen, China, the toxicity characteristics of Bacillus thuringiensis var. israelensis (Bti) IPS82 on Chironomus kiiensis Tokunaga were studied. Tests on fermentation products of IPS82 showed good correlations between toxicity, cell density, dissolved oxygen, and the spore-forming phase. In this study, bioassays were carried out with different stage larvae. Results showed that the LC50s (24 h postexposure) were 8.2, 15.2, 24.7, and 38.6 mg/liter for the 1st, 2nd, 3rd, and 4th instars, respectively. Tests on environmental factors influencing toxicity of Bti to C. kiiensis showed that sunlight is the most important factor, shortening the half-life of Bti from 21 days in dark to 10 days under sunlight. Temperature variations (15-30 degrees C) caused no impact on toxicity, but a 16% increase in larval mortality was observed at 35 degrees C. The toxicity of IPS82 was greatest at a pH of 7. In field trials, dosages above 100 mg/liter were effective in the control of C. kiiensis. Our study indicated that it is feasible to use Bti to control C. kiiensis in city source water. PMID:15825763

  8. Effects of anti-C23 (nucleolin) antibody on transcription of ribosomal DNA in Chironomus salivary gland cells

    SciTech Connect

    Egyhazi, E.; Pigon, A. ); Chang, Jinhong; Ghaffari, S.H.; Dreesen, T.D.; Wellman, S.E.; Case, S.T.; Olson, M.O.J. )

    1988-10-01

    Protein C23 (also called nucleolin or 100-kDa nucleolar protein) is a major nucleolar phosphoprotein involved in ribosome biogenesis. To determine the effects of protein C23 on preribosomal RNA (pre-rRNA) synthesis anti-C23 antiserum was microinjected into nuclei of Chironomus tentans salivary glands. Transcription was measured by incubation of the glands with {sup 32}P-labeled RNA precursors followed by microdissection of nucleoli, RNA extraction, and electrophoretic analyses. Injection of the anti-C23 antibody caused a 2- to 3.5-fold stimulation of {sup 32}P incorporation into 38 S pre-rRNA. No stimulation was observed in salivary glands injected with preimmune serum or antiserum preabsorbed with protein C23. The stimulatory effect was selective for pre-rRNA as indicated by the lack of stimulation of {sup 32}P incorporation into extranucleolar RNA. Injection of the antiserum produced little or no effect on pre-RNA processing as measured by the relative amounts of {sup 32}P-labeled intermediate cleavage products of pre-rRNA in stimulated versus control glands. These results suggest that protein C23 not only is involved in ribosome assembly but also plays a role in regulating the transcription of the preribosomal RNA.

  9. Toxicity and bioaccumulation of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) by Chironomus tentans and Lumbriculus variegatus

    SciTech Connect

    West, C.W.; Ankley, G.T.; Elonen, G.E.; Phipps, G.W.; Fernandez, J.D.; Libal, J.J.; Nessa, D.

    1994-12-31

    Invertebrate exposure to 2,3,7,8-TCDD is important, not necessarily because of their sensitivity (which appears to be less than that of fish) , but as a vector from chemical reservoirs in sediments, through the food chain, to sensitive species. Chironomus tentans and Lumbriculus variegatus are not only vectors for TCDD to fish species, but C. tentans may also be a direct vector to avian species which feed upon emergent insects. For this reason determination of the kinetics of TCDD uptake by invertebrates is important, especially for those with short life spans such as midges, or those that reproduce as rapidly as oligochaetes. In these experiments, these two species were fed contaminated food at three different TCDD levels spanning three orders of magnitude. Tissue residue levels were measured over a time period which included several different life stages and points in the reproductive cycle of the two species and uptake and deputation rates determined. As expected, no significant impacts of TCDD on growth, reproduction or biomass of the invertebrates were observed. From this information predictions can be made on bioaccumulation of TCDD from differing levels of contamination, and potential food chain transfer of the compound to more sensitive species.

  10. A comparison of the sublethal and lethal toxicity of four pesticides in Hyalella azteca and Chironomus dilutus.

    PubMed

    Hasenbein, Simone; Connon, Richard E; Lawler, Sharon P; Geist, Juergen

    2015-08-01

    Laboratory toxicity testing is the primary tool used for surface water environmental risk assessment; however, there are critical information gaps regarding the sublethal effects of pesticides. In 10-day exposures, we assessed the lethal and sublethal (motility and growth) toxicities of four commonly used pesticides, bifenthrin, permethrin, cyfluthrin, and chlorpyrifos, on two freshwater invertebrates, Chironomus dilutus and Hyalella azteca. Pyrethroids were more toxic than the organophosphate chlorpyrifos in both species. Bifenthrin was most toxic to H. azteca survival and growth. Cyfluthrin was most toxic to C. dilutus. However, cyfluthrin had the greatest effect on motility on both H. azteca and C. dilutus. The evaluated concentrations of chlorpyrifos did not affect C. dilutus motility or growth, but significantly impacted H. azteca growth. Motility served as the most sensitive endpoint in assessing sublethal effects at low concentrations for both species, while growth was a good indicator of toxicity for all four pesticides for H. azteca. The integration of sublethal endpoints in ambient water monitoring and pesticide regulation efforts could improve identification of low-level pesticide concentrations that may eventually cause negative effects on food webs and community structure in aquatic environments. PMID:25804662

  11. Potential use of acetylcholinesterase, glutathione-S-transferase and metallothionein for assessment of contaminated sediment in tropical chironomid, Chironomus javanus.

    PubMed

    Somparn, A; Iwai, C B; Noller, B

    2015-11-01

    Heavy metals and organophosphorus insecticide is known to act as disruptors for the enzyme system, leading to physiologic disorders. The present study was conducted to investigate the potential use of these enzymes as biomarkers in assessment of contaminated sediments on tropical chironomid species. Acetylcholinesterase (AChE), glutathione-S-transferase (GST) and metallothionein (MT) activity was measured in the fourth-instar chironomid larvae, Chironomus javanus, Kieffer, after either 48-hr or 96-hr exposure to organophosphorus insecticide, chlorpyrifos (0.01- 0.25 mg kg(-1)) or heavy metal cadmium (0.1-25 mg kg(-1)). Exposure to chlorpyrifos (0.01 mg kg(-1)) at 48 and 96 hr significantly of AChE activity (64.2%-85.9%) and induced GST activity (33.9-63.8%) when compared with control (P < 0.05). Moreover, exposure to cadmium (0.1 mg kg(-1)) at 48 and 96 hr also showed significant increas GST activity (11.7-40%) and MT level (9.0%-70.5%) when compared with control (P < 0.05). The results indicated the impact of enzyme activity on chlorpyrifos and cadmium contamination. Activity of AChE, GST and MT could serve as potential biomarkers for assessment and biomonitoring the effects of insecticide and heavy metal contamination in tropical aquatic ecosystems. PMID:26688973

  12. Rapid Recovery of Chironomidae (Diptera) in Little Mill Creek (Kansas, U.S.A.) After the Decommissioning of a Waste Water Treatment Plant

    NASA Astrophysics Data System (ADS)

    Bouchard, R. W.; Ferrington, L. C.

    2005-05-01

    In June 1995 the Lenexa Waste Water Treatment Plant was decommissioned, providing an opportunity to study recovery of Chironomidae community structure in Little Mill Creek. Using pupal exuviae, weekly changes in the species richness and composition of Chironomidae emerging upstream and downstream of the effluent outfall was evaluated from two weeks before decommissioning to eight weeks post-decommissioning. Chironomidae emergence was clearly different between upstream and downstream sites both before and shortly after effluent input ceased. Before decommissioning, sites immediately downstream of the effluent had low species richness and were dominated by Chironomus riparius (Meigen) and other tolerant taxa, with some recovery at sites farther downstream. Two weeks after decommissioning, only sites immediately downstream of the former effluent were clearly impacted, but effects were reduced compared to pre-recovery collections. At five weeks post-decommissioning, species richness was only slightly lower at the sites immediately downstream of the former effluent and the composition of common species (i.e., >5% of relative abundance) was similar between upstream and downstream sites. Rapid recovery of chironomid emergence below the sewage effluent likely resulted from both colonization of drifting larvae from upstream sources and adult dispersal and oviposition, indicating rapid responses in emergence as water quality conditions improved.

  13. Interlaboratory evaluation of Hyalella azteca and Chironomus tentans short-term and long-term sediment toxicity tests

    USGS Publications Warehouse

    Norberg-King, T. J.; Sibley, P.K.; Burton, G.A.; Ingersoll, C.G.; Kemble, N.E.; Ireland, S.; Mount, D.R.; Rowland, C.D.

    2006-01-01

    Methods for assessing the long-term toxicity of sediments to Hyalella azteca and Chironomus tentans can significantly enhance the capacity to assess sublethal effects of contaminated sediments through multiple endpoints. Sublethal tests allow us to begin to understand the relationship between short-term and long-term effects for toxic sediments. We present an interlaboratory evaluation with long-term and 10-d tests using control and contaminated sediments in which we assess whether proposed and existing performance criteria (test acceptability criteria [TAC]) could be achieved. Laboratories became familiar with newly developed, long-term protocols by testing two control sediments in phase 1. In phase 2, the 10-d and long-term tests were examined with several sediments. Laboratories met the TACs, but results varied depending on the test organism, test duration, and endpoints. For the long-term tests in phase 1, 66 to 100% of the laboratories consistently met the TACs for survival, growth, or reproduction using H. azteca, and 70 to 100% of the laboratories met the TACs for survival and growth, emergence, reproduction, and hatchability using C. tentans. In phase 2, fewer laboratories participated in long-term tests: 71 to 88% of the laboratories met the TAC for H. azteca, whereas 50 to 67% met the TAC for C. tentans. In the 10-d tests with H. azteca and C. tentans, 82 and 88% of the laboratories met the TAC for survival, respectively, and 80% met the TAC for C. tentans growth. For the 10-d and long-term tests, laboratories predicted similar toxicity. Overall, the interlaboratory evaluation showed good precision of the methods, appropriate endpoints were incorporated into the test protocols, and tests effectively predicted the toxicity of sediments. ?? 2006 SETAC.

  14. Effects of acid-volatile sulfide on metal bioavailability and toxicity to midge (Chironomus tentans) larvae in black shale sediments.

    PubMed

    Ogendi, George M; Brumbaugh, William G; Hannigan, Robyn E; Farris, Jerry L

    2007-02-01

    Metal bioavailability and toxicity to aquatic organisms are greatly affected by variables such as pH, hardness, organic matter, and sediment acid-volatile sulfide (AVS). Sediment AVS, which reduces metal bioavailability and toxicity by binding and immobilizing metals as insoluble sulfides, has been studied intensely in recent years. Few studies, however, have determined the spatial variability of AVS and its interaction with simultaneously extracted metals (SEM) in sediments containing elevated concentrations of metals resulting from natural geochemical processes, such as weathering of black shales. We collected four sediment samples from each of four headwater bedrock streams in northcentral Arkansa (USA; three black shale-draining streams and one limestone-draining stream). We conducted 10-d acute whole-sediment toxicity tests using the midge Chironomus tentans and performed analyses for AVS, total metals, SEMs, and organic carbon. Most of the sediments from shale-draining streams had similar total metal and SEM concentrations but considerable differences in organic carbon and AVS. Zinc was the leading contributor to the SEM molar sum, averaging between 68 and 74%, whereas lead and cadmium contributed less than 3%. The AVS concentration was very low in all but two samples from one of the shale streams, and the sum of the SEM concentrations was in molar excess of AVS for all shale stream sediments. No significant differences in mean AVS concentrations between sediments collected from shale-draining or limestone-draining sites were noted (p > 0.05). Midge survival and growth in black shale-derived sediments were significantly less (p < 0.001) than that of limestone-derived sediments. On the whole, either SEM alone or SEM-AVS explained the total variation in midge survival and growth about equally well. However, survival and growth were significantly greater (p < 0.05) in the two sediment samples that contained measurable AVS compared with the two sediments from the

  15. Effects of acid-volatile sulfide on metal bioavailability and toxicity to midge (Chironomus tentans) larvae in black shale sediments

    USGS Publications Warehouse

    Ogendi, G.M.; Brumbaugh, W.G.; Hannigan, R.E.; Farris, J.L.

    2007-01-01

    Metal bioavailability and toxicity to aquatic organisms are greatly affected by variables such as pH, hardness, organic matter, and sediment acid-volatile sulfide (AVS). Sediment AVS, which reduces metal bioavailability and toxicity by binding and immobilizing metals as insoluble sulfides, has been studied intensely in recent years. Few studies, however, have determined the spatial variability of AVS and its interaction with simultaneously extracted metals (SEM) in sediments containing elevated concentrations of metals resulting from natural geochemical processes, such as weathering of black shales. We collected four sediment samples from each of four headwater bedrock streams in northcentral Arkansa (USA; three black shale-draining streams and one limestone-draining stream). We conducted 10-d acute whole-sediment toxicity tests using the midge Chironomus tentans and performed analyses for AVS, total metals, SEMs, and organic carbon. Most of the sediments from shale-draining streams had similar total metal and SEM concentrations but considerable differences in organic carbon and AVS. Zinc was the leading contributor to the SEM molar sum, averaging between 68 and 74%, whereas lead and cadmium contributed less than 3%. The AVS concentration was very low in all but two samples from one of the shale streams, and the sum of the SEM concentrations was in molar excess of AVS for all shale stream sediments. No significant differences in mean AVS concentrations between sediments collected from shale-draining or limestone-draining sites were noted (p > 0.05). Midge survival and growth in black shale-derived sediments were significantly less (p < 0.001) than that of limestone-derived sediments. On the whole, either SEM alone or SEM-AVS explained the total variation in midge survival and growth about equally well. However, survival and growth were significantly greater (p < 0.05) in the two sediment samples that contained measurable AVS compared with the two sediments from the

  16. Effects of exposure to oil sands process-affected water from experimental reclamation ponds on Chironomus dilutus.

    PubMed

    Anderson, Julie; Wiseman, Steve B; Moustafa, Ahmed; El-Din, Mohamed Gamal; Liber, Karsten; Giesy, John P

    2012-04-15

    Effective detoxification of oil sands process-affected water (OSPW) is one issue associated with bitumen extraction in the Alberta oil sands. It has been suggested that reclamation ponds can be used to passively treat OSPW, potentially allowing for its safe return to the environment. In this study, OSPW was sampled in two batches (A and B) from the Syncrude Canada Ltd. West In-Pit (WIP) settling pond and from three experimental reclamation ponds - Big Pit, FE5, and TPW. Acute (10 d) and chronic (until adult emergence) exposures of Chironomus dilutus larvae to OSPW were conducted and survival, growth, development, and behavior were assessed. Masses of larvae exposed to WIP-OSPW were 64-77% less than the freshwater control (p < 0.001). Similarly, chronic exposure to WIP-OSPW resulted in significantly (p < 0.05) less pupation than in the freshwater control, with 31% (A) and 71% (B) less pupation of larvae exposed to WIP-OSPW. Rates of emergence were significantly less for larvae exposed to WIP-OSPW, with only 13% (A) and 8% (B) of larvae emerging as adults when exposed to WIP-OSPW, compared to 81% in the freshwater control (p < 0.0001). Pupation and emergence rates were significantly less in TPW than freshwater control (p < 0.05), but there were no differences observed in Big Pit or FE5. Lesser toxicity was observed in reclaimed OSPW compared to fresh OSPW and this coincided with lesser concentrations of NAs. The results presented are consistent with the hypothesis that an organic fraction is the cause of the toxicity of OSPW toward C. dilutus and that OSPW aged in reclamation ponds retains toxicity and therefore, more aggressive, targeted treatment of OSPW is required to accelerate decreases. PMID:22265614

  17. Bioconcentration of perfluoroalkyl substances by Chironomus plumosus larvae in water with different types of dissolved organic matters.

    PubMed

    Wen, Wu; Xia, Xinghui; Chen, Xi; Wang, Haotian; Zhu, Baotong; Li, Husheng; Li, Yang

    2016-06-01

    The effects of four types of dissolved organic matters (DOM) on the bioconcentration of perfluoroalkyl substances (PFASs) in Chironomus plumosus larvae have been studied. The PFASs included perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnA), and perfluorododecanoic acid (PFDoA). The DOM included humic acid (HA), fulvic acid (FA), tannic acid (TA), and a protein, peptone (PEP), and their concentrations ranged from 0 to 50 mg L(-1). The results showed that, upon bioconcentration equilibrium, the body burdens of longer perfluoroalkyl chain PFASs (PFOS, PFDA, PFUnA and PFDoA) decreased with PEP and HA concentrations while increased with FA and TA concentrations. When FA and TA concentrations increased from 0 to 50 mg L(-1), body burdens of these PFASs increased by 7.5%-148.8% and 5.7%-37.1%, respectively. However, the DOM had no significant impact on the body burdens of shorter perfluoroalkyl chain PFASs (PFOA and PFNA). All of the four types of DOM lowered not only the uptake rate constants (ku) of PFASs due to the decrease of freely dissolved PFAS concentrations, but also the elimination rate constants (ke) due to the inhibition effect of DOM on the PFAS elimination from the larvae. The reduction in the two constants varied with both DOM and PFAS types. In the presence of PEP and HA with larger molecular weights, the ku values decreased more than ke, leading to the decreased body burdens of longer perfluoroalkyl chain PFASs. As for FA and TA with smaller molecular weights, the ke values decreased more than ku, resulting in increased body burdens of longer perfluoroalkyl chain PFASs. This study suggests that the effects of DOM on PFAS bioconcentration depend not only on the concentration but also on the molecule weight of DOM, which should be considered in the bioavailability assessment of PFASs. PMID:26925752

  18. Occallatibacter riparius gen. nov., sp. nov. and Occallatibacter savannae sp. nov., acidobacteria isolated from Namibian soils, and emended description of the family Acidobacteriaceae.

    PubMed

    Foesel, Bärbel U; Mayer, Susanne; Luckner, Manja; Wanner, Gerhard; Rohde, Manfred; Overmann, Jörg

    2016-01-01

    Three Gram-negative, non-spore-forming, encapsulated bacteria were isolated from a Namibian river-bank soil (strains 277T and 307) and a semiarid savannah soil (strain A2-1cT). 16S rRNA gene sequence analyses placed them within subdivision 1 of the Acidobacteria and revealed 100 % similarity between strains 277T and 307 and 98.2 % similarity between A2-1cT and the former two strains. The closest relatives with validly published names were Telmatobacter bradus, Acidicapsa borealis and Acidicapsa ligni (94.7-95.9 % similarity to the type strains). Cells of all three strains were rod-shaped and motile and divided by binary fission. Ultrastructural analyses revealed a thick cell envelope, resulting mainly from a thick periplasmic space. Colonies of strains 277T and 307 were white to cream and light pink, respectively, while strain A2-1cT displayed a bright pink colour. All three strains were aerobic, chemoheterotrophic mesophiles with a broad temperature range for growth and a moderately acidic pH optimum. Sugars and complex proteinaceous substrates were the preferred carbon and energy sources. A few polysaccharides were degraded. The major quinone in all three strains was MK-8; MK-7 occurred in strain A2-1cT as a minor compound. Major fatty acids were iso-C15 : 0 and iso-C17 : 1ω7c. In addition, iso-C17 : 0 occurred in significant amounts. The DNA G+C contents of strains 277T, 307 and A2-1cT were 59.6, 59.9 and 58.5 mol%, respectively. Based on these characteristics, the three isolates are assigned to two novel species of the novel genus Occallatibacter gen. nov., Occallatibacter riparius sp. nov. [type strain 277T ( = DSM 25168T = LMG 26948T) and reference strain 307 ( = DSM 25169 = LMG 26947)] and Occallatibacter savannae sp. nov. [type strain A2-1cT ( = DSM 25170T = LMG 26946T)]. Together with several other recently described taxa, the novel isolates provide the basis for an emended description of the established family

  19. Effects of exposure to a combination of zinc- and lead-spiked sediments on mouthpart development and growth in Chironomus tentans.

    PubMed

    Martinez, Edward A; Moore, Barry C; Schaumloffel, John; Dasgupta, Nairanjana

    2004-03-01

    Exposures to either zinc or lead in contaminated sediments have been shown to induce characteristic deformities in larval chironomids. This study examined the effects of exposure to lead and zinc in combination on Chironomus tentans larvae. Proportions of mouthpart deformities in populations of larvae reared in sediments containing nominal combinations of lead and zinc were tested for additive, synergistic, and antagonistic interactions using logistic regression. Metal body burdens, body size measurements, and survival were used to evaluate toxicity and developmental impacts. Results demonstrate zinc and lead mixtures produce fewer deformities than the individual metal, so their interaction may be characterized as antagonistic. However, exposure to the metal mixtures also caused delayed development and failure to hatch. The apparent decline in deformities may be an artifact of higher mortalities or developmental effects. This research provides better understanding of some of the problems and considerations for use of chironomid population deformity proportions in bioassessments for sediment metal contamination. PMID:15285360

  20. Cytogenetic index and functional genome alterations in Chironomus piger Strenzke (Diptera, Chironomidae) in the assessment of sediment pollution: a case study of Bulgarian and UK rivers.

    PubMed

    Michailova, P; Ilkova, J; Dean, A P; White, K N

    2015-01-01

    The genotoxicity of trace metals in the sediments from a number of polluted sites on UK and Bulgarian rivers to Chironomus piger was assessed by an examination of genome instability as demonstrated by structural and functional changes to the salivary glands chromosomes. Based on the metal assays, the sediments were characterized to range from 'extremely' to 'strongly contaminated'. The cytogenetic index calculated on the basis of somatic structural chromosome alterations in the polytene chromosomes indicates a high level of pollution (0.07-0.06 in Bulgarian and 0.10-0.13 in UK stations). Exposure of C. piger to contaminated sediments resulted in a high level of chromosome damage as indicated by a somatic index of between 1.96 and 4.0. The transcription mechanism of the Balbiani rings and nucleolar organizer was damaged as their activity was either partially or completely suppressed. We have demonstrated that the C. piger genome is a sensitive sublethal indicator of sediment contamination, and is a highly suitable candidate for ecotoxicological monitoring of running waters. PMID:25450937

  1. Relative sensitivity of an amphipod Hyalella azteca, a midge Chironomus dilutus, and a unionid mussel Lampsilis siliquoidea to a toxic sediment

    USGS Publications Warehouse

    Ingersoll, Christopher G.; Kunz, James L.; Hughes, James P.; Wang, Ning; Ireland, D. Scott; Mount, Dave R.; Hockett, Russ J; Valenti, Ted W

    2015-01-01

    The objective of the present study was to evaluate the relative sensitivity of test organisms in exposures to dilutions of a highly toxic sediment contaminated with metals and organic compounds. One dilution series was prepared using control sand (low total organic carbon [TOC; <0.1%, low binding capacity for contaminants]) and a second dilution series was prepared using control sediment from West Bearskin Lake, Minnesota, USA (high TOC [~10% TOC, higher binding capacity for contaminants]). Test organisms included an amphipod (Hyalella azteca; 10-d and 28-d exposures), a midge (Chironomus dilutus; 20-d and 48-d exposures started with <1-h-old larvae, and 13-d and 48-d exposures started with 7-d-old larvae), and a unionid mussel (Lampsilis siliquoidea; 28-d exposures). Relative species sensitivitydepended on the toxicity endpoint and the diluent. All 3 species were more sensitive in sand dilutions than in West Bearskin Lake sediment dilutions. The <1-h-old C. dilutus were more sensitive than 7-d-old C. dilutus, but replicate variability was high in exposures started with the younger midge larvae. Larval biomass and adult emergence endpoints of C. dilutus exhibited a similar sensitivity. Survival, weight, and biomass of H. azteca were more sensitive endpoints in 28-d exposures than in 10-d exposures. Weight and biomass of L. siliquoidea were sensitive endpoints in both sand and West Bearskin Lake sediment dilutions. Metals, ammonia, oil, and other organic contaminants may have contributed to the observed toxicity.

  2. Toxicity of fluoranthene to Daphnia magna, Hyalella azteca, Chironomus tentans, and Stylaria lacustris in water-only and whole sediment exposures

    SciTech Connect

    Suedel, B.C.; Rodgers, J.H. Jr.

    1996-07-01

    Fluoranthene is a polycyclic aromatic hydrocarbon (PAH) with a hydrophobic nature (water solubility = 265 {mu}g/L; U.S. EPA 1980) and a propensity to sorb to sediments. Fluoranthene has a K{sub oc} of 4.65, an intermediate value for PAHs. Fluoranthene can be toxic to some aquatic organisms at concentrations lower than its aqueous solubility. Therefore, desorption from sediments could produce aqueous concentrations that are harmful to aquatic organisms. Very few studies have examined the toxicity of fluoranthene to freshwater organisms. Data for other PAHs show that crustaceans are the most sensitive species, followed by polychaete worms and fish. Effects of fluoranthene-amended sediments on selected marine benthic organisms were examined. The objectives of this research were to (1) determine the relative sensitivities of Daphnia magna Straus, Hyalella azteca Saussure, Chironomus tentans Fabricius, and Stylaria lacustris Linnaeus in 48-hr and 10-d aqueous phase exposures to fluoranthene; and (2) determine the relative responses of these organisms in 10-d fluoranthene-amended sediment exposures. 12 refs., 3 tabs.

  3. Relative sensitivity of an amphipod Hyalella azteca, a midge Chironomus dilutus, and a unionid mussel Lampsilis siliquoidea to a toxic sediment.

    PubMed

    Ingersoll, Chris G; Kunz, James L; Hughes, Jamie P; Wang, Ning; Ireland, D Scott; Mount, David R; Hockett, J Russell; Valenti, Theodore W

    2015-05-01

    The objective of the present study was to evaluate the relative sensitivity of test organisms in exposures to dilutions of a highly toxic sediment contaminated with metals and organic compounds. One dilution series was prepared using control sand (low total organic carbon [TOC; <0.1%, low binding capacity for contaminants]) and a second dilution series was prepared using control sediment from West Bearskin Lake, Minnesota, USA (high TOC [∼10% TOC, higher binding capacity for contaminants]). Test organisms included an amphipod (Hyalella azteca; 10-d and 28-d exposures), a midge (Chironomus dilutus; 20-d and 48-d exposures started with <1-h-old larvae, and 13-d and 48-d exposures started with 7-d-old larvae), and a unionid mussel (Lampsilis siliquoidea; 28-d exposures). Relative species sensitivity depended on the toxicity endpoint and the diluent. All 3 species were more sensitive in sand dilutions than in West Bearskin Lake sediment dilutions. The <1-h-old C. dilutus were more sensitive than 7-d-old C. dilutus, but replicate variability was high in exposures started with the younger midge larvae. Larval biomass and adult emergence endpoints of C. dilutus exhibited a similar sensitivity. Survival, weight, and biomass of H. azteca were more sensitive endpoints in 28-d exposures than in 10-d exposures. Weight and biomass of L. siliquoidea were sensitive endpoints in both sand and West Bearskin Lake sediment dilutions. Metals, ammonia, oil, and other organic contaminants may have contributed to the observed toxicity. PMID:25655578

  4. Bioavailability, toxicity and biotransformation of selenium in midge (Chironomus dilutus) larvae exposed via water or diet to elemental selenium particles, selenite, or selenized algae.

    PubMed

    Gallego-Gallegos, Mercedes; Doig, Lorne E; Tse, Justin J; Pickering, Ingrid J; Liber, Karsten

    2013-01-01

    Elemental selenium (Se) is generally considered to be biologically inert due to its insolubility in water. It is a common form of Se in sediment near uranium mining and milling operations in northern Saskatchewan, Canada. Nanosized particles of many materials exhibit different properties compared with their bulk phases, in some cases posing health and ecological risks. Here we investigated the bioavailability and toxicity of Se nanoparticles (SeNPs) using 10-day waterborne and dietary exposures to larvae of Chironomus dilutus, a common benthic invertebrate. For comparison, larvae were also exposed to waterborne dissolved selenite and to dietary selenomethionine as selenized algae. Larval Se accumulation was evaluated using graphite furnace atomic absorption spectroscopy or inductively coupled plasma mass spectroscopy for total Se and X-ray absorption spectroscopy for Se chemical speciation. Exposure to nanoparticulate Se resulted in Se bioaccumulation, at high concentrations, inhibiting larval growth in both waterborne and dietary exposures; larvae predominantly accumulated selenomethionine-like species regardless of uptake route or form of Se tested. Despite the observed Se accumulation, our findings suggest there is little risk of direct SeNP toxicity to benthic invertebrates in Se-contaminated sediments in northern Saskatchewan. Nevertheless, elemental Se in sediments may be biologically available and may contribute directly or indirectly to the risk of Se toxicity to egg-laying vertebrates (fish and piscivorous birds) in Se-contaminated aquatic systems. It thus may be necessary to include elemental Se as a source of potential Se exposure in ecological risk assessments. PMID:23234498

  5. Assessment of Sediment Risk in the North End of Tai Lake, China: Integrating Chemical Analysis and Chronic Toxicity Testing with Chironomus dilutus.

    PubMed

    Qi, Hongxue; Ma, Ping; Li, Huizhen; You, Jing

    2015-11-01

    Whole life-cycle bioassays with Chironomus dilutus were performed to evaluate sediment toxicity in Tai Lake, a typical freshwater lake in China. Meanwhile, contaminants of concern were analyzed in sediment. The sediments in Tai Lake showed no acute mortality in 10-day testing to C. dilutus. After chronic exposure to the sediments, however, adverse effects-including decreased survival and sublethal impairments of growth, emergence, and fecundity-were observed at most sites in Tai Lake. A variety of contaminants were detected in sediment with the total concentrations in the range of 504-889 ng/g dry weight (dw) for polycyclic aromatic hydrocarbons, 0.56-1.81 ng/g dw for polychlorinated biphenyls, 38.6-87.8 ng/g dw for polybrominated diphenyl ethers, 8.34-14.2 ng/g dw for organochlorine pesticides, 1.27-2.95 ng/g dw for organophosphate pesticides, 0.11-0.21 ng/g dw for pyrethroid pesticides, and 332-609 µg/g dw for metals. Finally, a canonical correlation analysis was applied to link chronic sediment toxicity to the toxic units of individual contaminants. Results suggested that two pesticides (hexachlorocyclohexane and chlorpyrifos) and two metals (chromium and nickel) in sediments from Tai Lake were the potential contributors to the noted toxicity in C. dilutus in the life-cycle toxicity testing. In conclusion, acute bioassays with the benthos were not sensitive enough to assess sediment toxicity in freshwater lakes in China, and it is desirable to integrate chronic toxicity testing with chemical analysis to better understand sediment risk. PMID:26003187

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

    PubMed

    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

  7. Effects of clay minerals and organic matter in formulated sediments on the bioavailability of sediment-associated uranium to the freshwater midge, Chironomus dilutus.

    PubMed

    Crawford, Sarah E; Liber, Karsten

    2015-11-01

    It is well established that bioavailability influences metal toxicity in aquatic ecosystems. However, the factors and mechanisms that influence uranium (U) bioavailability and toxicity in sediment have not been thoroughly evaluated, despite evidence that suggests different sediment components can influence the sorption and interaction of some metals. Given that dissolved U is generally accepted as being the primary bioavailable fraction of U, it is hypothesized that adsorption and interaction of U with different sediment components will influence the bioavailability of U in sediment. We investigated the effects of key sediment physicochemical properties on the bioavailability of U to a model freshwater benthic invertebrate, Chironomus dilutus. Several 10-day spiked sediment bioaccumulation experiments were performed, exposing C. dilutus larvae to a variety of formulated sediments spiked with different concentrations of U (5, 50 and/or 200 mg U/kg d.w.). Mean accumulation of U in C. dilutus larvae decreased significantly from 1195 to 10 mg U/kg d.w. as kaolin clay content increased from 0% to 60% in sediment spiked with 50 mg U/kg d.w. Similarly, higher organic matter content also resulted in a significant reduction of U bioaccumulation in C. dilutus larvae, indicating a reduction in U bioavailability. Concentrations of U in both the overlying water and sediment pore water displayed a strong positive relationship to U bioaccumulation in C. dilutus larvae (r(2) = 0.77, p<0.001 and r(2) = 0.57, p < 0.001, respectively) for all experiments, while total U concentrations in the sediment had a poor relationship to U bioaccumulation (r(2) = 0.10, p = 0.028). Results from this research confirm that sediment clay and organic matter content play a significant role in altering U bioavailability, which is important in informing risk assessments of U contaminated sites and in the development of site-specific sediment quality guidelines for U. PMID:26205073

  8. Contaminants in stream sediments from seven United States metropolitan areas: part II—sediment toxicity to the amphipod Hyalella azteca and the midge Chironomus dilutus

    USGS Publications Warehouse

    Kemble, Nile E.; Hardesty, Douglas K.; Ingersoll, Christopher G.; Kunz, James L.; Sibley, Paul K.; Calhoun, Daniel L.; Gilliom, Robert J.; Kuivila, Kathryn M.; Nowell, Lisa H.; Moran, Patrick W.

    2013-01-01

    Pyrethroids are hydrophobic compounds that have been observed to accumulate in sediments (Laskowski 2002). Toxicity of pyrethroids in field-collected sediment from small urban streams (Weston et al. 2005; Holmes et al. 2008; Ding et al. 2010; Domagalski et al. 2010) or with pyrethroids spiked into sediment (Amweg et al. 2006; Hintzen et al. 2009) have been evaluated primarily in 10 day lethality tests conducted with the amphipod Hyalella azteca. However, the sublethal effects in long-term exposures to pyrethroids in sediment have not been evaluated, and the distribution of pyrethroids sediments has not typically been evaluated in wadeable streams (Gilliom et al. 2006). This article is the second in a series that describe the results of a study of the distribution and toxicity of pyrethroids and other co-occurring trace elements and organic contaminants (PCBs, PAHs, OC pesticides) in stream sediments from 7 metropolitan areas across the United States (Moran et al. 2012). The study evaluated 98 sediment samples collected from streams ranging from undeveloped to highly urban and differs from previous studies by sampling larger wadeable streams and avoiding point sources (such as storm drains) and other inflows (Gilliom et al. 2006). Part 1 of the series characterizes sediment contaminants in relation to urbanization and other factors in the 7 metropolitan study areas (Nowell et al. 2012). Part 2 (this article) evaluates relationships between sediment chemistry and sediment toxicity in 28 day whole-sediment exposures conducted with the amphipod H. azteca and in 10 day whole-sediment exposure conducted with the midge Chironomus dilutus (USEPA U

  9. Endocrine disruption and oxidative stress in larvae of Chironomus dilutus following short-term exposure to fresh or aged oil sands process-affected water.

    PubMed

    Wiseman, S B; Anderson, J C; Liber, K; Giesy, J P

    2013-10-15

    Understanding the toxicity of oil sands process-affected water (OSPW) is a significant issue associated with the production of oil from the Alberta oil sands. OSPW is acutely and chronically toxic to organisms, including larvae of Chironomus dilutus. In this study, fresh OSPW ('WIP-OSPW') was collected from the West In-Pit settling pond and aged OSPW ('FE5-OSPW') was collected from the FE5 experimental reclamation pond, both of which are located on the Syncrude Canada Ltd. lease site near Fort McMurray, Alberta, Canada. Larvae of C. dilutus were exposed to a freshwater control, WIP-OSPW, or FE5-OSPW for 4 or 7 days and survival, growth, and markers of oxidative stress and endocrine disruption were assessed. Survival was not significantly different among treatment groups. Compared to masses of larvae exposed to freshwater, masses of larvae exposed to WIP-OSPW were 49% lesser on day 4 and 62% lesser on day 7. However, organisms exposed to FE5-OSPW did not have significantly lesser masses than controls. Abundances of transcripts of glutathione-s-transferase (gst), catalase (cat), and glutathione peroxidase (gpx), which are important for the response to oxidative stress, were significantly altered in larvae exposed to WIP-OSPW, but not FE5-OSPW, relative to controls. Peroxidation of lipids was greater in larvae exposed to WIP-OSPW, but not FE5-OSPW. Exposure to fresh OSPW might have caused endocrine disruption because abundances of transcripts of the steroid hormone receptors, ultraspiricle protein (usp), ecysteroid receptor (esr), and estrogen related receptor (err) were greater in larvae exposed to WIP-OSPW for 7 days, but not FE5-OSPW. These results suggest that lesser growth of larvae of C. dilutus exposed to fresh OSPW might be due to oxidative stress and disruption of endocrine processes, and that aging of OSPW attenuates these adverse effects. PMID:24096237

  10. A multi-platform metabolomics approach demonstrates changes in energy metabolism and the transsulfuration pathway in Chironomus tepperi following exposure to zinc.

    PubMed

    Long, Sara M; Tull, Dedreia L; Jeppe, Katherine J; De Souza, David P; Dayalan, Saravanan; Pettigrove, Vincent J; McConville, Malcolm J; Hoffmann, Ary A

    2015-05-01

    Measuring biological responses in resident biota is a commonly used approach to monitoring polluted habitats. The challenge is to choose sensitive and, ideally, stressor-specific endpoints that reflect the responses of the ecosystem. Metabolomics is a potentially useful approach for identifying sensitive and consistent responses since it provides a holistic view to understanding the effects of exposure to chemicals upon the physiological functioning of organisms. In this study, we exposed the aquatic non-biting midge, Chironomus tepperi, to two concentrations of zinc chloride and measured global changes in polar metabolite levels using an untargeted gas chromatography-mass spectrometry (GC-MS) analysis and a targeted liquid chromatography-mass spectrometry (LC-MS) analysis of amine-containing metabolites. These data were correlated with changes in the expression of a number of target genes. Zinc exposure resulted in a reduction in levels of intermediates in carbohydrate metabolism (i.e., glucose 6-phosphate, fructose 6-phosphate and disaccharides) and an increase in a number of TCA cycle intermediates. Zinc exposure also resulted in decreases in concentrations of the amine containing metabolites, lanthionine, methionine and cystathionine, and an increase in metallothionein gene expression. Methionine and cystathionine are intermediates in the transsulfuration pathway which is involved in the conversion of methionine to cysteine. These responses provide an understanding of the pathways affected by zinc toxicity, and how these effects are different to other heavy metals such as cadmium and copper. The use of complementary metabolomics analytical approaches was particularly useful for understanding the effects of zinc exposure and importantly, identified a suite of candidate biomarkers of zinc exposure useful for the development of biomonitoring programs. PMID:25781392

  11. Effect of sediment-associated pyrethroids, fipronil, and metabolites on Chironomus tentans growth rate, body mass, condition index, immobilization, and survival.

    PubMed

    Maul, Jonathan D; Brennan, Amanda A; Harwood, Amanda D; Lydy, Michael J

    2008-12-01

    Pyrethroids and fipronil insecticides partition to sediment and organic matter in aquatic systems and may pose a risk to organisms that use these matrices. It has been suggested that bioavailability of sediment-sorbed pesticides is reduced, but data on toxicity of sediment-associated pesticides for pyrethroids and fipronil are limited. In the current study, 10-d sediment exposures were conducted with larval Chironomus tentans for bifenthrin, lambda-cyhalothrin, permethrin, fipronil, fipronil-sulfide, and fipronil-sulfone, the last two being common fipronil metabolites. Sublethal endpoints included immobilization, instantaneous growth rate (IGR), body condition index, and growth estimated by ash-free dry mass (AFDM). Pyrethroid lethal concentrations to 50% of the population (LC50s) were 6.2, 2.8, and 24.5 microg/g of organic carbon (OC) for bifenthrin, lambda-cyhalothrin, and permethrin, respectively; with the former two lower than previously published estimates. Fipronil, fipronil-sulfide, and fipronil-sulfone LC50 values were 0.13, 0.16, and 0.12 microg/g of OC, respectively. Ratios of LC50s to sublethal endpoints (immobilization, IGR, and AFDM) ranged from 0.90 to 9.03. The effects on growth observed in the present study are important because of the unique dipteran life cycle involving pupation and emergence events. Growth inhibition would likely lead to ecological impacts similar to mortality (no emergence and thus not reproductively viable) but at concentrations up to 4.3 times lower than the LC50 for some compounds. In addition, C. tentans was highly sensitive to fipronil and metabolites, suggesting that dipterans may be important for estimating risk and understanding effects of phenylpyrazole-class insecticides on benthic macroinvertebrate communities. PMID:18699702

  12. Acute and chronic toxicity of the herbicide benzofenap (Taipan 300) to Chironomus tepperi Skuse (Diptera: Chironomidae) and Isidorella newcombi (Adams and Angas) (Gastropoda: Planorbidae).

    PubMed

    Wilson, A L; Stevens, M M; Watts, R J

    2000-02-01

    Acute and chronic toxicity tests were conducted on the herbicide benzofenap (Taipan 300) using two Australian freshwater invertebrates. The commercial formulation of benzofenap and a blank formulation containing only the adjuvants of Taipan 300 were tested against final instar larvae of the midge Chironomus tepperi and adults of the aquatic snail Isidorella newcombi. In 24-h acute bioassays the midge larvae did not show significant mortality at a nominal concentration of 1.2 mg/L active ingredient (AI), double the maximum notional concentration expected in rice fields after application of Taipan 300 at the permit rate of 2 L/ha. No significant snail mortality was recorded in acute bioassays (24-h exposure, 48-h recovery) at nominal concentrations up to 76 mg/L AI, which is over 120 times the maximum notional field concentration. In chronic assays, the pupation and emergence of C. tepperi was monitored after a 4-h pulse exposure of final instar larvae to Taipan 300 (nominal concentrations 0.001 to 0.1 mg/L AI) and adjuvant-only (0.1 mg/L equivalent) treatments. No statistically significant effects were observed, although emergence appeared to be delayed by higher benzofenap concentrations and by the adjuvant-only treatment. During snail bioassays, egg and feces production were monitored for 21 days after 24-h exposure to Taipan 300 (nominal concentrations 1.2 mg/L to 60 mg/L AI) and adjuvant-only treatments (60 mg/L equivalent). No significant chronic effects were proven against I. newcombi, despite a decline in egg mass production following exposure to all treatments and a reduction in the total numbers of eggs produced at the highest nominal concentrations tested (60 mg/L AI and adjuvant-only treatments). Similarly, feces production by snail pairs exposed to the majority of treatments declined, but these differences were not statistically significant. It is concluded that Taipan 300 does not represent a significant risk to mature C. tepperi larvae or adult I

  13. Whole-body distribution an Malpighian tubule transport of 2',5-dichloro-4'-nitrosalicylanilide (Bayer 73) and 3-trifluoromethyl-4-nitrophenol in larvae of the aquatic midge Chironomus tentans.

    PubMed

    Hansen, C R; Gauss, J D; Kawatski, J A

    1980-04-01

    1. Residues of the lampricides 14C-Bayer 73 (2',5-dichloro-4'-nitrosalicylanilide) and 14C-TFM (3-trifluoromethyl-4-nitrophenol) were absorbed from aqueous sublethal concn. by aquatic larvae of the midge Chironomus tentans. 2. Toxicant residues were widely distributed during early hours of exposure, but later and during a 24-h post-exposure period, they became concentrated in the trunk and intestinal tract; the posterior movement of Bayer 73 was more rapid than that of TFM. 3. During 4-h tests, Malpighian tubules of the chironomid actively transported Bayer 73 and TFM in vitro, and on a per tubule basis, more TFM was transported than Bayer 73. 4. Potassium cyanide inhibited tubule transport; serotonin had no effect. PMID:7415206

  14. Comparative acute toxicity to aquatic organisms of components of coal-derived synthetic fuels. [Selenastrum capricornutum; Nitzchia palea; Physa gyrina, Daphnia magna; Chironomus tentans; Gammarus minus; Pimephales promelas; Salmo gairdneri; Micropterus salmoides

    SciTech Connect

    Millemann, R.E.; Birge, W.J.; Black, J.A.; Cushman, R.M.; Daniels, K.L.; Franco, P.J.; Giddings, J.M.; McCarthy, J.F.; Stewart, A.J.

    1984-01-01

    In acute toxicity tests, green algae Selenaastrum capricornutum, diatoms Nitzschia palea, adult snails Physa gyrina, juvenile cladocerans Daphnia magna, larval midges Chironomus tentans, adult amphipods Gammarus minus, juvenile fathead minnows Pimephales promelas, and embryo-larva stages of rainbow trout Salmo gairdneri and largemouth bass Micropterus salmoides were exposed for 4 hours (algae), 48 hours (arthropods and snails), 96 hours (fathead minnows), 7 days (large-mouth bass), and 27 days (rainbow trout) to two phenols (phenol and ..beta..-naphthol), two azaarenes (quinoline and acridine), and two polycyclic aromatic hydrocarbons (naphthalene and phenanthrene) present in coal-derived oils. Median lethal or median effective concentrations (LC50s or EC50s) ranged from 0.03 mg/liter for phenanthrene and rainbow trout to 286.54 mg/liter for phenol and the green alga. The rainbow trout embryo-larva assay was the most sensitive of the test systems to all the chemicals except quinoline. For this last compound, systems with juvenile fathead minnows and largemouth bass embryos were the most sensitive. As test systems, fish embryos and larvae were the most sensitive, juvenile fathead minnows and arthropods had intermediate sensitivity, and algae and snails were the most resistant to the test compounds under the test conditions. Within each chemical class (phenols, azaarenes, and polycylcic aromatic hydrocarbons), toxicity increased with increased ring number except for the reversed relationship with the azaarenes and fathead minnows. Thus, ..beta..-naphthol (two rings) was 2 to 45 times more toxic than phenol (one ring); acridine (three rings) was 7 to 27 times more toxic than quinoline (two rings); and phenanthrene (three rings) was 3 to 9 times more toxic than naphthalene (two rings). 50 references.

  15. Coenosia Meigen (Diptera: Muscidae) from Angola: new species and records.

    PubMed

    Couri, Marcia S; Pont, Adrian C

    2016-01-01

    The study of unidentified material from Angola (Africa), deposited in the collection of the Natural History Museum, London, United Kingdom, has revealed three new Coenosia species: Coenosia lucens sp. nov., Coenosia flavohumeralis sp. nov. and Coenosia setosa sp. nov., and five new records: Coenosia macrochaeta (Emden, 1940), Coenosia nodosa Stein, 1913, Coenosia ochroprocta (Speiser, 1910), Coenosia planifrons Stein, 1913 and Coenosia translucida (Emden, 1940). Only one species of Coenosia had previously been recorded from Angola: Coenosia sanguenguei Zielke 1971. The new species are described with illustrations of the male terminalia, and diagnoses of the newly-recorded species with descriptions of the male terminalia are given. A list of all Muscidae species recorded from Angola is presented. PMID:27394753

  16. Effects of cadmium and resource quality on freshwater detritus processing chains: a microcosm approach with two insect species.

    PubMed

    Campos, Diana; Alves, Artur; Lemos, Marco F L; Correia, António; Soares, Amadeu M V M; Pestana, João L T

    2014-07-01

    Detritus processing is vital for freshwater ecosystems that depend on the leaf litter from riparian vegetation and is mediated by microorganisms and aquatic invertebrates. Shredder invertebrates transform coarse particulate organic matter into fine particulate organic matter used as food by collector species. Direct and indirect effects of contaminants can impair detritus processing and thus affect the functioning of these ecosystems. Here, we assessed the combined effects of a toxic metal (cadmium) and resource quality (leaf species) on detritus processing and shredder-collector interactions. We considered two types of leaves, alder and eucalyptus that were microbially conditioned under different Cd concentrations in the laboratory. The microbial communities present on leaves were analyzed by Denaturing Gradient Gel Electrophoresis (DGGE), and we also measured microbial respiration rates. Sericostoma vittatum (a caddisfly shredder) and Chironomus riparius (a midge collector) were also exposed to Cd and allowed to consume the corresponding alder or eucalyptus leaves. We evaluated C. riparius growth and leaf mass loss in multispecies microcosms. Cadmium exposure affected leaf conditioning and fungal diversity on both leaf species, as assessed by DGGE. Cadmium exposure also affected the mass loss of alder leaves by reductions in detritivore feeding, and impaired C. riparius growth. Chironomus riparius consumed alder leaf discs in the absence of shredders, but S. vittatum appear to promote C. riparius growth in treatments containing eucalyptus. These results show that indirect effects of contaminants along detritus-processing chains can occur through effects on shredder-collector interactions such as facilitation but they also depend on the nutritional quality of detritus and on sensitivity and feeding plasticity of detritivore species. PMID:24648031

  17. Evaluation of toxicity to the amphipod, Hyalella azteca, and to the midge, Chironomus dilutus; and bioaccumulation by the oligochaete, Lumbriculus variegatus, with exposure to PCB-contaminated sediments from Anniston, Alabama

    USGS Publications Warehouse

    Ingersoll, Christopher G.; Steevens, Jeffery A.; MacDonald, Donald D.; Brumbaugh, William G.; Coady, Matthew R.; Farrar, J. Daniel; Lotufo, Guilherme R.; Kemble, Nile E.; Kunz, James L.; Stanley, Jacob K.; Sinclair, Jesse A.

    2014-01-01

    The U.S. Environmental Protection Agency (USEPA) requested that as part of the remedial investigation for the Anniston, Alabama Polychlorinated Biphenyl (PCB) Site (Anniston PCB Site), that Pharmacia Corporation and Solutia Inc. (P/S) perform long-term reproduction toxicity tests with the amphipod, Hyalella azteca, and the midge, Chironomus dilutus, and bioaccumulation tests with the oligochaete, Lumbriculus variegatus, using sediment samples collected from reference locations and from Operable Unit 4 of the Anniston PCB Site. The sediment toxicity testing and sediment bioaccumulation results will be used by ARCADIS U.S., Inc. (ARCADIS) as part of a weight-of-evidence assessment to evaluate risks and establish sediment remediation goals for contaminants to sediment-dwelling organisms inhabiting the Anniston PCB Site. The goal of this study was to characterize relations between sediment chemistry and sediment toxicity and relations between sediment chemistry and sediment bioaccumulation in samples of sediments collected from the Anniston PCB Site. A total of 32 samples were evaluated from six test sites and one reference site to provide a wide range in concentrations of chemicals of potential concern (COPCs) including PCBs in samples of whole sediment. The goal of this study was not to determine the extent of sediment contamination across the Anniston PCB Site. Hence, the test sites or samples collected from within a test site were not selected to represent the spatial extent of sediment contamination across the Anniston PCB Site. Sediment chemistry, pore-water chemistry, and sediment toxicity data were generated for 26 sediment samples from the Anniston PCB Site. All of the samples were evaluated to determine if they qualified as reference sediment samples. Those samples that met the chemical selection criteria and biological selection criteria were identified as reference samples and used to develop the reference envelope for each toxicity test endpoint. Physical

  18. Phthalate esters: Testing for ecological effects

    SciTech Connect

    Brown, D.; Thompson, R.; Croudace, C.; Stewart, K.; Williams, N.

    1995-12-31

    Ortho-phthalate esters are produced in high tonnages for use as plasticizers, in particular for PVC. Their physical chemical properties are typically very low water solubility and high octanol/water partition coefficient. This combination of properties presents a number of experimental difficulties in the design and interpretation of ecological effect studies. These difficulties are described and results presented showing techniques for the performance of reproduction studies with the water flea, Daphnia magna, in aqueous solution and with the midge, Chironomus riparius, in sediments. The results which showed no effect for the phthalate esters tested are discussed in the context of other ecotoxicity data obtained on these products.

  19. The Parthenogenetic Cosmopolitan Chironomid, Paratanytarsus grimmii, as a New Standard Test Species for Ecotoxicology: Culturing Methodology and Sensitivity to Aqueous Pollutants.

    PubMed

    Gagliardi, Bryant S; Long, Sara M; Pettigrove, Vincent J; Hoffmann, Ary A

    2015-09-01

    Chironomids from the genus Chironomus are widely used in laboratory ecotoxicology, but are prone to inbreeding depression, which can compromise test results. The standard Chironomus test species (C. riparius, C. dilutus and C. yoshimatsui) are also not cosmopolitan, making it difficult to compare results between geographic regions. In contrast, the chironomid Paratanytarsus grimmii is cosmopolitan, and not susceptible to inbreeding depression because it reproduces asexually by apomictic parthenogenesis. However, there is no standardised culturing methodology for P. grimmii, and a lack of acute toxicity data for common pollutants (metals and pesticides). In this study, we developed a reliable culturing methodology for P. grimmii. We also determined 24-h first instar LC50s for the metals Cu, Pb, Zn, Cd and the insecticide imidacloprid. By developing this culturing methodology and generating the first acute metal and imidacloprid LC50s for P. grimmii, we provide a basis for using P. grimmii in routine ecotoxicological testing. PMID:26067705

  20. Clarification of Einfeldia Kieffer, 1922 (Diptera: Chironomidae) with E. australiensis (Freeman, 1961), comb. n. based on immature stages.

    PubMed

    Cranston, Peter S; Martin, Jon; Mulder, Monica; Spies, Martin

    2016-01-01

    The immature stages are described for the first time for Chironomus (Xenochironomus) australiensis Freeman (Diptera: Chironomidae) and the adult male is redescribed including from type specimens. The species does not belong to Chironomus Meigen or Xenochironomus Kieffer, but is best placed in a modestly expanded Einfeldia Kieffer. Application of this genus name is clarified, including by a lectotype fixation for its type species, E. pectoralis Kieffer, 1924. Einfeldia australiensis (Freeman) comb. n. provides the first record of the genus from Australia; otherwise the genus is reported confidently only from North America, Central America and western Europe to Japan. The immature stages of E. australiensis occur in relatively shallow mesotrophic to eutrophic dune lakes and maars with circum-neutral pH and high conductivity, from southeastern Queensland to southern Australia. The cytology is described briefly from larval salivary glands. Alternative genus placements for the species are discussed, and problems with Einfeldia and connected systematics in the tribe Chironomini are addressed. PMID:27615899

  1. Effect of indigenous animals on chronic end points in freshwater sediment toxicity tests

    SciTech Connect

    Reynoldson, T.B.; Day, K.E.; Clarke, C.; Milani, D. )

    1994-06-01

    Sediment toxicity tests were conducted using three species of benthic invertebrates, Chironomus riparius, Hyalella azteca, and Hexagenia limbata, with various densities of the oligochaete worm Tubifex tubifex. It was shown that indigenous animals, simulated by the presence of Tubifex tubifex, did not affect survival of the test species (P [>=] 0.05) but did reduce growth in all three test species and in two species at the lowest tested densities, equivalent to 1,460 worms per square meter. At densities of Tubifex tubifex equivalent to 20,000 m[sup [minus]2], the growth of Chironomus riparius was reduced by >90%, Hyalella azteca by >60%, and Hexagenia limbata by almost 50%. The densities of oligochaetes are equivalent to those found in many contaminated sites. Therefore, it is concluded that the presence of indigenous organisms can confound the interpretation of toxicity test results, based on chronic end points. It is recommended that removal of organisms by considered before toxicity tests are conducted with freshwater sediments from sites with large populations of benthic invertebrates, especially oligochaete worms.

  2. Toxicity of metal-contaminated sediments from the upper Clark Fork River, Montana, to aquatic invertebrates and fish in laboratory exposures

    SciTech Connect

    Kemble, N.E.; Brumbaugh, W.G.; Brunson, E.L.; Dwyer, F.J.; Ingersoll, C.G. . Midwest Science Center); Monda, D.P. ); Woodward, D.F. . Midwest Science Center)

    1994-12-01

    Sediments of the upper Clark Fork River, from the Butte and Anaconda area to Milltown Reservoir (230 km downstream), are contaminated with As, Cd, Cu, Pb, Mn, and Zn primarily from mining activities. The toxicity of pore water from these sediments was determined using Daphnia magna, rainbow trout, and Microtox[reg sign]. However, pore-water data from these exposures were questionable because of changes in the toxicity of pore-water samples after 5 to 7 d of storage. Whole-sediment tests were conducted with Hyalella azteca, Chironomus riparius, rainbow trout (Oncorhynchus mykiss) 21- to 28-d exposure and Daphnia magna. Sediment samples from Milltown Reservoir and the Clark Fork River were not generally lethal to test organisms. However, both reduced growth and delayed sexual maturation of amphipods were associated with exposure to elevated concentrations of metals in sediments from the reservoir and river. Relative sensitivity (most sensitive to least sensitive) of organisms in whole-sediment toxicity tests was: Hyalella azteca > Chironomus riparius > rainbow trout > Daphnia magna. Relative sensitivity (most sensitive to least sensitive) of the three end points evaluated with Hyalella azteca was: length > sexual maturation > survival. The lack of lethal effects on organisms may be related to temporal differences in sediment, acid-volatile sulfide, or organic carbon.

  3. Formulated sediment for use in whole-sediment toxicity testing

    SciTech Connect

    Kemble, N.E.; Dwyer, F.J.; Hardesty, D.K.; Ingersoll, C.G.

    1995-12-31

    A formulated control sediment was developed to provide consistent and acceptable biological endpoints for a variety of species used in whole sediment toxicity testing. In an attempt to develop such a sediment the authors conducted multiple tests to evaluate: (1) {alpha}-cellulose as an organic carbon source, (2) various TOC concentrations, (3) various grain sizes, (4) different food types, and (5) overlying waters. Studies were conducted with the amphipod Hyalella azteca the midges Chironomus riparius, Chironomus tentans and the oligochaete Lumbriculus variegatus in 10 d exposures and H. azteca in 28 d exposures. Sediment from West Bearskin Lake Minnesota was used as a control sediment with each species in each test. Survival of test organisms in all of the 10-d experiments, with the exception of C. riparius, was above the acceptable levels for a control sediment. Survival in the formulated sediments also was not significantly different when compared to the control sediment. Amphipod survival in the 28-d exposures was low; however, the use of reconstituted water in combination with the formulated sediment may have been a problem. The authors are currently evaluating various types of overlying water with formulated sediments and sublethal endpoints in each of the exposures (i.e., growth, sexual maturation or head capsule width).

  4. Predator prey interactions of Procambarus clarkii with aquatic macroinvertebrates in single and multiple prey systems

    NASA Astrophysics Data System (ADS)

    Correia, Alexandra Marçal; Bandeira, Nuno; Anastácio, Pedro Manuel

    2005-11-01

    Understanding the interspecific interactions of Procambarus clarkii with other aquatic macroinvertebrates will help to unveil the mechanisms and processes underlying biological invasiveness. The purpose of this study was to investigate predator-prey interactions of two ontogenic phases of P. clarkii with native and exotic species of aquatic macroinvertebrates at a single and multiple prey level. We performed laboratory experiments to determine the consumption and the behavioral responses of Chironomus riparius, Physa acuta and Corbicula fluminea to P. clarkii. The presence of P. clarkii significantly affected the abundance of C. riparius and P. acuta, but not of C. fluminea whether prey species were provided singly or simultaneously. The consumption of C. riparius by P. clarkii was higher than P. acuta for both crayfish sizes and situations (single/multiple prey systems) and C. fluminea was never consumed. Physa acuta was the only species that exhibited an anti-predator behavior to P. clarkii. Our results show that P. clarkii can have strong consumptive and trait effects on aquatic macroinvertebrate prey at a single and multiple prey level, resulting in differential impacts on different prey species. This study clarifies some aspects of the predator-prey interactions between P. clarkii and native as well as other exotic macroinvertebrate species that have invaded freshwater biocenosis worldwide.

  5. A new species of Xylota Meigen (Diptera: Syrphidae) from the Far East.

    PubMed

    Mutin, Valerii; Ichige, Katsuyoshi

    2014-01-01

    Xylota danieli Mutin & Ichige spec. nov. is proposed as the new name for Xylota amamiensis Shiraki sensu Mutin & Gilbert (1999), from the Russian Far East and Japan, which is described and figured. New synonymy is proposed for Xylota coquilletti Hervé-Bazin, 1914 (= X. coquilletti amamiensis Shiraki, 1968 syn. nov.; = X. vulgaris Yang & Cheng in Cheng & Yang, 1993 syn. nov.).  PMID:25544443

  6. Diversity of Hemerodromia Meigen, 1822 (Diptera: Empididae) in Thailand, the tip of a tropical iceberg?

    PubMed

    Plant, Adrian R

    2015-01-01

    The genus Hemerodromia in Thailand is revised and full descriptions and keys are provided for all 25 species. Twenty new species are recognised: H. alphalutea sp. nov., H. anisoserrata sp. nov., H. anomala sp. nov., H. attenuata sp. nov., H betalutea sp. nov., H. conspecta sp. nov., H. deltalutea sp. nov., H. deminuta sp. nov., H. demissa sp. nov., H. epsilutea sp. nov., H. etalutea sp. nov., H. gammalutea sp. nov., H. isochita sp. nov., H. namtokhinpoon sp. nov., H. ocellata sp. nov., H. oriens sp. nov., H. phahompokensis sp. nov., H. songsee sp. nov., H. systoechon sp. nov. and H. zetalutea sp. nov. Five species known previously from China are recognised: H. acutata Grootaert, Yang & Saigusa, H. flaviventris Yang & Yang, H. furcata Grootaert, Yang & Saigusa, H. fusca Yang & Yang and H. yunnanensis Yang & Yang. Hemerodromia songsee sp. nov. and H. fusca Yang & Yang are also recorded from Vietnam. Distribution maps of all species are presented. Four categories of distribution patterns of apparently endemic species were identified in (1) the northern mountains (2) the northern lowlands (3) the south, and (4) east of Thailand. Some lowland species with wide distributions in eastern Asia were interpreted as 'old Oriental elements'. Other montane species have wide distributions extending between the Himalayas and southeast China. Three lowland species have an apparently obligate association with alkaline, mineralised water courses where tufa deposition was evident. Tufa-linked assemblages of Hemerodromia may indicate a previously unrecognised and potentially diverse habitat for aquatic Empididae in Southeast Asia. Major historical factors determining contemporary distribution patterns were analysed in reference to a Climate History Model (Plant et al. 2012) and included (i) latitudinal migrations in response to climatically induced changes in the distribution of habitat (ii) radiation of high-elevation endemics from more widespread lowland forms (iii) historical connectivity and fragmentation of hydrological networks with possible marooning of taxa in stable tufa spring systems (iv) persistence of lowland forms in climatically 'buffered' stream environments during progressive aridification. Analysis of sampling methodology concluded that hand collecting was 2,000X more efficient at collecting numbers of Hemerodromia with a species discovery rate 775X greater than that with passive trapping methods (Malaise, flight interception and pan traps etc.) although both approaches are needed for full assessment of species richness. Consideration of the climatic, ecological and biogeographic complexity of tropical Southeast Asia suggests that an extremely rich Hemerodromia fauna awaits discovery in the region. PMID:26624466

  7. Meiotic segregation of five different reciprocal translocations in the onion fly, Hylemya antiqua (Meigen).

    PubMed

    Vosselman, L

    1981-01-01

    For one translocation (T14) with short interstitial segments in Hylemya antiqua significant differences in segregation behaviour between males and females were observed. In males the ratio of alternate:adjacent 1:adjacent 2 was approximately 7:3:0 and in females about 8:1:3. This difference is attributed to the difference in type of chromosome association. Female meiosis is chiasmate and male meiosis is achiasmate. It is suggested that meiotic pairing in males results in relative short "Coorientation Determining Distances" (CDDs) between homologous centromeres which favours alternate and adjacent 1 segregation. In females because of non-localized chiasmata on the average no differences in CDD between homologous and nonhomologous centromeres are expected. This might explain the occurrence of coorientation between non-homologous centromeres resulting in adjacent 2 segregations. Four other translocations with longer interstitial segments than T14 showed in males as well as females predominantly an alternate and adjacent 1 segregation, adjacent 2 was hardly found (0-3.6%). The longer distance between non-homologous centromeres is probably the reason. PMID:7472022

  8. Transfer modelling and toxicity evaluation of the effluent from an installation of cleansing and uranium recovery using a battery of bioassays.

    PubMed

    Gagnaire, Béatrice; Boyer, Patrick; Bonzom, Jean-Marc; Lecomte-Pradines, Catherine; Simon, Olivier; Gilbin, Rodolphe

    2011-01-01

    On July 7, 2008, a leak of effluent from an Installation of Cleansing and Uranium Recovery (Tricastin, France) led to the spillage of uranium in a stream. The acute toxicity of the effluent was evaluated, and compared to the toxicity of uranium nitrate in bioassays using several organisms: Chlamydomonas reinhardtii, Daphnia magna, Chironomus riparius and Danio rerio. A sediment bioassay was also performed on C. riparius using water and sediment sampled along the river. Results showed that effluent EC(50) 72 h was 0.65 mg U/l for algae and LC(50) 48 h was 1.67 mg U/l for daphnia, while values obtained for uranium nitrate were higher. The LC(50) 96 h of effluent to C. riparius was 22.7 mg U/l, similar to value for uranium nitrate; the sediment collected was not toxic to C. riparius larvae. The LOEC of effluent and uranium nitrate on HT(50) of D. rerio were similar (0.03 mg U/l), but larvae were more sensitive to uranium nitrate than to effluent. Our results suggest that other substances contained in the effluent could potentially be toxic to wildlife in association with uranium. In parallel, the modelling of the transfers based on uranium measurements in the surface water was used to fill data gaps and assess the impact along the river. These results provided an estimate of exposure conditions that occurred along the river. This approach allowed us to see that the risk to ecosystem during this incident was certainly low and concerned a short period of time, but it could have existed at least for some species. PMID:21107686

  9. Use of chironomids (Diptera: Chironomidae) as bioindicators of contaminant stress: Biochemical, chromosomal and developmental measures

    SciTech Connect

    Ciborowski, J.J.H.; Cervi, L.; Sinasac, D.; Pardalis, G.; Day, K.

    1995-12-31

    Sublethal environmental stresses produce effects ranging from subtle biochemical changes that protect an organism from damage, through developmental effects that interfere with growth and compromise fitness. Benthic chironomids live in intimate contact with the sediments to which most persistent chemicals are bound. Their short life cycle and unique developmental and genetic structure make them excellent candidates as biological indicators of stress. The authors evaluated the short and long-term responses of Chironomus riparius larvae to contaminants. To determine short-term stress responses, third and fourth instar Chironomus larvae were exposed to up to 1.5 {micro}L/g creosote or up to 100 {micro}g/g Cd for 12 h. Creosote-exposed larvae exhibited proteins of a molecular weight consistent with production of heat shock proteins of the HSP 70 family. Exposure to Cd induced significant enlargement of Balbiani Rings of the 4th chromosome in chironomid salivary glands, indicative of increased transcription of RNA precursors to salivary mucoproteins. Chironomus larvae individually reared from second instar larvae at [Cd] up to 40 {micro}g/g sediment exhibited increased incidence of mentum deformities, and delayed development that resulted in larger size at pupation. Thus deformities are biologically relevant indicators of stress. Overall, the results confirm the potential of chironomids as relevant bioindicators of contaminant stress.

  10. Sediment quality in Rio Guadiamar (SW, Spain) after a tailing dam collapse: contamination, toxicity and bioavailability.

    PubMed

    Riba, Inmaculada; Delvalls, T Angel; Reynoldson, Trefor B; Milani, Danielle

    2006-09-01

    An integrated assessment of sediment quality in the Guadiamar River after a mining spill was conducted. The concentration of different metals and other conventional parameters were measured in sediments located along the river. Four sediment toxicity tests (Hyalella azteca 28-day survival and growth test; Chironomus riparius 10-day survival and growth test; Hexagenia spp. 21-day survival and growth test; and Tubifex tubifex 28-day reproduction and survival test) were carried out to determine the effects associated with the accidental spill. The geochemical fractions of 6 metals (Fe, Mn, Zn, Cu, Pb, and Cd) were determined to establish the bioavailability of the metals. The relationship found in the concentrations of metals associated with the mobile fractions of the sediments in the sites studied is similar to the toxic mud from tailing pond and confirms that the toxic effects are associated with the metals Zn and Cd originating from the spill. PMID:16820209

  11. Identifying and quantifying interactions in a laboratory swarm

    NASA Astrophysics Data System (ADS)

    Puckett, James; Kelley, Douglas; Ouellette, Nicholas

    2013-03-01

    Emergent collective behavior, such as in flocks of birds or swarms of bees, is exhibited throughout the animal kingdom. Many models have been developed to describe swarming and flocking behavior using systems of self-propelled particles obeying simple rules or interacting via various potentials. However, due to experimental difficulties and constraints, little empirical data exists for characterizing the exact form of the biological interactions. We study laboratory swarms of flying Chironomus riparius midges, using stereoimaging and particle tracking techniques to record three-dimensional trajectories for all the individuals in the swarm. We describe methods to identify and quantify interactions by examining these trajectories, and report results on interaction magnitude, frequency, and mutuality.

  12. How Many Insects Does It Take to Make a Swarm?

    NASA Astrophysics Data System (ADS)

    Ouellette, Nicholas

    2014-03-01

    Aggregations of social animals, such as flocks of birds, schools of fish, or swarms of insects, are beautiful, natural examples of self-organized behavior far from equilibrium. They tend to display a range of emergent properties, from enhanced sensing to the rapid propagation of information throughout the aggregate. Many classes of models have been proposed to describe these systems, including agent-based models that specify explicit social forces between individuals and continuum models that abstract the interactions between individuals into some smooth advecting velocity field. Assessing these various modeling approaches requires comparison with empirical data. We will discuss measurements of laboratory mating swarms of the non-biting midge Chironomus riparius in the context of model assessment. In particular, we focus on the question of the small-number limit: how large must the population be before collective properties emerge?

  13. Selenium assimilation and loss by an insect predator and its relationship to Se subcellular partitioning in two prey types.

    PubMed

    Dubois, Maïtée; Hare, Landis

    2009-03-01

    Subcellular selenium (Se) distributions in the oligochaete Tubifex tubifex and in the insect Chironomus riparius did not vary with Se exposure duration, which was consistent with the observations that the duration of prey Se exposure had little influence on either Se assimilation or loss by a predatory insect (the alderfly Sialis velata). However, these two prey types differed in how Se was distributed in their cells. Overall, the predator assimilated a mean of 66% of the Se present in its prey, which was similar to the mean percentage of Se in prey cells (62%) that was theoretically available for uptake (that is, Se in the protein and organelle fractions). Likewise, data for cadmium, nickel and thallium suggest that predictions of trace element transfer between prey and predator are facilitated by considering the subcellular partitioning of these contaminants in prey cells. PMID:19110352

  14. Velocity correlations in laboratory insect swarms

    NASA Astrophysics Data System (ADS)

    Ni, R.; Ouellette, N. T.

    2015-12-01

    In contrast to animal groups such as bird flocks or migratory herds that display net, directed motion, insect swarms do not possess global order. Without such order, it is difficult to define and characterize the transition to collective behavior in swarms; nevertheless, visual observation of swarms strongly suggests that swarming insects do behave collectively. It has recently been suggested that correlation rather than order is the hallmark of emergent collective behavior. Here, we report measurements of spatial velocity correlation functions in laboratory mating swarms of the non-biting midge Chironomus riparius. Although we find some correlation at short distances, our swarms are in general only weakly correlated, in contrast to what has been observed in field studies. Our results hint at the potentially important role of environmental conditions on collective behavior, and suggest that general indicators of the collective nature of swarming are still needed.

  15. Bioaccumulation and food-chain transfer of polycyclic aromatic hydrocarbons and heavy metals: A laboratory and field investigation. Final report, 15 Oct 91-14 Oct 92

    SciTech Connect

    Clements, W.H.

    1992-10-14

    The extent to which heavy metals and Polycyclic aromatic hydrocarbons (PAH) may be transferred up the food chain from sediments to benthic invertebrates and then on to fish species was examined using both laboratory and field techniques. PAHs were shown to bioaccumulate in a chironomid invertebrate (chironomus riparius) to relatively high levels depending on the specific compound. Accumulation in a fish specie (Lepomis macrochirus) that was fed contaminated chironomids was found to be generally low. Mobilization of PAHs from sediments into water was affected by benthic organisms enhancing the bioavailability of these contaminants to other organisms. In field studies, certain benthic invertebrates and abiotic sediment components were also shown to accumulate heavy metals. This metal accumulation persisted even when metal concentrations in the water were diminishing.

  16. Intrinsic fluctuations and driven response of insect swarms

    NASA Astrophysics Data System (ADS)

    Ni, Rui; Puckett, James G.; Dufresne, Eric R.; Ouellette, Nicholas T.

    2015-03-01

    Much of our understanding of collective behaviour in social animals comes from passive observations of animal groups. To understand the group dynamics fully, however, we must also characterize the response of animal aggregations to disturbances. Using three-dimensional particle tracking, we study both the intrinsic fluctuations of laboratory swarms of the non-biting midge Chironomus riparius and the response of the swarms to controlled external perturbations: the amplitude-modulated sound of male midge wingbeats. Although these perturbations have an insignificant effect on the behavior of individuals, we find that they can have a strong impact on the collective movement. Intriguingly, the response of the swarm is similar reminiscent to of that of a passive equilibrium system to an external driving force, with microscopic fluctuations underlying combining to produce a macroscopic linear response over a wide range of driving frequencies.

  17. On the tensile strength of insect swarms.

    PubMed

    Ni, Rui; Ouellette, Nicholas T

    2016-01-01

    Collective animal groups are often described by the macroscopic patterns they form. Such global patterns, however, convey limited information about the nature of the aggregation as a whole. Here, we take a different approach, drawing on ideas from materials testing to probe the macroscopic mechanical properties of mating swarms of the non-biting midge Chironomus riparius. By manipulating ground-based visual features that tend to position the swarms in space, we apply an effective tensile load to the swarms, and show that we can quasi-statically pull single swarms apart into multiple daughter swarms. Our results suggest that swarms surprisingly have macroscopic mechanical properties similar to solids, including a finite Young's modulus and yield strength, and that they do not flow like viscous fluids. PMID:27559838

  18. Toxicity identification evaluation of sediments in Liaohe River.

    PubMed

    Ke, Xin; Gao, Lili; Huang, Hao; Kumar, Santosh

    2015-04-15

    Liaohe River has received significant attention in the northeast region and even in the entire country. As part of a recently completed water quality assessment, a series of water column and sediment toxicity tests was performed throughout the watershed. In the current study, we subjected sediments from the Liaohe River to toxicity identification evaluation manipulations and tests for chronic toxicity with midge (Chironomus riparius), with survival as the end point. In Phase I, the sediments were treated with zeolite, cation-exchange resin, and powdered coconut charcoal. Results confirmed that ammonia compounds were the major contaminants in terms of toxicity, although toxic effects from metals were also a concern in at least three sites. In Phase II identification, chemical analysis provided a strong evidence that the metals As and Cd are the probable causes of toxicity in the sediments, without the influence of ammonia. Temporally, ammonia is responsible for the toxicity of the selected sediments. PMID:25680882

  19. Emergent dynamics of laboratory insect swarms

    NASA Astrophysics Data System (ADS)

    Kelley, Douglas H.; Ouellette, Nicholas T.

    2013-01-01

    Collective animal behaviour occurs at nearly every biological size scale, from single-celled organisms to the largest animals on earth. It has long been known that models with simple interaction rules can reproduce qualitative features of this complex behaviour. But determining whether these models accurately capture the biology requires data from real animals, which has historically been difficult to obtain. Here, we report three-dimensional, time-resolved measurements of the positions, velocities, and accelerations of individual insects in laboratory swarms of the midge Chironomus riparius. Even though the swarms do not show an overall polarisation, we find statistical evidence for local clusters of correlated motion. We also show that the swarms display an effective large-scale potential that keeps individuals bound together, and we characterize the shape of this potential. Our results provide quantitative data against which the emergent characteristics of animal aggregation models can be benchmarked.

  20. Searching for effective forces in laboratory insect swarms

    NASA Astrophysics Data System (ADS)

    Puckett, James G.; Kelley, Douglas H.; Ouellette, Nicholas T.

    2014-04-01

    Collective animal behaviour is often modeled by systems of agents that interact via effective social forces, including short-range repulsion and long-range attraction. We search for evidence of such effective forces by studying laboratory swarms of the flying midge Chironomus riparius. Using multi-camera stereoimaging and particle-tracking techniques, we record three-dimensional trajectories for all the individuals in the swarm. Acceleration measurements show a clear short-range repulsion, which we confirm by considering the spatial statistics of the midges, but no conclusive long-range interactions. Measurements of the mean free path of the insects also suggest that individuals are on average very weakly coupled, but that they are also tightly bound to the swarm itself. Our results therefore suggest that some attractive interaction maintains cohesion of the swarms, but that this interaction is not as simple as an attraction to nearest neighbours.

  1. Influence of UV radiation on four freshwater invertebrates.

    PubMed

    Cywinska, A; Crump, D; Lean, D

    2000-11-01

    Laboratory tests confirmed a negative and variable response of the following four species to artificial UV radiation: Cypridopsis vidua, an ostracode; Chironomus riparius, a midge larvae; Hyalella azteca, an amphipod; and Daphnia magna, a daphnid. Severe damage occurred at UV-B irradiance ranging from 50 to 80% of incident summer values. Under constant exposure to UV and photosynthetically active radiation (PAR) the acute lethal response was recorded at 0.3, 0.8, 0.8 and 4.9 W m-2 UV-B for D. magna, H. azteca, C. riparius and C. vidua, respectively. Sublethal UV-B damage to invertebrates included impaired movement, partial paralysis, changes in pigmentation and altered water balance (bloating). A series of UV-B, UV-A and PAR treatments, applied separately and in combination, revealed a positive role for both UV-A and PAR in slowing down UV-B damage. Mean lethal concentration values of the species typically more tolerant to UV and PAR (Cypridopsis, Chironomus) decreased conspicuously when both UV-A and PAR were eliminated. For UV-B-sensitive species (Hyalella, Daphnia) these differences were notably smaller. We suggest that this gradation of sensitivity among the tested species demonstrates potential differences in repairing mechanisms which seem to work more efficiently for ostracodes and chironomids than for amphipods and daphnids. Manipulations with a cellulose acetate filter showed that lower range UV-B (280-290 nm), produced by FS-40 lamps, may cause excessive UV damage to invertebrates. PMID:11107851

  2. Preliminary study to compare body residues and sublethal energetic responses in benthic invertebrates exposed to sediment-bound 2,4,5-trichlorophenol

    SciTech Connect

    Penttinen, O.P.; Kukkonen, J.; Pellinen, J.

    1996-02-01

    Relationships between concentration of 2,4,5-trichlorophenol (TCP) in sediment, body residues of the chemical, and sublethal biological effects in three benthic invertebrates were studied. Uncontaminated lake sediment was spiked with four concentrations (23--85 {micro}g/g dry sediment) of TCP. Chironomid larvae (Chironomus riparius), oligochaete worms (Lumbriculus variegatus), and sphaeriid bivalves (Sphaerium corneum) were exposed to the sediment. The effect of chlorophenol on the rate of heat dissipation of animals was monitored by direct microcalorimetry. It appeared that both the behavior of the animals and their body residues explained the energetic response. Valve closure behavior of S. corneum reduced the accumulation of toxicant (< 0.3 {micro}mol/g) but was observed as a complex energetic response. Heat dissipation of L. variegatus was at the same level in control animals and those with high body residues of TCP (> 1.5 {micro}mol/g). Regardless of the amount of TCP accumulated to C. riparius (0.1--0.6 {micro}mol/g), the rate of heat dissipation was almost two times higher than that of the control animals, probably reflecting uncoupling of oxidative phosphorylation, which is the primary mode of toxic action of chlorophenols. However, when a threshold concentration was exceeded there was no concentration-response dependence until acute toxicity appears.

  3. Ecotoxicity of sediments in rivers: Invertebrate community, toxicity bioassays and the toxic unit approach as complementary assessment tools.

    PubMed

    de Castro-Català, Núria; Kuzmanovic, Maja; Roig, Neus; Sierra, Jordi; Ginebreda, Antoni; Barceló, Damià; Pérez, Sandra; Petrovic, Mira; Picó, Yolanda; Schuhmacher, Marta; Muñoz, Isabel

    2016-01-01

    The determination of the real toxicity of sediments in aquatic ecosystems is challenging and necessary for an appropriate risk assessment. Different approaches have been developed and applied over the last several decades. Currently, the joint implementation of chemical, ecological and toxicological tools is recommended for an appropriate and successful toxicity risk assessment. We chose the combination of the toxic unit approach with acute pore water tests (Vibrio fischeri, Pseudokirchneriella subcapitata and Daphnia magna) and whole-sediment exposure tests (V. fischeri, Chironomus riparius), together with invertebrate community composition (multivariate analyses) to detect short and long-term responses of the organisms in four rivers of the Iberian Peninsula. High toxicity was detected in three sites (the downstream sites of the Llobregat and the Júcar, and the most upstream site of the Ebro). We identified organophosphate insecticides and metals as the main variables responsible for this toxicity, particularly in the whole-sediment tests. In particular, chlorpyrifos was mostly responsible for the toxicity (TUs) of D. magna, coinciding with the C. riparius mortality (long-term toxicity) in the mentioned sites, and copper was the main pollutant responsible for the short-term toxicity of P. subcapitata. The combination of the different approaches allowed us to detect ecotoxicological effects in organisms and identify the main contributors to the toxicity in these multi-stressed rivers. PMID:26118861

  4. Critical body residue of compounds having different mode of action on energy metabolism in benthic invertebrates

    SciTech Connect

    Penttinen, O.P.; Kukkonen, J.

    1995-12-31

    The toxicity of organic chemicals with different mode of toxic action was evaluated by determining their effect on the metabolic rate of two common benthic invertebrates, midge larva (Chironomus riparius) and oligochate worm (Lumbriculus variegatus). The rate of metabolism was monitored by direct microcalorimetry and the change of heat output was related to the body residue of chemicals. The expected response of 2,4,5-trichlorophenol (TCP), known as an uncoupler of oxidative phosphorylation, was an increase of metabolic rate. The animals were exposed 24 h to water spiked with TCP (10 to 1,200 {micro}g/L) and they received the body residues of TCP in the range of 8.8 to 336 {micro}g/g wet wt (0.04 to 1.75 {micro}mol/g). The threshold concentration was 0.7 {micro}mol/g wet wt. (C. riparius) or 1.0 {micro}mol/g wet wt. (L. variegatus) above which the rate of heat dissipation increased in direct proportion to the concentration of TCP in tissue. At maximum, the metabolic rate increased by a factor of three. At the highest water concentration animals were dying and the metabolic rate was low. The energetic responses obtained with TCP are compared to those of a non-polar narcotic compound 1,2,4-trichlorobenzene and an other uncoupling agent, 2,4-dinitrophenol.

  5. The effect of manipulations of freshwater sediments on responses of benthic invertebrates in whole-sediment toxicity tests

    SciTech Connect

    Day, K.E.; Kirby, R.S.; Reynoldson, T.B.

    1995-08-01

    Manipulations of freshwater sediment were performed to remove indigenous organisms prior to conducting toxicity tests with three species of benthic invertebrates. The effects of these treatments on end points in bioassays were compared within and between two sediments, i.e., a ``clean`` sediment and a ``contaminated`` sediment. In addition, the effects of manipulations on the physicochemical structure of the two sediments and the presence of metals, PAHs, and PCBs in the contaminated sediment were examined. The amphipod Hyalella azteca was most sensitive to the manipulations and had low survival in sediment that was sterilized. Growth (milligrams dry weight per individual) was affected by the presence of contaminants. Survival of Chironomus riparius was not affected by any manipulation but was reduced by contaminants as well as indigenous organisms. Growth of C. riparius was higher in autoclaved sediment but lower in sediment containing endemic tubificid worms. Production of young by Tubifex tubifex increased in sediment that was irradiated, possibly due to increased detrital material. Particle size distribution, metals, nutrients, and PAHs varied little as a function of manipulation; however, sieving of sediment through 250-{micro}m mesh did reduce percent total organic carbon (TOC), percent loss on ignition (LOI), and concentrations of some PCBs in either clean or contaminated sediment. Manipulation of sediments to remove endemic species should be determined on a case-by-case basis and is specific to the organisms used in toxicity tests.

  6. Measuring cytochrome P450 activity in aquatic invertebrates: a critical evaluation of in vitro and in vivo methods.

    PubMed

    Gottardi, Michele; Kretschmann, Andreas; Cedergreen, Nina

    2016-03-01

    The first step in xenobiotic detoxification in aquatic invertebrates is mainly governed by the cytochrome P450 mixed function oxidase system. The ability to measure cytochrome P450 activity provides an important tool to understand macroinvertebrates' responses to chemical stressors. However, measurements of P450 activity in small aquatic invertebrates have had variable success and a well characterized assay is not yet available. The general lack of success has been scarcely investigated and it is therefore the focus of the present work. In particular, the suitability of the substrate selected for the assay, the sensitivity of the assay and the possible inhibition/attenuation of enzymatic activity caused by endogenous substances were investigated. 7-ethoxycoumarin-O-dealkylation activity of Daphnia magna, Chironomus riparius larvae and Hyalella azteca was assessed in vivo and in vitro and possible inhibition of enzymatic activity by macroinvertebrates homogenate was investigated. Activities of D. magna and C. riparius larvae measured in vivo were 1.37 ± 0.08 and 2.2 ± 0.2 pmol h(-1) organism(-1), respectively, while activity of H. azteca could not be detected. In vitro activity could be measured in C. riparius larvae only (500-1000 pmol h(-1) mg microsomal protein(-1)). The optimization of the in vitro assay has been especially long and resource consuming and particularly for D. magna, substances that inhibited cytochrome P450 activity seemed to be released during tissue homogenization preventing activity measurements in vitro. We therefore recommend testing the P450 inhibition potential of homogenate preparations prior to any investigation of P450 activity in vitro in macroinvertebrates. PMID:26686507

  7. Variation in developmental time for geographically distinct populations of the common green bottle fly, Lucilia sericata (Meigen).

    PubMed

    Gallagher, Meagan B; Sandhu, Sonia; Kimsey, Robert

    2010-03-01

    Time between death and discovery of remains, or postmortem interval (PMI), can be assessed using blow fly maggot age. Forensic entomologists rely on published, often nonlocal, species-specific developmental tables to determine maggot age. In a series of common garden experiments, we investigated the developmental rate variation between populations of Lucilia sericata collected from Sacramento, CA, San Diego, CA, and Easton, MA at 16 degrees C, 26 degrees C, and 36 degrees C. For the 16 degrees C trial the time measurement started at egg hatch, while for the higher temperatures the experiment began at oviposition; the wandering stage signified the endpoint for all experiments. The distribution of developmental times differed significantly (ANOVA, p < 0.001) between the three populations within each temperature treatment. We discovered that regional variation of developmental times within a blow fly species exists. This study demonstrates the importance of assembling local population-specific developmental tables when estimating larval age to determine PMI. PMID:20102471

  8. The Mycetophila ruficollis Meigen (Diptera, Mycetophilidae) group in Europe: elucidating species delimitation with COI and ITS2 sequence data

    PubMed Central

    Jürgenstein, Siiri; Kurina, Olavi; Põldmaa, Kadri

    2015-01-01

    Abstract European species of the Mycetophila ruficollis group are compared on the basis of morphology and sequences of mitochondrial cytochrome oxidase subunit one (COI) and the ITS2 region of nuclear ribosomal DNA. The study represents the first evaluation of morphology-based species delimitation of closely related fungus gnat species by applying molecular information. Detailed descriptions and illustrations of the male terminalia are presented along with a key for the identification of all nine European species of the group. Phylogenetic analyses of molecular data generally supported the morphological species discrimination. The barcoding region of COI superseded ITS2 rDNA in resolving species. In the COI barcoding region interspecific differences ranged from 2.9 to 10.6% and the intraspecific distance from 0.08 to 0.8%. Only COI data distinguished between the similar and closely related Mycetophila ichneumonea and Mycetophila uninotata of which the latter was observed to include cryptic species. The host range of some species is suggested to be narrower than previously considered and to depend on the forest type. Presented evidence indicates the importance of analysing sequence data of morphologically very similar mycetophages reared from identified host fungi for elucidating species delimitation as well as their geographic and host ranges. New country records, viz. Estonia for Mycetophila evanida, Georgia for Mycetophila ichneumonea, Mycetophila idonea and Mycetophila ruficollis, and Norway for Mycetophila strobli, widen the known distribution ranges of these species. PMID:26167119

  9. Genetic and phenotypic variation in central and northern European populations of Aedes (Aedimorphus) vexans (Meigen, 1830) (Diptera, Culicidae).

    PubMed

    Francuski, Ljubinka; Milankov, Vesna; Ludoški, Jasmina; Krtinić, Bosiljka; Lundström, Jan O; Kemenesi, Gábor; Ferenc, Jakab

    2016-06-01

    The floodwater mosquito Aedes vexans can be a massive nuisance in the flood plain areas of mainland Europe, and is the vector of Tahyna virus and a potential vector of Dirofilaria immitis. This epidemiologically important species forms three subspecies worldwide, of which Aedes vexans arabiensis has a wide distribution in Europe and Africa. We quantified the genetic and phenotypic variation in Ae. vexans arabiensis in populations from Sweden (northern Europe), Hungary, and Serbia (central Europe). A landscape genetics approach (FST , STRUCTURE, BAPS, GENELAND) revealed significant differentiation between northern and southern populations. Similar to genetic data, wing geometric morphometrics revealed two different clusters, one made by Swedish populations, while another included Hungarian and Serbian populations. Moreover, integrated genetic and morphometric data from the spatial analysis suggested groupings of populations into three clusters, one of which was from Swedish and Hungarian populations. Data on spatial analysis regarding an intermediate status of the Hungarian population was supported by observed Isolation-by-Distance patterns. Furthermore, a low proportion of interpopulation vs intrapopulation variance revealed by AMOVA and low-to-moderate FST values on a broader geographical scale indicate a continuous between-population exchange of individuals, including considerable gene flow on the regional scale, are likely to be responsible for the maintenance of the observed population similarity in Aе. vexans. We discussed data considering population structure in the light of vector control strategies of the mosquito from public health importance. PMID:27232139

  10. The effect of the volatile oils of Chenopodium ambrosioides and Thymus vulgaris against the larvae of Lucilia sericata (Meigen).

    PubMed

    Morsy, T A; Shoukry, A; Mazyad, S A; Makled, K M

    1998-08-01

    Nowadays, there are many problems with the use of chemical insecticides as resistance, environmental pollution, toxicity to man and animal... etc. All these required the investigation of a new line for controlling arthropod pests of medical and agricultural importance. The volatile oils of Chenopodium ambrosioides (American wormseed) and Thymus vulgaris (Tyme) proved to be effective against the third stage larvae of Lucilia sericata. The LC50 confidence limits were 70 ppm and 130 ppm for both volatile oils respectively. No doubt, the use of these plant volatile oils, which are widely distributed in the Egyptian flora, more cheap, more safe and without any pollution or hazard, is recommended. PMID:9707679

  11. First report of external ophthalmomyiasis caused by Lucilia sericata Meigen in a healthy patient without predisposing risk factors.

    PubMed

    Choi, Won; Kim, Ga Eon; Park, Seong Hwan; Shin, Sang Eon; Park, Ji Hye; Yoon, Kyung Chul

    2015-10-01

    A 72-year-old man with no medical history initially presented to the emergency room with severe tearing, redness, foreign body sensation, and pain in the left eye. He reported no previous history of any periocular trauma, malignancy, surgery, or systemic illness. On presentation, the patient only showed left periorbital edema and erythema in the left eyelid with no evidence of any skin malignancy. On slit lamp examination, multiple small whitish motile organisms were observed on the left conjunctival fornices. The organisms were removed, preserved, and identified as the third-stage larvae of Lucilia sericata (green bottle fly). The patient was treated with topical antibiotic and steroid eye drops and the inflammation resolved 1 week after treatment initiation. This is the first report of external ophthalmomyiasis caused by facultative parasite, L. sericata maggots in a healthy patient without any predisposing factors. PMID:25794816

  12. Thermal stress induces HSP70 proteins synthesis in larvae of the cold stream non-biting midge Diamesa cinerella Meigen.

    PubMed

    Lencioni, Valeria; Bernabò, Paola; Cesari, Michele; Rebecchi, Lorena; Cesari, Michele

    2013-05-01

    Laboratory experiments on the cold stenothermal midge Diamesa cinerella (Diptera, Chironomidae) were performed to study the relationship between increasing temperature and heat shock proteins (HSP70) expression at translational level (Western blotting). Thermotolerance of IV instar larvae collected in nature at 1.5-4.3°C during seasons was analyzed through short-term (1 h at ten different temperatures from 26°C to 35°C) and long-term (1-14 h at 26°C and 1-4 h at 32°C) heat shocks. A high thermotolerance was detected (LT50=30.9-32.8°C and LT100=34.0-37.8°C). However, survival decreased consistently with increasing exposure time, especially at higher temperature (LTime50=7.64 h at 26°C and LTime50=1.73 h at 32°C). The relationship between such heat resistance and HSP70 expression appeared evident because a relationship between HSP70 level and larval survival rate was generally found. A heat shock response (HSR) was consistent only in the summer larvae. The absence of HSR in the other populations coupled with even higher amounts of HSP70 than in summer, led us to hypothesize that other macromolecules and other adaptive mechanisms, apart from biochemical ones, are involved in the response of D. cinerella larvae to high temperature. Altogether these results stressed how in this midge the HSP70 protein family confers resistance against cold, being detected under natural conditions in control larvae collected in all seasons, but also against warm under experimental heat shocks. These results give new insights into possible responses to climate changes in freshwater insects within the context of global warming. PMID:23404797

  13. Effects of sediment-spiked lufenuron on benthic macroinvertebrates in outdoor microcosms and single-species toxicity tests.

    PubMed

    Brock, T C M; Bas, D A; Belgers, J D M; Bibbe, L; Boerwinkel, M-C; Crum, S J H; Diepens, N J; Kraak, M H S; Vonk, J A; Roessink, I

    2016-08-01

    Sediment ecotoxicity studies were conducted with lufenuron to (i) complement the results of a water-spiked mesocosm experiment with this lipophilic benzoylurea insecticide, (ii) to explore the predictive value of laboratory single-species tests for population and community-level responses of benthic macroinvertebrates, and (iii) to calibrate the tier-1 effect assessment procedure for sediment organisms. For this purpose the concentration-response relationships for macroinvertebrates between sediment-spiked microcosms and those of 28-d sediment-spiked single-species toxicity tests with Chironomus riparius, Hyalella azteca and Lumbriculus variegatus were compared. Lufenuron persisted in the sediment of the microcosms. On average, 87.7% of the initial lufenuron concentration could still be detected in the sediment after 12 weeks. Overall, benthic insects and crustaceans showed treatment-related declines and oligochaetes treatment-related increases. The lowest population-level NOEC in the microcosms was 0.79μg lufenuron/g organic carbon in dry sediment (μg a.s./g OC) for Tanytarsini, Chironomini and Dero sp. Multivariate analysis of the responses of benthic macroinvertebrates revealed a community-level NOEC of 0.79μg a.s./g OC. The treatment-related responses observed in the microcosms are in accordance with the results of the 28-d laboratory toxicity tests. These tests showed that the insect C. riparius and the crustacean H. azteca were approximately two orders of magnitude more sensitive than the oligochaete L. variegatus. In our laboratory tests, using field-collected sediment, the lowest 28-d EC10 (0.49μg a.s./g OC) was observed for C. riparius (endpoint survival), while for the standard OECD test with this species, using artificial sediment, a NOEC of 2.35μg a.s./g OC (endpoint emergence) is reported. In this particular case, the sediment tier-1 effect assessment using the chronic EC10 (field-collected sediment) or chronic NOEC (artificial sediment) of C

  14. Trait-based modelling of bioaccumulation by freshwater benthic invertebrates.

    PubMed

    Sidney, Livia Alvarenga; Diepens, Noël J; Guo, Xiaoying; Koelmans, Albert A

    2016-07-01

    Understanding the role of species traits in chemical exposure is crucial for bioaccumulation and toxicity assessment of chemicals. We measured and modelled bioaccumulation of polychlorinated biphenyls (PCBs) in Chironomus riparius, Hyalella azteca, Lumbriculus variegatus and Sphaerium corneum. We used a battery test procedure with multiple enclosures in one aquarium, which maximized uniformity of exposure for the different species, such that the remaining variability was due mostly to species traits. The relative importance of uptake from either pore water or sediment ingestion was manipulated by using 28 d aged standard OECD sediment with low (1%) and medium (5%) OM content and 13 months aged sediment with medium OM (5%) content. Survival was ≥76% and wet weight increased for all species. Reproduction of H. azteca and weight gain of H. azteca and S. corneum were significantly higher in the medium OM aged sediments than in other sediments, perhaps due to a more developed microbial community (i.e., increase in food resources). Biota-sediment accumulation factors (BSAF) ranged from 3 to 114, depending on species and PCB congener, with C. riparius (3-10)

  15. TiO2 nanoparticles for the remediation of eutrophic shallow freshwater systems: Efficiency and impacts on aquatic biota under a microcosm experiment.

    PubMed

    Bessa da Silva, Márcia; Abrantes, Nelson; Nogueira, Verónica; Gonçalves, Fernando; Pereira, Ruth

    2016-09-01

    The application of nanomaterials (NMs) in the remediation of eutrophic waters, particularly in the control of internal loading of nutrients, has been started, but limited investigations evaluated the effectiveness of these new treatment approaches and of their potential impacts on species from shallow freshwater lakes. The present work investigated, under a microcosm experiment, the application of a TiO2 nanomaterial both for reducing nutrient (mainly phosphorus and nitrogen forms) desorption and release from sediments (preventive treatment-PT) and for eliminating algal blooms (remediation treatment-RT). Furthermore, we also intended to assess the potential impacts of nano-TiO2 application on key freshwater species. The results showed the effectiveness of nano-TiO2 in controlling the release of phosphates from surface sediment and the subsequent reduction of total phosphorus in the water column. A reduction in total nitrogen was also observed. Such changes in nutrient dynamics contributed to a progressive inhibition of development of algae after the application of the NM in PT microcosms. Concerning the ability of nano-TiO2 to interact with algal cells, this interaction has likely occurred, mainly in RT, enhancing the formation of aggregates and their rapid settlement, thus reducing the algal bloom. Both treatments caused deleterious effects on freshwater species. In PT, Daphnia magna and Lemna minor showed a significant inhibition of several endpoints. Conversely, no inhibitory effect on the growth of Chironomus riparius was recorded. In opposite, C. riparius was the most affected species in RT microcosms. Such difference was probably caused by the formation of larger TiO2-algae aggregates in RT, under a high algal density, that rapidly settled in the sediment, becoming less available for pelagic species. In summary, despite the effectiveness of both treatments in controlling internal nutrient loading and in the mitigating algal bloom episodes, their negative

  16. Weight-of-evidence approach in assessment of ecotoxicological risks of acid sulphate soils in the Baltic Sea river estuaries.

    PubMed

    Wallin, Jaana; Karjalainen, Anna K; Schultz, Eija; Järvistö, Johanna; Leppänen, Matti; Vuori, Kari-Matti

    2015-03-01

    Acidity and leaching of metals from acid sulphate soils (ASSs) impair the water quality of receiving surface waters. The largest ASS areas in Europe are found in the coasts of the northern Baltic Sea. We used weight-of-evidence (WoE) approach to assess potential risks in 14 estuary sites affected by ASS in the Gulf of Finland, northern Baltic Sea. The assessment was based on exposure and effect profiles utilizing sediment and water metal concentrations and concurrent pH variation, sediment toxicity tests using the luminescent bacterium Vibrio fischeri and the midge Chironomus riparius, and the ecological status of benthic macroinvertebrate communities. Sediment metal concentrations were compared to national sediment quality criteria/guidelines, and water metal concentrations to environmental quality standards (EQSs). Hazard quotients (HQs) were established for maximum aluminium, cadmium and zinc concentrations at low pH based on applicable US EPA toxicity database. Sediment metal concentrations were clearly elevated in most of the studied estuaries. The EQS of cadmium (0.1 μg/l) was exceeded in 3 estuaries out of 14. The pH-minima were below the national threshold value (5.5) between good and satisfactory water quality in 10 estuaries. V. fischeri bioluminescence indicated toxicity of the sediments but toxic response was not observed in the C. riparius emergence test. Benthic invertebrate communities were deteriorated in 6 out of 14 sites based on the benthic invertebrate quality index. The overall ecotoxicological risk was assessed as low in five, moderate in three and high in five of the estuary sites. The risk assessment utilizing the WoE approach indicated that harmful effects of ASSs are likely to occur in the Baltic Sea river estuaries located at the ASS hotspot area. PMID:25506908

  17. Assessment of sediment ecotoxicological status as a complementary tool for the evaluation of surface water quality: the Ebro river basin case study.

    PubMed

    Roig, Neus; Sierra, Jordi; Nadal, Martí; Moreno-Garrido, Ignacio; Nieto, Elena; Hampel, Miriam; Gallego, Elena Perez; Schuhmacher, Marta; Blasco, Julián

    2015-01-15

    According to the European Water Framework Directive (WFD), assessment of surface water status is based on ecological and chemical status that is not always in coherence. In these situations, ecotoxicity tests could help to obtain a better characterization of the ecosystems. The general aim of this work is to design a methodology to study the ecotoxicological status of freshwater systems. This could be useful and complementary to ecological status, for a better ecological characterization of freshwater systems. For this purpose, sediments from thirteen sampling sites within the Ebro river watershed (NE Spain) were collected for ecotoxicity characterization. The ecotoxicity of pore water has been evaluated employing the test organisms Vibrio fischeri, Pseudokirschneriella subcapitata and Daphnia magna, while whole sediment ecotoxicity was evaluated using Vibrio fischeri, Daphnia magna, Nitzschia palea and Chironomus riparius. An analysis of acid-volatile sulfide (AVS) and simultaneously extracted metals (SEM) was performed to evaluate the sediment toxicity associated to bioavailable metals. Moreover, data about priority pollutants defined by the WFD in water, sediment and fish as well as data of surface water status of each sampling point were provided by the Monitoring and Control Program of the Ebro Water bodies. In general terms, whole sediment bioassays have shown more toxicity than pore water tests. Among the different organisms used, P. subcapitata and C. riparius were the most sensitive in pore water and whole sediment, respectively. Our evaluation of the ecotoxicological status showed high coincidences with the ecological status, established according to the WFD, especially when ecosystem disruption due to numerous stressors (presence of metals and organic pollution) was observed. These results allow us to confirm that, when chemical stressors affect the ecosystem functioning negatively, an ecotoxicological approach, provided by suitable bioassays in pore

  18. LABORATORY CULTURE OF CHIRONOMUS TENTANS FOR USE IN TOXICITY TESTING: OPTIMUM INITIAL EGG STOCKING DENSITIES

    EPA Science Inventory

    This study was conducted to determine the effet of initial culture stocking density on: (1) post-hatch (larval) dry weight, body length and head-capsule width at 10 and 20 days; (2) time to emergence; (3) number and sex of emergent adults; (4) number of larvae and pupae at test t...

  19. Freshwater in situ toxicity testing: Daphnia magna, Ceriodaphnia dubia, Pimephales promelas, Hyalella azteca and Chironomus tentans

    SciTech Connect

    Burton, G.A. Jr.

    1995-12-31

    The use of traditional laboratory toxicity test species in field exposures have proven to be a valuable assessment tool for monitoring effluent, water, sediment and storm water quality. Mimicking fluctuating exposures of stressors with associated interactions with differing physico-chemical variables is difficult. In situ exposures are conducted for similar time periods measuring similar response endpoints as in more traditional laboratory tests. However, organisms are transferred to the field and exposed in various types of test chambers. The author has observed responses which are similar and which are significantly different from simultaneous laboratory exposures. Temperature, dissolved oxygen, suspended solids, natural light, flow, and predation may affect in situ responses, but are often removed from laboratory exposures. The strengths and weaknesses observed with these test systems over the past few years will be reviewed.

  20. What food and feeding rates are optimum for the Chironomus dilutus sediment toxicity test method?

    EPA Science Inventory

    Laboratory tests with benthic macroinvertebrates conducted using standard toxicity test procedures are used to assess the potential toxicity of contaminated sediments. Results are compared across sites or for batches of samples, and the performance of organisms in control treatme...

  1. Increase in developmental instability in a field-collected Chironomus population maintained under laboratory conditions.

    PubMed

    Arambourou, Hélène; Branchu, Philippe; Beisel, Jean-Nicolas

    2015-06-01

    In order to be a relevant indicator of exposure towards teratogenic stressors, morphological defects should not be passed on to the next generation. In this study, we compare morphological variations in Chironomids collected from a contaminated river stretch with those of their progeny, reared in uncontaminated sediment under laboratory conditions. We focused on mentum defects (deformities, fluctuating asymmetry and mean shape change), measured by geometric morphometrics. We observed no significant variation in deformity rate between the parental generation and its progeny. On the contrary, we observed a significant increase in fluctuating asymmetry and a significant decrease in mentum centroid size in the offspring. Our results suggest that shape defects are not caused by direct exposure to teratogenic stressors alone. We propose four hypotheses to explain this: (a) teratogenic contaminants are present in egg-clutches, (b) contaminants at the sampling site have mutagenic effects, (c) costs of tolerance, and (d) contamination-induced genetic impoverishment. PMID:25749504

  2. Chironomus tentans bioassay for testing synthetic fuel products and effluents, with data on acridine and quinoline

    SciTech Connect

    Cushman, R.M.; McKamey, M.I.

    1981-05-01

    Sensitive tests of toxicity to aquatic insects are useful for assessing the effects of potential pollutants on aquatic ecosystems. Within the last few years, research emphasis has included the toxicity of coal-related synthetic fuel products and effluents to aquatic biota. As part of an Oak Ridge National Laboratory (ORNL) program to evaluate the environmental effects of synthetic fuel products and effluents, a series of tests is being used to measure the toxicity of whole and fractionated synthetic fuel products and effluents and representative pure compounds (polycyclic aromatic hydrocarbons, phenols, and azaarenes) to aquatic organisms. Synthetic fuel materials are complex mixtures of inorganic and organic substances, including aliphatic hydrocarbons, aromatic hydrocarbons, and N-, S-, and O-substituted aromatics. By testing fractions and components of whole materials, we can begin to explain observed toxic effects and recommend further treatment to reduce toxicity. Test organisms include freshwater crustaceans (Daphnia pulex and magna), green algae (Selenastrum capricornutum), blue-green algae (Microcystis aeruginosa), snails (Physa heterostropha and Helisoma sp.), fathead minnows (Pimephales promelas), bluegill sunfish (Lepomis macrochirus), and rainbow trout (Salmo gairdneri).

  3. Toxicity of solid residues resulting from wastewater treatment with nanomaterials.

    PubMed

    Nogueira, Verónica; Lopes, Isabel; Rocha-Santos, Teresa; Gonçalves, Fernando; Pereira, Ruth

    2015-08-01

    Nanomaterials (NMs) are widely recommended for wastewater treatments due to their unique properties. Several studies report the different advantages of nanotechnology in the remediation of wastewaters, but limited research has been directed toward the fate and potential impacts of the solid residues (SRs) produced after the application of such technologies. The present work aimed at investigating the ecotoxicity of SRs resulting from the treatment of three effluents (OOMW, kraft pulp mill, and mining drainage) with two NMs (TiO2 and Fe2O3). The invertebrate Chironomus riparius was selected as test organism and exposed to the residues. The effect on percentage of survival and growth was assessed. Results showed that the SRs from the treatments nano-TiO2(1.0gL(-1))/H2O2(0.5M) and nano-Fe2O3(1.0gL(-1))/H2O2(1.0M) from OOMW and nano-Fe2O3(0.75gL(-1))/H2O2(0.01M) from kraft pulp mill effluent exhibited lethal toxicity to C. riparius. Only the exposure to SRs resulting from the treatment with nano-Fe2O3(0.75gL(-1))/H2O2(0.01M) applied to the kraft pulp mill effluent significantly affected the growth rate based on the head capsule width. In terms of growth rate, based on the body length, it decreased significantly after exposure to the SRs from the treatments nano-TiO2 (1.0gL(-1)) and nano-Fe2O3(0.75gL(-1))/H2O2(0.01M) of kraft paper mill effluent and nano-Fe2O3(1.0gL(-1))/H2O2(1.0M) of OOMW. According to our study the SRs can promote negative effects on C. riparius. However, the effects are dependent on the type of effluent treated as well as on the organic and inorganic compounds attached to the NMs. PMID:26057932

  4. Improving sediment-quality guidelines for nickel: development and application of predictive bioavailability models to assess chronic toxicity of nickel in freshwater sediments.

    PubMed

    Vangheluwe, Marnix L U; Verdonck, Frederik A M; Besser, John M; Brumbaugh, William G; Ingersoll, Christopher G; Schlekat, Christan E; Garman, Emily Rogevich

    2013-11-01

    Within the framework of European Union chemical legislations an extensive data set on the chronic toxicity of sediment nickel has been generated. In the initial phase of testing, tests were conducted with 8 taxa of benthic invertebrates in 2 nickel-spiked sediments, including 1 reasonable worst-case sediment with low concentrations of acid-volatile sulfide (AVS) and total organic carbon. The following species were tested: amphipods (Hyalella azteca, Gammarus pseudolimnaeus), mayflies (Hexagenia sp.), oligochaetes (Tubifex tubifex, Lumbriculus variegatus), mussels (Lampsilis siliquoidea), and midges (Chironomus dilutus, Chironomus riparius). In the second phase, tests were conducted with the most sensitive species in 6 additional spiked sediments, thus generating chronic toxicity data for a total of 8 nickel-spiked sediments. A species sensitivity distribution was elaborated based on 10% effective concentrations yielding a threshold value of 94 mg Ni/kg dry weight under reasonable worst-case conditions. Data from all sediments were used to model predictive bioavailability relationships between chronic toxicity thresholds (20% effective concentrations) and AVS and Fe, and these models were used to derive site-specific sediment-quality criteria. Normalization of toxicity values reduced the intersediment variability in toxicity values significantly for the amphipod species Hyalella azteca and G. pseudolimnaeus, but these relationships were less clearly defined for the mayfly Hexagenia sp. Application of the models to prevailing local conditions resulted in threshold values ranging from 126 mg to 281 mg Ni/kg dry weight, based on the AVS model, and 143 mg to 265 mg Ni/kg dry weight, based on the Fe model. PMID:23983116

  5. Chronic toxicity of nickel-spiked freshwater sediments: variation in toxicity among eight invertebrate taxa and eight sediments.

    PubMed

    Besser, John M; Brumbaugh, William G; Ingersoll, Christopher G; Ivey, Chris D; Kunz, James L; Kemble, Nile E; Schlekat, Christian E; Garman, Emily Rogevich

    2013-11-01

    This study evaluated the chronic toxicity of Ni-spiked freshwater sediments to benthic invertebrates. A 2-step spiking procedure (spiking and sediment dilution) and a 2-stage equilibration period (10 wk anaerobic and 1 wk aerobic) were used to spike 8 freshwater sediments with wide ranges of acid-volatile sulfide (AVS; 0.94-38 µmol/g) and total organic carbon (TOC; 0.42-10%). Chronic sediment toxicity tests were conducted with 8 invertebrates (Hyalella azteca, Gammarus pseudolimnaeus, Chironomus riparius, Chironomus dilutus, Hexagenia sp., Lumbriculus variegatus, Tubifex tubifex, and Lampsilis siliquoidea) in 2 spiked sediments. Nickel toxicity thresholds estimated from species-sensitivity distributions were 97 µg/g and 752 µg/g (total recoverable Ni; dry wt basis) for sediments with low and high concentrations of AVS and TOC, respectively. Sensitive species were tested with 6 additional sediments. The 20% effect concentrations (EC20s) for Hyalella and Gammarus, but not Hexagenia, were consistent with US Environmental Protection Agency benchmarks based on Ni in porewater and in simultaneously extracted metals (SEM) normalized to AVS and TOC. For Hexagenia, sediment EC20s increased at less than an equimolar basis with increased AVS, and toxicity occurred in several sediments with Ni concentrations in SEM less than AVS. The authors hypothesize that circulation of oxygenated water by Hexagenia led to oxidation of AVS in burrows, creating microenvironments with high Ni exposure. Despite these unexpected results, a strong relationship between Hexagenia EC20s and AVS could provide a basis for conservative site-specific sediment quality guidelines for Ni. PMID:23657897

  6. Improving sediment-quality guidelines for nickel: development and application of predictive bioavailability models to assess chronic toxicity of nickel in freshwater sediments

    USGS Publications Warehouse

    Vangheluwe, Marnix L. U.; Verdonck, Frederik A. M.; Besser, John M.; Brumbaugh, William G.; Ingersoll, Christopher G.; Schlekat, Christan E.; Rogevich Garman, Emily

    2013-01-01

    Within the framework of European Union chemical legislations an extensive data set on the chronic toxicity of sediment nickel has been generated. In the initial phase of testing, tests were conducted with 8 taxa of benthic invertebrates in 2 nickel-spiked sediments, including 1 reasonable worst-case sediment with low concentrations of acid-volatile sulfide (AVS) and total organic carbon. The following species were tested: amphipods (Hyalella azteca, Gammarus pseudolimnaeus), mayflies (Hexagenia sp.), oligochaetes (Tubifex tubifex, Lumbriculus variegatus), mussels (Lampsilis siliquoidea), and midges (Chironomus dilutus, Chironomus riparius). In the second phase, tests were conducted with the most sensitive species in 6 additional spiked sediments, thus generating chronic toxicity data for a total of 8 nickel-spiked sediments. A species sensitivity distribution was elaborated based on 10% effective concentrations yielding a threshold value of 94 mg Ni/kg dry weight under reasonable worst-case conditions. Data from all sediments were used to model predictive bioavailability relationships between chronic toxicity thresholds (20% effective concentrations) and AVS and Fe, and these models were used to derive site-specific sediment-quality criteria. Normalization of toxicity values reduced the intersediment variability in toxicity values significantly for the amphipod species Hyalella azteca and G. pseudolimnaeus, but these relationships were less clearly defined for the mayfly Hexagenia sp. Application of the models to prevailing local conditions resulted in threshold values ranging from 126 mg to 281 mg Ni/kg dry weight, based on the AVS model, and 143 mg to 265 mg Ni/kg dry weight, based on the Fe model

  7. Bee (Hymenoptera: Apoidea) and hoverfly (Diptera: Syrphidae) pollinators in Pannonian habitats of Serbia, with a description of a new Eumerus Meigen species (Syrphidae).

    PubMed

    Markov, Zlata; Nedeljković, Zorica; Ricarte, Antonio; Vujić, Ante; Jovičić, Snežana; Józan, Zsolt; Mudri-Stojnić, Sonja; Radenković, Snežana; Ćetković, Aleksandar

    2016-01-01

    The diversity of bee (Hymenoptera: Apoidea) and hoverfly (Diptera: Syrphidae) pollinators from ten localities in Vojvodina, Serbia was surveyed. Among different types of Pannonian habitat (grasslands, heathland and scrub, woodland and forest habitats) all localities were categorised as forest and steppe. They were in protected areas, mostly undisturbed by human activity. Censuses of pollinators took place from 30 March to 10 October, 2014. We recorded 218 pollinator species; 135 bee species (42 Halictidae; 32 Apidae; 29 Andrenidae; 24 Megachilidae; 7 Colletidae; 1 Melittidae) and 83 species of hoverflies. We describe a new species of hoverfly, Eumerus pannonicus sp. nov., and compare it to other similar species. Based on our study, the Special Nature Reserve of Pašnjaci Velike Droplje is critical for the conservation of this new Eumerus-being only found at this locality-and other species such as Chrysotoxum lineare (Zetterstedt), which is rare in Europe and protected under Serbian legislation. The highest numbers of bee species were recorded in the Deliblato and Subotica sand areas (40 and 32, respectively), while Fruška Gora Mountain and the Vršac Mountains harboured the highest number of hoverfly species. PMID:27615823

  8. Meiotic disjunction and embryonic lethality in sex-linked double-translocation heterozygous males of the onion fly, Hylemya antiqua (Meigen).

    PubMed

    Vosselman, L; van Heemert, C

    1980-05-01

    The frequencies of disjunction types in double-translocation heterozygous males (2(6)2(Y)6(2)6XY(2)) in Hylemya antiqua have been established in MII cells and eggs of testcrosses.Several disjunction types occurred but four predominated. A correlation was found between the frequencies of the disjunction types and the relative position of the centromeres. The frequency of numerical non-disjunction (NND) was 4%. Differences in frequency of NND between sex-linked and autosomal translocations of H. antiqua are discussed. A good correspondence between the frequencies of unbalanced karyotypes, and embryonic and larval mortality was found. The total genetic load which can be induced by the T14/T61 males is estimated to be 60-65%. Some duplication/deficiency karyotypes appeared to be viable in pupal and even adult stages. In 2(6)2(6)2(Y)6(2)6(2)X males a regular coorientation between 2(Y) and X was observed, in spite of non-homologous centromeres and a complicated synapsis of 2(Y). Application possibilities of the present material for genetic control of H. antiqua are discussed. PMID:24301348

  9. Lucilia sericata strain from Colombia: Experimental colonization, life tables and evaluation of two artificial diets of the blowfly Lucilia sericata (Meigen) (Diptera: Calliphoridae), Bogotá, Colombia strain.

    PubMed

    Rueda, Luis C; Ortega, Luis G; Segura, Nidya A; Acero, Víctor M; Bello, Felio

    2010-01-01

    The objective of this work was to establish, under experimental laboratory conditions, a colony of Lucilia sericata, Bogotá-Colombia strain, to build life tables and evaluate two artificial diets. This blowfly is frequently used in postmortem interval studies and in injury treatment. The parental adult insects collected in Bogotá were maintained in cages at 22°C±1 average temperature, 60%±5 relative humidity and 12 h photoperiodicity. The blowflies were fed on two artificial diets that were evaluated over seven continuous generations. Reproductive and population parameters were assessed. The life cycle of the species was expressed in the number of days of the different stages: egg = 0.8±0.1, larvae I = 1.1±0.02, larvae II = 1.94±0.16, larvae III = 3.5±0.54, pupae = 6.55±0.47, male adult = 28.7±0.83 and female adult = 33.5±1.0. Total survival from egg stage to adult stage was 91.2% for diet 1, while for diet 2 this parameter was 40.5%. The lifetime reproductive output was 184.51±11.2 eggs per female. The population parameters, as well as the reproductive output of the blowflies that were assessed, showed relatively high values, giving evidence of the continuous increase of the strain over the different generations and making possible its maintenance as a stable colony that has lasted for more than two years. PMID:21031265

  10. The genus Sphegina Meigen (Diptera, Syrphidae) in a biodiversity hotspot: the thirty-six sympatric species in Kambaiti, Myanmar.

    PubMed

    Hippa, Heikki; Steenis, Jeroen Van; Mutin, Valeri A

    2015-01-01

    The material of Sphegina collected by René Malaise in Kambaiti, Myanmar, in 1934 includes S. (Sphegina) kumaoniensis Mutin and the following 35 new species: S. (Sphegina) uncinata, S. (Asiosphegina) achaeta, S. (A.) adusta, S. (A.) atricolor, S. (A.) bidens, S. (A.) bilobata, S. (A.) carinata, S. (A.) cerina, S. (A.) crassispina, S. (A.) crucivena, S. (A.) culex, S. (A.) cultrigera, S. (A.) ensifera, S. (A.) falcata, S. (A.) forceps, S. (A.) forficata, S. (A.) furva, S. (A.) gigas, S. (A.) index, S. (A.) malaisei, S. (A.) minuta, S. (A.) mirifica, S. (A.) nasuta, S. (A.) pollex, S. (A.) pollinosa, S. (A.) parvula, S. (A.) pusilla, S. (A.) radula, S. (A.) raduloides, S. (A.) siculifera, S. (A.) simplex, S. (A.) sinesmila, S. (A.) subradula, S. (A.) trichaeta and S. (A.) trispina. A key to the studied species is given. The world fauna of Sphegina now comprises 120 species. PMID:25947834

  11. The mode of bioturbation triggers pesticide remobilization from aquatic sediments.

    PubMed

    Bundschuh, Mirco; Schletz, Marco; Goedkoop, Willem

    2016-08-01

    After their release into the aquatic environment, contaminants may - depending on the physicochemical properties - adsorb to sediments. From there these contaminants can either be buried or remobilised by abiotic factors (e.g., resuspension) as well as by the bioturbating activity of sediment dwelling invertebrates. Little is, however, know about the effects of bioturbation on the fate of pesticides. Therefore, the present study quantified the impact of the bioturbation mode of benthic invertebrate species (bio-diffusor vs. bio-irrigation), the invertebrate density (i.e. 0-8 individuals per replicate), and the substance-inherent properties (i.e. hydrophobicity, water solubility) on the remobilization of sediment-associated pesticides in a laboratory-based set-up over 13 days. We found that both the bioturbation mode (i.e., species identity) and species density, as well as pesticide properties (i.e., hydrophobicity) affected the direction and magnitude of remobilisation of sediment-bound pesticides. The oligochaeta Lumbriculus variegatus showed a density-dependent effect on the remobilization of lindane to the water phase, whereas those with the amphipod Monoporeia affinis and larvae of the midge Chironomus riparius did not. Although these findings show that sediments not per definition are a sink for pesticides, the rates of pesticide remobilization are limited. This observation, thus, suggests that the risk for aquatic communities posed by the remobilization of pesticides from the sediment due to bioturbation is low. PMID:27107774

  12. Subcellular distribution of cadmium in two aquatic invertebrates: change over time and relationship to Cd assimilation and loss by a predatory insect.

    PubMed

    Dubois, Maï'tée; Hare, Landis

    2009-01-15

    We set out to determine if the efficiency of cadmium (Cd) assimilation and loss by a freshwater predator (the alderfly Sialis velata) differs when it is exposed, for various lengths of time, to Cd in either an insect (Chironomus riparius) or a worm (Tubifex tubifex). Prey were exposed to Cd in sediments for up to 28 days and then fractionated to measure Cd distributions in their cells. Cadmium subcellular distributions varied little over time for a given preytype but differed substantially between the two prey species; for example, the cytosol comprised a larger proportion of Cd in the insect (76%) than in the worm (34%). The predator assimilated proportionally more Cd from the insect (72%) than from the worm (46%) and these assimilation efficiencies were similar to the proportion of prey Cd that would theoretically be available to it (cytosolic Cd + organelle Cd). However, measurements of Cd in the predator's feces confirmed that to obtain an exact 1:1 relationship between predator assimilation efficiency and prey subcellular distribution we had to assume that approximately 50% of the Cd associated with the organelle fraction of T. tubifex was unavailable for digestion by the predator. Losses of Cd from the predator also varied depending on the type of prey that were the source of its Cd. PMID:19238964

  13. Sediment toxicity screening with cost-effective microbiotests and conventional assays: A comparative study

    SciTech Connect

    Vanciheluwe, M.L.; Janssen, C.R.; Persoone, G.

    1995-12-31

    A large monitoring study of freshwater sediments, using the TRIAD approach, was conducted in Flanders (Belgium). This paper reports on the results of the toxicity assessment of 80 sediment samples evaluated with a battery of microbiotests and conventional assays. Sediment pore waters, extracted by squeezing, were tested with the Microtox{reg_sign} (Vibrio fischerii) and Thamnotoxkit{trademark} F (Thamnocephalus platyurus) microbiotests and the conventional (acute) assays with algae (Selenastrum capricornutum) and daphnids (Daphnia magna). A newly developed 5 day ELS test with the catfish Clarias gariepinus was also applied to the pore waters. Solid-phase testing was performed with the Microtox Sp{reg_sign} assay and the 10 day tests with Chironomus riparius and Hyalella azteca. Uni- and multivariate statistical techniques were applied to the data matrix to select a minimal test battery from the water phase and solid phase assays and from all tests combined. The influence of sediment associated confounding factors on the validity of the test results obtained with the various assays will be discussed. Finally a comparison of the predictive power of the selected battery of signal tests and that of the complete battery will be made and the potential use of the minimal battery for the initial hazard assessment of contaminated sediments will be reviewed.

  14. Genomic basis of ecological niche divergence among cryptic sister species of non-biting midges

    PubMed Central

    2013-01-01

    Background There is a lack of understanding the evolutionary forces driving niche segregation of closely related organisms. In addition, pinpointing the genes driving ecological divergence is a key goal in molecular ecology. Here, larval transcriptome sequences obtained by next-generation-sequencing are used to address these issues in a morphologically cryptic sister species pair of non-biting midges (Chironomus riparius and C. piger). Results More than eight thousand orthologous open reading frames were screened for interspecific divergence and intraspecific polymorphisms. Despite a small mean sequence divergence of 1.53% between the sister species, 25.1% of 18,115 observed amino acid substitutions were inferred by α statistics to be driven by positive selection. Applying McDonald-Kreitman tests to 715 alignments of gene orthologues identified eleven (1.5%) genes driven by positive selection. Conclusions Three candidate genes were identified as potentially responsible for the observed niche segregation concerning nitrite concentration, habitat temperature and water conductivity. Additionally, signs of positive selection in the hydrogen sulfide detoxification pathway were detected, providing a new plausible hypothesis for the species’ ecological differentiation. Finally, a divergently selected, nuclear encoded mitochondrial ribosomal protein may contribute to reproductive isolation due to cytonuclear coevolution. PMID:23758757

  15. Deformities of chironomid larvae and heavy metal pollution: from laboratory to field studies.

    PubMed

    Di Veroli, A; Santoro, F; Pallottini, M; Selvaggi, R; Scardazza, F; Cappelletti, D; Goretti, E

    2014-10-01

    Mouthpart deformities of Chironomus riparius larvae (Diptera) have been investigated to evaluate the toxic effects of contamination by heavy metals in the Genna Stream (Central Italy), situated in an area subjected to intensive swine farms (40000 heads). The livestock farming (fertirrigation) contributes to metal pollution of the Genna Stream with an increase of copper, zinc, cadmium, chromium and nickel in the sediments of the downstream stations. The incidence of mentum deformities was very high at all sampling stations, about 56%. The highest values of deformities were found in the intermediate river reach (St. 3: 65%) and in March (66%), mainly due to an increase in severe deformities. The high incidence of severe deformities (30%) is attributed to the high pollution level by heavy metals in the sediments, in particular to copper and zinc, which showed the highest average value at St. 3 and in March. This field study reflected the relationships between sediment metal concentrations and chironomid mouthpart deformities, previously observed in laboratory tests, and highlighted these deformities as toxicity endpoints. This feature paves the way for their use as an effective tool in freshwater bioassessment monitoring programs to evaluate the toxic effects of metal contamination in freshwater ecosystems. PMID:25048882

  16. Whole effluent toxicity assessment at a wastewater treatment plant upgraded with a full-scale post-ozonation using aquatic key species.

    PubMed

    Magdeburg, Axel; Stalter, Daniel; Oehlmann, Jörg

    2012-08-01

    Ozonation as final wastewater (WW) polishing step, following conventional activated sludge treatment is increasingly implemented in sewage treatment for contaminant degradation to prevent surface water pollution. While the oxidative degradation of chemicals has been extensively investigated, the in vivo toxicological characteristics of ozonated whole effluents are rarely a matter of research. In the present study, whole effluents were toxicologically evaluated with an in vivo test battery before and after full-scale ozonation and subsequent sand filtration on site at a treatment plant. One aquatic plant (duckweed, Lemna minor) and five invertebrate species of different systematic groups (Lumbriculus variegatus, Chironomus riparius, Potamopyrgus antipodarum, Daphnia magna) were exposed to the effluents in a flow-through-designed test system with a test duration of 7-28 d. None of the considered toxicity endpoints correlated with the pollutant elimination. A tendency towards an increased toxicity after ozonation was apparent in three of the test systems showing [statistically] significant adverse effects in the L. variegatus toxicity test (decrease in reproduction and biomass). After sand filtration, adverse effects were reduced to a similar level like after conventional treatment. Solely the Daphnia reproduction test revealed beneficial effects after ozonation in combination with sand filtration. Results of the test battery indicate the formation of adverse oxidation products during WW ozonation. L. variegatus appeared to be the most sensitive of the five test species. Sand filtration effectively removes or detoxifies toxic oxidation products, as toxic effects were subsequently reduced to the level after conventional treatment. PMID:22560180

  17. Disturbance caused by freshwater releases of different magnitude on the aquatic macroinvertebrate communities of two coastal lagoons

    NASA Astrophysics Data System (ADS)

    Cañedo-Argüelles, Miguel; Rieradevall, Maria

    2010-06-01

    The response of the aquatic macroinvertebrate communities to freshwater releases of different magnitude and persistence was investigated in two Mediterranean coastal lagoons (Ca l'Arana and Ricarda). The study was carried out during 14 months (June 2004-July 2005) in which different environmental variables and the macroinvertebrate communities associated with two different habitats, the Phragmites australis belt and the deep area of the lagoons, were sampled monthly. Additionally, potential colonizing sources were identified through the analysis of Chironomidae pupal exuviae. The initial response of the communities to the freshwater releases was similar, being characterized by a peak of opportunistic taxa (mainly Naididae), but the late response was different for each lagoon. In the Ca l'Arana, the magnitude of the freshwater release was higher (salinity dropped below five, which is the limit commonly established for most freshwater species) and its persistence was also higher, allowing the colonization of the lagoon by new insect taxa, which replaced the brackish water species. In the Ricarda, the salinity never dropped beyond five and pre-disturbance conditions were rapidly re-established. This, together with the acclimatizing mechanisms showed by the species Chironomus riparius and Hediste diversicolor, permitted the recovery of the pre-disturbance macroinvertebrate community.

  18. Behavioural responses of freshwater planarians after short-term exposure to the insecticide chlorantraniliprole.

    PubMed

    Rodrigues, Andreia C M; Henriques, Jorge F; Domingues, Inês; Golovko, Oksana; Žlábek, Vladimír; Barata, Carlos; Soares, Amadeu M V M; Pestana, João L T

    2016-01-01

    Recent advances in video tracking technologies provide the tools for a sensitive and reproducible analysis of invertebrate activity under stressful conditions nurturing the field of behavioural ecotoxicology. This study aimed to evaluate behavioural responses of the freshwater planarian Dugesia subtentaculata exposed to a model compound, chlorantraniliprole (CAP). This compound is an anthranilic diamide insecticide and due to its neurotoxic action can, at low concentrations, impair behaviour of exposed organisms. Behavioural endpoints measured included feeding and locomotor activities. Feeding responses were based on planarian predatory behaviour using Chironomus riparius larvae as prey. Locomotion was measured by the traditional planarian locomotor velocity (pLMV) assay and additionally using an automated video tracking system using a Zebrabox(®) (Viewpoint, France) device. While feeding and pLMV were significantly impaired at 131.7μg/L CAP, the video tracking system showed that total distance covered by planarians was significantly reduced at concentrations as low as 26.2μg/L CAP. Our results show that more advanced automated video recording systems can be used in the development of sensitive bioassays allowing a reliable, time- and cost-effective quantification of behaviour in aquatic invertebrates. Due to their ecological relevance, behavioural responses should not be disregarded in risk assessment strategies and we advocate the suitability of planarians as suitable organisms for behavioural ecotoxicological studies. PMID:26561438

  19. Characterizing the effects of bisphenol A on sediment-dwelling benthic organisms.

    PubMed

    Staples, Charles; Mihaich, Ellen; Ortego, Lisa; Caspers, Norbert; Klečka, Gary; Woelz, Jan; Hentges, Steven

    2016-03-01

    Bisphenol A (BPA) is a high production volume chemical intermediate used primarily in the production of polycarbonate plastics and epoxy resins. It primarily enters surface water and sediment via effluent discharges during its manufacture and use. The physical properties of BPA suggest that sediment is a potential sink and may result in exposure to benthic organisms. Currently there are no studies measuring the chronic toxicity of BPA to benthic organisms via direct sediment exposure. The present study examined the chronic toxicity of BPA to 3 commonly used test organisms that are generally representative of invertebrates occupying the base of the benthic food web and for which standardized testing protocols are available: the oligochaete Lumbriculus variegatus (mean numbers and biomass), the midge Chironomus riparius (emergence and development rate), and the estuarine amphipod Leptocheirus plumulosus (survival, growth, and reproduction). No-observed-effect concentrations (NOECs) for the 3 species ranged from 12 mg/kg to 54 mg/kg dry weight. All NOEC values were higher than all measured concentrations of BPA in freshwater and marine sediments reported in reliable, fully reported studies from North America and Europe from the 1990s to the present. For the first time, there are studies with BPA measuring the chronic toxicity to 3 taxa of sediment dwelling invertebrates, which are suitable to support region-specific risk assessments. PMID:26297924

  20. Bluegill growth as modified by plant density: an exploration of underlying mechanisms

    USGS Publications Warehouse

    Savino, Jacqueline F.; Marschall, Elizabeth A.; Stein, Roy A.

    1992-01-01

    Bluegill (Lepomis macrochira) growth varies inconsistently with plant density. In laboratory and field experiments, we explored mechanisms underlying bluegill growth as a function of plant and invertebrate density. In the laboratory, bluegills captured more chironomids (Chironomus riparius) than damselflies (Enallagma spp. and Ischnura spp.), but energy intake per time spent searching did not differ between damselfly and chironomid treatments. From laboratory data, we described prey encounter rates as functions of plant and invertebrate density. In Clark Lake, Ohio, we created 0.05-ha mesocosms of inshore vegetation to generate macrophyte densities of 125, 270, and 385 stems/m2 of Potamogeton and Ceratophyllum and added 46-mm bluegill (1/m2). In these mesocosms, invertebrate density increased as a function of macrophyte density. Combining this function with encounter rate functions derived from laboratory data, we predicted that bluegill growth should peak at a high macrophyte density, greater than 1000 stems/m2, even though growth should change only slightly beyond 100 stems/m2. Consistent with our predictions, bluegills did not grow differentially, nor did their use of different prey taxa differ, across macrophyte densities in the field. Bluegills preferred chironomid pupae, which were relatively few in numbers but vulnerable to predation, whereas more cryptic, chironomid larvae, which were associated with vegetation but were relatively abundant, were eaten as encountered. Bluegill avoided physid snails. Contrary to previous work, vegetation did not influence growth or diet of bluegill beyond relatively low densities owing to the interaction between capture probabilities and macroinvertebrate densities.

  1. Toxicity assessment of sediments from three European river basins using a sediment contact test battery.

    PubMed

    Tuikka, A I; Schmitt, C; Höss, S; Bandow, N; von der Ohe, P C; de Zwart, D; de Deckere, E; Streck, G; Mothes, S; van Hattum, B; Kocan, A; Brix, R; Brack, W; Barceló, D; Sormunen, A J; Kukkonen, J V K

    2011-01-01

    The toxicity of four polluted sediments and their corresponding reference sediments from three European river basins were investigated using a battery of six sediment contact tests representing three different trophic levels. The tests included were chronic tests with the oligochaete Lumbriculus variegatus, the nematode Caenorhabditis elegans and the mudsnail Potamopyrgus antipodarum, a sub-chronic test with the midge Chironomus riparius, an early life stage test with the zebra fish Danio rerio, and an acute test with the luminescent bacterium Vibrio fischeri. The endpoints, namely survival, growth, reproduction, embryo development and light inhibition, differed between tests. The measured effects were compared to sediment contamination translated into toxic units (TU) on the basis of acute toxicity to Daphnia magna and Pimephales promelas, and multi-substance Potentially Affected Fractions of species (msPAF) as an estimate for expected community effects. The test battery could clearly detect toxicity of the polluted sediments with test-specific responses to the different sediments. The msPAF and TU-based toxicity estimations confirmed the results of the biotests by predicting a higher toxic risk for the polluted sediments compared to the corresponding reference sediments, but partly having a different emphasis from the biotests. The results demonstrate differences in the sensitivities of species and emphasize the need for data on multiple species, when estimating the effects of sediment pollution on the benthic community. PMID:20833427

  2. Swarm dynamics may give rise to Lévy flights

    PubMed Central

    Reynolds, Andrew M.; Ouellette, Nicholas T.

    2016-01-01

    “Continuous-time correlated random walks” are now gaining traction as models of scale-finite animal movement patterns because they overcome inherent shortcomings with the prevailing paradigm - discrete random walk models. Continuous-time correlated random walk models are founded on the classic Langevin equation that is driven by purely additive noise. The Langevin equation is, however, changed fundamentally by the smallest of multiplicative noises. The inclusion of such noises gives rise to Lévy flights, a popular but controversial model of scale-free movement patterns. Multiplicative noises have not featured prominently in the literature on biological Lévy flights, being seen, perhaps, as no more than a mathematical contrivance. Here we show how Langevin equations driven by multiplicative noises and incumbent Lévy flights arise naturally in the modelling of swarms. Model predictions find some support in three-dimensional, time-resolved measurements of the positions of individual insects in laboratory swarms of the midge Chironomus riparius. We hereby provide a new window on Lévy flights as models of movement pattern data, linking patterns to generative processes. PMID:27465971

  3. The toxicity of a neem insecticide to populations of culicidae and other aquatic invertebrates as assessed in in situ microcosms.

    PubMed

    Scott, I M; Kaushik, N K

    2000-10-01

    Microcosm trials were conducted with the botanical insecticide Margosan-O(R) to assess the potential hazards of the product to aquatic organisms. Laboratory chronic bioassays with water from the treated microcosms were conducted to provide an estimate of the residual effect of Margosan-O. Results from chronic tests showed Margosan-O toxicity to be greater in the laboratory exposures than in situ with Culicidae larvae exposed to the same concentrations. Residue analyses of the active ingredient, azadirachtin, determined that it had a half-life of 36 to 48 h in water exposed to natural sunlight. Two applications of Margosan-O at the recommended application rate for pests did not harm aquatic invertebrates that are categorized as planktonic and filter feeding (Culex sp. and Daphnia sp.). However, the benthic invertebrate (Chironomus riparius) was affected by multiple applications of neem. These results show that the use of Margosan-O and possibly other neem extracts in or near aquatic environments could lead to disturbances in benthic populations and may cause decreases in numbers of organisms that are important in food web and nutrient cycling processes. PMID:10948283

  4. Uptake, elimination, and biotransformation of the lampricide 3-trifluoromethyl-4-nitrophenol (TFM) by larvae of the aquatic midge Chironomus tentans.

    PubMed

    Kawatski, J A; Bittner, M A

    1975-05-01

    Accumulation of [14C]3-trifluoromethyl-4-nitrophenol ([14C]TFM) by chironomid larvae from sublethal aqueous concentrations is rapid and dependent on hardness of exposure water. TFM is readily biotransformed to at least two more polar derivatives, including sulfated TFM and TFM-glucuronide or galacturonide. Some TFM is also reduced to the phenol amine. Chironomids can quickly eliminate all TFM derivatives as well as the parent [14C]TFM. PMID:1154422

  5. The Influence of Test Conditions on the Performance of Chironomus dilutus and Hyalella azteca in Sediment Toxicity Tests

    EPA Science Inventory

    In most all sediment toxicity assessments, the performance of organisms in control sediments is a key parameter in defining sediment toxicity, whether through direct statistical comparison to control or by normalizing to control performance to compare results across sites or batc...

  6. Interlaboratory Evaluation of Hyalella Azteca and Chironomus Tentans Short-term and Long-term Sediment Toxicity Tests

    EPA Science Inventory

    This paper presents the results of interlaboratory toxicity tests on sediment toxicity methods for use in routine testing and this data has been presented in an EPA report and this is a summary of that data.

  7. PHOTO-INDUCED TOXICITY OF PAHS TO HYALELLA AZTECA AND CHIRONOMUS TENTANS: EFFECTS OF MIXTURES AND BEHAVIOR. (R823873)

    EPA Science Inventory

    In the aquatic environment, polycyclic aromatic hydrocarbon (PAH) contamination can result from several anthropogenic sources such as petroleum runoff, industrial processes, and petroleum spills. When ultraviolet light (UV) is present at sufficient intensity, the acute toxicity o...

  8. Tolerance of freshwater test organisms to formulated sediments for use as control materials in whole-sediment toxicity tests

    USGS Publications Warehouse

    Kemble, N.E.; Dwyer, F.J.; Ingersoll, C.G.; Dawson, T.D.; Norberg-King, T. J.

    1999-01-01

    A method is described for preparing formulated sediments for use in toxicity testing. Ingredients used to prepare formulated sediments included commercially available silt, clay, sand, humic acid, dolomite, and ??- cellulose (as a source of organic carbon). ??-Cellulose was selected as the source of organic carbon because it is commercially available, consistent from batch to batch, and low in contaminant concentrations. The tolerance of freshwater test organisms to formulated sediments for use as control materials in whole-sediment toxicity testing was evaluated. Sediment exposures were conducted for 10 d with the amphipod Hyalella azteca, the midges Chironomus riparius and C. tentans, and the oligochaete Lumbriculus variegatus and for 28 d with H. azteca. Responses of organisms in formulated sediments was compared with a field-collected control sediment that has routinely been used to determine test acceptability. Tolerance of organisms to formulated sediments was evaluated by determining responses to varying levels of ??-cellulose, to varying levels of grain size, to evaluation of different food types, or to evaluation of different sources of overlying water. In the 10-d exposures, survival of organisms exposed to the formulated sediments routinely met or exceeded the responses of test organisms exposed to the control sediment and routinely met test acceptability criteria required in standard methods. Growth of amphipods and oligochaetes in 10-d exposures with formulated sediment was often less than growth of organisms in the field-collected control sediment. Additional research is needed, using the method employed to prepare formulated sediment, to determine if conditioning formulated sediments before starting 10-d tests would improve the growth of amphipods. In the 28-d exposures, survival of H. azteca was low when reconstituted water was used as the source of overlying water. However, when well water was used as the source of overlying water in 28-d exposures

  9. The internal distribution of nickel and thallium in two freshwater invertebrates and its relevance to trophic transfer.

    PubMed

    Dumas, Julie; Hare, Landis

    2008-07-15

    Although nickel and thallium are present at potentially harmful concentrations in some lakes, there is little information on their bioaccumulation and transfer up aquatic food webs. To measure the propensity of animals for accumulating and transferring these contaminants along food chains, we exposed two common types of invertebrates, an insect (Chironomus riparius) and a worm (Tubifex tubifex), to these metals spiked into sediment. We then measured the subcellular distribution of Ni and Tl in these invertebrates to estimate the likelihood that these metals will have toxic effects on these prey or be transferred to higher trophic levels. In both species, at least half of their Ni and TI was present in fractions that are purportedly detoxified (granules and metal-binding proteins). Furthermore, based on information in the literature concerning prey subcellular fractions that are likely to be trophically available (TAM), we estimate that much of the Ni and TI in these animals (43-84%) is available for transfer to a predator. To test this prediction, we fed these invertebrates to the alderfly Sialis velata, and measured the efficiency with which this predator assimilated Ni and Tl from each prey type. The majority of both trace metals (58-83%) was assimilated by the predator, which suggests that these contaminants would be easily transferred along aquatic food chains and that models describing Ni and Tl accumulation by aquatic animals should consider food as a source of these metals. The proportion of metal that could potentially be taken up by a consumer (% TAM) and the actual percentage assimilated by S. velata fell on or reasonably close to a 1:1 line for the 4 prey-metal combinations. PMID:18754361

  10. An Evaluation of Several In-Lake Restoration Techniques to Improve the Water Quality Problem (Eutrophication) of Saint-Augustin Lake, Quebec, Canada

    NASA Astrophysics Data System (ADS)

    Galvez-Cloutier, Rosa; Saminathan, Sumathi K. M.; Boillot, Clotilde; Triffaut-Bouchet, Gaëlle; Bourget, Alexandre; Soumis-Dugas, Gabriel

    2012-05-01

    Increasing phosphorus (P) content and decreasing water quality of Saint-Augustin Lake, Quebec City, Canada, has led to implementation of an Integrated Watershed Management Plan to restore the lake. As a part of the plan, the effects of different restoration techniques on lake water quality and biological community (i.e., biological compatibility) were assessed during an isolated water enclosure study and laboratory microcosm assay, respectively. The restoration techniques include: (i) coagulation of P by alum only (20 mg L-1), (ii) active capping of sediments using a calcite layer of 10 cm, and (iii) a complete method involving both alum coagulation and calcite capping. The results showed that the total P (TP) was greatly decreased (76-95 %) by alum + calcite, followed by calcite only (59-84 %). Secchi depth was 106 % greater and chlorophyll a concentrations were declined by 19-78 % in the enclosure which received both alum and calcite. Results of the biological compatibility test showed that total phytoplankton biomass declined by 31 % in microcosms composed of alum + calcite. No significant ( P > 0.05) toxic effect was found on the survival of Daphnia magna and Hyalella azteca in both alum only and alum + calcite microcosms. Although the alum + calcite technique impaired the survival of Chironomus riparius, the midge emergence was much higher compared to alum only and control. Overall, the alum + calcite application was effective in controlling P release from sediment and lowering water column P concentrations, and thus improving the water quality and aquatic life of Saint-Augustin Lake. However, the TP concentrations are still higher than the critical limit (20 μg L-1) for aquatic life and the water column remained in the eutrophic state even after treatment. Increased TP concentrations, to higher than ambient levels of the lake, in the water column of all four enclosures, due to bioturbation artefact triggered by the platform installation, likely cause

  11. Tolerance of freshwater test organisms to formulated sediments for use as control materials in whole-sediment toxicity tests

    SciTech Connect

    Kemble, N.E.; Dwyer, F.J.; Ingersoll, C.G.; Dawson, T.D.; Norberg-King, T.J.

    1999-02-01

    A method is described for preparing formulated sediments for use in toxicity testing. Ingredients used to prepare formulated sediments included commercially available silt, clay, sand, humic acid, dolomite, and {alpha}-cellulose (as a source of organic carbon). {alpha}-Cellulose was selected as the source of organic carbon because it is commercially available, consistent from batch to batch, and low in contaminant concentrations. The tolerance of freshwater test organisms to formulated sediments for use as control materials in whole-sediment toxicity testing was evaluated. Sediment exposures were conducted for 10 d with the amphipod Hyalella azteca, the midges Chironomus riparius and C. tentans, and the oligochaete Lumbriculus variegatus and for 28 d with H. azteca. Responses of organisms in formulated sediments was compared with a field-collected control sediment that has routinely been used to determine test acceptability. Tolerance of organisms to formulated sediments was evaluated by determining responses to varying levels of {alpha}-cellulose, to varying levels of grain size, to evaluation of different food types, or to evaluation of different sources of overlying water. In the 10-d exposures, survival of organisms exposed to the formulated sediments routinely met or exceeded the responses of test organisms exposed to the control sediment and routinely met test acceptability criteria required in standard methods. Growth of amphipods and oligochaetes in 10-d exposures with formulated sediment was often less than growth of organisms in the field-collected control sediment. Additional research is needed, using the method employed to prepare formulated sediment, to determine if conditioning formulated sediments before starting 10-d tests would improve the growth of amphipods. In the 28-d exposures, survival of H. azteca was low when reconstituted water was used as the source of overlying water. However, when well water was used as the source of overlying water in

  12. Neonicotinoids in the Canadian aquatic environment: a literature review on current use products with a focus on fate, exposure, and biological effects.

    PubMed

    Anderson, J C; Dubetz, C; Palace, V P

    2015-02-01

    Developed to replace organophosphate and carbamate insecticides, neonicotinoids are structurally similar to nicotine. The three main neonicotinoid insecticides, imidacloprid, clothianidin, and thiamethoxam, are being re-evaluated by Health Canada's Pest Management Regulatory Agency (PMRA). An important aspect of the re-evaluation is the potential for effects in non-target organisms, including aquatic organisms. Leaching into surface waters is one of the major concerns surrounding extensive use of neonicotinoids, especially in close proximity to water bodies. The PMRA has classified IMI as 'persistent' with a 'high' leaching potential. Globally, neonicotinoids have been detected in a variety of water bodies, typically at concentrations in the low μg/L range. While IMI has been included in some monitoring exercises, there are currently very few published data for the presence of CLO and THM in Canadian water bodies. The majority of neonicotinoid toxicity studies have been conducted with IMI due to its longer presence on the market and high prevalence of use. Aquatic insects are particularly vulnerable to neonicotinoids and chronic toxicity has been observed at concentrations of IMI below 1 μg/L. Acute toxicity has been reported at concentrations below 20 μg/L for the most sensitive species, including Hyalella azteca, ostracods, and Chironomus riparius. Fish, algae, amphibians, and molluscs are relatively insensitive to IMI. However, the biological effects of THM and CLO have not been as well explored. The Canadian interim water quality guideline for IMI is 0.23 μg/L, but there is currently insufficient use, fate, and toxicological information available to establish guidelines for CLO and THM. Based on concentrations of neonicotinoids reported in surface waters in Canada and globally, there is potential for aquatic invertebrates to be negatively impacted by neonicotinoids. Therefore, it is necessary to address knowledge gaps to inform decisions around guidelines

  13. Chemical stress and metabolic rate in aquatic invertebrates: Threshold, dose-response relationships, and mode of toxic action

    SciTech Connect

    Penttinen, O.P.; Kukkonen, J.

    1998-01-01

    Four automatic compounds were evaluated in laboratory studies to investigate their accumulation and toxicant-induced changes in the rate of heat dissipation in the freshwater invertebrates Chironomus riparius and Lumbriculus variegatus. The sublethal energetic response detected by direct calorimetry was related to tissue chemical concentration by the threshold model and an attempt was made to apply the critical body residue (CBR) concept. Below the compound-specific tissue threshold concentration or CBR, no correlations were found between the dose and the metabolic rate, and the slopes of the regression were close to zero. Above the threshold, depending on the chemical, metabolic rate either increased or decreased. An increase in heat output produced by 2,4-dinitrophenol (2,4-DNP), pentachlorophenol (PCP), and 2,4,5-trichlorophenol (2,4,5-TCP) was closely correlated with the dose. The order of toxicity for these phenols was 2,4-DNP = PCP > 2,4,5-TCP, which reflects the interaction of compounds` lipophilicities and acidities and their combined influence on bioaccumulation and effects on the energy-transducing membrane by uncoupling oxidative phosphorylation. A decrease in the heat output caused by 1,2,4-trichlorobenzene (1,2,4-TCB) was more variable relative to dose. Also, 1,2,4-TCB required a much higher molar tissue threshold concentration ({approximately}2.0 {micro}mol/g wet weight) than required by phenols to generate the response. Both the metabolic response and the chemical threshold value were those expected to result from narcosis. Results suggest that calorimetric measures can identify not only the integrated physiologic response but also have some resolution of the mechanism of toxic effects.

  14. Do natural rubber latex condoms pose a risk to aquatic systems?

    PubMed

    Lambert, Scott; Johnson, Catherine; Keller, Virginie D J; Sinclair, Chris J; Williams, Richard J; Boxall, Alistair B A

    2013-12-01

    The presence and potential adverse effects of plastic-polymers in the environment are receiving increasing attention in the popular and scientific press. However, quantifying emissions, exposure and effects of these materials remains a challenge. This paper describes the application of a questionnaire survey to quantify emissions of condom material from the domestic household to the sewage waste stream. Condoms are an important mainstay for birth control and the reduction of sexually transmitted infections. Survey participants were estimated to flush condoms down the toilet 2.96% of the time, and emissions were calculated as 0.99 mg of condom material per person per day. Using information on screening efficiencies at sewage treatment plants, the questionnaire data was combined with a GIS-based water quality model (LF2000-WQX) to predicted environmental concentrations (PEC) in a UK river basin catchment. Annual average PECs of condom material were 0.08-0.2 μg L(-1), under the model scenario used. To put these PECs into context, rubber latex condom material was degraded in outdoor microcosms. This resulted in the formation of a complex mixture of substances including chemical degradation products and particles in the nano range. The direct effects of the degradation mixture were investigated using two freshwater organisms with different life cycle traits, the water column crustacean Daphnia magna and the sediment-dwelling larval of Chironomus riparius. Ecotoxicity tests investigated both acute and chronic endpoints and were shown to exhibit no toxic effects. This precluded the derivation of a genuine no-effect concentration. Hence, the results suggest that limited risk to invertebrates is associated with latex condom degradation products to the organisms tested. Future studies should extend this risk framework to assess risks of condoms to other taxonomic groups as well as the risks of other polymer materials. PMID:24162606

  15. Evaluation of numerical sediment quality targets for the St. Louis River Area of Concern

    USGS Publications Warehouse

    Crane, J.L.; MacDonald, D.D.; Ingersoll, C.G.; Smorong, D.E.; Lindskoog, R.A.; Severn, C.G.; Berger, T.A.; Field, L.J.

    2002-01-01

    Numerical sediment quality targets (SQTs) for the protection of sediment-dwelling organisms have been established for the St. Louis River Area of Concern (AOC), 1 of 42 current AOCs in the Great Lakes basin. The two types of SQTs were established primarily from consensus-based sediment quality guidelines. Level I SQTs are intended to identify contaminant concentrations below which harmful effects on sediment-dwelling organisms are unlikely to be observed. Level II SQTs are intended to identify contaminant concentrations above which harmful effects on sediment-dwelling organisms are likely to be observed. The predictive ability of the numerical SQTs was evaluated using the matching sediment chemistry and toxicity data set for the St. Louis River AOC. This evaluation involved determination of the incidence of toxicity to amphipods (Hyalella azteca) and midges (Chironomus tentans) within five ranges of Level II SQT quotients (i.e., mean probable effect concentration quotients [PEC-Qs]). The incidence of toxicity was determined based on the results of 10-day toxicity tests with amphipods (endpoints: survival and growth) and 10-day toxicity tests with midges (endpoints: survival and growth). For both toxicity tests, the incidence of toxicity increased as the mean PEC-Q ranges increased. The incidence of toxicity observed in these tests was also compared to that for other geographic areas in the Great Lakes region and in North America for 10- to 14-day amphipod (H. azteca) and 10- to 14-day midge (C. tentans or C. riparius) toxicity tests. In general, the predictive ability of the mean PEC-Qs was similar across geographic areas. The results of these predictive ability evaluations indicate that collectively the mean PEC-Qs provide a reliable basis for classifying sediments as toxic or not toxic in the St. Louis River AOC, in the larger geographic areas of the Great Lakes, and elsewhere in North America.

  16. Toxicity of CeO2 nanoparticles on a freshwater experimental trophic chain: A study in environmentally relevant conditions through the use of mesocosms.

    PubMed

    Bour, Agathe; Mouchet, Florence; Cadarsi, Stéphanie; Silvestre, Jérôme; Verneuil, Laurent; Baqué, David; Chauvet, Eric; Bonzom, Jean-Marc; Pagnout, Christophe; Clivot, Hugues; Fourquaux, Isabelle; Tella, Marie; Auffan, Mélanie; Gauthier, Laury; Pinelli, Eric

    2016-03-01

    The toxicity of CeO2 NPs on an experimental freshwater ecosystem was studied in mesocosm, with a focus being placed on the higher trophic level, i.e. the carnivorous amphibian species Pleurodeles waltl. The system comprised species at three trophic levels: (i) bacteria, fungi and diatoms, (ii) Chironomus riparius larvae as primary consumers and (iii) Pleurodeles larvae as secondary consumers. NP contamination consisted of repeated additions of CeO2 NPs over 4 weeks, to obtain a final concentration of 1 mg/L. NPs were found to settle and accumulate in the sediment. No effects were observed on litter decomposition or associated fungal biomass. Changes in bacterial communities were observed from the third week of NP contamination. Morphological changes in CeO2 NPs were observed at the end of the experiment. No toxicity was recorded in chironomids, despite substantial NP accumulation (265.8 ± 14.1 mg Ce/kg). Mortality (35.3 ± 6.8%) and a mean Ce concentration of 13.5 ± 3.9 mg/kg were reported for Pleurodeles. Parallel experiments were performed on Pleurodeles to determine toxicity pathways: no toxicity was observed by direct or dietary exposures, although Ce concentrations almost reached 100 mg/kg. In view of these results, various toxicity mechanisms are proposed and discussed. The toxicity observed on Pleurodeles in mesocosm may be indirect, due to microorganism's interaction with CeO2 NPs, or NP dissolution could have occurred in mesocosm due to the structural complexity of the biological environment, resulting in toxicity to Pleurodeles. This study strongly supports the importance of ecotoxicological assessment of NPs under environmentally relevant conditions, using complex biological systems. PMID:26152687

  17. Harmonization of standard toxicity test methods used in North America

    SciTech Connect

    Ingersoll, C.G.; Dwyer, F.J.; Ankley, G.T.

    1995-12-31

    Over the past two years, Environment Canada (EC) and the US Environmental Protection Agency (EPA) have developed standard methods for conducting toxicity and bioaccumulation tests with freshwater, estuarine, and marine sediments. Existing ASTM methods were used as a basis to harmonize these methods for conducting testing with either field-collected or laboratory-spiked sediments. For freshwater toxicity tests, methods are described by EC and EPA for the amphipod Hyalella azteca and the midges Chironomus tentans and C. riparius. Endpoints include 10- to 14-d survival of growth. Methods are also described by EPA for conducting 28-d bioaccumulation tests with the oligochaete Lumbriculus variegatus. For estuarine and marine toxicity tests, methods are described for several amphipods (i.e., Rhepoxynius abronius, Ampelisca abdita, Eohaustorius estuarius, Leptocheirus plumulosus). Endpoints include 10-d survival and reburial. EC is also developing methods for conducting toxicity tests with Atlantic, Pacific, and Arctic Canadian species of polychaetes. Methods are described by EPA for conducting 28-d bioaccumulation tests with a variety of mollusks (i.e., Macoma spp.) and polychaetes (i.e., Nereis spp.). Slight inconsistencies in methods between freshwater and estuarine/marine testing or between EC and EPA testing include: (1) static vs. flow-through conditions, (2) sieving of sediment, (3) types and quantity of food, (4) age of test organisms, or (4) duration of the test and required endpoints. Additional research is in progress to: (1) develop chronic toxicity tests with amphipods and midges measuring survival, growth, or reproduction, (2) develop whole-sediment toxicity identification evaluation (TIE) procedures, (3) refine sediment spiking procedures, and (4) field-validate laboratory tests.

  18. Stasis and flux among Saturniidae and Sphingidae on Massachusetts' (USA) offshore islands and the possible role of Compsilura concinnata (Meigen) as an agent of mainland New England moth declines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The lepidopteran fauna of Massachusetts’ offshore islands (USA), particularly Martha’s Vineyard and Nantucket, has been well-characterized, and comprises intact assemblages of disjunct, regionally rare, habitat-specialized, and otherwise threatened species that have declined elsewhere in New England...

  19. Toxicity and bioaccumulation of 2,3,7,8-tetrachlorodibenzo-p-dioxin in long-term tests with the freshwater benthic invertebrates Chironomus tentans and Lumbriculus variegatus

    SciTech Connect

    West, C.W.; Ankley, G.T.; Nichols, J.W.; Elonen, G.E.; Nessa, D.E.

    1997-06-01

    Two species of freshwater benthic invertebrates, Chronomus tentans and Lumbriculus variegatus, were exposed to three dietary concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and toxicity and bioaccumulation were determined. No toxic effects were observed in full life cycle tests with either species at tissue residue concentrations up to 9,533 ng TCDD/g lipid. The observed lack of sensitivity of the two species to TCDD was consistent with a presumed absence of the aryl hydrocarbon receptor in aquatic invertebrates. Predictions of lipid-normalized tissue concentrations were made based on lipid-normalized TCDD concentrations in the food and were within 15% of targeted concentrations in both species. Depuration studies indicated that TCDD elimination followed first-order kinetics, with elimination rate constants of 0.0014 to 0.0022 h{sup {minus}1} for L. variegatus and 0.0070 to 0.0099 h{sup {minus}1} for C. tentans. Half-lives ranged from 315 to 495 h in L. variegatus and from 70 to 99 h in C. tentans. The ability of invertebrates to accumulate relatively high concentrations of TCDD in the absence of toxic effects may be relevant to the transfer of contaminants through aquatic food webs to potentially sensitive vertebrate species.

  20. High quality draft genome sequence of Brachymonas chironomi AIMA4T (DSM 19884T) isolated from a Chironomus sp. egg mass

    PubMed Central

    2015-01-01

    Brachymonas chironomi strain AIMA4T (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 AIMA4T 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. PMID:26203340

  1. High quality draft genome sequence of Brachymonas chironomi AIMA4T (DSM 19884T) isolated from a Chironomus sp. egg mass

    DOE PAGESBeta

    Laviad, Sivan; Lapidus, Alla; Han, James; Haynes, Matthew; Reddy, TBK; Huntemann, Marcel; Pati, Amrita; Ivanova, Natalia N.; Mavromatis, Konstantinos; Lang, Elke; et al

    2015-05-27

    Brachymonas chironomi strain AIMA4T (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 AIMA4T in the genus Brachymonas. Here we describe the features of this organism, together with the complete genome sequence and annotation. We find the DNA GC content is 63.5%. The chromosome length is 2,509,395 bp. It encodes 2,382 proteins andmore » 68 RNA genes. Brachymonas chironomi genome is part of the Genomic Encyclopedia of Type Strains, Phase I: the one thousand microbial genomes (KMG) project.« less

  2. High quality draft genome sequence of Leucobacter chironomi strain MM2LBT (DSM 19883T) isolated from a Chironomus sp. egg mass

    SciTech Connect

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

    2015-05-08

    Leucobacter chironomi strain MM2LBT (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 MM2LBT 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 MM2LBT 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. We find that 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.

  3. High quality draft genome sequence of Brachymonas chironomi AIMA4T (DSM 19884T) isolated from a Chironomus sp. egg mass

    SciTech Connect

    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

    2015-05-27

    Brachymonas chironomi strain AIMA4T (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 AIMA4T in the genus Brachymonas. Here we describe the features of this organism, together with the complete genome sequence and annotation. We find 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. High quality draft genome sequence of Leucobacter chironomi strain MM2LBT (DSM 19883T) isolated from a Chironomus sp. egg mass

    DOE PAGESBeta

    Laviad, Sivan; Lapidus, Alla; Copeland, Alex; Reddy, T. B. K.; Huntemann, Marcel; Pati, Amrita; Ivanova, Natalia N.; Markowitz, Victor M.; Pukall, Rüdiger; Klenk, Hans-Peter; et al

    2015-05-08

    Leucobacter chironomi strain MM2LBT (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 MM2LBT 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 MM2LBT 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. We find thatmore » 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.« less

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

    NASA Astrophysics Data System (ADS)

    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.

  6. High quality draft genome sequence of Leucobacter chironomi strain MM2LBT (DSM 19883T) isolated from a Chironomus sp. egg mass

    PubMed Central

    2015-01-01

    Leucobacter chironomi strain MM2LBT (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 MM2LBT 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 MM2LBT 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. PMID:26203333

  7. An Asiatic Chironomid in Brazil: morphology, DNA barcode and bionomics

    PubMed Central

    Amora, Gizelle; Hamada, Neusa; Fusari, Lívia Maria; Andrade-Souza, Vanderly

    2015-01-01

    Abstract In most freshwater ecosystems, aquatic insects are dominant in terms of diversity; however, there is a disproportionately low number of records of alien species when compared to other freshwater organisms. The Chironomidae is one aquatic insect family that includes some examples of alien species around the world. During a study on aquatic insects in Amazonas state (Brazil), we collected specimens of Chironomidae that are similar, at the morphological level, to Chironomus kiiensis Tokunaga and Chironomus striatipennis Kieffer, both with distributions restricted to Asia. The objectives of this study were to provide morphological information on this Chironomus population, to investigate its identity using DNA barcoding and, to provide bionomic information about this species. Chironomus DNA barcode data were obtained from GenBank and Barcode of Life Data Systems (BOLD) and, together with our data, were analyzed using the neighbor-joining method with 1000 bootstrap replicates and the genetic distances were estimated using the Kimura-2-parameter. At the morphological level, the Brazilian population cannot be distinguished either from Chironomus striatipennis or Chironomus kiiensis, configuring a species complex but, at the molecular level our studied population is placed in a clade together with Chironomus striatipennis, from South Korea. Bionomic characteristics of the Brazilian Chironomus population differ from the ones of Chironomus kiiensis from Japan, the only species in this species complex with bionomic information available. The Brazilian Chironomus population has a smaller size, the double of the number of eggs and inhabits oligotrophic water, in artificial container. In the molecular analysis, populations of Chironomus striatipennis and Chironomus kiiensis are placed in a clade, formed by two groups: Group A (which includes populations from both named species, from different Asiatic regions and our Brazilian population) and Group B (with populations of

  8. Muscle attachment site (MAS) patterns for species determination in five species of Sarcophaga (Diptera: Sarcophagidae).

    PubMed

    Niederegger, Senta; Szpila, Krzysztof; Mall, Gita

    2016-01-01

    To further establish species determination using the muscle attachment site (MAS) pattern method, third instar larvae of five forensically important species of Sarcophaga Meigen were investigated: Sarcophaga argyrostoma (Robineau-Desvoidy), Sarcophaga caerulescens Zetterstedt, Sarcophaga melanura Meigen, Sarcophaga albiceps Meigen and Sarcophaga similis Meade. As in the previously investigated Calliphoridae, patterns were found to be species specific. The main feature of the Sarcophaga patterns is the divided central horizontal row of segment four. A genus pattern was established to be used as base for comparison in further species determination. PMID:26391172

  9. New data on the genus Platypalpus (Diptera: Hybotidae) from the Caucasus with description of seven new species.

    PubMed

    Kustov, Semen; Shamshev, Igor; Grootaert, Patrick

    2015-01-01

    Currently, 47 species of the genus Platypalpus are known from the Caucasus including fourteen species recorded herein for the first time: P. albicornis (Zetterstedt, 1842), P. baldensis (Strobl, 1899), P. caroli Grootaert, 1987, P. ciliaris (Fallén, 1816), P. clarandus (Collin, 1926), P. collini (Chvála, 1966), P. cothurnatus Macquart, 1827, P. infectus (Collin, 1926), P. longicornis (Meigen, 1822), P. luteicornis (Meigen, 1838), P. nigrinus (Meigen, 1822), P. pseudociliaris (Strobl, 1910), P. ruficornis (von Roser, 1840), and P. smirnovi Kovalev, 1978. In addition, seven new species are described: P. akhunensis sp. nov. (Russia: Krasnodarskiy Territory), P. kintrishiensis sp. nov. (Georgia), P. lantsovi sp. nov. (Georgia), P. pseudosilvahumidus sp. nov. (Russia: Krasnodarskiy Territory, Karachay-Cherkessia), P. sinevi sp. nov. (Russia: Karachay-Cherkessia), P. subcaucasicus sp. nov. (Russia: Krasnodarskiy Territory, Dagestan) and P. teberdaensis sp. nov. (Russia: Karachay-Cherkessia). A key to species of Platypalpus from the Caucasus is presented for the first time. PMID:26249871

  10. Rhipidia crane flies (Diptera: Limoniidae) from Korea.

    PubMed

    Podenas, Sigitas; Byun, Hye-Woo; Kim, Sam-Kyu

    2016-01-01

    Korean species of the crane fly genus Rhipidia Meigen, 1818 (Diptera: Limoniidae), are taxonomically revised. Rhipidia (Rhipidia) serena, new species, is described and figured. Rhipidia (R.) longa Zhang, Li, Yang, 2014, R. (R.) maculata Meigen, 1818 and R. (R.) sejuga Zhang, Li, Yang, 2014 are recorded for the first time in Korea. Previously known species, Rhipidia (R.) septentrionis Alexander, 1913 is redescribed and illustrated. Identification key for all Korean Rhipidia species is given. Most antennae, wings, male and female terminalia of all species are illustrated for the first time. PMID:27395731

  11. ACUTE AND CHRONIC TOXICITY OF CHLORDANE TO FISH AND INVERTEBRATES

    EPA Science Inventory

    The acute and chronic toxicity of technical chlordane to bluegill (Lepomis macrochirus), fathead minnow (Pimephales promelas), brook trout (Salvelinus fontinalis), Daphnia magna, Hyallela azteca, and Chironomus No. 51 were determined with flow-through conditions. The purpose was ...

  12. IN SITU BIOASSAY CHAMBER FOR ASSESSMENT OF SEDIMENT TOXICITY AND BIOACCUMULATION USING BENTHIC INVERTEBRATES

    EPA Science Inventory

    In this study, we describe the construction of a simple, inexpensive bioassay chamber for testing sediment toxicity (survival and growth) and bioaccumulation under field conditions using the midge Chironomus tentans and the oligochaete Lumbriculus variegatus. The test chamber is ...

  13. CHRONIC EFFECTS OF THE HERBICIDE DIURON ON FRESHWATER CLADOCERANS,AMPHIPODS,MIDGES,MINNOWS,WORMS, AND SNAILS

    EPA Science Inventory

    The chronic effects of the herbicide diuron on survival and reproduction of Daphnia pulex, and survival and growth of the amphipod Hyalella azteca, the midge Chironomus tentans, juvenile and embro/larval fathead minnows, Pimephales promelas, annelid worms, Lumbriculus variegatus,...

  14. AN ASSESSMENT OF THE TOXICITY OF PHTHALATE ESTERS TO FRESHWATER BENTHOS. 1. AQUEOUS EXPOSURES

    EPA Science Inventory

    Tests were performed with the freshwater invertebrates, Hyalella azteca, Chironomus tentans, and Lumbriculus variegatus to determine the acute toxicity of six phthalate esters, including dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), butylbenzyl ph...

  15. Comparisons of Sediment Test Volumes for Freshwater Solid Phase Sediment Toxicity Tests

    EPA Science Inventory

    Laboratory tests with benthic macroinvertebrates are commonly used to assess the potential toxicity of contaminated sediments, and detailed standard test procedures have been developed for various species. For freshwater, two benthic organisms, Hyalella azteca and Chironomus dil...

  16. Forage Quality of Irrigated Pasture Species as Affected by Irrigation Rate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The USDA-ARS Forage and Range Research Lab has initiated a breeding program to improve tall fescue (Festuca arundinaceae Screb.), orchardgrass (Dactylis glomerata L.) and meadow bromegrass (Bromus riparius Rehm.) in semiarid pasturelands, which are characterized by extreme temperature fluctuations a...

  17. Response of Lucilia sericata (Diptera: Calliphoridae) to Screwworm Oviposition Attractant

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The sheep blow fly, Lucilia sericata Meigen (Diptera: Calliphoridae), causes sheep myiasis in various parts of the world. The females are attracted to sheep, following various olfactory cues emanating from the sheep's body, and oviposit on suitable substrates on sheep ultimately causing myiasis. Ear...

  18. Cryopreservation of embryos of Lucilia sericata (Diptera: Calliphoridae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Embryos of Lucilia (Phaenicia) sericata (Meigen) (Diptera: Calliphoridae), the green blowfly, were successfully cryopreserved by vitrification in liquid nitrogen and stored for 8 yr. Embryos incubated at 19 deg. C for 17 h after oviposition were found to be the most appropriate stage to cryopreserve...

  19. A new genus and two new species of Oriental Oxycerini (Diptera, Stratiomyidae, Stratiomyinae) with notes on new generic synonyms in two other stratiomyine genera

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oxycerina gen.n. of the Oriental Stratiomyinae including two new species, O. merzi sp.n. and O. sabaha sp.n., is described and compared with related genera of Stratiomyinae and Raphiocerinae. The monotypic genus Scapanocnema Enderlein, 1914 is considered to be a synonym of Odontomyia Meigen, 1803 a...

  20. The first confirmed record of the leafminer Phytomyza rufipes (Diptera: Agromyzidae) in the United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phytomyza rufipes Meigen (Diptera: Agromyzidae) is a leafmining pest of Brassicaceae in Europe and other regions of the world. Once reported from Oregon in the United States, this record has since been found to be a misidentification. Here we report P. rufipes for the first time from California. We ...

  1. Potential transmission of West Nile virus in the British Isles: an ecological review of candidate mosquito bridge vectors.

    PubMed

    Medlock, J M; Snow, K R; Leach, S

    2005-03-01

    West Nile virus (WNV) transmitted by mosquitoes (Diptera: Culicidae) infects various vertebrates, being pathogenic for birds, horses and humans. After its discovery in tropical Africa, sporadic outbreaks of WNV occurred during recent decades in Eurasia, but not the British Isles. WNV reached New York in 1999 and spread to California by 2003, causing widespread outbreaks of West Nile encephalitis across North America, transmitted by many species of mosquitoes, mainly Culex spp. The periodic reappearance of WNV in parts of continental Europe (from southern France to Romania) gives rise to concern over the possibility of WNV invading the British Isles. The British Isles have about 30 endemic mosquito species, several with seasonal abundance and other eco-behavioural characteristics predisposing them to serve as potential WNV bridge vectors from birds to humans. These include: the predominantly ornithophilic Culex pipiens L. and its anthropophilic biotype molestus Forskal; tree-hole adapted Anopheles plumbeus Stephens; saltmarsh-adapted Ochlerotatus caspius Pallas, Oc. detritus Haliday and Oc. dorsalis (Meigen); Coquillettidia richiardii Ficalbi, Culiseta annulata Schrank and Cs. morsitans (Theobald) from vegetated freshwater pools; Aedes cinereus Meigen, Oc. cantans Meigen and Oc. punctor Kirby from seasonal woodland pools. Those underlined have been found carrying WNV in other countries (12 species), including the rarer British species Aedes vexans (Meigen), Culex europaeus Ramos et al., Cx. modestus Ficalbi and Oc. sticticus (Meigen) as well as the Anopheles maculipennis Meigen complex (mainly An. atroparvus van Thiel and An. messeae Falleroni in Britain). Those implicated as key vectors of WNV in Europe are printed bold (four species). So far there is no proof of any arbovirus transmission by mosquitoes in the British Isles, although antibodies to Sindbis, Tahyna, Usutu and West Nile viruses have been detected in British birds. Neighbouring European countries have

  2. Life cycle and production of chironomidae (diptera) in Biandantang, a typical macrophytic lake (Hubei, China)

    NASA Astrophysics Data System (ADS)

    Yun-Jun, Yan

    2000-09-01

    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. Instarfrequency 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.

  3. Preliminary list of horse flies (Diptera, Tabanidae) of Serbia

    PubMed Central

    Krčmar, Stjepan

    2011-01-01

    Abstract Thirty six species of horse flies (Tabanidae) were previously known from Serbia (Europe). The present faunistic study of horse flies (Tabanidae) has resulted in the recording of the 4 new species Atylotus fulvus (Meigen, 1804); Tabanus miki Brauer in Brauer and Bergenstamm, 1880; Tabanus unifasciatus Loew, 1858; and Heptatoma pellucens (Fabricius, 1776), in the fauna of Serbia. The genus Heptatoma Meigen, 1803 is cited for the first time in the fauna of Serbia. 40 species are currently known from Serbia, belonging to nine genera. The fauna can be considered relatively poorly studied. Most of the species belong to the Boreal-Eurasian type of fauna 23, followed by the South European group with 8 species, the Mediterranean group with 6 species, European group with 2 species and Central European group with 1 species. PMID:21998507

  4. Aedes mosquito species in western Saudi Arabia.

    PubMed

    Alikhan, Masroor; Al Ghamdi, Khalid; Mahyoub, Jazem Abdullah

    2014-01-01

    The Aedes Meigen (Diptera: Culicidae) mosquito species populations in the western region of Saudi Arabia, especially in and around Jeddah, are increasing, therefore increasing susceptibility of humans to the dengue virus. An extensive survey was carried out for one year, and four species were identified with the help of different pictorial keys available. The identification was based on morphological characteristics of adult female Aedes mosquitoes. PMID:25373216

  5. Metalimnobia crane flies (Diptera: Limoniidae) from Korea.

    PubMed

    Podenas, Sigitas; Byun, Hye-Woo

    2016-01-01

    Korean species of the crane fly genus Metalimnobia Matsumura, 1911 (Diptera: Limoniidae), are taxonomically revised. Metalimnobia (Metalimnobia) channpayna new species, is described and figured, M. (M.) bifasciata (Schrank, 1781), M. (M.) quadrinotata (Meigen, 1818) and M. (M.) zetterstedti (Tjeder, 1968) are listed for the first time in Korea, new information for previously known species, M. (M.) quadrimaculata (Linnaeus, 1760) is added. Identification key for all Korean Metalimnobia species is given. Wings, male and female terminalia are illustrated for all species. PMID:27395675

  6. New records of moth flies (Diptera: Psychodidae) from Croatia, with the description of Berdeniella keroveci sp.nov.

    PubMed

    Kvifte, Gunnar Mikalsen; Ivković, Marija; Klarić, Aleksandra

    2013-01-01

    Berdeniella keroveci sp. nov. is described based on males collected in Croatia. Current knowledge of the psychodid fauna of Croatia is reviewed and new records of 16 species are presented. Short taxonomic notes on Pericoma pseudocalcilega Krek, 1972, Pneumia balkanica (Krek, 1990), Pneumia mutua (Eaton, 1893), Clogmia albipunctata (Williston, 1893) and Lepiseodina tristis (Meigen, 1810) are given. In total, 33 species of Psychodidae are known to occur in Croatia. PMID:25112736

  7. ACUTE TOXICITY OF AQUEOUS AND CHIRNONOMUS DECORUS

    EPA Science Inventory

    Fourth instar larvae of the midge, Chironomus decorus, were exposed copper in water and copper in food and substrate (bound forms). opper present in aqueous forms was more toxic than when it was present in bound forms. he relationship between copper in water and copper in midges ...

  8. Bioavailability of fluoranthene in freshwater sediment toxicity tests

    SciTech Connect

    Suedel, B.C.; Rodgers, J.H. Jr. ); Clifford, P.A. )

    1993-01-01

    To examine equilibrium-partitioning model predictions of interstitial water concentrations of fluoranthene as part of the equilibrium-partitioning (EqP) approach to sediment quality criteria development, the bioavailability (toxicity) of fluoranthene-amended sediment to Hyalella azteca, Daphnia magna, and Chironomus tentans was determined. Fluoranthene was added to three freshwater sediments with similar organic carbon content. Predicted interstitial water concentrations from the equilibrium-partitioning model were similar to measured interstitial water concentrations for WRFS and TR sediment, but the model underpredicted measured values for LF sediment by a factor of two. EC50s for Daphnia magna, Hyalella azteca, and Chironomus tentans in interstitial water were a factor of two to five greater for LF than for WRFS and TR sediments. Factors other than organic carbon content of sediments probably contributed to the variability in bioavailability of fluoranthene. Based on 10-d sediment toxicity tests with Hylella azteca, Daphnia magna, and Chironomus tentans, organic carbon-normalized sediment concentrations were better predictors of toxicity than interstitial water and bulk sediment fluoranthene concentrations. In 10-d aqueous-phase tests with fluoranthene, Chironomus tentans and Hyalella azteca were twice as sensitive as Daphnia magna.

  9. Development of formulated reference sediments for freshwater and estuarine sediment testing

    SciTech Connect

    Suedel, B.C.; Rodgers, J.H. Jr. . Dept. of Biology)

    1994-07-01

    Sediments collected at various field locations may have chemical and physical constituents that influence test results and may contain organisms that cannot be readily removed. Thus, reference sediments are needed that can be formulated to match diverse freshwater and estuarine sediments encountered in comprehensive testing programs. This research evaluated formulated reference sediments in terms of (a) their ability to match field-collected sediments both chemically and physically; (b) their suitability as habitant (survival and reproduction) for typical invertebrate toxicity testing species (Hyalella azteca Saussure, Chironomus tentans Fabricius, and Daphnia magna Straus) during chronic exposures; and (c) their suitability as a substrate for Hyalella azteca, Chironomus tentans, Daphnia magna, Ceriodaphnia dubia Richard, and Pimephales promelas Rafinesque in 14-d whole-sediment exposures. Formulated reference sediments were prepared to match naturally occurring sediments with respect to particle-size distribution, organic matter, organic carbon, pH, solids, CEC, but not redox potential. After preparation, a conditioning period of at least 7 d was required for pH stabilization of formulated reference sediments. In culture experiments, formulated reference sediments was suitable for Hyalella azteca, Chironomus tentans, and Daphnia magna survival and reproduction for 56,40, and 28 d, respectively. Hyalella azteca, Chironomus tentans, Daphnia magna, Ceriodaphnia dubia and Pimephales promelas survival was [>=] 88% in 14-d exposures to formulated reference sediment. Formulated reference sediments may reduce some unexplained physical, chemical, or biological toxicity'' of field-collected sediments (e.g., organic matter) that may influence toxicity testing results.

  10. AN ASSESSMENT OF PHTHALATE ESTER TOXICITY TO FRESHWATER BENTHOS: 2. SEDIMENT EXPOSURES

    EPA Science Inventory

    Seven phthalate esters were evaluated for their stability and 10-d acute toxicity to the freshwater invertebrates Hyalella azteca and Chironomus tentans following incorporation into sediment. The chemicals were diethyl (DEP), di-n-butyl (DBP), di-n-hyxyl (DHP), di-[2-ethylhexyl] ...

  11. Diversity and ecology survey of mosquitoes potential vectors in Belgian equestrian farms: A threat prevention of mosquito-borne equine arboviruses.

    PubMed

    Boukraa, Slimane; de La Grandiere, Maria A; Bawin, Thomas; Raharimalala, Fara N; Zimmer, Jean-Yves; Haubruge, Eric; Thiry, Etienne; Francis, Frédéric

    2016-02-01

    Emergence of West Nile Virus was recently recorded in several European countries, which can lead to severe health problems in horse populations. Europe is also at risk of introduction of mosquito-borne equine alphavirus from Americas. Prevention of these arboviruses requires a clear understanding of transmission cycles, especially their vectors. To characterize mosquito fauna, their ecology and identify potential vectors of equine arboviruses in Belgium, entomological surveys of six equestrian farms located in the Wolloon Region were conducted during 2011-2012. The harvest of mosquitoes was based on larval sampling (272 samples from 111 breeding sites) and monthly adults trapping (CO2-baited traps, Mosquito Magnet Liberty Plus). Among 51,493 larvae and 319 adult mosquitoes collected, morphological identification showed the presence of 11 species: Anopheles claviger (Meigen), An. maculipennis s.l. (Meigen), An. plumbeus (Stephens), Culex hortensis (Ficalbi), Cx. territans (Walker), Cx. pipiens s.l. L., Cx. torrentium (Martini), Coquillettidia richiardii (Ficalbi), Culiseta annulata (Schrank), Aedes cantans (Meigen), Ae. geniculatus (Olivier). Molecular identification of Cx. pipiens species complex allowed the detection of three molecular forms, Pipiens (92.3%), Molestus (4.6%) and Hybrid (3.1%). Larvae of Cx. pipiens sl and Cx. torrentium were omnipresent and the most abundant species. Water troughs, ponds and slurry (liquid manure) were the most favorable breeding sites of mosquito larvae. Based upon behavior and ecology of the identified mosquito species, Studied Belgian equestrian farms seem to provide a suitable environment and breeding sites for the proliferation of potential vectors of arboviruses and those being a real nuisance problem for horses and neighboring inhabitants. PMID:26775817

  12. New Mycomya species from the Himalayas (Diptera, Mycetophilidae): 2. Subgenera Calomycomya, Cymomya, Neomycomya and Pavomya subg. n.

    PubMed

    Väisänen, Rauno

    2013-01-01

    Myconya Rondani specimens from the Himalayas, mostly Nepal and Myanmar, are revised. Pavoniya subg. n. is described. Altogether nine species from the subgenera Calomycoinya, Cymnoniya, Neoinycoinya and Pavomya subg. n. are recorded from the Himalayas and Indian subcontinent. The paper includes a key to the subgenera of Myconiya and the Himalayan species of Mycomya of the four subgenera. The following eight new species are described: M. aonyx, M. cuon, M. kainbaitiensis, M. marmota, M. paguina, M. panthera, M. ratufa and M. wah. Mycomyafiubriata (Meigen) is recorded from Myanmar. PMID:26217851

  13. New Black Fungus Gnats (Diptera, Sciaridae) of North America. Part II. Genus Bradysiopsis Tuomikoski, 1960.

    PubMed

    Mohrig, Werner; Kauschke, Ellen

    2016-01-01

    The genus Bradysiopsis Tuomikoski is new for the sciarid fauna of North America. It includes 6 species. Four of them are new for science. These are Bradysiopsis postvittigera sp. n., Br. praevittata sp. n., Br. praevittigera sp. n. and Br. subvittigera sp. n.. Two species, Br. vittata (Meigen, 1830) and Br. vittigera (Zetterstedt, 1851), are distributed in the Holarctic but new for North America. In this paper species are described, illustrated by figures and a key for classification as well as distribution data are given. PMID:27615840

  14. The influence of host number on the attraction of biting midges, Culicoides spp., to light traps.

    PubMed

    Garcia-Saenz, A; McCarter, P; Baylis, M

    2011-03-01

    A preliminary study was undertaken to investigate how the number of sheep below a light-suction trap affects the number of female Culicoides obsoletus Meigen (Diptera: Ceratopogonidae) caught. As the number of sheep increased from zero to three, the number of midges caught increased, but there appeared to be no further increase when six sheep were used. The lack of increase between three and six sheep is attributable to different activity rates on certain nights, perhaps in response to weather, and suggests, therefore, that catches in light traps increase linearly with sheep numbers, at least for small host numbers. PMID:20704653

  15. FAMILY ANISOPODIDAE.

    PubMed

    Amorim, Dalton De Souza; Falaschi, Rafaela Lopes; Oliveira, Sarah Siqueira

    2016-01-01

    This considerably small family is poorly known in Colombia, with only two species reported for the genus Sylvicola Harris (1776) so far. We synonymize Neomesochria Amorim & Tozoni (1994) to Mycetobia Meigen (1818), hence transferring the Dominican amber species Neomesochria antillea (Grimaldi 1991) and N. cryptambra (Grimaldi 1991), and the recent Neotropical species N. limanda (Stone 1966) and N. stonei (Lane & d'Andretta 1958) back to the genus Mycetobia. This paper provides new records for Mycetobia and Olbiogaster Osten-Sacken (1886) for Colombia. PMID:27395252

  16. New species and records of Metriocnemus van der Wulp s. str. from China (Diptera, Chironomidae)

    PubMed Central

    Li, Xing; Wang, Xin-hua

    2014-01-01

    Abstract The Chinese species of Metriocnemus van der Wulp s. str., 1874 is reviewed. M. (M.) calcaneum sp. n. is described and illustrated as adult male. M. (M.) albolineatus (Meigen) is recorded from China for the first time. M. (M.) beringensis (Cranston & Oliver), M. (M.) bilobatus Makarchenko & Makarchenko, M. (M.) caudigus Sæther, M. (M.) intergerivus Sæther, M. (M.) tamaokui Sasa and M. (M.) tristellus Edwards are recorded from the Oriental Region for the first time. A key to the males of 17 Chinese Metriocnemus (Metriocnemus) species is given. PMID:24693220

  17. Presence in the Balearic Islands (Spain) of the midges Culicoides imicola and Culicoides obsoletus group.

    PubMed

    Miranda, M A; Borràs, D; Rincón, C; Alemany, A

    2003-03-01

    An outbreak of the livestock viral disease bluetongue (BT) was detected during September and October 2000 in the Balearic Islands, Spain. Due to the lack of information about the species of Culicoides (Diptera: Ceratopogonidae) reported in the affected area, six farms in Majorca, four in Minorca and one in Ibiza were selected to carry out surveillance of Culicoides adults using light traps. Here, for the first time, we report the presence in the Balearic Islands of Culicoides imicola Keiffer, the main vector of BT, and the Culicoides obsoletus Meigen group. PMID:12680925

  18. An Asiatic Chironomid in Brazil: morphology, DNA barcode and bionomics.

    PubMed

    Amora, Gizelle; Hamada, Neusa; Fusari, Lívia Maria; Andrade-Souza, Vanderly

    2015-01-01

    In most freshwater ecosystems, aquatic insects are dominant in terms of diversity; however, there is a disproportionately low number of records of alien species when compared to other freshwater organisms. The Chironomidae is one aquatic insect family that includes some examples of alien species around the world. During a study on aquatic insects in Amazonas state (Brazil), we collected specimens of Chironomidae that are similar, at the morphological level, to Chironomuskiiensis Tokunaga and Chironomusstriatipennis Kieffer, both with distributions restricted to Asia. The objectives of this study were to provide morphological information on this Chironomus population, to investigate its identity using DNA barcoding and, to provide bionomic information about this species. Chironomus DNA barcode data were obtained from GenBank and Barcode of Life Data Systems (BOLD) and, together with our data, were analyzed using the neighbor-joining method with 1000 bootstrap replicates and the genetic distances were estimated using the Kimura-2-parameter. At the morphological level, the Brazilian population cannot be distinguished either from Chironomusstriatipennis or Chironomuskiiensis, configuring a species complex but, at the molecular level our studied population is placed in a clade together with Chironomusstriatipennis, from South Korea. Bionomic characteristics of the Brazilian Chironomus population differ from the ones of Chironomuskiiensis from Japan, the only species in this species complex with bionomic information available. The Brazilian Chironomus population has a smaller size, the double of the number of eggs and inhabits oligotrophic water, in artificial container. In the molecular analysis, populations of Chironomusstriatipennis and Chironomuskiiensis are placed in a clade, formed by two groups: Group A (which includes populations from both named species, from different Asiatic regions and our Brazilian population) and Group B (with populations of

  19. Do aquatic insects avoid cadmium-contaminated sediments?

    SciTech Connect

    Hare, L.; Shooner, F.

    1995-06-01

    The long-term colonization of profundal lake sediments having a range of spiked cadmium (Cd) concentrations (0.007 to 2.7 {mu}mol/g dry wt.) was measured in the field. Population densities of two of the most abundant colonizing insects (the chironomids Procladius [Holotanypus] sp., and Sergentia coracina) were unrelated to the Cd gradient, even though both taxa accumulated Cd in direct relation to its concentration in sediment Cd gradient Cd gradient. Cadmium concentrations in Chironomus (salinarius gp.) sp. larvae also responded positively to the sediment Cd gradient and ranged from 0.2 to 50 {mu}g/g. In contrast with the two other taxa, the abundance of Chironomus (salinarius gp.) sp. was the result of a behavioral or a toxic response, larvae of the three chironomid taxa were given a choice between field-control and Cd-spiked sediments in the laboratory. None of the taxa avoided the Cd-spiked sediments, suggesting that the lower abundance of Chironomus (salinarius gp.) sp. at high Cd concentrations in the field was due to Cd toxicity and not to avoidance of the Cd-rich sediments.

  20. Comparing the impacts of sediment-bound bifenthrin on aquatic macroinvertebrates in laboratory bioassays and field microcosms.

    PubMed

    Boyle, Rhianna L; Hoak, Molly N; Pettigrove, Vincent J; Hoffmann, Ary A; Long, Sara M

    2016-11-01

    We conducted two laboratory bioassays and two field microcosm exposures with bifenthrin (a synthetic pyrethroid) in order to evaluate the capacity of single-species laboratory bioassays to predict lethal and sublethal impacts on aquatic invertebrates in microcosms. For the laboratory species, Chironomus tepperi, larval survival was reduced by 24% at 53.66µg/g OC, while adult emergence was reduced at concentrations of 33.33µg/g OC and higher, with a 61% decrease at 77.78µg/g OC and no emergence at 126.67µg/g OC. The abundance of several other microcosm taxa was reduced in the microcosms at a similar concentration range (33.33µg/g OC and above), however there was no impact on the abundance of the congeneric species, Chironomus oppositus. The differences in impacts between test systems were potentially due to both differing species sensitivity and the interaction of ambient temperature with bifenthrin toxicity. Bifenthrin also was associated with early emergence of Chironomus sp. in both test systems, at concentrations of 10µg/g OC and higher (laboratory) and 43.90µg/g OC (microcosm), and with a significant decrease in the proportion of C. oppositus males in a microcosm. These findings indicate that while laboratory bioassays accurately predict many impacts in the field, there are some limitations to the predictive capacity of these tests. PMID:27544659

  1. Developing acute-to-chronic toxicity ratios for lead, cadmium, and zinc using rainbow trout, a mayfly, and a midge

    USGS Publications Warehouse

    Mebane, C.A.; Hennessy, D.P.; Dillon, F.S.

    2008-01-01

    In order to estimate acute-to-chronic toxicity ratios (ACRs) relevant to a coldwater stream community, we exposed rainbow trout (Oncorhynchus mykiss) to cadmium (Cd), lead (Pb), and zinc (Zn) in 96-h acute and 60+ day early-life stage (ELS) exposures. We also tested the acute and sublethal responses of a mayfly (Baetis tricaudatus) and a midge (Chironomus dilutus, formerly C. tentans) with Pb. We examine the statistical interpretation of test endpoints and the acute-to-chronic ratio concept. Increasing the number of control replicates by 2 to 3x decreased the minimum detectable differences by almost half. Pb ACR estimates mostly increased with increasing acute resistance of the organisms (rainbow trout ACRs Chironomus). The choice of test endpoint and statistical analysis influenced ACR estimates by up to a factor of four. When calculated using the geometric means of the no- and lowest-observed effect concentrations, ACRs with rainbow trout and Cd were 0.6 and 0.95; Zn about 1.0; and for Pb 3.3 and 11. The comparable Pb ACRs for the mayfly and Chironomus were 5.2 and 51 respectively. Our rainbow trout ACRs with Pb were about 5-20x lower than earlier reports with salmonids. We suggest discounting previous ACR results that used larger and older fish in their acute tests. ?? 2007 GovernmentEmployee: U.S. Geological Survey.

  2. Emergence of Culicoides obsoletus group species from farm-associated habitats in Germany.

    PubMed

    Steinke, S; Lühken, R; Balczun, C; Kiel, E

    2016-06-01

    Biting midges of the genus Culicoides (Diptera: Ceratopogonidae) may transmit several arboviruses to ruminant livestock. The species of the Obsoletus group are considered to be among the most important vectors of bluetongue virus (BTV) in northern Europe. As agricultural environments offer suitable habitats for the development of their immature stages, the emergence of adult Culicoides from potential breeding sites was investigated at 20 cattle farms throughout Germany in 2012 and 2013. In analyses of species-specific habitat preferences and relationships between Culicoides abundance in breeding substrates and their physicochemical characteristics, dungheaps emerged as the most important substrate for the development of Culicoides obsoletus sensu stricto (s.s.) (Meigen), whereas Culicoides chiopterus (Meigen) and Culicoides dewulfi Goetghebuer were generally restricted to cowpats. A decreasing pH value was associated with a higher abundance or a higher probability of observing these three species. Furthermore, the abundance of C. obsoletus s.s. was positively related to increasing moisture. Dungheaps were very productive breeding sites for this species and are therefore suggested as a target for potential control measures. PMID:26744290

  3. Does covering of farm-associated Culicoides larval habitat reduce adult populations in the United Kingdom?☆

    PubMed Central

    Harrup, L.E.; Gubbins, S.; Barber, J.; Denison, E.; Mellor, P.S.; Purse, B.V.; Carpenter, S.

    2014-01-01

    Culicoides biting midges (Diptera: Ceratopogonidae) are the biological vectors of a range of internationally important arboviruses of livestock, including bluetongue virus (BTV) and the recently emerging Schmallenberg virus (SBV). Culicoides species in the subgenus Avaritia (in the UK: Culicoides obsoletus Meigen, Culicoides scoticus Downes & Kettle, Culicoides dewulfi Goetghebuer and Culicoides chiopterus Meigen) have been implicated in BTV transmission in northern Europe and to a varying degree utilise cattle dung as a larval development substrate. The collection of cattle dung into heaps on farms provides a localised source of Culicoides emergence in close proximity to livestock. This study assesses the impact of covering dung heaps prior to the onset of adult Culicoides activity with the aim of reducing recruitment to the local adult populations at four livestock farms in England. Light suction trap catches of adult Culicoides from these farms were compared with those from four untreated control farms from a wide geographic range across the UK. It was demonstrated that implementing control of emergence from dung heaps did not have a significant impact upon the local adult subgenus Avaritia abundance at the treated farm holdings and that the onset of Culicoides activity was similarly unaffected. Use of this method in isolation is unlikely to have an effect in reducing the risk of BTV and SBV transmission. The implications of these results for control of farm-associated Culicoides in Europe are discussed. PMID:24472769

  4. Notes on the first instar larvae of Ctenophora and Nephrotoma (Diptera, Tipulidae).

    PubMed

    Podeniene, Virginija; Naseviciene, Nijole; Podenas, Sigitas

    2014-01-01

    1830 egg-larvae of 7 species belonging to long palped crane flies (Tipulidae): Ctenophora guttata Meigen, Nephrotoma pratensis Linnaeus, N. dorsalis Fabricius, N. scurra Meigen, N. flavescens Linnaeus, N. submaculosa Edwards and N. crocata Linnaeus were obtained from 22 females captured in Lithuania in 2011-2012. It took from five days to more than three weeks for eggs to hatch. Crane flies have four instars of larvae. Second, third and the last instar larvae are very similar, when the first instar or egg-larvae differs radically. Descriptions and illustrations of external morphology, chaetotaxy of abdominal segments, characters of head capsules and last abdominal segments are given for the previously unknown first instar larvae of Ct. guttata, N. crocata, N. dorsalis, N. flavescens, N. pratensis, N. scurra and poorly known N. submaculosa. It was found out that difference of head capsule and last abdominal segment among the first instar larvae of above mentioned species of genus Nephrotoma are more obvious than in last instar. During this study it was found, that such characters as shape of apical teeth of mandible, shape of basal segment of antenna and number of sensillae, shape of hypostomium and arrangement of sensory structures on labrum, differ among egg-larvae of Nephrotoma. It was found, that pads on frontal part of prothorax and shape of lateral plates of egg-larvae labrum of Nephrotoma differ significantly from that of Ctenophora and could be used as genus separating characters.  PMID:24870629

  5. Dataset of traumatic myiasis observed for three dominant screw worm species in North West Pakistan with first report of Wohlfahrtia magnifica (Schiner).

    PubMed

    Zaidi, Farrah; Fatima, Syeda Hira; Gul, Ayesha

    2016-09-01

    Regional surveys were carried out in different parts of North West Pakistan among domestic animals (N=57,921) including pets and livestock identifying cases of traumatic myiasis (n=1037). A total of four surveys focused general livestock population during Eid ul Adha (Eid surveys; incidence=1.21%) while another four surveys (Miscellaneous surveys; incidence=7.34%) targeted animal population brought to veterinary hospitals and dispensaries. Timeframe spanned four years from 2012 to 2015. Maggots were sampled and location of the wound was recorded for each host. Taxonomic identification used light and electron microscopic techniques. Our dataset shows three species as principle agents of myiasis (n=882) including Chrysomya bezziana Villeneuve (n=394), Wohlfahrtia magnifica (n=244) and Lucilia cuprina Wiedemann (n=244). Others (n=155) including Chrysomya megacephala (Fabricius), Chrysomya rufifacies (Macquart), Lucilia sericata (Meigen), Lucilia illustris (Meigen), Lucilia porphyrina (Walker), Hemipyrellia ligguriens (Wiedemann), Calliphora vicina (Robineau-Desvoidy), Sarcophaga crassipalpalis (Macquart) and Sarcophaga species were identified as species of minor importance. The obligatory screwworm species W. magnifica is a first report from Pakistan. The results based on this dataset are presented in a recent publication "Distribution Modeling of three screwworm species in the ecologically diverse landscape of North West Pakistan" (Zaidi et al., 2016) [1]. PMID:27570812

  6. Sarcosaprophagous Diptera assemblages in natural habitats in central Spain: spatial and seasonal changes in composition.

    PubMed

    Martín-Vega, D; Baz, A

    2013-03-01

    The composition and spatial distribution of sarcosaprophagous Diptera assemblages were studied using carrion-baited traps along a bioclimatic gradient of natural habitats in central Spain throughout the different seasons during 1 year. Calliphoridae and Muscidae were the most abundant families, accounting for, respectively, 41.9% and 35.1% of all Diptera specimens collected. Other abundant families were Heleomyzidae (8.4%), Sarcophagidae (6.9%) and Piophilidae (5.1%). Fly assemblage compositions differed among bioclimatic levels, with Chrysomya albiceps (Wiedemann) (Diptera: Calliphoridae) being the dominant species in mesomediterranean habitats, Muscina levida (Harris) (Diptera: Muscidae) the dominant species in supramediterranean habitats, and Prochyliza nigrimana (Meigen) (Diptera: Piophilidae) the dominant species in oromediterranean habitats. Differences in assemblage composition were also found among seasons. Thermophobic species such as Calliphora vicina Robineau-Desvoidy (Diptera: Calliphoridae) and some species of Heleomyzidae were well represented during autumn, winter and spring in the three bioclimatic levels sampled. By contrast, thermophilic species such as Ch. albiceps and Lucilia sericata (Meigen) (Diptera: Calliphoridae) and most Muscidae and Sarcophagidae species were more abundant during summer and in mesomediterranean habitats located at lower elevations. Knowledge of the preferences of some species for certain habitats may be of ecological and forensic value and may establish a starting point for further research. PMID:22774926

  7. Conditions for the return and simulation of the recovery of burrowing mayflies in western Lake Erie

    USGS Publications Warehouse

    Kolar, Cynthia S.; Hudson, Patrick L.; Savino, Jacqueline F.

    1997-01-01

    In the 1950s, burrowing mayflies, Hexagenia spp. (H. Limbata and H. Rigida), were virtually eliminated from the western basin of Lake Erie (a 3300 kmA? area) because of eutrophication and pollution. We develop and present a deterministic model for the recolonization of the western basin by Hexagenia to pre-1953 densities. The model was based on the logistic equation describing the population growth of Hexagenia and a presumed competitor, Chironomus (dipteran larvae). Other parameters (immigration, low oxygen, toxic sediments, competition with Chironomus, and fish predation) were then individually added to the logistic model to determine their effect at different growth rates. The logistic model alone predicts 10-41 yr for Hexagenia to recolonize western Lake Erie. Immigration reduced the recolonization time by 2-17 yr. One low-oxygen event during the first 20 yr increased recovery time by 5-17 yr. Contaminated sediments added 5-11 yr to the recolonization time. Competition with Chironomus added 8-19 yr to recovery. Fish predators added 4-47 yr to the time required for recolonization. The full model predicted 48-81 yr for Hexagenia to reach a carrying capacity of approximately 350 nymphs/mA?, or not until around the year 2038 if the model is started in 1990. The model was verified by changing model parameters to those present in 1970, beginning the model in 1970 and running it through 1990. Predicted densities overlapped almost completely with actual estimated densities of Hexagenia nymphs present in the western basin in Lake Erie in 1990. The model suggests that recovery of large aquatic ecosystems may lag substantially behind remediation efforts.

  8. New records of mites (Acari: Spinturnicidae) associated with bats (Mammalia, Chiroptera) in two Brazilian biomes: Pantanal and Caatinga.

    PubMed

    de Almeida, Juliana Cardoso; Martins, Mayara Almeida; Guedes, Patrícia Gonçalves; Peracchi, Adriano Lucio; Serra-Freire, Nicolau Maues

    2016-01-01

    A first survey of mite species that ectoparasitize bats in the states of Ceará and Mato Grosso was conducted. The specimens of bats and their mites were collected in areas of the Caatinga and Pantanal biomes. A total of 450 spinturnicids representing two genera and ten species was collected from 15 bat species in the Private Reserve of the Natural Patrimony Serra das Almas, Ceará State, Northeast Brazil and 138 spinturnicids represented by two genera and four species were found in seven bats species collected in Private Reserve of the Natural Patrimony Sesc Pantanal, Mato Grosso State, Central-Western Brazil. The occurrence of Cameronieta genus and the species Mesoperiglischrus natali as well as four new associations (Periglischrus iheringi - Chiroderma vizottoi; P. micronycteridis - Micronycteris sanborni; P. paracutisternus - Trachops cirrhosus; Spinturnix americanus - Myotis riparius) are registered for the first time in Brazil. PMID:26982558

  9. Indoors forensic entomology: colonization of human remains in closed environments by specific species of sarcosaprophagous flies.

    PubMed

    Pohjoismäki, Jaakko L O; Karhunen, Pekka J; Goebeler, Sirkka; Saukko, Pekka; Sääksjärvi, Ilari E

    2010-06-15

    Fly species that are commonly recovered on human corpses concealed in houses or other dwellings are often dependent on human created environments and might have special features in their biology that allow them to colonize indoor cadavers. In this study we describe nine typical cases involving forensically relevant flies on human remains found indoors in southern Finland. Eggs, larvae and puparia were reared to adult stage and determined to species. Of the five species found the most common were Lucilia sericata Meigen, Calliphora vicina Robineau-Desvoidy and Protophormia terraenovae Robineau-Desvoidy. The flesh fly Sarcophaga caerulescens Zetterstedt is reported for the first time to colonize human cadavers inside houses and a COI gene sequence based DNA barcode is provided for it to help facilitate identification in the future. Fly biology, colonization speed and the significance of indoors forensic entomological evidence are discussed. PMID:20304573

  10. Five new records of bee flies (Bombyliidae, Diptera) from Saudi Arabia with zoogeographical remarks.

    PubMed

    El-Hawagry, Magdi S; Dhafer, Hathal M Al

    2015-01-01

    Five bee-fly species (Bombyliidae, Diptera) have been listed in this paper as new to the Kingdom of Saudi Arabia. Four of the recorded species have been identified to the level of species, namely: Bombomyiadiscoidea (Fabricius, 1794), Spogostylumcandidum (Sack, 1909), Exoprosopalinearis Bezzi, 1924, and Exoprosopaminos (Meigen, 1804), while the fifth one only to genus, Desmatoneura sp. The species have been collected from Al-Baha and Asir Provinces in the south-western part of the Kingdom. One of the four identified species, Exoprosopalinearis, has an Afrotropical affinity, and another two, Spogostylumcandidum and Bombomyiadiscoidea, have considerable Afrotropical distributions, and this result agrees to some extent with studies considering these parts of the Arabian Peninsula, including Al-Baha and Asir Provinces, having Afrotropical influences and may be included in the Afrotropical Region rather than in the Palaearctic Region or the Eremic zone. PMID:25878533

  11. Biology and immature stages of Pherbellia limbata (Diptera: Sciomyzidae), a parasitoid of the terrestrial snail Granaria frumentum.

    PubMed

    Nerudová-Horsáková, Jana; Murphy, William L; Vala, Jean-Claude

    2016-01-01

    The very rare Palaearctic Pherbellia limbata (Meigen, 1830) lives in limestone steppes and other xerothermic habitats in central and southern Europe. For the first time, the egg, first-, second- and third-instar larvae and the puparium are described. Scanning electron micrographs of various morphological features of immature stages are provided. Larvae of P. limbata are parasitoids exclusively of the terrestrial snail Granaria frumentum (Draparnaud, 1801). Results of this study are integrated with those of previous studies of the biology, ecology, immature stages, and mollusc-prey habitat of the other 28 (of 96) Pherbellia species for which life cycles have been completely or partially elucidated. Recent published taxonomic approaches to clarifying the phylogeny of the Sciomyzidae are discussed, particularly those involving DNA analyses of Pherbellia species. PMID:27395157

  12. Non-Nutritive Polyol Sweeteners Differ in Insecticidal Activity When Ingested by Adult Drosophila melanogaster (Diptera: Drosophilidae)

    PubMed Central

    O’Donnell, Sean; Baudier, Kaitlin; Marenda, Daniel R.

    2016-01-01

    Previous work showed the non-nutritive polyol sweetener Erythritol was toxic when ingested by Drosophila melanogaster (Meigen, 1930). This study assessed whether insect toxicity is a general property of polyols. Among tested compounds, toxicity was highest for erythritol. Adult fruit flies (D. melanogaster) fed erythritol had reduced longevity relative to controls. Other polyols did not reduce longevity; the only exception was a weaker but significant reduction of female (but not male) longevity when flies were fed D-mannitol. We conclude at least some non-nutritive polyols are not toxic to adult D. melanogaster when ingested for 17 days. The longer time course (relative to erythritol) and female specificity of D-mannitol mortality suggests different mechanisms for D-mannitol and erythritol toxicity to D. melanogaster. PMID:27271968

  13. Biting midges of the genus Culicoides in South Carolina zoos.

    PubMed

    Nelder, Mark P; Swanson, Dustin A; Adler, Peter H; Grogan, William L

    2010-01-01

    Biting midges of the genus Culicoides (Diptera: Ceratopogonidae) were collected during the summer of 2007 at the Greenville and Riverbanks Zoos in South Carolina with Centers for Disease Control and Prevention (CDC) traps equipped with ultraviolet or incandescent lights and baited with carbon dioxide. Sixteen species of Culicoides were collected, four of which represented more than 80%. They were Culicoides guttipennis (Coquillett), Culicoides mulrenanni Beck, Culicoides obsoletus (Meigen), and Culicoides sanguisuga (Coquillett). C. guttipennis was found on a dead colobus monkey and a dead golden-headed lion tamarin; Culicoides husseyi Wirth & Blanton was collected from an unidentified, abandoned bird's nest. Ultraviolet light-equipped traps captured significantly more Culicoides specimens than traps with incandescent light. Half of the collected species previously have been associated with vertebrate pathogens, indicating a potential risk to captive animals. PMID:20569132

  14. Effect of Channel Blockers on the Smooth Muscle of the Adult Crop of the Queen Blowfly, Phormia regina

    PubMed Central

    Stoffolano, John G.; Danai, Laura; Chambers, James

    2013-01-01

    Few studies have examined the various factors affecting the rate of contraction of the supercontractile muscles of the crop lobes of adult Phormia regina Meigen (Diptera: Calliphoridae). Using an in situ bioassay of the crop organ, various ion channel blockers were tested and it was demonstrated that in all cases the blockers (i.e., against the following conductances: Cl- , Ca2+ , Na+, and a FMRF-amide action) significantly reduced the contraction rates of the crop lobes, which were filled with 4.5 µL of 1.0 M sucrose containing 10 mM of the dye amaranth. Benzyltrimethylammonium chloride, never before reported for its effect on insect muscle, was as effective in suppressing crop muscle contraction as benzethonium chloride, which is a reported agonist of dromyosuppressin. PMID:24205919

  15. Comments on the association of immatures of Hemerodromia (Diptera, Empididae) and Simulium (Diptera, Simuliidae), and first record of this association in the Atlantic Forest (Brazil).

    PubMed

    Sánchez Molina, Óscar; Gil-Azevedo, Leonardo Henrique

    2016-11-01

    Larvae of Empididae (Diptera) prey on black fly immatures and its pupae can be collected from pupal cases of Simuliidae (Diptera). The aim of our work was to report the second record of association between immatures of Empididae and Simuliidae in the Neotropical Region and the first for the Atlantic Forest (Rio de Janeiro, Brazil). We collected 4982 pupae and exuviae of Simulium Latreille, (Diptera, Simuliidae) and found three with a pupa of Hemerodromia Meigen (Diptera, Empididae) inside. This shows that the use of black flies cocoons by dance flies occurs at extremely low frequencies, which might explain why this association is so rarely recorded. Our results are relevant for a better comprehension of the predator-prey relationship between these families. PMID:27456938

  16. Traumatic Myiasis Caused by an Association of Sarcophaga tibialis (Diptera: Sarcophagidae) and Lucilia sericata (Diptera: Calliphoridae) in a Domestic Cat in Italy

    PubMed Central

    Pezzi, Marco; Whitmore, Daniel; Chicca, Milvia; Lanfredi, Margherita; Leis, Marilena

    2015-01-01

    We describe here a rare case of traumatic myiasis occurred in August 2014, caused by an association of 2 Diptera species, Sarcophaga tibialis Macquart (Diptera: Sarcophagidae) and Lucilia sericata (Meigen) (Diptera: Calliphoridae), in a domestic cat in northern Italy. Species identification was based on adult male morphology. The present case is the first report of S. tibialis as an agent of myiasis in Italy, and also the first ever report of myiasis caused by an association of S. tibialis and L. sericata. The cat developed an extensive traumatic myiasis in a large wound on the rump, which was treated pharmacologically and surgically. The biology, ecology, and distribution of S. tibialis and L. sericata are also discussed. A literature review is provided on cases of myiasis caused by S. tibialis, and cases of myiasis by L. sericata involving cats worldwide and humans and animals in Italy. PMID:26323846

  17. Biting Midges of the Genus Culicoides in South Carolina Zoos

    PubMed Central

    Nelder, Mark P.; Swanson, Dustin A.; Adler, Peter H.; Grogan, William L.

    2010-01-01

    Biting midges of the genus Culicoides (Diptera: Ceratopogonidae) were collected during the summer of 2007 at the Greenville and Riverbanks Zoos in South Carolina with Centers for Disease Control and Prevention (CDC) traps equipped with ultraviolet or incandescent lights and baited with carbon dioxide. Sixteen species of Culicoides were collected, four of which represented more than 80%. They were Culicoides guttipennis (Coquillett), Culicoides mulrenanni Beck, Culicoides obsoletus (Meigen), and Culicoides sanguisuga (Coquillett). C. guttipennis was found on a dead colobus monkey and a dead golden-headed lion tamarin; Culicoides husseyi Wirth & Blanton was collected from an unidentified, abandoned bird's nest. Ultraviolet light-equipped traps captured significantly more Culicoides specimens than traps with incandescent light. Half of the collected species previously have been associated with vertebrate pathogens, indicating a potential risk to captive animals. PMID:20569132

  18. Checklist and pictorial key to fourth-instar larvae of mosquitoes (Diptera: Culicidae) of Saudi Arabia.

    PubMed

    Al Ahmad, Azzam M; Sallam, Mohamed F; Khuriji, Mohamed A; Kheir, Salah M; Azari-Hamidian, Shahyad

    2011-07-01

    The Kingdom of Saudi Arabia includes fauna from three zoogeographic regions: the Afrotropical, Oriental, and Palaearctic regions. To study the mosquito (Diptera: Culicidae) fauna of these regions in Saudi Arabia, larval collections were made at 15 sites during 2005-2006. Thirty-three species representing nine genera were found. Six species, Anopheles culicifacies Giles s.l., Anopheles subpictus Grassi s.l., Culex arbieeni Salem, Culex simpsoni Theobald, Culex univittatus Theobald, and Ochlerotatus detritus Haliday are reported for the first time for Saudi Arabia. An annotated checklist and an illustrated key to the fourth-instar larvae of the 33 species are presented, along with some remarks about problematic species. Eleven species of genus Anopheles Meigen, five species of tribe Aedini, 13 species of genus Culex L., two species of genus Culiseta Felt, one species of genus Lutzia Theobald, and one species of genus Uranotaenia Lynch Arribátlzaga were recorded during the study. PMID:21845930

  19. Comparative ultrastructure of pretarsi in five calyptrate species.

    PubMed

    Wang, Q K; Yang, Y Z; Li, X Y; Li, K; Zhang, D

    2016-06-01

    Pretarsi are the most important structures that allow flies to walk on various smooth surfaces and act as contact sensory organs. The pretarsal ultrastructure, including adhesive pads, claws, unguitractors, and bristles, of five calyptrate species are presented and described in detail, including Calliphora calliphoroides (Rohdendorf, 1931), Lucilia sericata (Meigen, 1826), Sarcophaga portschinskyi (Rohdendorf, 1937), Muscina stabulans (Fallen, 1817) and Portschinskia magnifica Pleske, 1926. Two types of tenent setae (spoon-tipped and spatula-tipped) are present on the ventral side of pulvilli in all species. The density of tenent setae and the pulvilli area in forelegs, midlegs, and hindlegs of both sexes are different. Among the five species, Ca. calliphoroides has unusually large pulvilli to its body size. These results provide morphological details that help to understand the movement and attachment of flies. PMID:26916893

  20. Non-Nutritive Polyol Sweeteners Differ in Insecticidal Activity When Ingested by Adult Drosophila melanogaster (Diptera: Drosophilidae).

    PubMed

    O'Donnell, Sean; Baudier, Kaitlin; Marenda, Daniel R

    2016-01-01

    Previous work showed the non-nutritive polyol sweetener Erythritol was toxic when ingested by Drosophila melanogaster (Meigen, 1930). This study assessed whether insect toxicity is a general property of polyols. Among tested compounds, toxicity was highest for erythritol. Adult fruit flies (D. melanogaster) fed erythritol had reduced longevity relative to controls. Other polyols did not reduce longevity; the only exception was a weaker but significant reduction of female (but not male) longevity when flies were fed D-mannitol. We conclude at least some non-nutritive polyols are not toxic to adult D. melanogaster when ingested for 17 days. The longer time course (relative to erythritol) and female specificity of D-mannitol mortality suggests different mechanisms for D-mannitol and erythritol toxicity to D. melanogaster. PMID:27271968

  1. Taxonomic review of the major larval pests of bolete fungi (Boletaceae) in Europe: The Pegomya fulgens, furva and tabida species groups (Diptera: Anthomyiidae).

    PubMed

    Michelsen, Verner

    2015-01-01

    A taxonomic review of the European species of the Pegomya fulgens, furva and tabida species groups is given with emphasis on characters of importance for the identification of males and females. These Pegomya species groups are represented in Europe by two, two and nine species, respectively. Their mycophagous larvae may all feed exclusively on bolete sporocarps of Leccinum and Boletus aff. edulis. Their relationships and biology are summarized. Each species is given a selective list of references and synonymy, richly illustrated descriptions of males and females, a list or summary of the examined material, and a synopsis of the known distribution and biology. Pegomya ringdahli sp. nov., previously confused with P. scapularis (Zetterstedt, 1846), is described from Fennoscandia. Lectotypes are designated for Anthomyia fulgens Meigen, 1826 and Pegomyia (Pegomyia) furva Ringdahl, 1938. An identification key is given to all 17 species (males and females) of Pegomya that supposedly feed as larvae on sporocarps of Boletaceae and Suillaceae in Europe. PMID:26624089

  2. Insecticidal sesquiterpene from Alpinia oxyphylla against Drosophila melanogaster.

    PubMed

    Miyazawa, M; Nakamura, Y; Ishikawa, Y

    2000-08-01

    In the course of screening for novel naturally occurring insecticides from Chinese crude drugs, an MeOH extract of Alpinia oxyphylla was found to possess insecticidal activity against larvae of Drosophila melanogaster Meigen. From the extract, an insecticidal compound was isolated by bioassay-guided fractionation and identified as nootkatone (1) by GC, GC-MS, and (1)H and (13)C NMR spectroscopy. In bioassays for insecticidal activity, 1 showed an LC(50) value of 11.5 micromol/mL of diet against larvae of D. melanogaster and an LD(50) value of 96 microg/adult against adults. Epinootkatol (1A), however, showed slight insecticidal activity in both assays, indicating that the carbonyl group at the 2-position in 1 was the important function for enhanced activity of 1. PMID:10956162

  3. Synanthropy and temporal variability of Calliphoridae living in Cosenza (Calabria, southern Italy).

    PubMed

    Greco, Silvia; Brandmayr, Pietro; Bonacci, Teresa

    2014-01-01

    The aim of this study was to investigate the synanthropy of Diptera: Calliphoridae, insects of forensic importance, in Calabria (southern Italy). The study lasted 2 years, from February 2010 to January 2012, and was carried out in three areas of Cosenza province representing "urban", "rural", and "wild" environments. Bottle traps baited with pork were used to catch Calliphoridae. Six species were identified, Calliphora vicina Robineau-Desvoidy 1830, Calliphora vomitoria (L.), Chrysomya albiceps (Wiedemann 1819), Lucilia ampullacea Villeneuve 1922, Lucilia caesar (L.), and Lucilia sericata (Meigen 1826). Data on phenologies in the study areas are reported for these species and the Synanthropy Index was calculated to evaluate their relationship with the human environment. PMID:25527571

  4. New records of Trichoceridae (Diptera) from the island of Mallorca ​

    PubMed Central

    Petrašiūnas, Andrius

    2016-01-01

    Abstract Background The Trichoceridae are a small family distributed mainly in the Holarctic Region, most of which are associated with cold seasons and even snow. From the Iberian peninsula, 5 species have been recorded; however only a single previous occurence record exists from the Balearic islands. New information In this paper we present new records of two species from Mallorca, of which Trichocera (Saltrichocera) saltator (Harris, 1776) has not previously been recorded from the Balearic islands. Trichocera (Saltrichocera) annulata Meigen, 1818 is recorded for the first time from Mallorca. We furthermore discuss the species' distributions within the Mediterranean region and report new morphological data for the Mallorca island form of T. saltator. PMID:26929719

  5. Five new records of bee flies (Bombyliidae, Diptera) from Saudi Arabia with zoogeographical remarks

    PubMed Central

    El-Hawagry, Magdi S.; Dhafer, Hathal M. Al

    2015-01-01

    Abstract Five bee-fly species (Bombyliidae, Diptera) have been listed in this paper as new to the Kingdom of Saudi Arabia. Four of the recorded species have been identified to the level of species, namely: Bombomyia discoidea (Fabricius, 1794), Spogostylum candidum (Sack, 1909), Exoprosopa linearis Bezzi, 1924, and Exoprosopa minos (Meigen, 1804), while the fifth one only to genus, Desmatoneura sp. The species have been collected from Al-Baha and Asir Provinces in the south-western part of the Kingdom. One of the four identified species, Exoprosopa linearis, has an Afrotropical affinity, and another two, Spogostylum candidum and Bombomyia discoidea, have considerable Afrotropical distributions, and this result agrees to some extent with studies considering these parts of the Arabian Peninsula, including Al-Baha and Asir Provinces, having Afrotropical influences and may be included in the Afrotropical Region rather than in the Palaearctic Region or the Eremic zone. PMID:25878533

  6. The Drosophila melanogaster cinnabar gene is a cell autonomous genetic marker in Aedes aegypti (Diptera: Culicidae).

    PubMed

    Sethuraman, Nagaraja; O'Brochta, David A

    2005-07-01

    The cinnabar gene of Drosophila melanogaster (Meigen) encodes for kynurenine hydroxylase, an enzyme involved in ommochrome biosynthesis. This gene is commonly included as a visible genetic marker in gene vectors used to create transgenic Aedes aegypti (L.) that are homozygous for the khw allele, the mosquito homolog of cinnabar. Unexpectedly, the phenotype of cells expressing kynurenine hydroxylase in transgenic Ae. aegypti is cell autonomous as demonstrated by the recovery of insects heterozygous for the kynurenine hydroxylase transgene with mosaic eye color patterns. In addition, a transgenic gynandromorph was recovered in which one-half of the insect was expressing the kynurenine hydroxylase transgene, including one eye with red pigmentation, whereas the other half of the insect was homozygous khw and included a white eye. The cell autonomous behavior of cinnabar in transgenic Ae. aegypti is unexpected and increases the utility of this genetic marker. PMID:16119567

  7. Comparative Mt Genomics of the Tipuloidea (Diptera: Nematocera: Tipulomorpha) and Its Implications for the Phylogeny of the Tipulomorpha

    PubMed Central

    Mao, Meng; Li, Xuankun; Cameron, Stephen L.; de Jong, Herman; Wang, Mengqing; Yang, Ding

    2016-01-01

    A traditionally controversial taxon, the Tipulomorpha has been frequently discussed with respect to both its familial composition and relationships with other Nematocera. The interpretation of internal relationships within the Tipuloidea, which include the Tipulidae sensu stricto, Cylindrotomidae, Pediciidae and Limoniidae, is also problematic. We sequenced the first complete mitochondrial (mt) genome of Symplecta hybrida (Meigen, 1804), which belongs to the subfamily Chioneinae of family Limoniidae, and another five nearly complete mt genomes from the Tipuloidea. We did a comparative analysis of these mt genomics and used them, along with some other representatives of the Nematocera to construct phylogenetic trees. Trees inferred by Bayesian methods strongly support a sister-group relationship between Trichoceridae and Tipuloidea. Tipulomorpha are not supported as the earliest branch of the Diptera. Furthermore, phylogenetic trees indicate that the family Limoniidae is a paraphyletic group. PMID:27341029

  8. Review of the Psychodinae from Mallorca, Spain, with description of Pericoma unipennata, sp. n. (Diptera, Psychodidae)

    PubMed Central

    Kvifte, Gunnar Mikalsen; Stokkan, Morten; Wagner, Rüdiger

    2016-01-01

    Abstract We review the Psychodinae of Mallorca, recognising fifteen species based on recent collections and available literature. Previously unpublished data is presented for eleven species, of which Neoarisemus ibericus Wagner, 1978, Mormia tenebricosa (Vaillant, 1954), Clogmia albipunctata (Williston, 1893), Lepiseodina rothschildi (Eaton, 1913), Paramormia ustulata (Walker, 1856), Philosepedon pyrenaicus Vaillant, 1974 and Psychoda (Psycha) grisescens Tonnoir, 1922 are first records for Mallorca. An old record of Pericoma trifasciata (Meigen, 1804) is considered doubtful. Pericoma unipennata sp. n is described and illustrated based on a male collected at Deía. Distributional data are reviewed for all newly recorded species. Based on the Psychodinae fauna, the zoogeographical affinities of Mallorca are briefly discussed. PMID:27110192

  9. Review of the Psychodinae from Mallorca, Spain, with description of Pericoma unipennata, sp. n. (Diptera, Psychodidae).

    PubMed

    Kvifte, Gunnar Mikalsen; Stokkan, Morten; Wagner, Rüdiger

    2016-01-01

    We review the Psychodinae of Mallorca, recognising fifteen species based on recent collections and available literature. Previously unpublished data is presented for eleven species, of which Neoarisemus ibericus Wagner, 1978, Mormia tenebricosa (Vaillant, 1954), Clogmia albipunctata (Williston, 1893), Lepiseodina rothschildi (Eaton, 1913), Paramormia ustulata (Walker, 1856), Philosepedon pyrenaicus Vaillant, 1974 and Psychoda (Psycha) grisescens Tonnoir, 1922 are first records for Mallorca. An old record of Pericoma trifasciata (Meigen, 1804) is considered doubtful. Pericoma unipennata sp. n is described and illustrated based on a male collected at Deía. Distributional data are reviewed for all newly recorded species. Based on the Psychodinae fauna, the zoogeographical affinities of Mallorca are briefly discussed. PMID:27110192

  10. Identification of Blood Meal Sources in Aedes vexans and Culex quinquefasciatus in Bernalillo County, New Mexico

    PubMed Central

    Greenberg, Jacob A.; Lujan, Daniel A.; DiMenna, Mark A.; Wearing, Helen J.; Hofkin, Bruce V.

    2013-01-01

    Culex quinquefasciatus Say (Diptera: Culicidae) and Aedes vexans Meigen are two of the most abundant mosquitoes in Bernalillo County, New Mexico, USA. In this study, a polymerase chain reaction based methodology was used to identify the sources of blood meals taken by these two species. Ae. vexans was found to take a large proportion of its meals from mammals. Although less specific in terms of its blood meal preferences, Cx. quinquefasciatus was found to feed more commonly on birds. The results for Ae. vexans are similar to those reported for this species in other parts of their geographic range. Cx. quinquefasciatus appears to be more variable in terms of its host feeding under different environmental or seasonal circumstances. The implications of these results for arbovirus transmission are discussed. PMID:24224615

  11. Identification of transport processes in bioirrigated muddy sediments by [18F]fluoride PET (Positron Emission Tomography).

    PubMed

    Roskosch, Andrea; Lewandowski, Jörg; Bergmann, Ralf; Wilke, Florian; Brenner, Winfried; Buchert, Ralph

    2010-06-01

    In aquatic environments transport processes across the sediment-water interface are intensified by bioirrigating macrozoobenthos. Transport processes caused by Chironomus plumosus larvae dwelling in U-tubes were investigated by dynamic small animal Positron Emission Tomography (PET) with [18F]fluoride. Significant tracer transport from the burrows into the sediment was detected; penetration was deeper at the outlet branch of the burrow than at the inlet branch. Hence, advection plays a significant role in exchange between water in the burrows and muddy sediment. PMID:20185319

  12. Worthy of their name: how floods drive outbreaks of two major floodwater mosquitoes (Diptera: Culicidae).

    PubMed

    Berec, Ludĕk; Gelbic, Ivan; Sebesta, Oldrich

    2014-01-01

    An understanding of how climate variables drive seasonal dynamics of mosquito populations is critical to mitigating negative impacts of potential outbreaks, including both nuisance effects and risk of mosquito-borne infectious disease. Here, we identify climate variables most affecting seasonal dynamics of two major floodwater mosquitoes, Aedes vexans (Meigen, 1830) and Aedes sticticus (Meigen, 1838) (Diptera: Culicidae), along the lower courses of the Dyje River, at the border between the Czech Republic and Austria. Monthly trap counts of both floodwater mosquitoes varied both across sites and years. Despite this variability, both models used to fit the observed data at all sites (and especially that for Ae. sticticus) and site-specific models fitted the observed data quite well. The most important climate variables we identified-temperature and especially flooding-were driving seasonal dynamics of both Aedes species. We suggest that flooding determines seasonal peaks in the monthly mosquito trap counts while temperature modulates seasonality in these counts. Hence, floodwater mosquitoes indeed appear worthy of their name. Moreover, the climate variables we considered for modeling were able reasonably to predict mosquito trap counts in the month ahead. Our study can help in planning flood management; timely notification of people, given that these mosquitoes are a real nuisance in this region; public health policy management to mitigate risk from such mosquito-borne diseases as that caused in humans by the Tahyna virus; and anticipating negative consequences of climate change, which are expected only to worsen unless floods, or the mosquitoes themselves, are satisfactorily managed. PMID:24605456

  13. Distribution Modeling of three screwworm species in the ecologically diverse landscape of North West Pakistan.

    PubMed

    Zaidi, Farrah; Fatima, Syeda Hira; Khisroon, Muhammad; Gul, Ayesha

    2016-10-01

    North West Pakistan (NWP) is characterized by four eco-zones: Northern Montane Region, North Western Hills, Submontane Region and Indus Plains. Present study identified 1037 cases of traumatic myiasis in the region during 2012-2015. Screw worm larvae were classified as 12 species: Chrysomya bezziana (Villeneuve), Chryomya megacephala (Fabricius), Chrysomya rufifacies (Macquart), Lucilia cuprina (Wiedemann), Lucilia sericata (Meigen), Lucilia illustris (Meigen), Lucilia porphyrina (Walker), Hemipyrellia ligguriens (Wiedemann), Calliphora vicina (Robineau-Desvoidy), Wohlfahrtia magnifica (Schiner), Sarcophaga crassipalpalis (Macquart), Sarchophaga species. Among these C. bezziana, L. cuprina and W. magnifica with approximately 882 case reports were the principal agents of traumatic myiasis. The species W. magnifica is a first report from Pakistan. In order to investigate spatial distribution of these dominant species we used MaxEnt niche model. Our results revealed a well-established occurrence of C. bezziana and L. cuprina in the four eco-regions while W. magnifica is currently contained in the Submontane Region. Several hot spot areas of infestation were detected all characterized by high human population density showing synanthropic nature of these species. Wohlfahrtia magnifica was excluded from Northern Montane Region with severe winters and Southern Indus Plains with harsh summers revealing that invasive species are initially sensitive to extreme of temperatures. Presence of L. cuprina in the wet areas of North Humid Belt (Maximum annual precipitation: 1641mm) depicted a moisture preference of the species. In perspective of changing climate and future predictions of severe events such as droughts and flooding in NWP, W. magnifica can potentially alter the species composition. Considering these findings in an eco-geographically dynamic region of Pakistan we predict that two factors (1) Growing human population (2) Climatic conditions, equally contribute to range

  14. The mermithid species Isomermis lairdi (Nematoda, Mermithidae), previously only known in Africa, found in Europe

    PubMed Central

    Gradinarov, Denis

    2014-01-01

    Abstract The present work contributs to the knowledge on the aquatic mermithids (Nematoda, Mermithidae) occurring in black flies – an insufficiently studied group of parasitic nematodes. Isomermis lairdi Mondet, Poinar & Bernadou, 1977, described from larvae of Simulium damnosum Theobald, 1903 in Western Africa, is reported to occur in Bulgaria. The species was isolated from larvae of Simulium ornatum Meigen, 1818 in a local population of simuliids in a mountain stream near Jeleznitsa Village, Sofia district. Postparasitic juveniles of mermithids were obtained from the hosts and reared to the adult stage. The species was identified by morphological and morphometrical characters of postparasitic juveniles, and of male and female individuals. In the summer of 2012 a relatively high rate of mermithid infection in a local host population was detected (prevalence up to 44.1%). In August of the next year host abundance had considerably declined and other simuliid species, Simulium variegatum Meigen, 1818 and Simulium reptans (Linnaeus, 1758), predominated in the investigated locality. In West Africa, Isomermis lairdi is considered to be a potential biological agent for reducing the population density of the Simulium damnosum complex – the main vector of human onchocerciasis. In Europe, species of the Simulium ornatum complex are among the vectors of onchocerciasis of cattle and deer. The mermithids presumably play a certain role in the epidemiology of these diseases. A brief discussion on the taxonomy of the genus Isomermis Coman, 1953, and of the feasibility of molecular methods in mermithid taxonomy is provided. The species Isomermis lairdi is reported for the first time from Europe. PMID:25493063

  15. Toxicity of ammonia in pore-water and in the water column to freshwater benthic invertebrates

    SciTech Connect

    Whiteman, F.W.; Kahl, M.D.; Rau, D.M.; Balcer, M.D.; Ankley, G.T.

    1994-12-31

    Ammonia has been mentioned as both a primary toxicant and a factor that can produce false positive results in laboratory sediment tests using benthic invertebrates. This study developed a sediment dosing system that percolates an ammonia solution through sediment to achieve target porewater ammonia concentrations that remain stable over four and ten day spiked sediment tests. Ten day flow-through water-only tests and ten day spiked sediment tests were used to determine the toxicity of ammonia in the water column and in the sediment pore-water to the oligochaete Lumbriculus variegatus and the midge Chironomus tentans. Four-day tests were run with the amphipod Hyalella azteca. The relationship between water column ammonia toxicity and sediment pore-water ammonia toxicity is influenced by the organism`s association with the sediment. For Lumbriculus variegatus and Chironomus tentans that burrow into the sediment and are in direct contact with the porewater, the pore-water LC50 for ammonia is 30--40% higher than the water-only LC50 for each species. Hyalella azteca is epibenthic and avoids ammonia spiked sediment, thus ammonia in the water column is considerably more toxic than the pore-water ammonia with the porewater LC50 about 800% higher than the water only LC50.

  16. Conversion of carotenoids into vitamins A(1) and A(2) in two species of freshwater fish.

    PubMed

    Gross, J; Budowski, P

    1966-12-01

    1. Examination of two zooplankton species predominating in fish ponds, Daphnia magna and Chironomus larvae, revealed the presence of alpha- and beta-carotene, echinenone, canthaxanthin and 3-hydroxy-4-oxo-beta-carotene in Daphnia, and beta-carotene and cryptoxanthin ester in Chironomus. No specific provitamins A(2) (containing a 3,4-dehydro-beta-ionone ring) were detected. 2. Guppies (Lebistes reticulatus) and platies (Xiphophorus variatus) were found to form vitamin A from beta-carotene and from its oxygen-containing derivatives isozeaxanthin, canthaxanthin and astaxanthin. Slight conversion into vitamin A(2) seemed to occur simultaneously. 3,4-Dehydro-3'-hydroxy-beta-carotene formed little vitamin A, and the latter was mainly of the A(2) type. Lutein was devoid of provitamin A properties. 3. In addition to vitamin A, beta-carotene was detected in fish receiving the 4-oxo- and 4-hydroxy-carotenoids. A reaction scheme for the conversion of carotenoids into retinal and and 3,4-dehydroretinal is presented. 4. It is concluded that natural 4-oxo derivatives of beta-carotene may play a significant role as vitamin A precursors for fish. PMID:16742455

  17. Conversion of carotenoids into vitamins A1 and A2 in two species of freshwater fish

    PubMed Central

    Gross, Jeana; Budowski, P.

    1966-01-01

    1. Examination of two zooplankton species predominating in fish ponds, Daphnia magna and Chironomus larvae, revealed the presence of α- and β-carotene, echinenone, canthaxanthin and 3-hydroxy-4-oxo-β-carotene in Daphnia, and β-carotene and cryptoxanthin ester in Chironomus. No specific provitamins A2 (containing a 3,4-dehydro-β-ionone ring) were detected. 2. Guppies (Lebistes reticulatus) and platies (Xiphophorus variatus) were found to form vitamin A from β-carotene and from its oxygen-containing derivatives isozeaxanthin, canthaxanthin and astaxanthin. Slight conversion into vitamin A2 seemed to occur simultaneously. 3,4-Dehydro-3′-hydroxy-β-carotene formed little vitamin A, and the latter was mainly of the A2 type. Lutein was devoid of provitamin A properties. 3. In addition to vitamin A, β-carotene was detected in fish receiving the 4-oxo- and 4-hydroxy-carotenoids. A reaction scheme for the conversion of carotenoids into retinal and and 3,4-dehydroretinal is presented. 4. It is concluded that natural 4-oxo derivatives of β-carotene may play a significant role as vitamin A precursors for fish. PMID:16742455

  18. Patent literature on mosquito repellent inventions which contain plant essential oils--a review.

    PubMed

    Pohlit, Adrian Martin; Lopes, Norberto Peporine; Gama, Renata Antonaci; Tadei, Wanderli Pedro; Neto, Valter Ferreira de Andrade

    2011-04-01

    Bites Bites of mosquitoes belonging to the genera Anopheles Meigen, Aedes Meigen, Culex L. and Haemagogus L. are a general nuisance and are responsible for the transmission of important tropical diseases such as malaria, hemorrhagic dengue and yellow fevers and filariasis (elephantiasis). Plants are traditional sources of mosquito repelling essential oils (EOs), glyceridic oils and repellent and synergistic chemicals. A Chemical Abstracts search on mosquito repellent inventions containing plant-derived EOs revealed 144 active patents mostly from Asia. Chinese, Japanese and Korean language patents and those of India (in English) accounted for roughly 3/4 of all patents. Since 1998 patents on EO-containing mosquito repellent inventions have almost doubled about every 4 years. In general, these patents describe repellent compositions for use in topical agents, cosmetic products, incense, fumigants, indoor and outdoor sprays, fibers, textiles among other applications. 67 EOs and 9 glyceridic oils were individually cited in at least 2 patents. Over 1/2 of all patents named just one EO. Citronella [Cymbopogon nardus (L.) Rendle, C.winterianus Jowitt ex Bor] and eucalyptus (Eucalyptus LʼHér. spp.) EOs were each cited in approximately 1/3 of all patents. Camphor [Cinnamomum camphora (L.) J. Presl], cinnamon (Cinnamomum zeylanicum Blume), clove [Syzygium aromaticum (L.) Merr. & L.M. Perry], geranium (Pelargonium graveolens LʼHér.), lavender (Lavandula angustifolia Mill.), lemon [Citrus × limon (L.) Osbeck], lemongrass [Cymbopogon citratus (DC.) Stapf] and peppermint (Mentha × piperita L.) EOs were each cited in > 10% of patents. Repellent chemicals present in EO compositions or added as pure “natural” ingredients such as geraniol, limonene, p-menthane-3,8-diol, nepetalactone and vanillin were described in approximately 40% of all patents. About 25% of EO-containing inventions included or were made to be used with synthetic insect control agents having mosquito

  19. Methods for measuring the toxicity and bioaccumulation of sediment-associated contaminants with freshwater invertebrates

    SciTech Connect

    Not Available

    1994-06-01

    The procedures are described for testing freshwater organisms in the laboratory to evaluate the toxicity or bioaccumulation of contaminants associated with whole sediments. Sediments may be collected from the field or spiked with compounds in the laboratory. Toxicity methods are outlined for two organisms, the amphipod Hyalella azteca and the midge Chironomus tentans. The toxicity tests are conducted for 10 d in 300 ml chambers containing 100 ml of sediment and 175 ml of overlying water. Overlying water is renewed daily and test organisms are fed during the toxicity tests. The endpoint in the toxicity test with H. azteca is survival and the endpoints in the toxicity test with C. tentans are survival and growth. Procedures are primarily described for testing freshwater sediments; however, estaurine sediments (up to 15%) can also be tested with H. azteca. Guidance for conducting 28-d bioaccumulation tests with the oligochaete Lumbriculus variegatus is provided in the manual.

  20. Toxicity of fluoride to aquatic species and evaluation of toxicity modifying factors.

    PubMed

    Pearcy, Krysta; Elphick, James; Burnett-Seidel, Charlene

    2015-07-01

    The present study was performed to investigate the toxicity of fluoride to a variety of freshwater aquatic organisms and to establish whether water quality variables contribute substantively to modifying its toxicity. Water hardness, chloride, and alkalinity were tested as possible toxicity modifying factors for fluoride using acute toxicity tests with Hyalella azteca and Oncorhynchus mykiss. Chloride appeared to be the major toxicity modifying factor for fluoride in these acute toxicity tests. The chronic toxicity of fluoride was evaluated with a variety of species, including 3 fish (Pimephales promelas, O. mykiss, and Salvelinus namaycush), 3 invertebrates (Ceriodaphnia dubia, H. azteca, and Chironomus dilutus), 1 plant (Lemna minor), and 1 alga (Pseudokirchneriella subcapitata). Hyalella azteca was the most sensitive species overall, and O. mykiss was the most sensitive species of fish. The role of chloride as a toxicity modifying factor was inconsistent between species in the chronic toxicity tests. PMID:25732700

  1. Aquatic invertebrate ecology during a simulated botulism epizootic in a Sacramento Valley wetland

    USGS Publications Warehouse

    Hicks, J.M.; Euliss, N.H., Jr.; Harris, S.W.

    1997-01-01

    We investigated the effect of decomposing duck carcasses on aquatic invertebrate numbers, biomass, and taxonomic composition in a seasonally flooded, impounded wetland in the Sacramento Valley, California during August-November 1988 and 1989. Major invertebrate taxa were copepods (Cyclopoida, occurred in 8.3% of samples), water fleas (Daphnidae, 8.9%), water boatmen (Corisella, 10.4%), and midge larvae (Goeldichironomus, 9.3%; Chironomus, 11.5%; Tanypus, 17.2%). We found no treatment (carcass present or no carcass) by sampling day interaction for these taxa. We found a significant difference between sample plots with carcasses and those without carcasses only for Daphnidae counts and Corisella wet weights. We found significant differences among sampling days for these taxa that were probably statistical artifacts. We were unable to detect any effect of duck carcasses on aquatic invertebrate community structure and the potential availability of invertebrates as waterfowl food.

  2. Parachironomus Lenz from China and Japan (Diptera, Chironomidae)

    PubMed Central

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

    2015-01-01

    Abstract 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 Parachironomus monochromus (van der Wulp) are recorded from China for the first time, thus are redescribed from Chinese specimens. Parachironomus kamaabeus Sasa & Tanaka and Parachironomus toneabeus Sasa & Tanaka are new junior synonyms of Parachironomus 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 Parachironomus 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. PMID:25901113

  3. Acute and chronic toxicity testing of bisphenol A with aquatic invertebrates and plants.

    PubMed

    Mihaich, Ellen M; Friederich, Urs; Caspers, Norbert; Hall, A Tilghman; Klecka, Gary M; Dimond, Stephen S; Staples, Charles A; Ortego, Lisa S; Hentges, Steven G

    2009-07-01

    Bisphenol A (BPA, 4,4'-isopropylidine diphenol) is a commercially important chemical used primarily as an intermediate in the production of polycarbonate plastic and epoxy resins. Extensive effect data are currently available, including long-term studies with BPA on fish, amphibians, crustaceans, and mollusks. The aim of this study was to perform additional tests with a number of aquatic invertebrates and an aquatic plant. These studies include acute tests with the midge (Chironomus tentans) and the snail (Marisa cornuarietis), and chronic studies with rotifers (Brachionus calyciflorus), amphipods (Hyalella azteca), and plants (Lemna gibba). The effect data on different aquatic invertebrate and plant species presented in this paper correspond well with the effect and no-effect concentrations (NOECs) available from invertebrate studies in the published literature and are within the range found for other aquatic species tested with BPA. PMID:19327838

  4. Heavy metal bioaccumulation in sediment, common reed, algae, and blood worm from the Shoor river, Iran.

    PubMed

    Hamidian, Amir Hossein; Zareh, Maryam; Poorbagher, Hadi; Vaziri, Leila; Ashrafi, Sohrab

    2016-03-01

    Concentrations of 11 metals (cadmium, zinc, copper (Cu), vanadium (V), lead, magnesium (Mg), manganese, aluminum, iron (Fe), chromium (Cr), and nickel), and one metalloid (arsenic (As)) were measured in sediment, common reed (Phragmites australis), algae (Spirogyra sp.), and blood worm (Chironomus sp.) tissues of samples collected from the Shoor river. Samples were dried, acid digested, and the concentrations of metals were measured using inductively coupled plasma-optical emission spectrometer. A higher concentration of heavy metals was accumulated in Spirogyra and Chironomids than sediment and common reed. The highest rate of accumulation was found for Mg, V, Fe, As, Cu, and Cr. Spirogyra and Chironomids are capable of accumulating and thereby removing metals from polluted water bodies and are suitable for biomonitoring purposes. PMID:24105065

  5. Validation and sensitivity comparisons of micro-scale toxicity tests for the evaluation of freshwater sediment toxicity

    SciTech Connect

    Riebel, P.; Bureau, J.; Blaise, C.; Michaud, J.R.

    1995-12-31

    A three-year study is currently underway to develop a representative and cost-effective battery of toxicity tests for evaluating freshwater sediment and porewater toxicity. Among the tests currently being evaluated are the following: Microtox{trademark} chronic test, Microtox{trademark} solid-phase test, Microtox{trademark} liquid phase test, Thamnotoxkit F{trademark}, Rotoxkit F{trademark}, Daphnia magna IQ test{trademark}, Sediment Toxkit, SOS Chromotest, a Selenastrum capricornutum short exposure assay, and trout hepatocyte assays. Conventional sediment tests with Chironomus tentans, Hyalella azteca and Lumbriculus variegatus, as well as benthic macroinvertebrate community assessments and sediment chemical characterizations are being conducted at two contaminated sites. Toxicity test reproducibility, sensitivity, practicality, cost and ecological relevance are discussed.

  6. Pyrethroid insecticides in urban salmon streams of the Pacific Northwest.

    PubMed

    Weston, D P; Asbell, A M; Hecht, S A; Scholz, N L; Lydy, M J

    2011-10-01

    Urban streams of the Pacific Northwest provide spawning and rearing habitat for a variety of salmon species, and food availability for developing salmon could be adversely affected by pesticide residues in these waterbodies. Sediments from Oregon and Washington streams were sampled to determine if current-use pyrethroid insecticides from residential neighborhoods were reaching aquatic habitats, and if they were at concentrations acutely toxic to sensitive invertebrates. Approximately one-third of the 35 sediment samples contained measurable pyrethroids. Bifenthrin was the pyrethroid of greatest concern with regards to aquatic life toxicity, consistent with prior studies elsewhere. Toxicity to Hyalella azteca and/or Chironomus dilutus was found in two sediment samples at standard testing temperature (23 °C), and in one additional sample at a more environmentally realistic temperature (13 °C). Given the temperature dependency of pyrethroid toxicity, low temperatures typical of northwest streams can increase the potential for toxicity above that indicated by standard testing protocols. PMID:21592636

  7. A new model for 20-hydroxyecdysone and dibenzoylhydrazine binding: a homology modeling and docking approach.

    PubMed Central

    Wurtz, J. M.; Guillot, B.; Fagart, J.; Moras, D.; Tietjen, K.; Schindler, M.

    2000-01-01

    The ecdysone receptor (ECR), a nuclear transcription factor controlling insect development, is a novel target for insecticides such as dibenzoylhydrazines with low environmental and toxicological impacts. To understand the high selectivity of such synthetic molecules toward ECR, two homology models of the Chironomus tentans ECR ligand-binding domain (LDB) have been constructed by taking as templates the known LBD crystal structures of the retinoic acid and vitamin D receptors. Docking of 20-hydroxyecdysone (20E) and dibenzoylhydrazines to the receptor suggests a novel superposition of the natural and synthetic molecules; the N-tert-butyl substituent of the dibenzoylhydrazines extends significantly beyond the 20E volume. Our ECR-LBD protein models rationalize how 20E and dibenzoylhydrazines interact with the ligand-binding pocket. The homology model complexes provide new insights that can be exploited in the rational design of new environmentally safe insecticides. PMID:10892801

  8. Consequences of physical disturbance by tadpoles and snails on chironomid larvae.

    PubMed

    Pal, Gargi; Aditya, Gautam; Hazra, Niladri

    2014-01-01

    Indirect interactions among community members impact on organisms. The effects of two snails, banded pond snail, Bellamya bengalensis (Lamarck), and Red-rimmed melania, Melanoides tuberculata (Müller), and tadpoles of Asian common toad, Duttaphrynus melanostictus (Schneider), on nonbiting midge larvae, Chironomus striatipennis Kieffer, were observed in experimental microcosm. Decrease in tube number and tube length of midge larvae was observed compared to control condition due to introduction of selected above mentioned organisms. The direct effects of non-predator organisms on the midge larvae are due to physical disturbance that destroys their tubes. This may result in vulnerability of midge larvae to predators in the wild. So the community structure may be altered by indirect effects, where one or more species, through their direct disturbance, indirectly change the abundance of other species. PMID:24672384

  9. Consequences of Physical Disturbance by Tadpoles and Snails on Chironomid Larvae

    PubMed Central

    Pal, Gargi; Aditya, Gautam; Hazra, Niladri

    2014-01-01

    Indirect interactions among community members impact on organisms. The effects of two snails, banded pond snail, Bellamya bengalensis (Lamarck), and Red-rimmed melania, Melanoides tuberculata (Müller), and tadpoles of Asian common toad, Duttaphrynus melanostictus (Schneider), on nonbiting midge larvae, Chironomus striatipennis Kieffer, were observed in experimental microcosm. Decrease in tube number and tube length of midge larvae was observed compared to control condition due to introduction of selected above mentioned organisms. The direct effects of non-predator organisms on the midge larvae are due to physical disturbance that destroys their tubes. This may result in vulnerability of midge larvae to predators in the wild. So the community structure may be altered by indirect effects, where one or more species, through their direct disturbance, indirectly change the abundance of other species. PMID:24672384

  10. Potential ecological risk of heavy metal contamination in sediments and macrobenthos in coastal wetlands induced by freshwater releases: A case study in the Yellow River Delta, China.

    PubMed

    Li, Ming; Yang, Wei; Sun, Tao; Jin, Yuwan

    2016-02-15

    We investigated the nine heavy metal contents in the sediments and macrobenthos of the Yellow River Delta Wetlands using three experimental areas that received freshwater releases and one reference area that did not. Heavy metal contents, the single-factor contamination index (SFCI), the metal contamination index (MCI), and the biota-sediment accumulation factor (BSAF) were used to evaluate the potential ecological risk and bioaccumulation. We found that As exceeded the national standard value by more than 50%, and that the ranges of SFCI for each metal were generally larger in autumn than in spring. MCI showed no clear pattern, but the BSAF results suggest that Cd bioaccumulates from sediments to macrobenthos. Pollution-resistant species such as Corophium sinense, Chironomus sp., and Einfeldia sp. became dominant in the areas receiving freshwater releases, and provide direct evidence of ecological risk in the wetlands. Our results provide preliminary information to guide managers for ecological risk assessments. PMID:26719069

  11. Using a battery of bioassays, benthic phytoplankton and the AUSRIVAS method to monitor long-term coal tar contaminated sediment in the Cache la Poudre River, Colorado.

    PubMed

    Oberholster, P J; Botha, A-M; Cloete, T E

    2005-12-01

    This survey provides information on sediment toxicity and structural characteristics of the macroinvertebrates and benthic phytoplankton at 10 locations in the Cache la Poudre River after long-term exposure to coal tar residue. The application of the Australian river bioassessment system (AUSRIVAS) as well as a biotest battery was used to evaluate the river 'health' condition. Coal tar is a dense nonaqueous-phase liquid of significant environmental concern due to its toxicity and persistence in the subsurface. Organisms like Selenastrum capricornutum, Daphnia magna and Chironomus tentans, representing different complexities in the biosphere, were selected as test systems for ecotoxicological studies. The results obtained in this study indicate that a biotest battery, macroinvertebrate and benthic phytoplankton communities are in principle suitable biological tools for evaluation of toxic oil and coal-derived substances in long-term contaminated river sediment. PMID:16289670

  12. [Mode of formation of the flight muscles in a nematocerous Diptera].

    PubMed

    Lebart-Pedebas, M C; Auber, J

    1982-01-01

    An electron microscope study was conducted on the origin of the dorsal longitudinal muscles of a Nematocerous Diptera (Chironomus). These imaginal muscles arise from three pairs of slender larval muscles that are characterized by the presence of myoblasts located beneath the basal lamina and adhering to the sarcoplasmic membrane. During the last larval instar the myoblasts increase in number, each of the associated muscle fibers loses its contractile material and splits longitudinally into two to form six columns of sarcoplasm. Differentiation of the fibrillar material begins in each of the six muscle rudiments after the adhering myoblasts have become incorporated. There are several possible origins for these myoblasts: they may be embryonic cells that persist in association with the larval muscle fibers; or --as in the case of Cyclorrhaphous Diptera-- they may migrate from elsewhere to invest these fibers. PMID:7138012

  13. Structure and function of eukaryotic chromosomes

    SciTech Connect

    Hennig, W.

    1987-01-01

    Contents: Introduction; Polytene Chromosomel Giant Chromosomes in Ciliates; The sp-I Genes in the Balbiani Rings of Chironomus Salivary Glands; The White Locus of Drosophila Melanogaster; The Genetic and Molecular Organization of the Dense Cluster of Functionally Related Vital Genes in the DOPA Decarboxylase Region of the Drosophila melanogaster Genome; Heat Shock Puffs and Response to Environmental Stress; The Y Chromosomal Lampbrush Loops of Drosophila; Contributions of Electron Microscopic Spreading Preparations (''Miller Spreads'') to the Analysis of Chromosome Structure; Replication of DNA in Eukaryotic Chromosomes; Gene Amplification in Dipteran Chromosomes; The Significance of Plant Transposable Elements in Biologically Relevant Processes; Arrangement of Chromosomes in Interphase Cell Nuclei; Heterochromatin and the Phenomenon of Chromosome Banding; Multiple Nonhistone Protein-DNA Complexes in Chromatin Regulate the Cell- and Stage-Specific Activity of an Eukaryotic Gene; Genetics of Sex Determination in Eukaryotes; Application of Basic Chromosome Research in Biotechnology and Medicine. This book presents an overview of various aspects of chromosome research.

  14. Feeding habits of Solea senegalensis in earthen ponds in Sado estuary

    NASA Astrophysics Data System (ADS)

    Castelo Branco, Maria Ana; Arruda, Marco A.; Gamito, Sofia

    2010-11-01

    The senegale sole, Solea senegalensis Kaup, 1858, is a commercially valuable fish and it is beginning to be cultured in a semi-intensive way in fish farms in southern European countries. The present study was initiated to investigate the diet of S. senegalensis under semi-extensive conditions. The feeding habits of sole were studied in two earthen ponds of a fish farm in the Sado estuary. In one earthen pond, artificial fish ration was given. S. senegalensis feeds on few prey items, its diet is mainly composed of insect larvae ( Chironomus salinarus) and polychaeta ( Hediste diversicolor). The diet composition of this species suggests feeding specialization, by consuming mainly annelids and insect larvae and by avoiding other items, extremely abundant in the environment, such as gastropods. In the water reservoir where ration was given, some fish consumed simultaneously benthic organism together with ration. However, benthic organisms seem to be the most important component of S. senegalensis diet.

  15. A stable isotope dilution method for measuring bioavailability of organic contaminants

    PubMed Central

    Delgado-Moreno, Laura; Gan, Jay

    2014-01-01

    Methods for determining bioavailability of organic contaminants suffer various operational limitations. We explored the use of stable isotope labeled references in developing an isotope dilution method (IDM) to measure the exchangeable pool (E) of pyrene and bifenthrin as an approximation of their bioavailability in sediments. The exchange of deuterated bifenthrin or pyrene with its native counterpart was completed within 48 h. The derived E was 38–82% for pyrene and 28–59% for bifenthrin. Regression between E and the sum of rapid and slow desorption fractions obtained from sequential desorption showed a slope close to 1.0. The ability of IDM to predict bioavailability was further shown from a strong relationship (r2 > 0.93) between E and bioaccumulation into Chironomus tentans. Given the abundance of stable isotope labeled references and their relatively easy analysis, the IDM has the potential to become a readily adoptable tool for estimating organic contaminants bioaccessibility in various matrices. PMID:23434573

  16. A mini review of the high mobility group proteins of insects.

    PubMed

    Aleporou-Marinou, Vassiliki; Marinou, Haroula; Patargias, Theocharis

    2003-10-01

    High mobility group (HMG) proteins are an abundant class of chromosomal proteins facilitate assembly of higher order structures. The mammalian HMG proteins have been grouped into three distinct families on the basis of their characteristic functional sequence: the HMGB, the HMGN, and the HMGA family. The HMG proteins of Drosophila melanogaster and Chironomus tentans are the best characterized dipteran insect HMG proteins. Three abundant members of this group of nonhistone proteins were detected in those insects. Two of them belong to the HMGB family and one to the HMGA family. The possible relatedness of these proteins to the formation of higher order nucleoprotein structures and their possible role in the regulation of transcription is discussed. PMID:14974679

  17. Aquatic safety of Lagenidium giganteum: effects on freshwater fish and invertebrates.

    PubMed

    Nestrud, L B; Anderson, R L

    1994-11-01

    Eleven freshwater species were exposed to a zoosporeproducing fungus, Lagenidium giganteum, with the goal of determining species sensitivity with standard and new test procedures. The tests included standard, 4-day acute exposures of cladocerans (Ceriodaphnia dubia, Daphnia pulex, and D. magna) and the fathead minnow (Pimephales promelas). Standard 7-day chronic exposures of C. dubia and a 7-day embryo-larval exposure of P. promelas were also conducted. New, 4-day acute, methods were developed for mosquitos (Aedes aegypti), chironomids (Chironomus sp.), oligochaetes (Lumbriculus sp.), cyclopoid copepods, snails (Physa sp.), hydrozoans (Hydra sp.), and ostracods. To assess L. giganteum zoospore (z) infectivity, each test included daily bioassays with the mosquito (A. aegypti), a target organism. Four-day A. aegypti LC50s ranged from 81 to 516 z/ml. Ceriodaphnia dubia acute test LC50s were as low as 6700 z/ml and the 96-hr LC50 from the chronic test was near 6250 z/ml with reproductive impairment at 12,500 z/ml. Daphnia sp. were also susceptible, with LC50s near 7700 z/ml for D. pulex and 9400 z/ml for D. magna. Chironomus tentans was infected at concentrations of > or = 5000 z/ml, but mortality was low and an LC50 could not be calculated even after exposures to 50,000 z/ml. The 7-day, early life stage test with P. promelas produced reduced larva growth in most treatments. Several species (Hydra sp., L. variegatus, ostracoda, copepoda, Physa sp., and P. promelas) were not affected in acute tests at exposures of 50,000 z/ml. The data show, contrary to many reports, that L. giganteum may affect some nontarget aquatic species. The key to successful laboratory tests is monitoring and maintaining the zoospores infection capacity. PMID:7806894

  18. Factors Influencing the Stable Oxygen and Hydrogen Isotopic Composition (δ 18O and δ D) of a Subarctic Freshwater Lake Ecosystem

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Wooller, M. J.

    2005-12-01

    Previous studies have shown that the stable oxygen and hydrogen isotopic compositions (δ 18O and δD) in various animal tissues can be used to examine past climates and animal migration pattern. Little attention has been paid to the relative roles of diet and water influencing the overall δ 18O and δD of animal tissues in freshwater ecosystems. It is unclear whether different trophic levels in a freshwater lake ecosystem have an identical relationship to the water that surrounds them. The δ18O and δD values of animal tissues may be controlled by numerous different factors, including metabolic and biosynthetic isotopic fractionation and variations of δ 18O and δD in the food available. We began to examine these issues by analyzing the δ 18O and δD throughout a freshwater aquatic ecosystem at Smith Lake in Alaska. We collected samples representing primary producers and consumers (primary and secondary). Samples included green algae, various aquatic plants, such as Nuphar variegatum (water lily), Polygonum amphibium (water smartweed), Carex utriculata (sedge), Utricularia vulgaris (common bladderwort), Typha latifolia (common cattail), and a range of aquatic invertebrates, including Chironomus. sp (midge), Zygoptera (damselfly), Anisoptera (dragonfly), Dytiscidae (diving beetle) and Euhirudinea (leeches). The δ 18O and δD of Smith Lake water were ~-13.5e and -129.0e, respectively, and we present the δ 18O and δD of the rest of the ecosystem relative to these data. For instance, the δ 18O of chironomus sp. was ~12.1, which is greater than the of the lake water. Preliminary results suggest the extent of the fractionation between δ 18O of chironomids vs. lake water δ 18O is consistent with previous studies. Our data provide an insight into the range of variations that could be expected within a single freshwater ecosystem.

  19. Ligand-dependent Bohr effect of Chrionomus hemoglobins.

    PubMed

    Steffens, G; Buse, G; Wollmer, A

    1977-01-01

    The O2 and CO Bohr effects of monomeric and dimeric hemoglobins of the insect Chironomus thummi thummi were determined as proton releases upon ligation. For the O2 Bohr effect of the monomeric hemoglobin III a maximum value of 0.20 H+/heme was obtained at pH 7.5. Upon ligation with CO, however, only 0.04 H+/heme were released at the same pH. In agreement with this finding isoelectric focusing experiments revealed different isoelectric points for O2-liganded and CO-liganded states of hemoglobin III. Analogous results were obtained in the cases of the monomeric hemoglobin IV and the dimeric hemoglobins of Chironomus thummi thummi; here O2 Bohr effects of 0.43 and 0.86 H+/heme were observed. For the corresponding CO Bohr effects values of 0.08 and 0.31 H+/heme were obtained respectively. On the basis of the available structural data the reduced CO Bohr effect in hemoglobin III is discussed as arising from a steric hindrance of the CO ligand by the side chain of isoleucine-E11, obstructing the movement of the heme-iron upon reaction with carbon monoxide. It should, however, be noted that ligands, according to their different electron donor and acceptor properties, may generally induce different conformational changes and thus different Bohr effects, in those hemoglobins in which distinct tertiary and/or quaternary constraints have not evolved. The general utilization of CO instead of O2 as allosteric effector is ruled out by the results reported here. PMID:12977

  20. Effects of triazine herbicides on organophosphate insecticide toxicity in Hyalella azteca.

    PubMed

    Trimble, A J; Lydy, M J

    2006-07-01

    The frequent use of pesticides in agricultural and commercial settings has led some researchers to devote their attention to studying the effects of mixtures of these compounds as they co-occur in the environment. Recent studies have demonstrated the potentiating effects of triazine herbicides, such as atrazine and its analogs, to the toxicity of a variety of organophosphate (OP) insecticides. One such OP insecticide, chlorpyrifos, has been the topic of much concern because of its prevalence in the environment. This study focused on examining the effects of 10 select triazine herbicides at concentrations of 1 mumole/L (approximately 200 mug/L) to chlorpyrifos with Hyalella azteca. The compounds selected include atrazine, three of its degradation products, and six other herbicide active ingredients. Toxicity tests were performed using a two-way analysis of variance matrix design with effect levels determined by way of probit analysis. Atrazine was found to have the greatest acutely lethal effect to H. azteca, followed by its closest degradation product, deethylatrazine. Two of the six atrazine analogs, simazine and cyanazine, also showed significant effects to the insecticide's toxicity. Synergistic ratios (SRs) were calculated to compare the effect magnitudes for each of the herbicides. The highest ratio obtained was with atrazine (SR = 1.42). A majority of the past studies involving mixtures of triazines and OPs have examined the potentiation effects of active-use triazine herbicides on Chironomus species. However, compared with the acute effects previously obtained for Chironomus species, H. azteca show a higher tolerance to the presence of the triazine herbicides, even at levels often considered as being at the high end of environmentally relevant concentrations. When coupled with past studies from our laboratory, this research helps to provide a better understanding of the toxic effects of herbicide-insecticide interactions. PMID:16508794

  1. Studies and evaluation of the potential toxicity of decabromodiphenyl ethane to five aquatic and sediment organisms.

    PubMed

    Hardy, M L; Krueger, H O; Blankinship, A S; Thomas, S; Kendall, T Z; Desjardins, D

    2012-01-01

    The potential toxicity of decabromodiphenyl ethane (DBDP-Ethane) was explored in 5 types of organisms residing in the water column and/or sediment, e.g. Oncorhynchus mykiss, Pseudokirchneriella subcapitata, Daphnia magna, Chironmus riparius, and Lumbriculus variegates. Fish, algae or Daphnia were unaffected by acute exposures to water accommodated fractions of 110mg DBDP-Ethane/L. Chronic exposure to DBDP-Ethane at the highest dose tested, 5000mg/kg dry sediment, did not affect midge mean development times, emergence or development rates or oligochaete survival, reproduction or dry weight. The chronic EC50, LOEC and NOEC were ≥5000mg/kg in the two sediment species. Applying an assessment factor of 50, the unbounded predicted no effect concentration (PNEC(sediment)) was 100mg/kg dry sediment. The calculated PNEC indicates DBDPE-Ethane presents little risk to sediment organisms. These results add to DBDP-Ethane's existing database in the terrestrial compartment and mammals. PMID:21862128

  2. Influence of particle surfaces on the bioavailability to different species of 2,4-dichlorophenol and pentachlorophenol

    SciTech Connect

    Davies, N.A.; Edwards, P.A.; Lawrence, M.A.M.; Taylor, M.G.; Simkiss, K. . School of Animal and Microbial Sciences)

    1999-07-15

    Studies on the bioavailability of contaminants that accumulate in sediments have been complicated by the chemical and structural variability of substrates and by the different biological properties of test organisms that are used by regulators. The purpose of this work was to overcome some of these difficulties by devising a test system that used artificial particles with known chemical surfaces. These were coated with 2,4-dichlorophenol or pentachlorophenol and fed to oligochete worms (Lumbriculus variegatus) and midge larvae (Chironimus riparius). The adsorption coefficient (K[sub d]) of the particle surface was compared with the concentration of contaminant accumulated by the test organisms. There were major differences in bioaccumulation between the two species used despite identical particles and pollutants. This clearly reflects differences in the uptake and detoxification pathways between species. The particle surface and its interaction with the chlorophenols was a major factor in the accumulation of the contaminants in an organism. The techniques that are described provide a way of standardizing results between different natural sediments and different test organisms and provide some insights into the processes involved in bioaccumulation from particle surfaces.

  3. Range extension of Myotis midastactus​ (Chiroptera, Vespertilionidae) to Paraguay

    PubMed Central

    Idárraga, Liu; Wilson, Don Ellis

    2015-01-01

    Abstract Background Myotis midastactus Moratelli and Wilson, 2014 (Vespertilionidae, Myotinae) was described from the Myotis simus Thomas, 1901 complex based on collections from the Bolivian Savannah. New information Four vouchers previously assigned to M. simus from the Alto Chaco in Paraguay (West of the Paraguay River) are reassigned here to M. midastactus. These specimens extend the geographic distribution of M. midastactus 1200 km southward, and constitute the first evidence of the species in the country. Based on other material from the Brazilian Pantanal and Cerrado, Central Paraguay and north-eastern Argentina, we also discuss the identity of simus-like populations south of the Amazon Basin. The status of these populations is still unclear, but the little evidence we have at hand indicates that these populations may represent another taxon—M. guaycuru Proença, 1943; whereas M. simus seems to be restricted to the Amazon basin. This hypothesis is still very speculative and requires further investigation. With the assignment of material from Alto Chaco to M. midastactus, seven species of Myotis are confirmed for Paraguay: M. albescens, M. lavali, M. levis, M. midastactus, M. nigricans, M. riparius, and M. ruber. PMID:26379462

  4. The legacy of pesticide pollution: An overlooked factor in current risk assessments of freshwater systems.

    PubMed

    Rasmussen, Jes J; Wiberg-Larsen, Peter; Baattrup-Pedersen, Annette; Cedergreen, Nina; McKnight, Ursula S; Kreuger, Jenny; Jacobsen, Dean; Kristensen, Esben A; Friberg, Nikolai

    2015-11-01

    We revealed a history of legacy pesticides in water and sediment samples from 19 small streams across an agricultural landscape. Dominant legacy compounds included organochlorine pesticides, such as DDT and lindane, the organophosphate chlorpyrifos and triazine herbicides such as terbutylazine and simazine which have long been banned in the EU. The highest concentrations of legacy pesticides were found in streams draining catchments with a large proportion of arable farmland suggesting that they originated from past agricultural applications. The sum of toxic units (SumTUD.magna) based on storm water samples from agriculturally impacted streams was significantly higher when legacy pesticides were included compared to when they were omitted. Legacy pesticides did not significantly change the predicted toxicity of water samples to algae or fish. However, pesticide concentrations in bed sediment and suspended sediment samples exceeded safety thresholds in 50% of the samples and the average contribution of legacy pesticides to the SumTUC.riparius was >90%. Our results suggest that legacy pesticides can be highly significant contributors to the current toxic exposure of stream biota, especially macroinvertebrate communities, and that those communities were primarily exposed to legacy pesticides via the sediment. Additionally, our results suggest that neglecting legacy pesticides in the risk assessment of pesticides in streams may severely underestimate the risk of ecological effects. PMID:26207877

  5. In-stream validation of the effects of intermittent sediment toxicity on recruitment of juvenile unionid mussels

    SciTech Connect

    Yeager, M.M.; Cherry, D.S.; Scott, J.C.; Van Hassel, J.H.

    1994-12-31

    A triad approach was used to assess sediment toxicity in the Clinch River, Virginia to determine if sediment bound toxicants are contributing to decreased recruitment of unionid mussel populations. Eleven sites in the Clinch River and one site in a tributary, which exhibited suitable mussel habitat, were included in the analysis. Physical characteristics of the sediment revealed similar particle size distribution and percent water content at the twelve sites; however, three of the sites exhibited high volatile organic compounds. Total recoverable metals analysis of lead, zinc and copper in the interstitial water showed fluctuating metal concentrations throughout the river on different sampling dates. Sediment bioassays using C. riparius, D. magna, and H. azteca identified intermittent toxicity which may be related to non-point runoff from rain events. At ten of the twelve sites, mussel density surveys indicated decreased recruitment despite apparent suitable habitat. Invertebrate community structure analysis identified eight of the twelve sites as having significantly lower total abundance than the reference side and six of the twelve sites as s supporting significantly fewer taxa. In-situ juvenile mussel testing was used to determine the degree to which toxicity may impair juvenile recruitment in unionid populations.

  6. Performance of painted plywood and cloth Nzi traps relative to Manitoba and greenhead traps for tabanids and stable flies.

    PubMed

    Mihok, Steve; Carlson, David A

    2007-04-01

    Experiments were conducted to adapt the cloth Nzi trap to a format suitable for fixed applications in biting fly sampling or control. Catches of tabanids [Tabanus L., Chrysops (Meigen), and Hybomitra Enderlein], and stable flies [Stomoxys calcitrans (L.)] in painted plywood traps were compared with those in standard phthalogen blue cloth traps, and in similarly painted cloth traps. The Manitoba horse fly trap and the Tabanus nigrovittatus Macquart "greenhead" box trap were used as additional standards during one tabanid season. Shiny features of traps reduced catches, e.g., paint on cloth instead of wood, or use of aluminum screening instead of netting. Nevertheless, appropriately painted plywood Nzi traps caught as many biting flies as did standard cloth Nzi traps, if paint finishes were matte, and with the use of phthalogen blue colorants. Nzi traps collected about the same tabanid fauna as the Manitoba and T. nigrovittatus traps, but with improved catches of Chrysops and Tabanus. Recommendations are provided on appropriate color matching, and selection of readily-available materials for trap construction. PMID:17461091

  7. Seasonal Dynamics, Parity Rate, and Composition of Culicoides (Diptera: Ceratopogonidae) Occurring in the Vicinity of Wild and Domestic Ruminants in the Czech Republic.

    PubMed

    Rádrová, Jana; Mračková, Marie; Galková, Zdenka; Lamka, Jírí; Račka, Karol; Barták, Pavel; Votýpka, Jan

    2016-03-01

    In the light of the emergence of bluetongue and Schmallenberg viruses in northern and central Europe, an extensive entomological survey within the framework of a bluetongue control program was undertaken from 2008 to 2013 in the Czech Republic to investigate Culicoides biting midges (Diptera: Ceratopogonidae) collected in close proximity of domestic livestock and semiwild ruminants. Insects were sampled using CDC black-light suction traps placed overnight near ruminants in farms or in forest game preserves to provide data on Culicoides fauna collected near these two groups of hosts inhabiting different environments. From almost a half million biting midge specimens collected at 41 sampling sites, 34 species were identified including three species newly recorded for the Czech Republic: Culicoides (Oecacta) clastrieri Callot, Kremer & Deduit, Culicoides (Oecacta) odiatus Austen, and Culicoides (Pontoculicoides) saevus Kieffer. The Culicoides obsoletus species group, incriminated as a bluetongue virus vector, was predominant in both domestic livestock (91%) and semiwild game (52%). A relatively high proportion (around 30%) of C. obsoletus Meigen females with pigmented abdomen (= more likely parous) was observed from spring till autumn. In contrast, adult biting midges were found to be largely absent during at least three winter months, approximately December till March, which could be considered as the biting midge vector-free period. PMID:26701798

  8. Spatial heterogeneity of mitochondrial DNA and allozymes among populations of white-tailed deer and mule deer

    USGS Publications Warehouse

    Cronin, M.A.; Nelson, M.; Pac, D.

    1991-01-01

    A raccoon. (Procyon lotor) was observed in a weakened condition for several days at a farm a few miles east of Salisbury, Maryland. It was then caught and held in captivity for a few days. It continued to become weaker and on May 3, 1954, B. Mixon of the Maryland Department of Game and Inland Fish submitted it to us for study. There was no evidence of trauma, either internal or external. The fur was matted over the right hind leg, the inguinal region, and over much of the left hind leg. Inspection revealed the presence of thousands of larvae of the green-bottle fly, Phaenicia sericata, (Meigen}1 actively tunneling in and out of the skin and subcutaneous tissue. Muscle under lying infested skin appeared healthy and untraumatized. A few larvae were in comers of the eyes but none were found in other orifices. Gross and microscopic examination of tissue from the raccoon gave no indication of any acute process which might have led to its moribund condition. James (1947. The flies that cause myiasis in man. U. S. Govt. Print. Off.) and Hall (1948: The blowflies of North America.. Thom. Say Foundation) indicate that P. sericata may vary in virulence, some strains becoming parasitic with an ability to invade healthy tissue. In all probability, the larvae described above hatched from eggs originally laid in a skin wound although no evidence for this was found.

  9. Differential responses to artificial selection on oviposition site preferences in Drosophila melanogaster and D. simulans.

    PubMed

    Soto, Eduardo M; Betti, María I L; Hurtado, Juan; Hasson, Esteban

    2015-12-01

    The preference-performance relationship in plant-insect interactions is a central theme in evolutionary ecology. Among many insects, eggs are vulnerable and larvae have limited mobility, making the choice of an appropriate oviposition site one of the most important decisions for a female. We investigated the evolution of oviposition preferences in Drosophila melanogaster Meigen and Drosophila simulans Sturtevant by artificially selecting for the preference for 2 natural resources, grape and quince. The main finding of our study is the differential responses of D. melanogaster and D. simulans. Although preferences evolved in the experimental populations of D. melanogaster, responses were not consistent with the selection regimes applied. In contrast, responses in D. simulans were consistent with expectations, demonstrating that this species has selectable genetic variation for the trait. Furthermore, crosses between D. simulans divergent lines showed that the genetic factors involved in grape preference appear to be largely recessive. In summary, our artificial selection study suggests that D. melanogaster and D. simulans possess different genetic architectures for this trait. PMID:25263841

  10. Blow fly Lucilia sericata nuclease digests DNA associated with wound slough/eschar and with Pseudomonas aeruginosa biofilm.

    PubMed

    Brown, A; Horobin, A; Blount, D G; Hill, P J; English, J; Rich, A; Williams, P M; Pritchard, D I

    2012-12-01

    In chronic wounds, it may be clinically important to remove extracellular bacterial and patient DNA as its presence may impede wound healing and promote bacterial survival in biofilm, in which extracellular DNA forms part of the biofilm architecture. As medicinal maggots, larvae of Lucilia sericata Meigen (Diptera: Calliphoridae) have been shown to efficiently debride wounds it became of interest to investigate their excretions/secretions (ES) for the presence of a deoxyribonuclease (DNAse) activity. Excretions/secretions products were shown to contain a DNAse, with magnesium, sodium and calcium metal ion dependency, and a native molecular mass following affinity purification of approximately 45 kDa. The affinity purified DNAse degraded genomic bacterial DNA per se, DNA from the slough/eschar of a venous leg ulcer, and extracellular bacterial DNA in biofilms pre-formed from a clinical isolate of Pseudomonas aeruginosa. The latter finding highlights an important attribute of the DNAse, given the frequency of P. aeruginosa infection in non-healing wounds and the fact that P. aeruginosa virulence factors can be toxic to maggots. Maggot DNAse is thus a competent enzyme derived from a rational source, with the potential to assist in clinical wound debridement by removing extracellular DNA from tissue and biofilm, and promoting tissue viability, while liberating proteinaceous slough/eschar for debridement by the suite of proteinases secreted by L. sericata. PMID:22827809

  11. Effects of Floral Scent, Color and Pollen on Foraging Decisions and Oocyte Development of Common Green Bottle Flies.

    PubMed

    Brodie, Bekka S; Smith, Maia A; Lawrence, Jason; Gries, Gerhard

    2015-01-01

    The common green bottle fly Lucilia sericata (Meigen) and other filth flies frequently visit pollen-rich composite flowers such as the Oxeye daisy, Leucanthemum vulgare Lam. In laboratory experiments with L. sericata, we investigated the effect of generic floral scent and color cues, and of Oxeye daisy-specific cues, on foraging decisions by recently eclosed flies. We also tested the effect of a floral pollen diet with 0-35% moisture content on the ability of females to mature their oocytes. Our data indicate that (1) young flies in the presence of generic floral scent respond more strongly to a uniformly yellow cue than to any other uniform color cue (green, white, black, blue, red) except for ultraviolet (UV); (2) the floral scent of Oxeye daisies enhances the attractiveness of a yellow cue; and (3) moisture-rich pollen provides nutrients that facilitate ovary maturation of flies. With evidence that L. sericata exploits floral cues during foraging, and that pollen can be an alternate protein source to animal feces and carrion, Pollen apparently plays a major role in the foraging ecology of L. sericata and possibly other filth flies. These flies, in turn, may play a significant role as pollinators, as supported by a recently published study. PMID:26717311

  12. Identification and transcriptional profiling of differentially expressed genes associated with response to UVA radiation in Drosophila melanogaster (Diptera: Drosophilidae).

    PubMed

    Zhou, Li-Jun; Zhu, Zhi-Hui; Liu, Zhen-Xing; Ma, Wei-Hua; Desneux, Nicolas; Lei, Chao-Liang

    2013-10-01

    Ultraviolet A (UVA) radiation, the major component of solar ultraviolet (UV) radiation reaching the earth's surface, leads to negative effects in insects, such as oxidative stress, photoreceptor damage, and cell death. To better understand the molecular mechanisms of insect response to UVA radiation, suppression subtractive hybridization (SSH) and real-time quantitative polymerase chain reaction approaches were combined to reveal differential transcript expression in Drosophila melanogaster Meigen, 1830 (Diptera: Drosophilidae). In this study, two subtractive cDNA libraries were constructed and sequenced, obtaining 131 high-quality unique expressed sequence tags (ESTs) that were up- or downregulated in D. melanogaster exposed to UVA radiation for 0.5 h. Of the 131 ESTs, 102 unique ESTs were differentially expressed and classified into 10 functional categories. The results showed that UVA radiation induces expression of genes related to stress and defense response and metabolism. Potential transcription factor binding motifs upstream of these genes are associated with multiple signaling pathways that may help the insect cope with the stress of UVA radiation. To our knowledge, this is the first analysis of insect response to UVA radiation at the transcriptional level. Our results reveal that UVA radiation influences the expression profiles of stress-responsive genes and provide further insights into the mechanisms of adaptive response to UVA radiation stress. PMID:24331622

  13. Ostrinia nubilalis parasitism and the field abundance of non-target insects in transgenic Bacillus thuringiensis corn (Zea mays).

    PubMed

    Bourguet, Denis; Chaufaux, Josette; Micoud, Annie; Delos, Marc; Naibo, Bernard; Bombarde, Fany; Marque, Gilles; Eychenne, Nathalie; Pagliari, Carine

    2002-10-01

    In this study, we evaluated in field trials the effects on non-target species, of transgenic corn producing the Cry1Ab toxin of Bacillus thuringiensis (Bt). In 1998, we collected Ostrinia nubilalis (Hübner) larvae from transgenic Bt corn (Novartis Hybrid 176) and non-Bt corn at four geographical sites. We found a significant variation in parasitism by the tachinids Lydella thompsoni (Herting) and Pseudoperichaeta nigrolineata (Walker) among sites, and more parasitism in non-Bt than in Bt fields. The Bt effect did not vary significantly among fields. In 1999, we performed a field experiment at two sites, comparing the temporal abundance of non-target arthropods in Bt corn (Monsanto Hybrid MON810) and non-Bt corn. The non-target insects studied included the aphids Metopolophium dirhodum (Walker), Rhopalosiphum padi (L.) and Sitobion avenae (F.), the bug Orius insidiosus (Say), the syrphid Syrphus corollae (Meigen), the ladybird Coccinella septempunctata (L.), the lacewing Chrysoperla carnea (Stephens), thrips and hymenopteran parasitoids. For all species but one, the number of individuals varied greatly over the season but did not differ between the types of corn. The only exception was thrips which, at one site, was significantly more abundant in Bt corn than in non-Bt corn. However this difference did not remain significant when we took the multiple tests into account. Implications for pest resistance management, population dynamics and risk assessment are discussed. PMID:15612256

  14. Biogeography of Drosophila (Diptera: Drosophilidae) in East and Southeast Asia

    PubMed Central

    Robert Liu, Fu-Guo; Tsaur, Shun-Chern; Huang, Hsiao-Ting

    2015-01-01

    The causes of high biological diversity in biodiversity hotspots have long been a major subject of study in conservation biology. To investigate this matter, we conducted a phylogeographic study of five Drosophila (Diptera: Drosophilidae) species from East and Southeast Asia: Drosophila albomicans Duda, D. formosana Duda, D. immigrans Sturtevant, D. melanogaster Meigen, and D. simulans Sturtevant. We collected 185 samples from 28 localities in eight countries. From each collected individual, we sequenced the autosomal extra sex comb gene (esc) and seven mitochondrial genes, including nicotinamide adenine dinucleotide hydrate-reductase dehydrogenase subunit 4 (ND4), ND4L, tRNA-His, tRNA-Pro, tRNA-Thr, partial ND5, and partial ND6. Phylogenetic analyses using maximum- likelihood and Bayesian methods revealed interesting population structure and identified the existence of two distinct D. formosana lineages (Southeast Asian and Taiwanese populations). Genetic differentiation among groups of D. immigrans suggests the possibility of endemic speciation in Taiwan. In contrast, D. melanogaster remained one extensively large population throughout East and Southeast Asia, including nearby islets. A molecular clock was used to estimate divergence times, which were compared with past geographical events to infer evolutionary scenarios. Our findings suggest that interglacial periods may have caused population isolation, thus enhancing population differentiation more strongly for some of the Drosophila species. The population structure of each Drosophila species in East and Southeast Asia has been influenced by past geographic events. PMID:26078303

  15. Maintenance of residual activity of Bt toxin by using natural and synthetic dyes: a novel approach for sustainable mosquito vector control.

    PubMed

    Chandrashekhar, Patil; Rahul, Suryawanshi; Hemant, Borase; Chandrakant, Narkhede; Bipinchandra, Salunke; Satish, Patil

    2015-01-01

    Mosquito control protein from Bacillus thuringiensis gets inactivated with exposure to sunlight. To address this issue, the potential of synthetic and natural dye was investigated as sunlight protectants. Bt SV2 in absence of dyes when exposed to sunlight showed reduced effectiveness against the fourth instars of mosquito larvae. Whereas acriflavin, congo red and violacein were able to maintain 86.4%, 91.6% and 82.2% mosquito larvicidal efficacy of Bt SV2 against IVth instars larvae of Anopheles stephensi Meigen after exposure to sunlight. Similarly, beetroot dye, acriflavin, congo red and violacein maintained 98.4%, 97.1%, 90.8% and 70.7% larvicidal activities against Aedes aegypti Linnaeus after sunlight exposure. Prodigiosin was found to be the best photo-protectant by simultaneously protecting and enhancing Bt activity by 6.16% and 22.16% against A. stephensi and A. aegypti, respectively. Combination of dyes with Bt formulations can be a good strategy for mosquito control programmes in tropical and sub-tropical regions. PMID:25699646

  16. Evaluation of matrix-assisted laser desorption/ionization time of flight mass spectrometry for characterization of Culicoides nubeculosus biting midges.

    PubMed

    Kaufmann, C; Ziegler, D; Schaffner, F; Carpenter, S; Pflüger, V; Mathis, A

    2011-03-01

    Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) has shown promise in species identification of insect species. We evaluated its potential to consistently characterize laboratory-reared biting midges of the species Culicoides nubeculosus (Meigen) (Diptera: Ceratopogonidae). Twenty-one reproducible potential biomarker masses for C. nubeculosus were identified under different experimental treatments. These treatments included the homogenization of insects in either water or known concentrations of formic acid. The biomarker masses were present independent of age, gender and different periods of storage of individuals in 70% ethanol (a standard preservation method). It was found that the presence of blood in females reduced the intensity of the MALDI-TOF pattern, necessitating the removal of the abdomen before analysis. The protein profiles of a related non-biting midge, Forcipomyia sp. (Diptera: Ceratopogonidae), and of Aedes japonicus japonicus (Theobald) (Diptera: Culicidae) mosquitoes were also examined and were distinctly different. These findings provide preliminary data to optimize future studies in differentiation of species within the Culicoides genus using MALDI-TOF MS which is a rapid, simple, reliable and cost-effective technique. PMID:21118284

  17. The impacts of larval density and protease inhibition on feeding in medicinal larvae of the greenbottle fly Lucilia sericata.

    PubMed

    Wilson, M R; Nigam, Y; Jung, W; Knight, J; Pritchard, D I

    2016-03-01

    Larval therapy, the therapeutic use of blowfly larvae to treat chronic wounds, is primarily used in debridement. There are, however, gaps in current knowledge of the optimal clinical application of the therapy and mechanisms of action in the debridement process. Using an artificial assay, two studies were undertaken to investigate these aspects of larval debridement by Lucilia sericata Meigen (Diptera: Calliphoridae); the first studied the effects of the density of larvae on tissue digestion and larval mass, and the second considered the effects on the same parameters of incorporating protease inhibitors into the feeding substrate. The total mass of tissue digested increased with larval density until saturation was observed at 5.0-7.5 larvae/cm(2) . This range was considered optimal as lower doses resulted in the removal of less tissue and higher doses offered no additional tissue removal and appeared to exacerbate competition for feeding. In the second study, increased protease inhibitor concentration led to significant decreases in tissue digestion and larval mass, suggesting that serine proteases, particularly trypsin, may play major roles in larval digestion. Such information is important in elucidating the main constituents that make up larval digestive products and may be significant in the development of new therapies. PMID:26463514

  18. Biting midges (Diptera: Ceratopogonidae) from Martín García Island, Argentina.

    PubMed

    Ronderos, María M; Marino, Pablo I; Díaz, Florentina; Estévez, Ana L

    2011-09-01

    Nearly 230 species of biting midges have been recorded or described from Argentina; 38 of them are known from the Buenos Aires province and only one is cited from Martín García Island. This paper presents the results raised from six collecting trips which took place on the island during spring 2005, summer 2006 and autumn 2009. Diverse sampling sites including permanent and temporary aquatic environments were chosen, most of the ten sampling sites were ponds of diverse origin, some of these environments were covered with floating vegetation as Lemna gibba, Lemna minuscule, Salvinia biloba, Salvinia minima, Azolla filiculoides, Limnobium laevigatum, Pistia stratiotes, Spirodela intermedia, Wolffiella oblonga and Wolffia columbiana. Other sites were placed in urban and suburban areas. Adults were collected with sweep nets at sunrise and sunset and with light traps at intervals of four to five hours at night, depending on electricity availability on the island. Larvae and pupae were collected with different implements depending on characteristics of each surveyed aquatic habitat. In free standing water, they were captured with small sieves or hand pipettes and micropipettes, flotation techniques were utilized for sampling vegetated areas, free and rooted floating hydrophytes were extracted for removing insects among them. Thirteen species of Ceratopogonidae were collected, three of Atrichopogon Kieffer, three of Forcipomyia Meigen, two of Dasyhelea Kieffer, four of Culicoides Latreille, and one of Bezzia Kieffer, all representing new records from the island. PMID:22017124

  19. The Sarcophagidae (Insecta: Diptera) described by Chien-ming Chao and Xue-zhong Zhang.

    PubMed

    Zhang, Dong; Zhang, Ming; Li, Zijuan; Pape, Thomas

    2015-01-01

    The twenty-nine species-group names of Sarcophagidae proposed by Chien-ming Chao and Xue-zhong Zhang are reviewed. Of these names, twenty-four are available, while five are unavailable nomina nuda. Of the twenty-four available names, nine are considered valid, fifteen as invalid: thirteen junior synonyms, one unnecessary replacement name and one junior primary homonym. Holotypes of all species, and allotypes when available, are photographed and the species redescribed based on the type material. Eight new synonyms are proposed: Miltogramma tibita Chao & Zhang, 1988, syn. n. of Miltogramma taeniata Meigen, 1824; Sphenometopa luridimacula Chao & Zhang, 1988, syn. n. of Sphenometopa stackelbergiana Rohdendorf, 1967; Sphenometopa mesomelaenae Chao & Zhang, 1988, syn. n. of Sphenometopa stelviana (Brauer & Bergenstamm, 1891); Sphenometopa altajica Rohdendorf, 1971, syn. n. of Sphenometopa stelviana (Brauer & Bergenstamm, 1891); Sarcophila mongolica Chao & Zhang, 1988, syn. n. of Sarcophila latifrons (Fallén, 1817); Wohlfahrtia brevicornis Chao & Zhang, 1996, syn. n. of Wohlfahrtia grunini Rohdendorf, 1969; Wohlfahrtia hirtiparafacialis Chao & Zhang, 1996, syn. n. of Wohlfahrtia magnifica (Schiner, 1862); and Wohlfahrtiodes mongolicus Chao & Zhang, 1988, syn. n. of Asiosarcophila kaszabi Rohdendorf & Verves, 1978. The genus Asiosarcophila Rohdendorf & Verves, 1978 is herewith reported from China for the first time, along with the five species A. kaszabi, M. taeniata, S. stackelbergiana, S. stelviana and W. grunini. PMID:25947705

  20. The Effect of Combinations of Food Insects for Continuous Rearing of the Wing Polymorphic Water Strider Limnogonus Fossarum fossarum (Hemiptera: Gerridae).

    PubMed

    Hirooka, Y; Hagizuka, C; Ohshima, I

    2016-01-01

    The water strider Limnogonus fossarum fossarum (F.) (Hemiptera: Gerridae) shows a macropterous, micropterous, and apterous polymorphism. Although a long photoperiod condition induces winged morphs, preliminary studies have revealed that crossing between winged morphs increased the proportion of macropterous individuals, suggesting that the genetic factors also affect wing-morph determination in this species. Assessing the genetic backgrounds of wing polymorphism requires constant and repeatable methods for rearing. This study attempts to establish a continuous rearing method for L. f. fossarum under constant diet conditions. Initially, we maintain the water striders with two Drosophila species as a food, but viability until adulthood is less than 20%. We then add the storage pest Plodia interpunctella (Hübner), which are readily reared in the laboratory, to the diets. As a result, nymphs fed on P. interpunctella (even only until the second instar) show significantly higher viability and shorter developmental period than nymphs fed on Drosophila alone. Moreover, feeding on D. melanogaster (Meigen) reared on cholesterol-enriched medium instead of a normal medium significantly increases viability in the next generation. This means that only the two food-insect species are enough for establishing a substantial number of individuals in segregating generations (F2 and backcross), limiting DNA and RNA contaminations from food insects with genome information. Thus, the present rearing method opens the way to elucidating the genetic backgrounds of the wing polymorphism in L. f. fossarum. PMID:27620554

  1. The Effect of Combinations of Food Insects for Continuous Rearing of the Wing Polymorphic Water Strider Limnogonus Fossarum fossarum (Hemiptera: Gerridae)

    PubMed Central

    Hirooka, Y.; Hagizuka, C.; Ohshima, I.

    2016-01-01

    The water strider Limnogonus fossarum fossarum (F.) (Hemiptera: Gerridae) shows a macropterous, micropterous, and apterous polymorphism. Although a long photoperiod condition induces winged morphs, preliminary studies have revealed that crossing between winged morphs increased the proportion of macropterous individuals, suggesting that the genetic factors also affect wing-morph determination in this species. Assessing the genetic backgrounds of wing polymorphism requires constant and repeatable methods for rearing. This study attempts to establish a continuous rearing method for L. f. fossarum under constant diet conditions. Initially, we maintain the water striders with two Drosophila species as a food, but viability until adulthood is less than 20%. We then add the storage pest Plodia interpunctella (Hübner), which are readily reared in the laboratory, to the diets. As a result, nymphs fed on P. interpunctella (even only until the second instar) show significantly higher viability and shorter developmental period than nymphs fed on Drosophila alone. Moreover, feeding on D. melanogaster (Meigen) reared on cholesterol-enriched medium instead of a normal medium significantly increases viability in the next generation. This means that only the two food-insect species are enough for establishing a substantial number of individuals in segregating generations (F2 and backcross), limiting DNA and RNA contaminations from food insects with genome information. Thus, the present rearing method opens the way to elucidating the genetic backgrounds of the wing polymorphism in L. f. fossarum. PMID:27620554

  2. Sequential sampling: A cost-effective approach for monitoring benthic macroinvertebrates in environmental impact assessments

    SciTech Connect

    Resh, V.H.; Price, D.G.

    1984-01-01

    Sequential sampling is a method for monitoring benthic macroinvertebrates that can significantly reduce the number of samples required to reach a decision, and consequently, decrease the cost of benthic sampling in environmental impact assessments. Rather than depending on a fixed number of samples, this analysis cumulatively compares measured parameter values (for example, density, community diversity) from individual samples, with thresholds that are based on specified degrees of precision. In addition to reducing sample size, a monitoring program based on sequential sampling can provide clear-cut decisions as to whether a priori-defined changes in the measured parameter(s) have or have not occurred. As examples, sequential sampling programs have been developed to evaluate the impact of geothermal energy have been developed to evaluate the impact of geothermal energy development on benthic macroinvertebrate diversity at The Geysers, California, and for monitoring the impact of crude oil contamination on chironomid midge (Cricotopus bicinctus (Meigen) and C. mackenziensis Oliver) population densities in the Trail River, Northwest Territories, Canada.

  3. Comparative analysis of distribution and abundance of West Nile and Eastern Equine Encephalomyelitis virus vectors in Suffolk County, New York, using human population density and land use/cover data

    USGS Publications Warehouse

    Rochlin, I.; Harding, K.; Ginsberg, H.S.; Campbell, S.R.

    2008-01-01

    Five years of CDC light trap data from Suffolk County, NY, were analyzed to compare the applicability of human population density (HPD) and land use/cover (LUC) classification systems to describe mosquito abundance and to determine whether certain mosquito species of medical importance tend to be more common in urban (defined by HPD) or residential (defined by LUC) areas. Eleven study sites were categorized as urban or rural using U.S. Census Bureau data and by LUC types using geographic information systems (GISs). Abundance and percent composition of nine mosquito taxa, all known or potential vectors of arboviruses, were analyzed to determine spatial patterns. By HPD definitions, three mosquito species, Aedes canadensis (Theobald), Coquillettidia perturbans (Walker), and Culiseta melanura (Coquillett), differed significantly between habitat types, with higher abundance and percent composition in rural areas. Abundance and percent composition of these three species also increased with freshwater wetland, natural vegetation areas, or a combination when using LUC definitions. Additionally, two species, Ae. canadensis and Cs. melanura, were negatively affected by increased residential area. One species, Aedes vexans (Meigen), had higher percent composition in urban areas. Two medically important taxa, Culex spp. and Aedes triseriatus (Say), were proportionally more prevalent in residential areas by LUC classification, as was Aedes trivittatus (Coquillett). Although HPD classification was readily available and had some predictive value, LUC classification resulted in higher spatial resolution and better ability to develop location specific predictive models.

  4. Forensically important calliphoridae (diptera) associated with pig carrion in rural north-central Florida

    USGS Publications Warehouse

    Gruner, Susan V.; Slone, D.H.; Capinera, J.L.

    2007-01-01

    A study to determine the relative abundance and seasonality of forensically important blow flies (Diptera: Calliphoridae) in rural north-central Florida was conducted using pig carcasses (Sus scrofa L.) as models for human bodies. Seven species of Calliphoridae were collected: Lucilia coeruleiviridis (=Phoenicia) (Macquart), Cochliomyia macellaria (F.), Chrysomya rufifaces (Macquart), Phormia regina (Meigen), Chrysomya megacephala (F.), and a few specimens of Calliphora livida Hall, and Calliphora vicina Robineau-Desvoidy. Species composition in aerial collections of adult flies, preserved larval collections, and samples of larvae reared to the adult stage were all highly correlated. Relative abundance of the species found was significantly different, with L. coeruleiviridis the most abundant species year-round. The relative abundance of the collected species varied significantly by day of decomposition and by season, with significant interactions between season and day, season and species, and day and species. L. coeruleiviridis, C. macellaria, C. rufifaces, and P. regina were found during the entire year, two C. vicina specimens and 11 C. livida specimens were collected from December to March, whereas C. megacephala was collected only from June through September. ?? 2007 Entomological Society of America.

  5. In vitro effects of household products on Calliphoridae larvae development: implication for forensic entomology.

    PubMed

    Aubernon, Cindy; Devigne, Cedric; Hedouin, Valery; Gosset, Didier; Charabidze, Damien

    2015-01-01

    Several parameters can delay the first arrival of flies on a corpse and the subsequent development of the larvae. This study focuses on the development of Lucilia sericata (Diptera: Calliphoridae) (Meigen, 1826) on household chemical-contaminated substrates. bleach, perfume, hydrochloric acid, caustic soda, insecticide, mosquito repellent, and gasoline in quantities consistent with an amount that could possibly be spilled on a corpse were mixed with beef liver to simulate contaminated fleshes. Larvae were bred at 25 °C on these media until emergence. Four developmental parameters were followed: survival rates, development times, sex ratios, and adult sizes. Hydrochloric acid, insecticide, and gasoline killed all larvae. In low quantities, caustic soda and mosquito repellent increased the development time and decreased the adult size. However, high quantities of these chemicals killed all larvae. Lastly, bleach and perfume did not affect the survival rate and barely impacted the development time or adult size. These results demonstrate common household products spilled on a corpse can strongly affect the development of Calliphoridae larvae. The effects of such products should be considered in forensic entomology cases. PMID:25066081

  6. Mating Experience and Food Deprivation Modulate Odor Preference and Dispersal in Drosophila melanogaster Males

    PubMed Central

    Wang, Shu-Ping; Guo, Wei-Yan; Muhammad, Shahid Arain; Chen, Rui-Rui; Mu, Li-Li; Li, Guo-Qing

    2014-01-01

    Rotting fruits offer all of the known resources required for the livelihood of Drosophila melanogaster Meigen (Diptera: Drosophilidae). During fruit fermentation, carbohydrates and proteins are decomposed to produce volatile alcohols and amines, respectively. It is hypothesized that D. melanogaster adults can detect these chemical cues at a distance to identify and locate the decaying fruits. In the present paper, we compared the olfactory responses and movement of male flies varying in mating status and nutritional state to methanol, ethanol, and ammonia sources using a glass Y-tube olfactometer. In general, ethanol vapor at low to moderate concentrations repelled more hungry mated males than satiated ones. In contrast, methanol showed little difference in the attractiveness to males at different nutritional states and mating status. Moreover, ammonia attracted more hungry mated males. The attractiveness increased almost linearly with ammonia concentration from lowest to highest. When ammonia and artificial diet were put together in the odor arm, the responses of male flies to mixed odor mimicked the response to ammonia. Furthermore, odorant concentration, mating status, and nutritional state affected the flies' dispersal. Mated and starved males dispersed at a higher rate than virgin and satiated ones. Thus, our results showed that starved, mated males increased dispersal and preferred ammonia that originated from protein. PMID:25368075

  7. Distribution of individual members of the mosquito Anopheles maculipennis complex in Germany identified by newly developed real-time PCR assays.

    PubMed

    Lühken, R; Czajka, C; Steinke, S; Jöst, H; Schmidt-Chanasit, J; Pfitzner, W; Becker, N; Kiel, E; Krüger, A; Tannich, E

    2016-06-01

    Owing to their role as vectors of malaria parasites, species of the Anopheles maculipennis complex (Diptera: Culicidae) Meigen were intensively studied in the past, but with the disappearance of malaria in Germany in the middle of the last century, the interest in this field of research declined. A comprehensive ecological analysis of the current species distribution for Germany is lacking. Between 2010 and 2013, a total of 1445 mosquitoes of the An. maculipennis complex were collected at 72 different sites in Germany. The samples comprise 722 single individuals as well as 723 individuals in 90 pools of up to 25 mosquitoes. All samples were analysed with newly developed species-specific qPCR assays for the identification of the four German species using nucleotide differences within the internal transcribed spacer 2 (ITS2) ribosomal DNA. All gathered data were used for species distribution modelling. The overall prevalence of An. messeae s.l. was highest with 98.89% of all pools; An. daciae with 6.93% of all individuals and An. messeae s.s. with 69.53%. The prevalence of the other two species was relatively low: An. maculipennis s.s. with 13.30% of all individuals (6.67% of all pools) and An. atroparvus with 1.80% of all individuals (1.11% of all pools). PMID:26787387

  8. Croatian aquatic dance flies (Diptera: Empididae: Clinocerinae and Hemerodromiinae): species diversity, distribution and relationship to surrounding countries.

    PubMed

    Ivković, Marija; Gračan, Romana; Horvat, Bogdan

    2013-01-01

    A checklist of aquatic Empididae (dance flies) from Croatia (36 species in subfamily Clinocerinae and 14 species in subfamily Hemerodromiinae) is presented, including information related to the Ecoregions in which species were found and specific species traits. Clinocerinae are represented by five genera, with Wiedemannia Zetterstedt being most species rich (20 species) and Clinocerella Engel least numerous with only one species. In Hemerodromiinae there are 8 species of Chelifera Macquart and 6 species and Hemerodromia Meigen. In addition, a discussion related to the species included and excluded from the list is provided. Most species are univoltine with adults emerging in Spring and Summer, although Kowarzia barbatula Mik and Wiedemannia (Eucelidia) zetterstedti (Fallén) are present throughout the year and Wiedemannia (Chamaedipsia) aequilobata Mandaron occurrs in Winter. The Croatian species assemblage is similar to the well-studied fauna of neighboring Slovenia (63 spp.). It is recommended that some rare species and the streams they inhabit should be considered for greater protection. PMID:26473217

  9. Volatile pheromone signalling in Drosophila.

    PubMed

    Smith, Dean P

    2012-03-01

    Once captured by the antenna, 11-cis vaccenyl acetate (cVA) binds to an extracellular binding protein called LUSH that undergoes a conformational shift upon cVA binding. The stable LUSH-cVA complex is the activating ligand for pheromone receptors present on the dendrites of the aT1 neurones, comprising the only neurones that detect cVA pheromone. This mechanism explains the single molecule sensitivity of insect pheromone detection systems. The receptor that recognizes activated LUSH consists of a complex of several proteins, including Or67d, a member of the tuning odourant receptor family, Orco, a co-receptor ion channel, and SNMP, a CD36 homologue that may be an inhibitory subunit. In addition, genetic screens and reconstitution experiments reveal additional factors that are important for pheromone detection. Identification and functional dissection of these factors in Drosophila melanogaster Meigen should permit the identification of homologous factors in pathogenic insects and agricultural pests, which, in turn, may be viable candidates for novel classes of compounds to control populations of target insect species without impacting beneficial species. PMID:24347807

  10. Response of Lucilia sericata (Diptera: Calliphoridae) to Screwworm Oviposition Attractant.

    PubMed

    Chaudhury, M F; Zhu, J J; Skoda, S R

    2015-07-01

    The sheep blowfly, Lucilia sericata Meigen (Diptera: Calliphoridae), causes sheep myiasis in various parts of the world. Female flies are attracted to sheep following various olfactory cues emanating from the sheep's body, and oviposit on suitable substrates on sheep ultimately causing myiasis. Earlier workers attempted to reduce fly population in the field, with some success, using traps baited with various attractants. This research was conducted to determine if L. sericata would respond to a recently developed synthetic attractant that has attracted gravid screwworms, Cochliomyia hominivorax Coquerel, and stimulated them to oviposit. Results of the laboratory bioassays demonstrated that gravid females L. sericata were attracted to substrates treated with the synthetic screwworm attractant composed of five compounds--dimethyl disulfide, dimethyl trisulfide, phenol, p-cresol, and indole. Tests with various combinations of these compounds suggest that the sulfur compounds and indole are the most important compounds to elicit attraction and stimulate oviposition, while phenol and p-cresol may have minor roles. Semiochemical baits based on these compounds may be useful in the field to trap gravid L. sericata. PMID:26335458

  11. Drosophila melanogaster locomotion in cold thin air.

    PubMed

    Dillon, Michael E; Frazier, Melanie R

    2006-01-01

    The alpine environment is likely to challenge insect locomotion because of low mean temperatures and reduced barometric pressure. In this study, we measured the direct and interactive effects of these factors on walking and flight performance of wild-caught Drosophila melanogaster Meigen. We found that decreased temperature and decreased air pressure both reduced walking speed and flight performance. Flies walked more slowly at 18 degrees C and in the lowest air pressure treatment (34 kPa). This treatment, equivalent in air pressure to the top of Mount Everest, was the only air pressure that significantly reduced fly walking speed. Therefore, walking performance in the wild is likely limited by temperature, but not oxygen availability. In contrast to walking performance, low but ecologically realistic air pressures dramatically reduced overall flight performance. The effects of reduced air pressure on flight performance were more pronounced at colder temperatures. Reduced flight performance in high altitude conditions was primarily driven by an increased reluctance for flies to initiate flight rather than outright failure to fly. Such reluctance to fly in high altitude conditions may in part explain the prevalence of aptery and brachyptery in high altitude insects. The observed interactive effects of temperature and air pressure on flight performance confirm the importance of simultaneously manipulating both of these factors when studying the impact of altitudinal conditions on insect physiology and behavior. PMID:16391358

  12. Species Composition and Seasonal Distribution of Mosquito Larvae (Diptera: Culicidae) in Southern New Jersey, Burlington County.

    PubMed

    Verna, Thomas N

    2015-09-01

    A total of 36,495 larvae consisting of 45 species from 11 genera were collected from 7,189 sites from southern New Jersey, Burlington County between the months of March and October, 2001-2014. Density and seasonal distribution were determined among natural and artificial habitat. The most dominant species collected from natural habitat was Aedes vexans (Meigen) followed by Ochlerotatus canadensis canadensis (Theobald), Culex restuans Theobald, Culex pipiens L., and Culex territans Walker. The most dominant species collected from artificial habitat was Aedes albopictus (Skuse) followed by Ochlerotatus japonicus japonicus (Theobald), Cx. restuans, Cx. pipiens, and Ochlerotatus triseriatus (Say). Cx. restuans and Cx. pipiens were the only species categorized as dominant among both natural and artificial habitat and comprised greater than half the total density. Sympatry was common among dominant species from artificial habitat where a significant percentage of the total collection contained multiple species. The most common types of natural habitats were forested depressions and stream flood plains whereas rimless vehicle tires and various plastic containers were the most common artificial habitats. The pitcher plant Sarracenia purpurea L. was the only habitat exclusive to one species. PMID:26336214

  13. Decomposition of Concealed and Exposed Porcine Remains in the North Carolina Piedmont.

    PubMed

    Cammack, J A; Cohen, A C; Kreitlow, K L; Roe, R M; Watson, D W

    2016-01-01

    We examined the decomposition and subsequent insect colonization of small pig carrion (Sus scrofa (L.)) placed in concealed and open environments during spring, summer, and fall in Raleigh, North Carolina, as a model for juvenile human remains. Remains were concealed in simulated attics in three manners, ranging from minimal to well-concealed. Concealment had a significant effect on the insect community colonizing the remains across all three seasons; the beetles Necrobia rufipes (DeGeer) (Cleridae) and Dermestes maculatus (DeGeer) (Coleoptera: Dermestidae) were the only species indicative of remains located indoors, whereas numerous fly (Diptera: Calliphoridae, Muscidae, Sepsidae, and Piophilidae) and beetle (Coleoptera: Silphidae, Staphylinidae, and Histeridae) species and an ant species (Hymenoptera: Formicidae, Prenolepis sp.) were indicative of remains located outdoors. Season also significantly affected the insect species, particularly the blow flies (Diptera: Calliphoridae) colonizing remains: Lucilia illustris (Meigen) was indicative of the spring, Cochliomyia macellaria (F.) and Chrysomya megacephala (F.) were indicative of the summer, and Calliphora vicina Robineau-Desvoidy and Calliphora vomitoria (L.) were indicative of the fall. In addition, across all seasons, colonization was delayed by 35–768 h, depending on the degree of concealment. These differences among the insect communities across seasons and concealment treatments, and the effects of concealment on colonization indicate that such information is important and should to be considered when analyzing entomological evidence for criminal investigations. PMID:26590193

  14. Laboratory and field evaluations of chemical and plant-derived potential repellents against Culicoides biting midges in northern Spain.

    PubMed

    González, M; Venter, G J; López, S; Iturrondobeitia, J C; Goldarazena, A

    2014-12-01

    The efficacy of 23 compounds in repelling Culicoides biting midges (Diptera: Ceratopogonidae), particularly Culicoides obsoletus (Meigen) females, was determined by means of a Y-tube olfactometer. The 10 most effective compounds were further evaluated in landing bioassays. The six most promising compounds (including chemical and plant-derived repellents) were evaluated at 10% and 25% concentrations in field assays using Centers for Disease Control (CDC) light traps. At least three compounds showed promising results against Culicoides biting midges with the methodologies used. Whereas olfactometer assays indicated DEET at 1 µg/µL to be the most effective repellent, filter paper landing bioassays showed plant-derived oils to be better. Light traps fitted with polyester mesh impregnated with a mixture of octanoic, decanoic and nonanoic fatty acids at 10% and 25% concentrations collected 2.2 and 3.6 times fewer midges than control traps and were as effective as DEET, which is presently considered the reference standard insect repellent. The best plant-derived product was lemon eucalyptus oil. Although these have been reported as safe potential repellents, the present results indicate DEET and the mixture of organic fatty acids to be superior and longer lasting. PMID:25079042

  15. Effects of Floral Scent, Color and Pollen on Foraging Decisions and Oocyte Development of Common Green Bottle Flies

    PubMed Central

    Brodie, Bekka S.; Smith, Maia A.; Lawrence, Jason; Gries, Gerhard

    2015-01-01

    The common green bottle fly Lucilia sericata (Meigen) and other filth flies frequently visit pollen-rich composite flowers such as the Oxeye daisy, Leucanthemum vulgare Lam. In laboratory experiments with L. sericata, we investigated the effect of generic floral scent and color cues, and of Oxeye daisy-specific cues, on foraging decisions by recently eclosed flies. We also tested the effect of a floral pollen diet with 0–35% moisture content on the ability of females to mature their oocytes. Our data indicate that (1) young flies in the presence of generic floral scent respond more strongly to a uniformly yellow cue than to any other uniform color cue (green, white, black, blue, red) except for ultraviolet (UV); (2) the floral scent of Oxeye daisies enhances the attractiveness of a yellow cue; and (3) moisture-rich pollen provides nutrients that facilitate ovary maturation of flies. With evidence that L. sericata exploits floral cues during foraging, and that pollen can be an alternate protein source to animal feces and carrion, Pollen apparently plays a major role in the foraging ecology of L. sericata and possibly other filth flies. These flies, in turn, may play a significant role as pollinators, as supported by a recently published study. PMID:26717311

  16. [Anopheles mosquitoes (Diptera, Culicidae) of the Tien Shan: morphological, cytogenetic, and molecular genetic analysis].

    PubMed

    Gordeev, M I; Zvantsov, A B; Goriacheva, I I; Shaĭkevich, E V; Ezhov, M N; Usenbaev, N T; Shapieva, Zh Zh; Zhakhongirov, Sh M

    2008-01-01

    Morphological, cytogenetic, and molecular genetic studies of the Anopheles fauna in the valley and foothills of the Tien Shan identified 5 species of malaria mosquitoes: An. artemievi Gordeev et al., An. messeae Fall, An. claviger Meigen, An. hyrcanus Pallas, An. pulcherrimus Theobald, and superpictus Grassi. An. claviger, An. hyrcanus, and An. messeae were prevalent in the Northern Tien-Shan. An. artemievi, An. claviger, An. hyrcanus, An. messeae, and An. superpictus were detected in the Western Tien Shan. An. artemievi was first recorded in Kazakhstan. An. artemievi, An. claviger, and An. superpictus were noted in the Inferior Tien Shan. An. messeae was first observed in the Issyk Kul hollow. An. artemievi, An. claviger, and An. superpictus were habitants of the foothills of the South-Western Tien Shan. An. artemievi, An. hyrcanus, An. superpictus, and An. pulcherrimus were in the plain. An. pulcherrimus and An. superpicts mosquitoes are regarded as important vectors in the new malaria foci of the Fergana regions. The role of An. artemievi in the transmission of malaria is to be specified. PMID:18822504

  17. Synanthropy of Calliphoridae and Sarcophagidae (Diptera) in Bogotá, Colombia.

    PubMed

    Pinilla Beltran, Y T; Segura, N A; Bello, F J

    2012-06-01

    Calliphoridae and Sarcophagidae have medical and forensic importance. Species of these families are the first insects colonizing corpses and are, therefore, useful in establishing postmortem interval and as indicators in corpse transfer. The synanthropic index (SI) measures the relation of dipteran species with human settlements. Our main objective was to determine the synanthropic index of these families during the rainy and dry seasons in Bogotá. Captures were carried out using traps with baits (beef liver) in three zones (urban, rural, and forest areas). In the family Calliphoridae, the most abundant species were Calliphora vicina (Robineau-Desvoidy) with a sinanthropy index (SI) of +83.1, followed by Lucilia sericata (Meigen) (SI = +92.2) and Compsomyiops verena (Walker) (SI = +42.0). Calliphora nigribasis (Macquart) was not associated with human settlements, while Sarconesiopsis magellanica (Le Guillou) was present in the three zones and considered hemisynanthropic (SI = +19.0). Roraimomusca roraima (Townsend) was reported for the first time in Bogotá and was a non-synanthropic species (SI = -36.0). On the other hand, in Sarcophagidae, three species were collected: Ravinia rufipes (Twonsend), Ravinia colombiana (Lopes), and Boettcheria sp1, which were abundant in the rural and forest zones, the first having a dual characterization as synanthropic and hemisynanthropic, while the other two were hemisynanthropic. Our data showed differences in the association of Calliphoridae species with the three environments, whereas Sarcophagidae were distributed in locations with a lower human impact. PMID:23950049

  18. Oviposition site preferences and performance in natural resources in the human commensals Drosophila melanogaster and D. simulans.

    PubMed

    Soto, Eduardo M; Soto, Ignacio M; Cortese, Marcelo D; Hasson, Esteban

    2011-01-01

    The choice of egg laying site and progeny's performance in a rearing site are important components of habitat selection. Despite the huge amount of genetic, morphological, behavioral and physiological data regarding Drosophila melanogaster Meigen and D. simulans Sturtevant, oviposition site preferences remain poorly known. We investigated resource preference (acceptance and choice) and performance (measured as larval viability, developmental time and wing size) in Vitis vinifera Linneo (grape) and Cydonia oblonga Miller (quince), two fruit plants that D. melanogaster and D. simulans use as breeding substrates in Western Argentina. Females of both species preferred V. vinifera over C. oblonga when offered to lay eggs on grape and/or quince, with D. melanogaster showing a more biased preference for V. vinifera than its sibling. Concerning performance, flies reared in C. oblonga developed faster than in V. vinifera, regardless of the species and D. simulans had a shorter developmental time than D. melanogaster. We also observed inter and intraspecific (between flies reared in different resources) differences in wing size and shape. Our study provides novel data concerning ecological aspects scarcely addressed in these species, and suggest that the use of different resource may be a relevant factor in their recent evolutionary history. PMID:21540639

  19. Flying the fly: long-range flight behavior of Drosophila melanogaster to attractive odors.

    PubMed

    Becher, Paul G; Bengtsson, Marie; Hansson, Bill S; Witzgall, Peter

    2010-06-01

    The fruit fly, Drosophila melanogaster Meigen (Diptera: Drosophilidae), is a model for how animals sense, discriminate, and respond to chemical signals. However, with D. melanogaster our knowledge of the behavioral activity of olfactory receptor ligands has relied largely on close-range attraction, rather than on long-range orientation behavior. We developed a flight assay to relate chemosensory perception to behavior. Headspace volatiles from vinegar attracted 62% of assayed flies during a 15-min experimental period. Flies responded irrespective of age, sex, and mating state, provided they had been starved. To identify behaviorally relevant chemicals from vinegar, we compared the responses to vinegar and synthetic chemicals. Stimuli were applied by a piezoelectric sprayer at known and constant release rates. Re-vaporized methanol extracts of Super Q-trapped vinegar volatiles attracted as many flies as vinegar. The main volatile component of vinegar, acetic acid, elicited significant attraction as a single compound. Two other vinegar volatiles, 2-phenyl ethanol and acetoin, produced a synergistic effect when added to acetic acid. Geosmin, a microbiological off-flavor, diminished attraction to vinegar. This wind tunnel assay based on a conspicuous and unambiguous behavioral response provides the necessary resolution for the investigation of physiologically and ecologically relevant odors and will become an essential tool for the functional analysis of the D. melanogaster olfactory system. PMID:20437263

  20. A compound produced by fruigivorous Tephritidae (Diptera) larvae promotes oviposition behavior by the biological control agent Diachasmimorpha longicaudata (Hymenoptera: Braconidae).

    PubMed

    Stuhl, Charles; Sivinski, John; Teal, Peter; Paranhos, Beatriz; Aluja, Martin

    2011-06-01

    Tephritid fruit fly parasitoids use fruit-derived chemical cues and the vibrations that result from larval movements to locate hosts sequestered inside fruit. However, compounds produced by the larvae themselves have not been previously described nor their significance to parasitoid foraging determined. We collected the volatiles from four species of tropical and subtropical Tephritidae: Anastrepha suspensa (Loew), Bactrocera dorsalis Hendel, Bactrocera cucurbitae Coquillett, and Ceratitis capitata (Wiedemann), representing two subfamilies (Dacinae and Trypetinae). Para-ethylacetophenone, an analog of a known tephritid parasitoid attractant, was a major constituent of all four, and was not associated with larvae of another acalypterate fly, Drosophila melanogaster Meigen, or with the calypterate Musca domestica L. It also was present in volatiles from whole, A. suspensa infested fruits of Eugenia uniflora (L.). Para-ethylacetophenone was not necessarily produced as a direct consequence of fruit consumption because it also was detected from larvae that developed in two artificial diets and in spent diets subsequent to larval development. Sensillae on both the antennae and ovipositor of the opiine braconid fruit fly parasitoid, Diachasmimorpha longicaudata (Ashmead) responded to the para-ethylacetophenone in larval volatiles and as a synthetic. Although a potential cue to foraging parasitoids, para-ethylacetophenone showed no long range (>1m) attractiveness to the adult female parasitoid, but did stimulate ovipositor-insertion and oviposition into both a natural (fruit) and an artificial (parafilm) substrate. Thus it may prove useful in colonizing and mass-rearing opine fruit fly parasitoids. PMID:22251652

  1. Delaying onion planting to control onion maggot (Diptera: Anthomyiidae): efficacy and underlying mechanisms.

    PubMed

    Nault, Brian A; Werling, Benjamin P; Straub, Richard W; Nyrop, Jan P

    2011-10-01

    Onion maggot, Delia antiqua (Meigen) (Diptera: Anthomyiidae), is an important pest of onion, Allium cepa L., in northern temperate areas, especially in the Great Lakes region of North America Management of D. antiqua relies on insecticide use at planting, but insecticide resistance can cause control failures that threaten the long-term viability of this strategy. Delaying the time onions are planted was investigated as an alternative management approach for D. antiqua and the ecological and behavioral mechanisms underlying host age and insect relationships were examined in laboratory and field experiments. Delaying onion planting by two to four weeks reduced damage to onions by 35 and 90%, respectively. Onions planted later emerged later and this reduced the period overwintered flies had to oviposit on the plants. Moreover, flies tended to lay few to no eggs on these young, late-planted onions. As anticipated, D. antiqua laid 4-8 times more eggs on older onions than on young onions, and older onions were more resilient to injury caused by D. antiqua neonates compared with younger onions. However, the resiliency to maggot attack lessened as the density of D. antiqua increased from 2 to 10 eggs per plant, which probably explains why greater levels of maggot damage are typically observed in early onion plantings compared with later plantings. Delaying onion planting until mid-May reduced D. antiqua damage without jeopardizing the period required to produce marketable yield, but this cultural tactic must be combined with other management strategies to prevent economic loss. PMID:22066192

  2. Severe infestation of blow flies in a raccoon

    USGS Publications Warehouse

    Kilham, L.; Herman, C.M.

    1955-01-01

    A raccoon. (Procyon lotor) was observed in a weakened condition for several days at a farm a few miles east of Salisbury, Maryland. It was then caught and held in captivity for a few days. It continued to become weaker and on May 3, 1954, B. Mixon of the Maryland Department of Game and Inland Fish submitted it to us for study. There was no evidence of trauma, either internal or external. The fur was matted over the right hind leg, the inguinal region, and over much of the left hind leg. Inspection revealed the presence of thousands of larvae of the green-bottle fly, Phaenicia sericata, (Meigen}1 actively tunneling in and out of the skin and subcutaneous tissue. Muscle under lying infested skin appeared healthy and untraumatized. A few larvae were in comers of the eyes but none were found in other orifices. Gross and microscopic examination of tissue from the raccoon gave no indication of any acute process which might have led to its moribund condition. James (1947. The flies that cause myiasis in man. U. S. Govt. Print. Off.) and Hall (1948: The blowflies of North America.. Thom. Say Foundation) indicate that P. sericata may vary in virulence, some strains becoming parasitic with an ability to invade healthy tissue. In all probability, the larvae described above hatched from eggs originally laid in a skin wound although no evidence for this was found.

  3. New taxa of Carpomyini, with special emphasis on Goniglossum (Diptera: Tephritidae: Trypetinae).

    PubMed

    Freidberg, Amnon

    2016-01-01

    Goniglossum Rondani, hitherto a monobasic genus, is reinstated from synonymy under Carpomya Costa. A second species, Goniglossum liat n. sp., is described nearly two centuries after the description of the first species and 160 years after the description of Goniglossum. G. liat is described from Israel (also known from Turkey) and compared with G. wiedemanni (Meigen), an essentially European species, which is the type-species of Goniglossum and the only other known congener. The two species differ in details of the mesonotal and pleural color pattern (e.g., tip of scutellum with three small black spots in G. wiedemanni, whereas with one large spot in G. liat), structure of the male and female terminalia (e.g., the aculeus of G. wiedemanni is distinctly narrower apically than that of G. liat, and its tip has significantly fewer teeth), and host plant associations (Bryonia alba L. and B. dioica Jacq. are hosts of G. wiedemanni, whereas Bryonia cretica L. and B. syriaca Boiss. are hosts of G. liat). Myiopardalis Bezzi is also reinstated from synonymy under Carpomya. C. tica Norrbom, originally described in Carpomya, is transferred to Norrbomella, new genus, as its type and only included species. PMID:27470836

  4. Mitogen-activated protein kinase p38b interaction with delta class glutathione transferases from the fruit fly, Drosophila melanogaster.

    PubMed

    Wongtrakul, Jeerang; Sukittikul, Suchada; Saisawang, Chonticha; Ketterman, Albert J

    2012-01-01

    Glutathione transferases (GSTs) are a family of multifunctional enzymes involved in xenobiotic biotransformation, drug metabolism, and protection against oxidative damage. The p38b mitogen-activated protein kinase is involved in cellular stress response. This study screened interactions between Drosophila melanogaster Meigen (Diptera: Drosophilidae) Delta class glutathione transferases (DmGSTs) and the D. melanogaster p38b MAPK. Therefore, 12 DmGSTs and p38b kinase were obtained as recombinant proteins. The study showed that DmGSTD8 and DmGSTD11b significantly increased p38b activity toward ATF2 and jun, which are transcription factor substrates. DmGSTD3 and DmGSTD5 moderately increased p38b activity for jun. In addition, GST activity in the presence of p38b was also measured. It was found that p38b affected substrate specificity toward CDNB (1-chloro-2,4-dinitrobenzene) and DCNB (1,2-dichloro-4-nitrobenzene) of several GST isoforms, i.e., DmGSTD2, DmGSTD5, DmGSTD8, and DmGSTD11b. The interaction of a GST and p38b can affect the substrate specificity of either enzyme, which suggests induced conformational changes affecting catalysis. Similar interactions do not occur for all the Delta enzymes and p38b, which suggests that these interactions could be specific. PMID:23438069

  5. Potential for mosquitoes (Diptera: Culicidae) from Florida to transmit Rift Valley fever virus.

    PubMed

    Turell, Michael J; Britch, Seth C; Aldridge, Robert L; Kline, Daniel L; Boohene, Carl; Linthicum, Kenneth J

    2013-09-01

    We evaluated Aedes atlanticus Dyar and Knab, Aedes infirmatus Dyar and Knab, Aedes vexans (Meigen), Anopheles crucians Wiedemann, Coquillettidia perturbans (Walker), Culex nigripalpus Theobald, Mansonia dyari Belkin, Heinemann, and Page, and Psorophora ferox (Von Humboldt) from Florida to determine which of these species should be targeted for control should Rift Valley fever virus (RVFV) be detected in North America. Female mosquitoes that had fed on adult hamsters inoculated with RVFV were incubated for 7-21 d at 26 degrees C, then allowed to refeed on susceptible hamsters, and tested to determine infection, dissemination, and transmission rates. We also inoculated mosquitoes intrathoracically, held them for 7 d, and then allowed them to feed on a susceptible hamster to check for a salivary gland barrier. When exposed to hamsters with viremias > or = 10(7.6) plaque-forming units per milliliter of blood, at least some individuals in each of the species tested became infected; however, Cx. nigripalpus, An. crucians, and Ae. infirmatus were essentially incompetent vectors in the laboratory because of either a midgut escape or salivary gland barrier. Each of the other species should be considered as potential vectors and would need to be controlled if RVFV were introduced into an area where they were found. Additional studies need to be conducted with other geographic populations of these species and to determine how environmental factors affect transmission. PMID:24180117

  6. Annotated catalogue of the Tachinidae (Insecta, Diptera) of the Afrotropical Region, with the description of seven new genera

    PubMed Central

    O’Hara, James E.; Cerretti, Pierfilippo

    2016-01-01

    regalis Cerretti & O’Hara, sp. n. (South Africa), and Myxophryxe satanas Cerretti & O’Hara, sp. n. (South Africa) (Exoristinae, Goniini); and Stiremania Cerretti & O’Hara with type species Stiremania karoo Cerretti & O’Hara, gen. n. and sp. n. (South Africa), and Stiremania robusta Cerretti & O’Hara, sp. n. (South Africa) (Exoristinae, Goniini). Paraclara Bezzi, 1908 is transferred from the Cylindromyiini to the Hermyini, comb. n. Sarrorhina Villeneuve, 1936 is transferred from the Minthoini to the Graphogastrini, comb. n. Three genera are newly recorded from the Afrotropical Region: Madremyia Townsend, 1916 (Eryciini); Paratrixa Brauer & Bergenstamm, 1891 (Blondeliini); and Simoma Aldrich, 1926 (Goniini). Three genera previously recorded from the Afrotropical Region are no longer recognized from the region: Calozenillia Townsend, 1927 (Palaearctic, Oriental and Australasian regions); Eurysthaea Robineau-Desvoidy, 1863 (Palaearctic, Oriental and Australasian regions); and Trixa Meigen, 1824 (Palaearctic and Oriental regions). Two species are newly recorded from the Afrotropical Region: Amnonia carmelitana Kugler, 1971 (Ethiopia, Kenya); and Simoma grahami Aldrich, 1926 (Namibia). Three species previously recorded from the Afrotropical Region are no longer recognized from the region: Euthera peringueyi Bezzi, 1925 (Oriental Region); Hamaxia incongrua Walker, 1860 (Palaearctic, Oriental and Australasian regions); Leucostoma tetraptera (Meigen, 1824) (Palaearctic Region). New replacement names are proposed for five preoccupied names of Afrotropical species: Billaea rubida O’Hara & Cerretti for Phorostoma rutilans Villeneuve, 1916, preoccupied in the genus Billaea Robineau-Desvoidy, 1830 by Musca rutilans Fabricius, 1781, nom. n.; Cylindromyia braueri O’Hara & Cerretti for Ocyptera nigra Villeneuve, 1918, preoccupied in the genus Cylindromyia Meigen, 1803 by Glossidionophora nigra Bigot, 1885, nom. n.; Cylindromyia rufohumera O’Hara & Cerretti for Ocyptera

  7. Annotated catalogue of the Tachinidae (Insecta, Diptera) of the Afrotropical Region, with the description of seven new genera.

    PubMed

    O'Hara, James E; Cerretti, Pierfilippo

    2016-01-01

    . n. (South Africa), and Myxophryxe satanas Cerretti & O'Hara, sp. n. (South Africa) (Exoristinae, Goniini); and Stiremania Cerretti & O'Hara with type species Stiremania karoo Cerretti & O'Hara, gen. n. and sp. n. (South Africa), and Stiremania robusta Cerretti & O'Hara, sp. n. (South Africa) (Exoristinae, Goniini). Paraclara Bezzi, 1908 is transferred from the Cylindromyiini to the Hermyini, comb. n. Sarrorhina Villeneuve, 1936 is transferred from the Minthoini to the Graphogastrini, comb. n. Three genera are newly recorded from the Afrotropical Region: Madremyia Townsend, 1916 (Eryciini); Paratrixa Brauer & Bergenstamm, 1891 (Blondeliini); and Simoma Aldrich, 1926 (Goniini). Three genera previously recorded from the Afrotropical Region are no longer recognized from the region: Calozenillia Townsend, 1927 (Palaearctic, Oriental and Australasian regions); Eurysthaea Robineau-Desvoidy, 1863 (Palaearctic, Oriental and Australasian regions); and Trixa Meigen, 1824 (Palaearctic and Oriental regions). Two species are newly recorded from the Afrotropical Region: Amnonia carmelitana Kugler, 1971 (Ethiopia, Kenya); and Simoma grahami Aldrich, 1926 (Namibia). Three species previously recorded from the Afrotropical Region are no longer recognized from the region: Euthera peringueyi Bezzi, 1925 (Oriental Region); Hamaxia incongrua Walker, 1860 (Palaearctic, Oriental and Australasian regions); Leucostoma tetraptera (Meigen, 1824) (Palaearctic Region). New replacement names are proposed for five preoccupied names of Afrotropical species: Billaea rubida O'Hara & Cerretti for Phorostoma rutilans Villeneuve, 1916, preoccupied in the genus Billaea Robineau-Desvoidy, 1830 by Musca rutilans Fabricius, 1781, nom. n.; Cylindromyia braueri O'Hara & Cerretti for Ocyptera nigra Villeneuve, 1918, preoccupied in the genus Cylindromyia Meigen, 1803 by Glossidionophora nigra Bigot, 1885, nom. n.; Cylindromyia rufohumera O'Hara & Cerretti for Ocyptera scapularis Villeneuve, 1944, preoccupied in

  8. Plant-bacteria bioremediation agents affect the response of plant bioindicators independent of 2-chlorobenzoic acid degradation

    SciTech Connect

    Siciliano, S.D.; Germida, J.J.

    1995-12-31

    Plants are known to degrade toxicants in soil and are potentially useful bioremediation agents. The authors developed plant-bacteria associations (e.g., Meadow brome [Bromus riparius] and Pseudomonas aeruginosa strain R75) that degrade 2-chlorobenzoic acid (2CBA) in soil, and assessed their success using Slender wheatgrass (Agropyron trachycaulum) germination as a bioindicator of 2CBA levels. Gas chromatography was used to chemically assess 2CBA levels. Specific plant-bacteria bioremediation treatments decreased soil 2CBA levels by 17 to 52%, but bioindicator response did not correspond to chemical analysis. Contaminated and uncontaminated soil was subjected to bioremediation treatments. After 42 days, uncontaminated soil was collected and amended to various 2CBA levels. This soil and the remediated soil were analyzed by the plant bioindicator and gas chromatography. Bioremediation treatments altered germination of Slender wheatgrass in both contaminated and noncontaminated soils to a similar extent. These treatments decreased the toxicity of 2CBA to Slender wheatgrass in both contaminated and noncontaminated soils to a similar extent. These treatments decreased the toxicity of 2CBA to Slender wheatgrass at low 2CBA levels, but increased the toxicity of 2CBA at high 2CBA levels. For example, germination in soil subjected to the Meadow brome and R75 treatment was increased by ca. 30% at 50 mg kg{sup {minus}1} 2CBA, but decreased by ca. 50% at 150 mg kg{sup {minus}1} 2CBA. The results indicate that specific plant-bacteria bioremediation treatments affect plant bioindicator response independent of 2CBA degradation, and may confound efforts to determine the toxicity of 2CBA in soil.

  9. Insulin signaling regulates neurite growth during metamorphic neuronal remodeling

    PubMed Central

    Gu, Tingting; Zhao, Tao; Hewes, Randall S.

    2014-01-01

    Summary Although the growth capacity of mature neurons is often limited, some neurons can shift through largely unknown mechanisms from stable maintenance growth to dynamic, organizational growth (e.g. to repair injury, or during development transitions). During insect metamorphosis, many terminally differentiated larval neurons undergo extensive remodeling, involving elimination of larval neurites and outgrowth and elaboration of adult-specific projections. Here, we show in the fruit fly, Drosophila melanogaster (Meigen), that a metamorphosis-specific increase in insulin signaling promotes neuronal growth and axon branching after prolonged stability during the larval stages. FOXO, a negative effector in the insulin signaling pathway, blocked metamorphic growth of peptidergic neurons that secrete the neuropeptides CCAP and bursicon. RNA interference and CCAP/bursicon cell-targeted expression of dominant-negative constructs for other components of the insulin signaling pathway (InR, Pi3K92E, Akt1, S6K) also partially suppressed the growth of the CCAP/bursicon neuron somata and neurite arbor. In contrast, expression of wild-type or constitutively active forms of InR, Pi3K92E, Akt1, Rheb, and TOR, as well as RNA interference for negative regulators of insulin signaling (PTEN, FOXO), stimulated overgrowth. Interestingly, InR displayed little effect on larval CCAP/bursicon neuron growth, in contrast to its strong effects during metamorphosis. Manipulations of insulin signaling in many other peptidergic neurons revealed generalized growth stimulation during metamorphosis, but not during larval development. These findings reveal a fundamental shift in growth control mechanisms when mature, differentiated neurons enter a new phase of organizational growth. Moreover, they highlight strong evolutionarily conservation of insulin signaling in neuronal growth regulation. PMID:24357229

  10. Relay cropping cauliflower with lettuce as a means to manage first-generation cabbage maggot (Diptera: Anthomyiidae) and minimize cauliflower yield loss.

    PubMed

    Parsons, C K; Dixon, P L; Colbo, M

    2007-06-01

    First-generation cabbage maggot, Delia radicum (L.) (Diptera: Anthomyiidae), can cause extensive damage to newly transplanted brassica crops. This study investigated the use of relay cropping, a form of intercropping that involves overlapping two crops in the same field for a short period, as a means to 1) reduce first-generation D. radicum egg numbers by disrupting female host finding and 2) minimize yield loss by reducing the time that crops overlap. Because of the high incidence of two other Delia species, Delia platura (Meigen) and Delia florilega (Zetterstedt), treatment effects on these insects also were considered. In both years of the study (2003 and 2004), there were fewer D. radicum eggs collected from the base of cauliflower, Brassica oleracea variety botrytis, plants relay cropped with lettuce, Lactuca sativa L., than in monoculture. D. platura/D. florilega also laid fewer eggs on cauliflower in the relay crop than in monoculture in 2003, but in 2004 the opposite was true, there were more D. platura/D. florilega eggs laid on the relay-cropped cauliflower. After peak D. radicum oviposition, the lettuce was harvested. Cauliflower curd weights and diameters were comparable between treatments in both years. Plant loss because of D. platura/ D. florilega feeding in the 2004 relay-cropped plots resulted in reduced yields in these plots compared with the monoculture. Although further investigation is needed into the effects of relay cropping on other pests within this system, this is the first study to demonstrate that relay cropping can reduce egg laying by D. radicum at the scale studied while minimizing competition between component crops for key resources. PMID:17598546

  11. Complex Feeding Tracks of the Sessile Herbivorous Insect Ophiomyia maura as a Function of the Defense against Insect Parasitoids

    PubMed Central

    Ayabe, Yoshiko; Ueno, Takatoshi

    2012-01-01

    Because insect herbivores generally suffer from high mortality due to their natural enemies, reducing the risk of being located by natural enemies is of critical importance for them, forcing them to develop a variety of defensive measures. Larvae of leaf-mining insects lead a sedentary life inside a leaf and make conspicuous feeding tracks called mines, exposing themselves to the potential risk of parasitism. We investigated the defense strategy of the linear leafminer Ophiomyia maura Meigen (Diptera: Agromyzidae), by focusing on its mining patterns. We examined whether the leafminer could reduce the risk of being parasitized (1) by making cross structures in the inner area of a leaf to deter parasitoids from tracking the mines due to complex pathways, and (2) by mining along the edge of a leaf to hinder visually searching parasitoids from finding mined leaves due to effective background matching of the mined leaves among intact leaves. We quantified fractal dimension as mine complexity and area of mine in the inner area of the leaf as interior mine density for each sample mine, and analyzed whether these mine traits affected the susceptibility of O. maura to parasitism. Our results have shown that an increase in mine complexity with the development of occupying larvae decreases the probability of being parasitized, while interior mine density has no influence on parasitism. These results suggest that the larval development increases the host defense ability through increasing mine complexity. Thus the feeding pattern of these sessile insects has a defensive function by reducing the risk of parasitism. PMID:22393419

  12. Environmental factors associated with Phormia regina (Diptera: Calliphoridae) oviposition.

    PubMed

    Berg, Maureen C; Benbow, M Eric

    2013-03-01

    The period of insect activity (PIA) contributes information to estimates of the minimum postmortem interval in forensic investigations and begins with blow fly attraction and oviposition on a resource such as carrion or a human corpse. Incorrectly estimating nocturnal oviposition could alter PIA estimates by up to at least 12 h; however, the extent of this difference in PIA would depend on environmental and geographic factors. To date, the literature on the extent and frequency of blow fly nocturnal oviposition is conflicting. Our objectives were as follows: 1) to measure the effects of artificial lighting and beef liver bait height above ground on nocturnal and diurnal oviposition, and 2) to monitor oviposition through the night on swine carcasses exposed to the environment at dusk in different habitats over 3 yr. We documented no consistent nocturnal oviposition in any trial using beef liver or on carcasses in different habitats and seasons. There were statistically significant effects of light and height of bait above the ground on diurnal oviposition of Phormia regina (Meigen) in August of 2009, the only month with mean night temperatures > 20 degrees C. In August there also was significantly greater diurnal oviposition on liver bait placed on the ground compared with bait elevated 1 m. Our results suggest that nocturnal oviposition is rare in the natural environment. However, we found enhanced diurnal oviposition of P. regina under conditions of ambient temperatures > 20 degrees C the night before oviposition. Additional studies are needed to better understand the ecological mechanisms governing blow fly oviposition important to forensic entomology. PMID:23540135

  13. Comparative study of mitotic chromosomes in two blowflies, Luciliasericata and L.cluvia (Diptera, Calliphoridae), by C- and G-like banding patterns and rRNA loci, and implications for karyotype evolution.

    PubMed

    Chirino, Mónica G; Rossi, Luis F; Bressa, María J; Luaces, Juan P; Merani, María S

    2015-01-01

    The karyotypes of Luciliacluvia (Walker, 1849) and Luciliasericata (Meigen, 1826) from Argentina were characterized using conventional staining and the C- and G-like banding techniques. Besides, nucleolus organizer regions (NORs) were detected by fluorescent in situ hybridization (FISH) and silver staining technique. The chromosome complement of these species comprises five pairs of autosomes and a pair of sex chromosomes (XX/XY, female/male). The autosomes of both species have the same size and morphology, as well as C- and G-like banding patterns. The X and Y chromosomes of Luciliacluvia are subtelocentric and easily identified due to their very small size. In Luciliasericata, the X chromosome is metacentric and the largest of the complement, showing a secondary constriction in its short arm, whereas the Y is submetacentric and smaller than the X. The C-banding patterns reflect differences in chromatin structure and composition between the subtelocentric X and Y chromosomes of Luciliacluvia and the biarmed sex chromosomes of Luciliasericata. These differences in the sex chromosomes may be due to distinct amounts of constitutive heterochromatin. In Luciliacluvia, the NORs are placed at one end of the long-X and of the long-Y chromosome arms, whereas one of the NORs is disposed in the secondary constriction of the short-X chromosome arm and the other on the long-Y chromosome arm in Luciliasericata. Although the G-like banding technique does not yield G-bands like those in mammalian chromosomes, it shows a high degree chromosomal homology in both species because each pair of autosomes was correctly paired. This chromosome similarity suggests the absence of autosomal rearrangements during karyotype evolution in the two species studied. PMID:25893078

  14. Mosquito and Arbovirus Activity During 1997–2002 in a Wetland in Northeastern Mississippi

    PubMed Central

    CUPP, E. W.; TENNESSEN, K. J.; OLDLAND, W. K.; HASSAN, H. K.; HILL, G. E.; KATHOLI, C. R.; UNNASCH, T. R.

    2008-01-01

    The species composition and population dynamics of adult mosquitoes in a wetland near Iuka, MS, were analyzed over a 6-yr period (1997–2002) and reverse transcription-polymerase chain reaction (PCR) detection rates of arboviruses determined during five of those years. Blood meals of three likely vector species were identified using a PCR-based method that allows identification of the host to species. Culex erraticus (Dyar & Knab) composed 51.9% of the population during the 6-yr period with 295 females collected per trap night. Eastern equine encephalomyelitis (EEE) virus was detected in six genera of mosquitoes [Coquillettidia perturbans (Walker), Culex restuans Theobald, Culex salinarius Coquillett, Culex erraticus (Dyar & Knab), Anopheles crucians Wiedemann, Anopheles quadrimaculatus Say, Aedes vexans (Meigen), Ochlerotatus triseriatus Say, and Psorophora ferox Humboldt) with positive pools occurring in 1998, 1999, and 2002. Culiseta melanura Coquillett occurred at a low level (<1%) and was not infected. Saint Louis encephalitis virus was detected once in a single pool of Cx. erraticus in 1998. Neither West Nile virus nor LaCrosse virus was found. Minimum infection rates per 1000 females tested of competent vectors of EEE virus were variable and ranged from 0.14 for Cx. erraticus to 40.0 for Oc. triseriatus. Thirty-nine species of birds were identified in the focus with blood-engorged mosquitoes found to contain meals (n = 29) from eight avian species. The majority of meals was from the great blue heron, Ardea herodias L. (n = 55%), but when bird abundance data were adjusted for avian mass, the brown-headed cowbird, Molothrus ater (Boddaert); blue jay, Cyanocitta cristata (L.); and northern mockingbird, Mimus polyglottos (L.), were overrepresented as hosts. PMID:15185956

  15. Complex feeding tracks of the sessile herbivorous insect Ophiomyia maura as a function of the defense against insect parasitoids.

    PubMed

    Ayabe, Yoshiko; Ueno, Takatoshi

    2012-01-01

    Because insect herbivores generally suffer from high mortality due to their natural enemies, reducing the risk of being located by natural enemies is of critical importance for them, forcing them to develop a variety of defensive measures. Larvae of leaf-mining insects lead a sedentary life inside a leaf and make conspicuous feeding tracks called mines, exposing themselves to the potential risk of parasitism. We investigated the defense strategy of the linear leafminer Ophiomyia maura Meigen (Diptera: Agromyzidae), by focusing on its mining patterns. We examined whether the leafminer could reduce the risk of being parasitized (1) by making cross structures in the inner area of a leaf to deter parasitoids from tracking the mines due to complex pathways, and (2) by mining along the edge of a leaf to hinder visually searching parasitoids from finding mined leaves due to effective background matching of the mined leaves among intact leaves. We quantified fractal dimension as mine complexity and area of mine in the inner area of the leaf as interior mine density for each sample mine, and analyzed whether these mine traits affected the susceptibility of O. maura to parasitism. Our results have shown that an increase in mine complexity with the development of occupying larvae decreases the probability of being parasitized, while interior mine density has no influence on parasitism. These results suggest that the larval development increases the host defense ability through increasing mine complexity. Thus the feeding pattern of these sessile insects has a defensive function by reducing the risk of parasitism. PMID:22393419

  16. Entomopathogenic Fungus as a Biological Control for an Important Vector of Livestock Disease: The Culicoides Biting Midge

    PubMed Central

    Ansari, Minshad Ali; Pope, Edward C.; Carpenter, Simon; Scholte, Ernst-Jan; Butt, Tariq M.

    2011-01-01

    Background The recent outbreak of bluetongue virus in northern Europe has led to an urgent need to identify control measures for the Culicoides (Diptera: Ceratopogonidae) biting midges that transmit it. Following successful use of the entomopathogenic fungus Metarhizium anisopliae against larval stages of biting midge Culicoides nubeculosus Meigen, we investigated the efficacy of this strain and other fungi (Beauveria bassiana, Isaria fumosorosea and Lecanicillium longisporum) as biocontrol agents against adult C. nubeculosus in laboratory and greenhouse studies. Methodology/Findings Exposure of midges to ‘dry’ conidia of all fungal isolates caused significant reductions in survival compared to untreated controls. Metarhizium anisopliae strain V275 was the most virulent, causing a significantly decrease in midge survival compared to all other fungal strains tested. The LT50 value for strain V275 was 1.42 days compared to 2.21–3.22 days for the other isolates. The virulence of this strain was then further evaluated by exposing C. nubeculosus to varying doses (108–1011 conidia m−2) using different substrates (horse manure, damp peat, leaf litter) as a resting site. All exposed adults were found to be infected with the strain V275 four days after exposure. A further study exposed C. nubeculosus adults to ‘dry’ conidia and ‘wet’ conidia (conidia suspended in 0.03% aq. Tween 80) of strain V275 applied to damp peat and leaf litter in cages within a greenhouse. ‘Dry’ conidia were more effective than ‘wet’ conidia, causing 100% mortality after 5 days. Conclusion/Significance This is the first study to demonstrate that entomopathogenic fungi are potential biocontrol agents against adult Culicoides, through the application of ‘dry’ conidia on surfaces (e.g., manure, leaf litter, livestock) where the midges tend to rest. Subsequent conidial transmission between males and females may cause an increased level of fungi-induced mortality in midges

  17. Oral Delivery of Double-Stranded RNA in Larvae of the Yellow Fever Mosquito, Aedes aegypti: Implications for Pest Mosquito Control

    PubMed Central

    Singh, Aditi D.; Wong, Sylvia; Ryan, Calen P.; Whyard, Steven

    2013-01-01

    RNA interference has already proven itself to be a highly versatile molecular biology tool for understanding gene function in a limited number of insect species, but its widespread use in other species will be dependent on the development of easier methods of double-stranded RNA (dsRNA) delivery. This study demonstrates that RNA interference can be induced in the mosquito Aedes aegypti L. (Diptera: Culicidae) simply by soaking larvae in a solution of dsRNA for two hours. The mRNA transcripts for β-tubulin, chitin synthase-1 and -2, and heat shock protein 83 were reduced between 30 and 50% three days post-dsRNA treatment. The dsRNA was mixed with a visible dye to identify those individuals that fed on the dsRNA, and based on an absence of RNA interference in those individuals that contained no dye within their guts, the primary route of entry of dsRNA is likely through the gut epithelium. RNA interference was systemic in the insects, inducing measurable knock down of gene expression in tissues beyond the gut. Silencing of the β-tubulin and chitin synthase-1 genes resulted in reduced growth and/or mortality of the larvae, demonstrating the utility of dsRNA as a potential mosquito larvicide. Silencing of chitin synthase-2 did not induce mortality in the larvae, and silencing of heat shock protein 83 only induced mortality in the insects if they were subsequently subjected to a heat stress. Drosophila melanogaster Meigen (Diptera: Drosophilidae) larvae were also soaked in dsRNA designed to specifically target either their own β-tubulin gene, or that of A. aegypti, and significant mortality was only seen in larvae treated with dsRNA targeting their own gene, which suggests that dsRNA pesticides could be designed to be species-limited. PMID:24224468

  18. Sarcophaga (Liosarcophaga) tibialis Macquart 1851 (Diptera: Sarcophagidae): micromorphology of preimaginal stages of a fly of medical and veterinary interest.

    PubMed

    Paños-Nicolás, Ángela; Arnaldos, M Isabel; García, Ma Dolores; Ubero-Pascal, Nicolás

    2015-11-01

    Sarcophagids are a large family of Diptera, with a worldwide distribution. They are related to decomposing organic matter and are very interesting for health science and in forensic cases since many species produce myiasis and occur in human corpses. This family is considered difficult to study, particularly with regard to their immature stages, to which little attention has been paid. Genus Sarcophaga Meigen, 1826 is composed of species of very similar morphology, making very difficult to distinguish. Knowledge of the immature stages of this genus is important because such stages occupy the greater part of the life cycle, so that establishing a basis for their identification will increase their usefulness in systematic and applied sciences. This contribution presents a detailed study of the morphological features, both external and internal, of the preimaginal stages of Sarcophaga (Liosarcophaga) tibialis Macquart, 1851, providing a taxonomical context for the correct identification of Liosarcophaga species of forensic interest in the Iberian Peninsula. Both light and scanning electron microscopy were applied. Complete descriptions of every stage are provided and illustrated, and their usefulness for species comparison, taking into account our uneven knowledge of morphologically immature stages of this subgenus, is indicated. Features of the cephalopharyngeal skeleton, such as the shape of the mouth hook and the intermediate and basal sclerites, and external morphology, such as the pattern of spinose band and anterior and posterior spiracles, proved useful for separating species. Finally, tentative identification keys based on light microscopy observation to distinguish S. (L.) tibialis from other species of forensic interest belonging to Liosarcophaga subgenus are proposed for every immature stage. PMID:26227140

  19. Comparative study of mitotic chromosomes in two blowflies, Lucilia sericata and L. cluvia (Diptera, Calliphoridae), by C- and G-like banding patterns and rRNA loci, and implications for karyotype evolution

    PubMed Central

    Chirino, Mónica G.; Rossi, Luis F.; Bressa, María J.; Luaces, Juan P.; Merani, María S.

    2015-01-01

    Abstract The karyotypes of Lucilia cluvia (Walker, 1849) and Lucilia sericata (Meigen, 1826) from Argentina were characterized using conventional staining and the C- and G-like banding techniques. Besides, nucleolus organizer regions (NORs) were detected by fluorescent in situ hybridization (FISH) and silver staining technique. The chromosome complement of these species comprises five pairs of autosomes and a pair of sex chromosomes (XX/XY, female/male). The autosomes of both species have the same size and morphology, as well as C- and G-like banding patterns. The X and Y chromosomes of Lucilia cluvia are subtelocentric and easily identified due to their very small size. In Lucilia sericata, the X chromosome is metacentric and the largest of the complement, showing a secondary constriction in its short arm, whereas the Y is submetacentric and smaller than the X. The C-banding patterns reflect differences in chromatin structure and composition between the subtelocentric X and Y chromosomes of Lucilia cluvia and the biarmed sex chromosomes of Lucilia sericata. These differences in the sex chromosomes may be due to distinct amounts of constitutive heterochromatin. In Lucilia cluvia, the NORs are placed at one end of the long-X and of the long-Y chromosome arms, whereas one of the NORs is disposed in the secondary constriction of the short-X chromosome arm and the other on the long-Y chromosome arm in Lucilia sericata. Although the G-like banding technique does not yield G-bands like those in mammalian chromosomes, it shows a high degree chromosomal homology in both species because each pair of autosomes was correctly paired. This chromosome similarity suggests the absence of autosomal rearrangements during karyotype evolution in the two species studied. PMID:25893078

  20. Thermoregulation in larval aggregations of carrion-feeding blow flies (Diptera: Calliphoridae)

    USGS Publications Warehouse

    Slone, D.H.; Gruner, Susan V.

    2007-01-01

    The growth and development of carrion-feeding calliphorid (Diptera Calliphoridae) larvae, or maggots, is of great interest to forensic sciences, especially for estimation of a postmortem interval (PMI). The development rate of calliphorid larvae is influenced by the temperature of their immediate environment. Heat generation in larval feeding aggregations (=maggot masses) is a well-known phenomenon, but it has not been quantitatively described. Calculated development rates that do not include internally generated temperatures will result in overestimation of PMI. Over a period of 2.5 yr, 80 pig, Sus scrofa L., carcasses were placed out at study sites in north central Florida and northwestern Indiana. Once larval aggregations started to form, multiple internal and external temperatures, and weather observations were taken daily or every few days between 1400 and 1800 hours until pupation of the larvae. Volume of each aggregation was determined by measuring surface area and average depth. Live and preserved samples of larvae were taken for species identification. The four most common species collected were Lucilia coeruleiviridis (=Phaenicia) (Macquart) (77%), Cochliomyia macellaria (F.) (8.3%), Chrysomya rufifaces (Macquart) (7.7%), and Phormia regina (Meigen) (5.5%). Statistical analyses showed that 1) volume of a larval mass had a strong influence on its temperature, 2) internal temperatures of masses on the ground were influenced by soil temperature and mass volume, 3) internal temperatures of masses smaller than 20 cm3 were influenced by ambient air temperature and mass volume, and 4) masses larger than 20 cm3 on the carcass had strongly regulated internal temperatures determined only by the volume of the mass, with larger volumes associated with higher temperatures. Nonsignificant factors included presence of rain or clouds, shape of the aggregation, weight of the carcass, species composition of the aggregation, time since death, or season.

  1. Exposure of sheep to mosquito bites: possible consequences for the transmission risk of Rift Valley Fever in Senegal.

    PubMed

    Chevalier, V; Mondet, B; Diaite, A; Lancelot, R; Fall, A G; Ponçon, N

    2004-09-01

    Rift Valley Fever (RVF) is a growing health problem in West Africa. In northern Senegal, the candidate vectors of this arbovirosis are Aedes (Aedimorphus) vexans Meigen and Culex (Culex) poicilipes Theobald (Diptera: Culicidae). Domestic ruminants are the reservoirs of the virus. A study was undertaken during the 2002 rainy season to assess spatial and temporal variations in exposure to mosquito bites in sheep herds, and to evaluate the possible consequences on the risk of RVF transmission to sheep. Mosquitoes were collected with sheep-baited traps. The number of Ae. vexans females (the predominant species during the 2002 rainy season) trapped per trap-night was the dependent variable in statistical analyses. The trapping periods were divided into six series of two to five consecutive days, from July to November 2002. Three temporary ponds were selected according to their ecological features: depth, bank slope, size and vegetation cover. Traps were laid on the pond bank and in the nearest available compound, close to the sheep night pen. Data were analysed using mixed-effects Poisson models. The explanatory variables were the trapping period, the pond, and the capture site. The exposure to mosquito bites varied according to the pond type, suggesting that the risk of transmission was spatially heterogeneous. However, there was no obvious trend in transmission risk due to the effect of the distance from the compound to the pond. The period with the highest exposure was in October, i.e. when transhumant herds left the Ferlo to relocate to their dry-season settlement. It is thus hypothesized that transhumance, the seasonal movements of herds, plays a significant role in the dissemination of RVF virus in the region. PMID:15347392

  2. Behavioral responses of Drosophila to biogenic levels of carbon dioxide depend on life-stage, sex and olfactory context.

    PubMed

    Faucher, Cécile; Forstreuter, Manfred; Hilker, Monika; de Bruyne, Marien

    2006-07-01

    Drosophila melanogaster (Meigen) detects and uses many volatiles for its survival. Carbon dioxide (CO(2)) is detected in adults by a special class of olfactory receptor neurons, expressing the gustatory receptor Gr21a. The behavioral responses to CO(2) were investigated in a four-field olfactometer bioassay that is new for Drosophila. We determined (1) whether the sensitivity of this response changes with odor context, and (2) if it depends on sex and life stage. When CO(2) was added to ambient air in one field and tested against ambient air in the three other fields, individually observed adults avoided CO(2) (0.1-1% above ambient), but did not respond to a low rise of 0.02%. We relate this behavior to measurements of CO(2) production in bananas and flies. When 0.02% CO(2) was combined with the odor of apple cider vinegar in one field of the olfactometer and tested against ambient air in the three other fields, the addition of CO(2) did not affect the attractiveness of apple cider vinegar alone. However, this combination of CO(2) and vinegar became repellent when it was tested against vinegar at ambient CO(2) concentrations in the three other fields. This ;odor background effect' was female-specific, revealing a sexually dimorphic behavior. The new assay allowed us to test larvae under similar conditions and compare their behavior to that of adults. Like adults, they avoided CO(2), but with lower sensitivity. Larvae lacking neurons expressing Gr21a lost their avoidance behavior to CO(2), but kept their positive response to vinegar odor. Hence, Gr21a-expressing neurons mediate similar behaviors in larvae and adults. PMID:16809465

  3. Genomic and karyotypic variation in Drosophila parasitoids (Hymenoptera, Cynipoidea, Figitidae).

    PubMed

    Gokhman, Vladimir E; Johnston, J Spencer; Small, Chiyedza; Rajwani, Roma; Hanrahan, Shawn J; Govind, Shubha

    2011-01-01

    Drosophila melanogaster Meigen, 1830 has served as a model insect for over a century. Sequencing of the 11 additional Drosophila Fallen, 1823 species marks substantial progress in comparative genomics of this genus. By comparison, practically nothing is known about the genome size or genome sequences of parasitic wasps of Drosophila. Here, we present the first comparative analysis of genome size and karyotype structures of Drosophila parasitoids of the Leptopilina Förster, 1869 and Ganaspis Förster, 1869 species. The gametic genome size of Ganaspis xanthopoda (Ashmead, 1896) is larger than those of the three Leptopilina species studied. The genome sizes of all parasitic wasps studied here are also larger than those known for all Drosophila species. Surprisingly, genome sizes of these Drosophila parasitoids exceed the average value known for all previously studied Hymenoptera. The haploid chromosome number of both Leptopilina heterotoma (Thomson, 1862) and Leptopilina victoriae Nordlander, 1980 is ten. A chromosomal fusion appears to have produced a distinct karyotype for Leptopilina boulardi (Barbotin, Carton et Keiner-Pillault, 1979)(n = 9), whose genome size is smaller than that of wasps of the Leptopilina heterotoma clade. Like Leptopilina boulardi, the haploid chromosome number for Ganaspis xanthopoda is also nine. Our studies reveal a positive, but non linear, correlation between the genome size and total chromosome length in Drosophila parasitoids. These Drosophila parasitoids differ widely in their host range, and utilize different infection strategies to overcome host defense. Their comparative genomics, in relation to their exceptionally well-characterized hosts, will prove to be valuable for understanding the molecular basis of the host-parasite arms race and how such mechanisms shape the genetic structures of insectcommunities. PMID:24260630

  4. Blood feeding induces hemocyte proliferation and activation in the African malaria mosquito, Anopheles gambiae Giles

    PubMed Central

    Bryant, William B.; Michel, Kristin

    2014-01-01

    Malaria is a global public health problem, especially in sub-Saharan Africa, where the mosquito Anopheles gambiae Giles serves as the major vector for the protozoan Plasmodium falciparum Welch. One determinant of malaria vector competence is the mosquito's immune system. Hemocytes are a critical component as they produce soluble immune factors that either support or prevent malaria parasite development. However, despite their importance in vector competence, understanding of their basic biology is just developing. Applying novel technologies to the study of mosquito hemocytes, we investigated the effect of blood meal on hemocyte population dynamics, DNA replication and cell cycle progression. In contrast to prevailing published work, the data presented here demonstrate that hemocytes in adult mosquitoes continue to undergo low basal levels of replication. In addition, blood ingestion caused significant changes in hemocytes within 24 h. Hemocytes displayed an increase in cell number, size, granularity and Ras-MAPK signaling as well as altered cell surface moieties. As these changes are well-known markers of immune cell activation in mammals and Drosophila melanogaster Meigen, we further investigated whether a blood meal changes the expression of hemocyte-derived immune factors. Indeed, hemocytes 24 h post-blood meal displayed higher levels of critical components of the complement and melanization immune reactions in mosquitoes. Taken together, this study demonstrates that the normal physiological process of a blood meal activates the innate immune response in mosquitoes. This process is likely in part regulated by Ras-MAPK signaling, highlighting a novel mechanistic link between blood feeding and immunity. PMID:24363411

  5. Feeding and attraction of non-target flies to spinosad-based fruit fly bait.

    PubMed

    Wang, Xin-Geng; Messing, Russell H

    2006-10-01

    A spinosad-based fruit fly bait, GF-120, has recently become a primary tool for area-wide suppression or eradication of pest tephritid fruit flies. The present study assessed the attraction and feeding of five non-target fly species to GF-120 in Hawaii. These non-target flies include three beneficial tephritid species [Eutreta xanthochaeta (Aldrich), Tetreuaresta obscuriventris (Loew), Ensina sonchi (L.)] introduced for weed biological control, an endemic Hawaiian tephritid [Trupanea dubautiae (Bryan)] (all Diptera: Tephritidae) and the cosmopolitan Drosophila melanogaster Meigen (Diptera: Drosophilidae). All five non-target fly species were susceptible to GF-120, as was the target pest Mediterranean fruit fly Ceratitis capitata (Wiedemann). Feeding on, or even brief tasting of, GF-120 killed all fly species within 2 h. When individual flies were provided with a choice of GF-120 or honey solution, there was no difference in the frequency of first food encounter by E. xanthochaeta, D. melanogaster or C. capitata. The other three non-target species approached honey more often than GF-120 in their first food encounter. Feeding times on GF-120 and honey were not significantly different for D. melanogaster and C. capitata, while the other four non-target species fed longer on honey than on GF-120. There was no significant difference in feeding time on honey versus GF-120 between males and females of each species. These results suggest that area-wide treatment using GF-120 for the purpose of eradication of pest fruit flies has potential negative impacts on these and other non-target fly species in Hawaii. PMID:16835891

  6. Morphological Markers for Cryopreservation in the Embryonic Development of Drosophila suzukii (Diptera: Drosophilidae).

    PubMed

    Landi, Silvia; Gargani, Elisabetta; Paoli, Francesco; Simoni, Sauro; Roversi, Pio Federico

    2015-08-01

    Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) is an invasive pest recently reported in Europe whose spread into new areas has caused severe economic damage to many agricultural crops. There are serious concerns about the currently available chemical insecticides because of their low efficacy in controlling the species and their environmental impact; so, several studies have focused on environmentally safe strategies. The sterile insect technique (SIT), which requires colony maintenance in laboratory and production of large numbers of live animals, can be utilized in pest management programs and could be integrated with other control strategies if the potential risks associated with the rearing and maintenance of the insect line under laboratory conditions are given sufficient attention. In this regard, the ability to cryobiologically preserve such stocks would be of substantial value. Important prerequisites for long-term cryopreservation are determination of the embryonic stages, identification of specific embryonic stages, and knowledge of development time. This paper describes the main visible markers for the different stages of embryonic development and determines the timing of development at 25°C. D. suzukii embryogenesis lasts 23-25 h at 25°C and can be divided into 17 stages defined by specific morphological markers. The point at which 50% of embryos are at Stage 14 and 50% are at Stage 15, the most tolerant stages for cryopreservation treatment, as ascertained for Drosophila melanogaster Meigen in prior studies, is reached in 14-15 h. The efficiency of this procedure might be impaired by the retention of eggs in the oviducts, making it impossible to determine the stage of embryonic development for ∼25% of laid eggs. PMID:26470330

  7. Estimating the age of Calliphora vicina eggs (Diptera: Calliphoridae): determination of embryonic morphological landmarks and preservation of egg samples.

    PubMed

    Martín-Vega, Daniel; Hall, Martin J R

    2016-05-01

    Blow fly eggs may sometimes be the only entomological evidence recovered in a forensic case, especially in cooler weather when hatching might take several days: hence, a method for estimating their age is greatly needed. However, developmental data on blow fly eggs are mainly limited to records of the time to larval hatching. The current paper describes the morphological changes occurring during embryogenesis of the blow fly Calliphora vicina Robineau-Desvoidy and their timing in relation to temperature, in order to determine those characters which can be used for simple egg age estimation using light microscopy. At 7.3 and 25 °C, 15 easily visualised morphological landmarks were determined in C. vicina living embryos, allowing for their age estimation with a resolution of 10-20 % of total egg developmental time. The observed age intervals were compared to the embryonic stages described for the fruit fly Drosophila melanogaster Meigen, which are used as reference data in multiple developmental studies. Moreover, current guidelines for preservation of egg samples, which recommend the placement of living eggs directly into 80 % ethanol, were tested against the hot water killing (HWK) method prior to preservation in 80 % ethanol, recommended for larval and pupal specimens. Direct placement of eggs into 80 % ethanol caused marked decomposition of samples, and no morphological landmarks were discernible. On the other hand, HWK fixation prior to preservation in 80 % ethanol enabled visualisation of 11 of the 15 age-specific morphological landmarks that were discernible in living embryos. Therefore, HWK fixation prior to preservation in 80 % ethanol is recommended for egg samples, thus unifying the protocols for collecting entomological evidence. PMID:26753872

  8. Long-Term Resistance of Drosophila melanogaster to the Mushroom Toxin Alpha-Amanitin

    PubMed Central

    Mitchell, Chelsea L.; Yeager, Roger D.; Johnson, Zachary J.; D’Annunzio, Stephanie E.; Vogel, Kara R.; Werner, Thomas

    2015-01-01

    Insect resistance to toxins exerts not only a great impact on our economy, but also on the ecology of many species. Resistance to one toxin is often associated with cross-resistance to other, sometimes unrelated, chemicals. In this study, we investigated mushroom toxin resistance in the fruit fly Drosophila melanogaster (Meigen). This fruit fly species does not feed on mushrooms in nature and may thus have evolved cross-resistance to α-amanitin, the principal toxin of deadly poisonous mushrooms, due to previous pesticide exposure. The three Asian D. melanogaster stocks used in this study, Ama-KTT, Ama-MI, and Ama-KLM, acquired α-amanitin resistance at least five decades ago in their natural habitats in Taiwan, India, and Malaysia, respectively. Here we show that all three stocks have not lost the resistance phenotype despite the absence of selective pressure over the past half century. In response to α-amanitin in the larval food, several signs of developmental retardation become apparent in a concentration-dependent manner: higher pre-adult mortality, prolonged larva-to-adult developmental time, decreased adult body size, and reduced adult longevity. In contrast, female fecundity nearly doubles in response to higher α-amanitin concentrations. Our results suggest that α-amanitin resistance has no fitness cost, which could explain why the resistance has persisted in all three stocks over the past five decades. If pesticides caused α-amanitin resistance in D. melanogaster, their use may go far beyond their intended effects and have long-lasting effects on ecosystems. PMID:25978397

  9. Interaction of Omega, Sigma, and Theta Glutathione Transferases with p38b Mitogen-Activated Protein Kinase from the Fruit Fly, Drosophila melanogaster

    PubMed Central

    Wongtrakul, J.; Janphen, K.; Saisawang, C.; Ketterman, A.J.

    2014-01-01

    Glutathione S-transferases (GSTs) are a diverse family of phase II detoxification enzymes found in almost all organisms. Besides playing a major role in the detoxification of xenobiotic and toxic compounds, GSTs are also involved in the regulation of mitogen activated protein (MAP) kinase signal transduction by interaction with proteins in the pathway. An in vitro study was performed for Theta, Omega, Sigma GSTs and their interaction with MAP kinase p38b protein from the fruit fly Drosophila melanogaster Meigen (Diptera: Drosophilidae). The study included the effects of all five Omega class GSTs (DmGSTO1, DmGSTO2a, DmGSTO2b, DmGSTO3, DmGSTO4), all five Theta class GSTs (DmGSTT1, DmGSTT2, DmGSTT3a, DmGSTT3b, DmGSTT4), and one Sigma class glutathione transferase on the activity of Drosophila p38b, including the reciprocal effect of this kinase protein on glutathione transferase activity. It was found that DmGSTT2, DmGSTT3b, DmGSTO1, and DmGSTO3 activated p38b significantly. Substrate specificities of GSTs were also altered after co-incubation with p38b. Although p38b activated DmGSTO1, DmGSTO2a, and DmGSTT2, it inhibited DmGSTT3b and DmGSTO3 activity toward xenobiotic and physiological substrates tested. These results suggest a novel link between Omega and Theta GSTs with the p38b MAP kinase pathway. PMID:25373207

  10. Effects of spatial and temporal variation of acid-volatile sulfide on the bioavailability of copper and zinc in freshwater sediments

    SciTech Connect

    Besser, J.M.; Ingersoll, C.G.; Giesy, J.P.

    1996-03-01

    Variation in concentrations of acid-volatile sulfide (AVS) in sediments from the upper Clark Fork River of Montana, USA, was associated with differences in bioaccumulation of Cu and Zn and growth of larvae of the midge, Chironomus tentans. Growth of midge larvae was significantly greater and bioaccumulation of Cu was significantly less in surface sections (0--3 cm depth) of sediment cores, which had greater concentrations of AVS and lesser ratios of simultaneously extracted metals to AVS (SEM:AVS ratios) than in subsurface sediments (6--9 cm). Concentrations of AVS were significantly less in sediments incubated with oxic overlying water for 9 weeks than in the same sediments incubated under anoxic conditions. Bioaccumulation of Cu differed significantly between incubation treatments, corresponding to differences in concentrations of AVS and SEM:AVS ratios, although midge growth did not. Bioaccumulation of Zn did not differ significantly between depth strata of sediment cores or between incubation treatments. When results from the two sets of bioassays were combined, bioaccumulation of Cu and Zn, but not growth, was significantly correlated with SEM:AVS ratios and other estimates of bioavailable metal fractions in sediments. Growth of midge larvae was significantly correlated with bioaccumulation of Zn, but not Cu, suggesting that Zn was the greater contributor to the toxicity of these sediments. Assessments of the toxicity of metal-contaminated freshwater sediments should consider the effects of spatial and temporal variation in AVS concentrations on metal bioavailability.

  11. Toxicity and bioaccumulation of sediment-associated contaminants using freshwater invertebrates: A review of methods and applications

    SciTech Connect

    Ingersoll, C.G.; Ankley, G.T.; Benoit, D.A.

    1995-11-01

    This paper reviews recent developments in methods for evaluating the toxicity and bioaccumulation of contaminants associated with freshwater sediments and summarizes example case studies demonstrating the application of these methods. Over the past decade, research has emphasized development of more specific testing procedures for conducting 10-d toxicity tests with the amphipod Hyalella azteca and the midge Chironomus tentans. Toxicity endpoints measured in these tests are survival for H. azteca and survival and growth for C. tentans. Guidance has also been developed for conducting 28-d bioaccumulation tests with the oligochaete Lumbriculus variegatus, including determination of bioaccumulation kinetics for different compound classes. These methods have been applied to a variety of sediments to address issues ranging from site assessments to bioavailability of organic and inorganic contaminants using field-collected and laboratory-spiked samples. Survival and growth of controls routinely meet or exceed test acceptability criteria. Results of laboratory bioaccumulation studies with L. variegatus have been confirmed with comparisons to residues (PCBs, PAHs, DDT) present from synoptically collected field populations of oligochaetes. Additional method development is currently underway to develop chronic toxicity tests and to provide additional data-confirming responses observed in laboratory sediment tests with natural benthic populations.

  12. Effect of zeolite on toxicity of ammonia in freshwater sediments: Implications for toxicity identification evaluation procedures

    SciTech Connect

    Besser, J.M.; Ingersoll, C.G.; Leonard, E.N.; Mount, D.R.

    1998-11-01

    Techniques for reducing ammonia toxicity in freshwater sediments were investigated as part of a project to develop toxicity identification and evaluation (TIE) procedures for whole sediments. Although ammonia is a natural constituent of freshwater sediments, pollution can lead to ammonia concentrations that are toxic to benthic invertebrates, and ammonia can also contribute to the toxicity of sediments that contain more persistent contaminants. The authors investigated the use of amendments of a natural zeolite mineral, clinoptilolite, to reduce concentrations of ammonia in sediment pore water. Zeolites have been widely used for removal of ammonia in water treatment and in aqueous TIE procedures. The addition of granulated zeolite to ammonia-spiked sediments reduced pore-water ammonia concentrations and reduced ammonia toxicity to invertebrates. Amendments of 20% zeolite (v/v) reduced ammonia concentrations in pore water by {ge}70% in spiked sediments with ammonia concentrations typical of contaminated freshwater sediments. Zeolite amendments reduced toxicity of ammonia-spiked sediments to three taxa of benthic invertebrates (Hyalella azteca, Lumbriculus variegatus, and Chironomus tentans), despite their widely differing sensitivity to ammonia toxicity. In contrast, zeolite amendments did not reduce acute toxicity of sediments containing high concentrations of cadmium or copper or reduce concentrations of these metals in pore waters. These studies suggest that zeolite amendments, used in conjunction with toxicity tests with sensitive taxa such as H. azteca, may be an effective technique for selective reduction of ammonia toxicity in freshwater sediments.

  13. Integrated sediment quality assessment through biomarker responses and bioavailability measurements: Application in Tai Lake, China.

    PubMed

    Qi, Hong-Xue; Li, Hui-Zhen; Ma, Ping; You, Jing

    2015-09-01

    A weight of evidence (WoE) framework has been applied to assess sediment quality of a typical freshwater lake, Tai Lake in China, where the sediments were contaminated by various chemicals but showed no acute lethality to the benthic invertebrate, Chironomus dilutus. A quantitative scoring method was employed to integrate three lines of evidence (LoE), including adverse effects in life cycle bioassays, biomarker responses, and bioavailability-based chemical analysis. Six biomarkers were determined in C. dilutus after the exposure to the sediments from Tai Lake and provided sensitive indication of sublethal effects at the molecular level. The biomarkers included cytochrome P450, glutathione S-transferase, carboxylesterase, acetylcholinesterase, catalase, and lipid peroxidation. The changes of the biomarkers were summarized for individual sampling sites by computing the integrated biomarker response (IBR) indices. Complementary information was also confirmed by the interrelationship of the LoEs. The IBR indices gained before pupation correlated well with the impairments of emergence of the midges, and altered acetylcholinesterase was corroborated by the detection of chlorpyrifos, an organophosphate pesticide. The relationship between bioavailable toxic units estimated by Tenax extractable concentrations of chemicals in sediment and the observed toxicity in the midges helped to identify the putative toxicity contributors to C. dilutus. Overall, the WoE method clearly distinguished the contaminated sites and ranked them by the level of contamination. Sediment-associated pesticides, particularly γ-hexachlorocyclohexane and chlorpyrifos, were the possible contributors to chronic toxicity to the midges. PMID:26004354

  14. Bridging levels of pharmaceuticals in river water with biological community structure in the Llobregat River basin (northeast Spain).

    PubMed

    Muñoz, Isabel; López-Doval, Julio C; Ricart, Marta; Villagrasa, Marta; Brix, Rikke; Geiszinger, Anita; Ginebreda, Antoni; Guasch, Helena; de Alda, M José López; Romaní, Anna M; Sabater, Sergi; Barceló, Damià

    2009-12-01

    A wide range of human pharmaceuticals are present at low concentrations in freshwater systems, particularly in sections of polluted river. These compounds show high biological activity, often associated with a high stability. These characteristics imply a potential impact of these substances on aquatic biota even when present at low environmental concentrations. Low flow conditions in Mediterranean rivers, most of which flow through densely populated areas and are subjected to intensive water use, increase the environmental risk of these emergent compounds. Here, we studied whether pharmaceuticals in river water affect the local benthic community structure (diatoms and invertebrates). For this purpose, we analyzed the occurrence of pharmaceuticals along the Llobregat River and examined the benthic community structure (diatoms and invertebrates) of this system. Some pharmaceutical products in the Llobregat River registered concentrations greater than those cited in the literature. Multivariate analyses revealed a potential causal association between the concentrations of some anti-inflammatories and beta-blockers and the abundance and biomass of several benthic invertebrates (Chironomus spp. and Tubifex tubifex). Further interpretation in terms of cause-and-effect relationships is discussed; however, it must be always taken with caution because other pollutants also may have significant contributions. Combined with further community experiments in the laboratory, our approach could be a desirable way to proceed in future risk management decisions. PMID:19908929

  15. Do acid volatile sulfides (AVS) influence the accumulation of sediment-bound metals to benthic invertebrates under natural field conditions?

    PubMed

    De Jonge, Maarten; Dreesen, Freja; De Paepe, Josefina; Blust, Ronny; Bervoets, Lieven

    2009-06-15

    The present study evaluates the influence of acid volatile sulfides (AVS) on accumulation of sediment-bound metals in benthic invertebrates under natural field conditions. Natural sediments, pore water, surface water, and two species of widespread benthic invertebrates (Chironomus gr. thummi and Tubifex tubifex) were collected from 17 historical polluted Flemish lowland rivers and measured for metal concentrations. Different sediment characteristics were determined (AVS, organic matter, clay content) and multiple regression was used to study their relationship with accumulated metals in the invertebrates. Physical and chemical analysis of the field samples indicated low metal concentrations in the water and pore water, but very high metal concentrations in the sediment and the invertebrates, especially for Pb (5.99 micromol/ g). In general, metal accumulation in chironomids and tubificid worms was most strongly correlated with total metal concentrations in the sediment and sediment metal concentrations normalized for organic matter and clay content. Following the results of the linear regression model, AVS did not turn out to be a significant variable in describing variation in metal accumulation. Our study clearly demonstrates that, in addition to the results gained from experiments under lab conditions, benthic invertebrates can accumulate metals from unspiked field sediments even when there's an excess of AVS. PMID:19603670

  16. Toxicity and bioaccumulation of sediment-associated contaminants using freshwater invertebrates: A review of methods and applications

    USGS Publications Warehouse

    Ingersoll, C.G.; Ankley, G.T.; Benoit, D.A.; Brunson, E.L.; Burton, G.A.; Dwyer, F.J.; Hoke, R.A.; Landrum, P.F.; Norberg-King, T. J.; Winger, P.V.

    1995-01-01

    This paper reviews recent developments in methods for evaluating the toxicity and bioaccumulation of contaminants associated with freshwater sediments and summarizes example case studies demonstrating the application of these methods. Over the past decade, research has emphasized development of more specific testing procedures for conducting 10-d toxicity tests with the amphipod Hyalella azteca and the midge Chironomus tentans. Toxicity endpoints measured in these tests are survival for H. azteca and survival and growth for C. tentans. Guidance has also been developed for conducting 28-d bioaccumulation tests with the oligochaete Lumbriculus variegatus, including determination of bioaccumulation kinetics for different compound classes. These methods have been applied to a variety of sediments to address issues ranging from site assessments to bioavailability of organic and inorganic contaminants using field-collected and laboratory-spiked samples. Survival and growth of controls routinely meet or exceed test acceptability criteria. Results of laboratory bioaccumulation studies with L. variegatus have been confirmed with comparisons to residues (PCBs, PAHs, DDT) present from synoptically collected field populations of oligochaetes. Additional method development is currently underway to develop chronic toxicity tests and to provide additional data-confirming responses observed in laboratory sediment tests with natural benthic populations.

  17. Unfolding and inactivation of proteins by counterions in protein-nanoparticles interaction.

    PubMed

    Ghosh, Goutam; Gaikwad, Pallavi S; Panicker, Lata; Nath, Bimalendu B; Mukhopadhyaya, Rita

    2016-09-01

    In this work, the structure and activity of proteins; such as, hen egg lysozyme (HEWL) and calf intestine alkaline phosphatase (CIAP); have been investigated after incubation with surface coated iron oxide nanoparticles (IONPs) in water. IONPs were coated with counterions bound charge-ligands and were named as the charge-ligand counterions iron oxide nanoparticles (CLC-IONPs). The coating was done with tri-lithium citrate (TLC) and tri-potassium citrate (TKC) to have negative surface charge of CLC-IONPs and Li(+) and K(+), respectively, as counterions. To have positive surface charge, IONPs were coated with cetylpyridinium chloride (CPC) and cetylpyridinium iodide (CPI) having Cl(-) and I(-), respectively, as counterions. The secondary structure of proteins was measured using far ultraviolet circular dichroism (CD) spectroscopy which showed that both proteins were irreversibly unfolded after incubation with CLC-IONPs. The unfolded proteins were seen to be functionally inactive, as confirmed through their activity assays, i.e., HEWL with Escherichia coli (E. coli) and CIAP with para-nitrophenyl phosphate (pNPP). Additionally, we have observed that monomeric hemoglobin (Hb) from radio-resistant insect Chironomus ramosus (ChHb) was also partially unfolded upon interaction with CLC-IONPs. This work clearly shows the role of counterions in protein inactivation via protein-nanoparticles interaction and, therefore, CLC-IONPs could be used for therapeutic purpose. PMID:27182654

  18. Aquatic Insect Emergence in Post-Harvest Flooded Agricultural Fields in the Southern San Joaquin Valley, California

    NASA Astrophysics Data System (ADS)

    Moss, R. C.; Blumenshine, S.; Fleskes, J.

    2005-05-01

    California's Southern San Joaquin Valley is one of the most important waterbird areas in North America, but has suffered a disproportionate loss of wetlands when compared to other California regions. This project analyzes the habitat value of post-harvest flooded cropland by measuring the emergence of aquatic insects across multiple crop types. Aquatic insect emergence was sampled from post-harvest flooded fields of four crop types (alfalfa, corn, tomato, wheat), August-October, 2003-2004. Emergence was measured using traps deployed with a stratified random distribution to sample between and within field variation. Emergence rate and emergent biomass was significantly higher in flooded tomato fields. Results from corn fields indicate that flooding depth was correlated (r=0.095) with both diel temperature fluctuation and emergence rate. Chironomus dilutus larvae were grown in environmental chambers, under two thermal treatments with the same mean but different amplitudes (high: 15°-32°C, low: 20°-26°C) to investigate thermal fluctuation effects on survival and biomass. Larval survival (4x) and biomass (2x) were significantly greater in the low versus high temperature fluctuation treatment. This research has the potential to affect agricultural management throughout the 12,600 km2 region, increase aquatic insect production and aid in the recovery of declining bird populations.

  19. Chronic toxicity of tire and road wear particles to water- and sediment-dwelling organisms.

    PubMed

    Panko, Julie M; Kreider, Marisa L; McAtee, Britt L; Marwood, Christopher

    2013-01-01

    Tire and road wear particles (TRWP) consist of a complex mixture of rubber, and pavement released from tires during use on road surfaces. Subsequent transport of the TRWP into freshwater sediments has raised some concern about the potential adverse effects on aquatic organisms. Previous studies have shown some potential for toxicity for tread particles, however, toxicity studies of TRWP collected from a road simulator system revealed no acute toxicity to green algae, daphnids, or fathead minnows at concentrations up to 10,000 mg/kg under conditions representative of receiving water bodies. In this study, the chronic toxicity of TRWP was evaluated in four aquatic species. Test animals were exposed to whole sediment spiked with TRWP at concentrations up to 10,000 mg/kg sediment or elutriates from spiked sediment. Exposure to TRWP spiked sediment caused mild growth inhibition in Chironomus dilutus but had no adverse effect on growth or reproduction in Hyalella azteca. Exposure to TRWP elutriates resulted in slightly diminished survival in larval Pimephales promelas but had no adverse effect on growth or reproduction in Ceriodaphnia dubia. No other endpoints in these species were affected. These results, together with previous studies demonstrating no acute toxicity of TRWP, indicate that under typical exposure conditions TRWP in sediments pose a low risk of toxicity to aquatic organisms. PMID:23001428

  20. The role of a water bug, Sigara striata, in freshwater food webs.

    PubMed

    Klecka, Jan

    2014-01-01

    Freshwater food webs are dominated by aquatic invertebrates whose trophic relationships are often poorly known. Here, I used laboratory experiments to study the role of a water bug, Sigara striata, as a potential predator and prey in food webs of stagnant waters. Multiple-choice predation experiment revealed that Sigara, which had been considered mostly herbivorous, also consumed larvae of Chironomus midges. Because they often occur in high densities and are among the most ubiquitous aquatic insects, Sigara water bugs may be important predators in fresh waters. A second experiment tested the role of Sigara as a potential prey for 13 common invertebrate predators. Mortality of Sigara inflicted by different predators varied widely, especially depending on body mass, foraging mode (ambush/searching) and feeding mode (chewing/suctorial) of the predators. Sigara was highly vulnerable to ambush predators, while searching predators caused on average 8.1 times lower mortality of Sigara. Additionally, suctorial predators consumed on average 6.6 times more Sigara individuals than chewing predators, which supports previous results hinting on potentially different predation pressures of these two types of predators on prey populations. The importance of these two foraging-related traits demonstrates the need to move from body mass based to multiple trait based descriptions of food web structure. Overall, the results suggests that detailed experimental studies of common but insufficiently known species can significantly enhance our understanding of food web structure. PMID:24883250

  1. Chironomidae From a Sewage Treatment Station of Southern Brazil

    NASA Astrophysics Data System (ADS)

    Signoretti, R. P.; Sonoda, K. C.; Ferraz, E.

    2005-05-01

    As the great number of insects living and reproducing at a municipal sewage treatment station located in Piracicaba City and the fear about how dangerous it could be for human healthy, a study was conduct to identify the taxa presented there and to analyze their community structure using stable isotopes. The Chironomidae identification was performed on specific level. The sewage treatment station is a man-made wetland system, situated 30m nearby the Piracicaba River. It treats the sewage from an urban area with 3000 inhabitants. The sewage discharge varies from 133 to 186L/s/ha. The samples were taken on the ending of the rainy season with a D-frame net. The material was washed (210mm mesh size), sorted and preserved in 70% alcohol. Chironomidae had a low participation in the community, with 14.9% of the specimens. Goeldichironomus serratus (47.8% from total Chironomidae), G. holoprasinus (43.5%) and Chironomus decorus (8.7%) were identified. Those species are worldwide recognized as pollution-resistant, used as indicators of environmental water quality. The wetland studied showed low dissolved oxygen (1.5mg/L) on the sampling period and the presence of those Chironomidae species should be expected. The low diversity and high dominance are common features for those impacted environments.

  2. Bioaccumulation of heavy metals in pre-fledgling tree swallows, Tachycineta bicolor

    SciTech Connect

    Kraus, M.L. )

    1989-09-01

    Wetlands in urbanized areas are frequently degraded by human activity. The Hackensack River Estuary in Northeastern New Jersey is no exception. This estuary contains over 1,600 acres of landfill, and receives various levels of treated effluent from seven different sewage treatment plants. Heavy metals are a common pollutant in the Hackensack River Basin. Bioaccumulation of heavy metals in birds is a well documented phenomenon. Studies have shown that near shore predatory birds have higher mercury levels in their feathers than do pelagic predatory birds. Other studies have shown that insectivorous pied flycatcher nestlings and black-crowned night heron pre-fledglings show heavy metal body burdens that correlate well with the distance of their nests from a heavy metal source. The tree swallow (Tachycineta bicolor) is a common summer resident in the Hackensack Meadowlands. This species readily nests in man-made nest boxes, and has used boxes erected for this purpose in the Hackensack Meadowlands District (HMD). The swallows feed primarily on adult midges (Chironomus decorus) which are prevalent in the region. This relationship makes the tree swallows and midges an ideal model for food chain bioaccumulation studies.

  3. Measuring pyrethroids in sediment pore water using matrix-solid phase microextraction.

    PubMed

    Hunter, Wesley; Yang, Yu; Reichenberg, Fredrik; Mayer, Philipp; Gan, Jianying

    2009-01-01

    Pyrethroids are hydrophobic insecticides commonly used in both agricultural and urban environments. Their high toxicity to aquatic organisms, including benthic invertebrates, and detection in the sediment at many locations in California, U.S.A., have spawned interest in understanding their bioavailability in bed sediments. A recent study showed good correlation between uptake of 14C-permethrin in Chironomus tentans and solid-phase microextraction (SPME) fibers in sediments. The present study was directed at the development of an SPME technique applicable to trace levels of nonlabeled pyrethroids in sediment. Disposable polydimethylsiloxane fibers were used to detect freely dissolved pore-water concentrations of bifenthrin, fenpropathrin, cis-permethrin, trans-permethrin, cyfluthrin, cypermethrin, and esfenvalerate under agitated and static conditions. Partition equilibrium between fiber and sediment was reached in <5 d when the samples were agitated on a shaker at low speed, while much longer times (>23 d) were needed without agitation. Polydimethylsiloxane to water partition ratios (K(PDMS)) of the seven pyrethroids were measured separately and ranged from 2.83 x 10(5) to 1.89 x 10(6). When applied to field-contaminated sediments, agitated matrix-SPME was able to detect pore-water concentrations as low as 0.1 ng/L. The method developed in the present study may be coupled with bioassays to gain mechanistic understanding of factors affecting pyrethroid toxicities, and applied to field samples to better predict sediment toxicities from pyrethroid contamination. PMID:18712946

  4. Conformations of peptide fragments comprising the complete sequence of component III of Chi t I and their relationship to T-cell stimulation.

    PubMed

    Czisch, M; Liebers, V; Bernstein, R; Chen, Z; Baur, X; Holak, T A

    1994-08-16

    Conformational preferences of synthetic peptides that span the complete sequence of Chironomus thummi hemoglobin (Chi t I) component III were studied by nuclear magnetic resonance (NMR) and CD spectroscopies. The peptides, 19-21 amino acids in length, were studied in water, except for the C-terminal peptide, which was investigated in DMSO-d6. NMR showed that all investigated peptides lacked uniquely folded conformations in water at 4 degrees C and pH 3.0 or at 10 degrees C and pD 6.6 in DMSO. However, some preferential helix-like conformations for the peptides corresponding to the helices of the folded protein could be seen in solution. These peptides showed characteristic interactions for conformations in both the beta- and alpha-regions of phi-psi space, based on strong C alpha H(i)-NH(i + 1) interactions, and on NH-NH, C alpha H(i)-NH-(i + 2), C alpha H(i)-NH(i + 3), and C alpha H(i)-C beta H(i + 3) interactions, respectively. Helical motifs seem not to be the most important factors in determining MHC-binding and/or T-cell recognition. However, there is a tendency that more stabilized secondary structures show higher T-cell stimulation. PMID:8068617

  5. Macroinvertebrate responses to nickel in multisystem exposures.

    PubMed

    Custer, Kevin W; Kochersberger, Jon P; Anderson, Padrick D; Fetters, Kyle J; Hummel, Steven; Burton, G Allen

    2016-01-01

    Metals introduced to sediments undergo a variety of complexation and partitioning changes that affect metal bioavailability. Using simultaneously extracted metal (SEM)/acid volatile sulfide (AVS) and organic carbon (f(OC)) models, the authors examined nickel (Ni) toxicity and bioavailability in 2 field studies (using streamside mesocosm and in situ colonization) and 1 laboratory study. The streamside mesocosm experiments indicated that benthic communities (Ephemeroptera, abundance, and taxa richness) responded negatively to increasing SEM(Ni) /AVS and (SEM(Ni) -AVS)/f(OC) models. In the in situ colonization study, taxa richness, abundance, and Ephemeroptera, Plecoptera, and Trichoptera (EPT) taxa decreased with increasing SEM(Ni) and SEM(Ni)/AVS values. Nickel-spiked sediments were tested in the laboratory with indigenous field-collected mayflies (Anthopotamus verticis, Isonychia spp., and Stenonema spp) and a beetle (Psephenus herricki), and with laboratory-cultured Hyalella azteca and Chironomus dilutus. The amphipod H. azteca was the most sensitive organism tested, and the mayflies Anthopotamus verticis and Stenonema spp. were the most sensitive indigenous organisms to Ni-spiked sediments. These studies help discern which factors are important in determining Ni toxicity and bioavailability at the individual, population, and community levels. PMID:26178528

  6. A chironomid (Diptera: Chironomidae) midge population study and laboratory evaluation of larvicides against midges inhabiting the lagoon of Venice, Italy.

    PubMed

    Ali, A; Majori, G; Ceretti, G; D'Andrea, F; Scattolin, M; Ferrarese, U

    1985-03-01

    Chironomid larval densities in the saltwater lagoon of Venice, Italy, were assessed in the spring of 1984. Four organophosphates; chlorpyrifos, temephos, fenthion and fenitrothion, and three pyrethroids; cypermethrin, permethrin and deltamethrin, were tested in the laboratory against field-collected larvae. Three industrial formulations of Bacillus thuringiensis var. israelensis (B.t.i.) were also tested as midge larvicides. Only Chironomus salinarius occurred in the benthic samples taken from different sections of the lagoon. The densities of this species ranged from 0 to 38,976 larvae/m2. The highest mean larval density of 15,673/m2 was encountered in a section of the lagoon adjacent to Venice airport and receiving large quantities of raw sewage. The lowest mean density (less than 1 larva/m2) existed in another area of the lagoon receiving discharge from chemical industry. Cypermethrin and permethrin were 21-233X more active against the larvae than the four organophosphates. Chlorpyrifos was the most active organophosphate. Formulations of B.t.i. were economically ineffective against the larvae. PMID:3880214

  7. Toxicity of anionic polyacrylamide formulations when used for erosion control in agriculture.

    PubMed

    Weston, Donald P; Lentz, Rodrick D; Cahn, Michael D; Ogle, R Scott; Rothert, Amanda K; Lydy, Michael J

    2009-01-01

    Addition of anionic polyacrylamide (PAM) to agricultural irrigation water can dramatically reduce erosion of soils. However, the toxicity of PAM to aquatic life, while often claimed to be low, has not been thoroughly evaluated. Five PAM formulations, including two oil-based products, one water-based product, one granular product and one tablet product, were evaluated for acute and/or chronic toxicity to five species commonly used for freshwater toxicity testing [Hyalella azteca (Saussure), Chironomus dilutus (Shobanov et al.), Ceriodaphnia dubia (Richard), Pimephales promelas (Rafinesque), and Selenastrum capricornutum (Printz)]. When applied as an oil-based product, acute toxicity was seen to four of the five species at concentrations less than the 10 mg/L that is often used for erosion control. Toxicity was diminished, but still remained, after passage of the irrigation water across an agricultural field, indicating a potential impact to nearby surface waters. Results from the non-oil-based products indicated minimal toxicity associated with PAM even at concentrations 10 times those used in agriculture when applied in the granular form, as a tablet, or in a water-based liquid. These data suggest that other agents in the oil-based products, such as surfactants or emulsifiers, rather than the PAM itself, contribute to the toxicity. Care is required in selecting an appropriate PAM formulation when the potential exists for entry of tailwater to nearby surface waters. PMID:19141814

  8. Ecotoxicological impact of Zequanox®, a novel biocide, on selected non-target Irish aquatic species.

    PubMed

    Meehan, Sara; Shannon, Adam; Gruber, Bridget; Rackl, Sarahann M; Lucy, Frances E

    2014-09-01

    Effective, species-specific zebra mussel control is needed urgently for Ireland׳s freshwater bodies, which became infested with non-native zebra mussels in the 1990s. Zequanox®, a newly commercialized product for zebra and quagga mussel control, is composed of dead Pseudomonas fluorescens CL 145A cells. This paper describes ecotoxicology tests on three representative native Irish freshwater species: Anodonta (duck mussel), Chironomus plumosus (non-biting midge), and Austropotamobius pallipes (white-clawed crayfish). The species were exposed to Zequanox in a 72-h static renewal toxicity test at concentrations of 100-750mg active ingredient per liter (mga.i./L). Water quality parameters were measured every 12-24h before and after water and product renewal. After 72h, endpoints were reported as LC10, LC50, and LC100. The LC50 values derived were (1) Anodonta: ≥500mga.i./L (2) C. plumosus: 1075mga.i./L, and (3) A. pallipes: ≥750mga.i./L. These results demonstrate that Zequanox does not negatively affect these organisms at the concentration required for >80percent zebra mussel mortality (150mg a.i/L) and the maximum allowable treatment concentration in the United Sates (200mga.i./L). They also show the overall species-specificity of Zequanox, and support its use in commercial facilities and open waters. PMID:24927392

  9. A long-term assessment of pesticide mixture effects on aquatic invertebrate communities.

    PubMed

    Hasenbein, Simone; Lawler, Sharon P; Geist, Juergen; Connon, Richard E

    2016-01-01

    To understand the potential effects of pesticide mixtures on aquatic ecosystems, studies that incorporate increased ecological relevance are crucial. Using outdoor mesocosms, the authors examined long-term effects on aquatic invertebrate communities of tertiary mixtures of commonly used pesticides: 2 pyrethroids (permethrin, λ-cyhalothrin) and an organophosphate (chlorpyrifos). Application scenarios were based on environmentally relevant concentrations and stepwise increases of lethal concentrations from 10% (LC10) to 50% (LC50) based on laboratory tests on Hyalella azteca and Chironomus dilutus; repeated applications were meant to generally reflect runoff events in a multiple-grower or homeowner watershed. Pyrethroids rapidly dissipated from the water column, whereas chlorpyrifos was detectable even 6 wk after application. Twelve of 15 macroinvertebrate and 10 of 16 zooplankton taxa responded to contaminant exposures. The most sensitive taxa were the snail Radix sp., the amphipod H. azteca, the water flea Daphnia magna, and copepods. Environmentally relevant concentrations had acute effects on D. magna and H. azteca (occurring 24 h after application), whereas lag times were more pronounced in Radix sp. snails and copepods, indicating chronic sublethal responses. Greatest effects on zooplankton communities were observed in environmentally relevant concentration treatments. The results indicate that insecticide mixtures continue to impact natural systems over multiple weeks, even when no longer detectable in water and bound to particles. Combinations of indirect and direct effects caused consequences across multiple trophic levels. PMID:26565581

  10. Assessment of the ecological effects of arsenic on a southern Ohio, USA stream.

    PubMed

    Huddleston, George M; Dorn, Philip B; Gillespie, W Barry; Wong, Diana C L; Slocomb, John P

    2009-04-01

    Davis Creek is a southern Ohio, USA stream that receives a permitted discharge from the Belpre Elastomers Plant (BEP). A sediment quality triad investigation of Davis Creek was conducted over a 2-y period that included sediment and surface water chemistry measurements, toxicity tests of whole sediment, interstitial and surface water, and benthic and artificial substrate community assessments. The concentration of arsenic in surface and interstitial water was below United States Environmental Protection Agency ambient water quality criteria and was not toxic in laboratory tests (Ceriodaphnia dubia, Pimephales promelas). Similarly, sediments did not significantly affect survival and growth of Hyalella azteca and Chironomus tentans at most sampling locations despite sediments exceeding arsenic sediment screening values in nearly all samples collected. Differences in benthic community structure, determined by rapid bioassessment and Hester-Dendy sampling methods, were related primarily by variations in sediment moisture, particle size, and ammonia and not to arsenic concentrations. The Invertebrate Community Index (ICI) for Davis Creek was lower than values established for other warm-water ecoregional reference streams in Ohio. However, this ICI comparison may have been invalid because, unlike the reference streams, the Davis Creek watershed is small with intermittent headwater flow that limits macroinvertebrate recruitment and energy input. The sediment quality triad investigation indicated that Davis Creek was not significantly affected by arsenic associated with the BEP discharge despite having measured arsenic concentrations that exceeded sediment screening values. PMID:19055317

  11. Dissipation of insecticidal Cry1Ac protein and its toxicity to nontarget aquatic organisms.

    PubMed

    Li, Yan-Liang; Du, Juan; Fang, Zhi-Xiang; You, Jing

    2013-11-20

    The widespread cultivation of Bacillus thuringiensis crops has raised public concerns on their risk to nontarget organisms. Persistence of Cry1Ac protein in soil, sediment and water and its toxicity to nontarget aquatic organisms were determined. The dissipation of Cry1Ac toxin was well described using first order kinetics, with the half-lives (DT50) ranging from 0.8 to 3.2, 2.1 to 7.6 and 11.0 to 15.8 d in soil, sediment and water, respectively. Microbial degradation played a key role in the dissipation of Cry1Ac toxin and high temperature accelerated the processes. Cry1Ac toxin was more toxic to the midge Chironomus dilutus than the amphipod Hyalella azteca, with the median lethal concentration (LC50) of C. dilutus being 155 ng/g dry weight and 201 ng/mL in 10-d sediment and 4-d water bioassays, respectively. While Cry1Ac toxin showed toxicity to the midges, risk of Bt proteins to aquatic nontarget organisms was limited because their environmentally relevant concentrations were much lower than the LC50s. PMID:24151928

  12. Shock chloramination: potential treatment for Chironomidae (Diptera) larvae nuisance abatement in water supply systems.

    PubMed

    Broza, M; Halpern, M; Teltsch, B; Porat, R; Gasith, A

    1998-08-01

    In the early 1990s, infestations of midge larvae (Chironomidae, Chironomus sp.) were discovered in the potable water system of Tel Aviv, Israel. Control measures, such as draining and cleaning tanks, spraying water into the tank's air space, and electrocution traps of midge adults, were either inadequate or ineffective. In this system, monochloramine concentrations of up to 0.75 mg/liter are used routinely as a secondary disinfectant. This chemical was tested in the laboratory as a toxicant of midge larvae. The mortality of 4th instar midge larvae after short exposure to high chloramine concentrations (LC50 values of 32 mg/liter for 75 min) suggested the efficacy of instituting a Shock Chloramination treatment program. Tanks were partially drained until they contained only 20 cm of water and were then temporarily disconnected. Chloramine was added to this water to produce a concentration of approximately 70 mg/liter for 1-2 h. Subsequently, all dead chironomids were flushed out, and the tank was refilled to attain the operational volume of water. A 2nd identical treatment of water in the tank was suggested 7 d later to kill midges from reproductive adults and egg-masses that survived the 1st treatment. This treatment program was tested in commercial covered tanks and gave complete control of these pests for 6-10 wk. These results suggest that this treatment program may effectively prevent midge outbreaks in Israel's drinking water supply system during the height of the summer. PMID:9725031

  13. Sediment toxicity and deformities of chironomid larvae in Lake Piediluco (Central Italy).

    PubMed

    Di Veroli, Alessandra; Selvaggi, Roberta; Pellegrino, Roberto Maria; Goretti, Enzo

    2010-03-01

    The chemical analysis of the bottom sediments of the Lake Piediluco (Central Italy) has been carried out in order to individuate the potential correlation between the sediment toxicity and the high incidence of mouthpart deformities in chironomid larvae (biological indicators) found in this lake. The environmental contamination has been analyzed by determining the concentrations of the main heavy metals (lead, copper, cadmium, chromium, zinc and nickel), and the concentrations of organic compounds of anthropic source: PAHs, NPPs and OCPs. Heavy metals concentrations have pointed out a non-elevated contamination grade for the Lake Piediluco. The highest level of metals has been detected in the western area that feels the effect of the continuous tributaries incoming load. Also, concerning PAHs, NPPs and OCPs the lake does not present high values of pollution. The highest concentrations of the organic toxicants has been observed in the eastern sector of the lake, which presents typical lentic characteristics. A clear relationship has not found between the toxic substances present in the lacustrine sediments and the deformities incidence for chironomid larvae, which represent an index of environmental alteration. Probably, the mouthpart deformities found in the chironomid larvae of Chironomus plumosus are affected by a synergic action due to the whole toxic mixture present in the sediments of the Lake Piediluco. PMID:20172586

  14. Bioavailability of metals and toxicity identification of the sediment pore waters from Plow Shop Pond, Fort Devens, Massachusetts

    SciTech Connect

    Jop, K.; Putt, A.; Shepherd, S.; Askew, A.; Bleiler, J.; Reed, S.; George, C.

    1995-12-31

    Plow Shop Pond is a shallow, 30-acre pond located at Fort Devens, Massachusetts. An ecological risk assessment was conducted at Plow Shop Pond as part of a remedial investigation. Preliminary analysis revealed high concentrations of arsenic, copper, chromium, lead, and mercury in the sediment. Therefore, a laboratory testing program was incorporated into this investigation to assess the toxicity of sediments to aquatic organisms. The screening testing program included short-term chronic exposure of Ceriodaphnia dubia to pore waters, 10-day exposures of Chironomus tentans and Hyalella azteca to bulk sediments and a bioaccumulation study with Lumbriculus variegatus. Survival and reproduction of C. dubia, growth of amphipods and reproduction of oligochaetes appeared to indicate sediment toxicity at some sites within the pond. Although high concentrations of arsenic, copper, mercury and lead were detected in the whole sediments and pore waters, the response could not be correlated to a particular element. Also, relatively low bioaccumulation of methyl mercury and high uptake of inorganic mercury was established for three sediment samples. To characterize and identify the source of toxicity, a toxicity identification evaluation program using sediments collected at several locations was performed. The pore water from these samples was used for fractionation coupled with a 10-day test using H. azteca. Survival and growth were evaluated as endpoints during the exposures. Partitioning of metals and their bioavailability was influenced primarily by organic carbon and AVS concentration. At least two constituents were responsible for the toxicity.

  15. Ecological assessment of a metal-contaminated pond in southern New England

    SciTech Connect

    Bleiler, J.A.; Fogg, A.; Reed, S.; Jop, K.; Putt, A.; George, C.

    1995-12-31

    An integrated ecological risk assessment was conducted to evaluate toxicity and bioaccumulation associated with sediment contamination in Plow Shop Pond (PSP), a 30-acre pond bordered by a landfill in central Massachusetts. Data from sediment and fish tissue analysis, as well as, results of sediments toxicity tests and a benthic community survey, were considered in the assessment. Arsenic, chromium, copper, lead, manganese, and mercury were found at elevated concentrations in PSP sediments. Fish tissue body weight appeared to be a good predictor of mercury contaminate burden in PSP, with heavier fish having higher concentrations of mercury. Macroinvertebrate community data suggested that PSP may be slightly impacted relative to a reference pond, with a significantly lower taxa richness and fewer pollution-intolerant species than the reference site. Despite the high levels of metals in PSP, only moderate levels of acute toxicity were observed in screening level sediment toxicity tests with Hyalella azteca, Chironomus tentans, and Ceriodaphnia dubia. Reduced growth and reproduction were observed in these tests, indicating potential sub-lethal effects in exposed to PSP sediments. It is likely that high levels of Acid Volatile Sulfides and Total Organic Carbon in PSP sediment have increased its metal-binding capacity, thus reducing bioavailability and toxicity of the inorganics in sediment. A dilution series Toxicity Identification Evaluation (TIE) was implemented to help identify stressors in PSP. The results of the integrated risk assessment at PSP are being used to evaluate remedial alternatives and to make risk management decisions.

  16. Identifying the cause of sediment toxicity in agricultural sediments: the role of pyrethroids and nine seldom-measured hydrophobic pesticides.

    PubMed

    Weston, Donald P; Ding, Yuping; Zhang, Minghua; Lydy, Michael J

    2013-01-01

    Few currently used agricultural pesticides are routinely monitored for in the environment. Even if concentrations are known, sediment LC(50) values are often lacking for common sediment toxicity testing species. To help fill this data gap, sediments in California's Central Valley were tested for nine hydrophobic pesticides seldom analyzed: abamectin, diazinon, dicofol, fenpropathrin, indoxacarb, methyl parathion, oxyfluorfen, propargite, and pyraclostrobin. Most were detected, but rarely at concentrations acutely toxic to Hyalella azteca or Chironomus dilutus. Only abamectin, fenpropathrin, and methyl parathion were found at concentrations of potential concern, and only in one or two samples. One-quarter of over 100 samples from agriculture-affected waterways exhibited toxicity, and in three-fourths of the toxic samples, pyrethroids exceeded concentrations expected to cause toxicity. The pyrethroid Bi-fen-thrin in particular, as well as lambda-cyhalothrin, cypermethrin, esfenvalerate, permethrin, and the organophosphate chlorpyrifos, were primarily responsible for the observed toxicity, rather than the more novel analytes, despite the fact that much of the sampling targeted areas of greatest use of the novel pesticides. PMID:22832339

  17. Laboratory and field studies on the effect of molinate, clomazone, and thiobencarb on nontarget aquatic invertebrates.

    PubMed

    Burdett, A S; Stevens, M M; Macmillan, D L

    2001-10-01

    The midge Chironomus tepperi was used in laboratory experiments to assess the relative toxicity of formulated molinate, clomazone, and thiobencarb, three herbicides used in Australian rice crops. Static bioassays were initiated with first-instar larvae at herbicide concentrations between 0.0625 and 2 times the anticipated field concentrations (AFCs) expected from the registered application rates. Adult emergence success, development time, and wing length were used as indices of the effect of each herbicide. Clomazone had no effect on any parameters at concentrations up to 0.288 mg/L (p > 0.05). Molinate significantly increased development time at concentrations equivalent to the AFC (3.6 mg/L) and above (p < 0.05). Thiobencarb reduced emergence success of adult C. tepperi at 0.0625 times the AFC (0.1875 mg/L) as well as decreasing male adult size and increasing development time for males and females at 0.125 times the AFC (p < 0.05). Nontarget effects of the herbicides on aquatic invertebrate communities were assessed in shallow experimental ponds using commercial application rates. One week after treatment, only thiobencarb had a significant effect, suppressing populations of chironomids, calanoids, and cyclopoids (p < 0.05). Four weeks later, all populations had recovered, equaling or exceeding control densities. PMID:11596755

  18. The interaction of actinide and lanthanide ions with hemoglobin and its relevance to human and environmental toxicology.

    PubMed

    Kumar, Amit; Ali, Manjoor; Ningthoujam, Raghumani S; Gaikwad, Pallavi; Kumar, Mukesh; Nath, Bimalendu B; Pandey, Badri N

    2016-04-15

    Due to increasing use of lanthanides/actinides in nuclear and civil applications, understanding the impact of these metal ions on human health and environment is a growing concern. Hemoglobin (Hb), which occurs in all the kingdom of living organism, is the most abundant protein in human blood. In present study, effect of lanthanides and actinides [thorium: Th(IV), uranium: U(VI), lanthanum: La(III), cerium: Ce(III) and (IV)] on the structure and function of Hb has been investigated. Results showed that these metal ions, except Ce(IV) interacted with carbonyl and amide groups of Hb, which resulted in the loss of its alpha-helix conformation. However, beyond 75μM, these ions affected heme moiety. Metal-heme interaction was found to affect oxygen-binding of Hb, which seems to be governed by their closeness with the charge-to-ionic-radius ratio of iron(III). Consistently, Ce(IV) being closest to iron(III), exhibited a greater effect on heme. Binding constant and binding stoichiometry of Th(IV) were higher than that of U(VI). Experiments using aquatic midge Chironomus (possessing human homologous Hb) and human blood, further validated metal-Hb interaction and associated toxicity. Thus, present study provides a biochemical basis to understand the actinide/lanthanide-induced interference in heme, which may have significant implications for the medical and environmental management of lanthanides/actinides toxicity. PMID:26799219

  19. Acid mine drainage and its impact in the Black Creek watershed, Virginia

    SciTech Connect

    Yeager, J.L.; Cherry, D.S.; Bidwell, J.R.

    1995-12-31

    A one-year study was conducted to determine the impacts of acid min drainage (AMD) on the Black Creek watershed in Wise County, Virginia. Water quality, metal content of sediment and water column, soil pH, macroinvertebrate assemblages, habitat assessment and toxicity testing were used to assess the impact in the watershed. A total of 22 sites in the creek and surrounding watershed were actively monitored. This included six primary sources of AMD. Conductivity measurements > 1,000 {micro}hmos/cm were found at eight sites and pH was consistently below 6.0 at seven. Of six metals analyzed, magnesium was highest in the water column, ranging from 16.5 mg/L to 130 mg/L. Aluminum and iron were both elevated in the sediment with iron concentrations as high as 176,000 mg/kg. An increase in sediment metal concentrations was noted when progressing downstream in the creek. Of nine high wall and spoils areas sampled, soil pH was acidic in eight sites, ranging from 5.5 to 3.1. Macroinvertebrate assemblages and habitat assessment indicate that much of the creek is impacted by AMD or heavy siltation. Laboratory bioassays with Daphnia magna and Chironomus tentans have indicated both acute and chronic toxicity of water and sediment samples from selected sites within the creek. Potential recovery of the system is being addressed through a sediment purging study. Restoration options will be considered once the degree of impact is fully characterized.

  20. Ecological risk assessment of urban creek sediments contaminated by untreated domestic wastewater: potential contribution of antimicrobials and a musk fragrance.

    PubMed

    Tamura, Ikumi; Kimura, Kumiko; Kameda, Yutaka; Nakada, Norihide; Yamamoto, Hiroshi

    2013-01-01

    Despite the fact that some hydrophobic pharmaceuticals and personal care products (PPCPs) have been found to accumulate in river sediments, little is known about the contribution of these compounds to the toxicity of the whole sediment. We sampled river sediments from two urban creeks with an unsewered drainage area to investigate the toxicity for a benthic organism, Chironomus yoshimatsui. The concentrations of selected hydrophobic PPCPs, triclosan (TCS), triclocarban (TCC) and galaxolide (HHCB) were analysed using gas chromatographic mass spectroscopy or liquid chromatographic mass spectroscopy and were found to lie within the range 50 to 200 ng g(-1). The toxicity of the three individual contaminants for the chironomid was also determined. The toxicity of TCC was found to be the strongest, with an NOEC value of 2.5 microg g(-1). Combining the toxicity and measured environmental concentration, the ecological risk was assessed and the contribution of these contaminants to the whole sediment toxicity estimated, assuming additivity. The hazard quotient of all three compounds, determined without assessment factor, ranged between 0.01 and 0.1. The combined contribution of the three compounds to total sediment toxicity was as high as 8.2%, but other unknown factors may also make an important contribution. PMID:24191491

  1. Close coupling between transcription and exit of mRNP from the cell nucleus

    SciTech Connect

    Kylberg, Karin; Bjoerkroth, Birgitta; Ivarsson, Birgitta; Fomproix, Nathalie; Daneholt, Bertil

    2008-05-01

    Transcription is intimately coupled to co-transcriptional formation of mRNP particles and their preparation for export. In the dipteran Chironomus tentans we have now investigated whether on-going transcription is closely linked also to the ensuing transfer of the mRNPs from genes to cytoplasm. The assembly and nucleocytoplasmic transport of a specific mRNP particle, the Balbiani ring (BR) RNP granule, were visualized in larval salivary glands by electron microscopy. When transcription was inhibited with DRB or actinomycin D (AMD), the growing BR mRNPs disappeared from the genes. The two inhibitors affected the distribution of BR mRNPs in the nucleoplasm and in the nuclear pores in essentially the same way. At the nuclear pore complexes (NPCs) the basket-associated and translocating mRNPs were substantially reduced in number, the translocating RNPs being essentially absent after 90 min treatment. Remarkably, the amount of BR mRNPs in the nucleoplasm did not change. We conclude that on-going transcription is required for the mRNPs to exit from the cell nucleus. Interruption of transcription seems to primarily affect the intranuclear movement of BR mRNPs and/or prevent the binding of mRNPs to the NPCs rather than to directly interfere with translocation per se.

  2. Exclusion of mRNPs and ribosomal particles from a thin zone beneath the nuclear envelope revealed upon inhibition of transport

    SciTech Connect

    Kylberg, Karin; Bjoerk, Petra; Fomproix, Nathalie; Ivarsson, Birgitta; Wieslander, Lars; Daneholt, Bertil

    2010-04-01

    We have studied the nucleocytoplasmic transport of a specific messenger RNP (mRNP) particle, named Balbiani ring (BR) granule, and ribosomal RNP (rRNP) particles in the salivary glands of the dipteran Chironomus tentans. The passage of the RNPs through the nuclear pore complex (NPC) was inhibited with the nucleoporin-binding wheat germ agglutinin, and the effects were examined by electron microscopy. BR mRNPs bound to the nuclear basket increased in number, while BR mRNPs translocating through the central channel decreased, suggesting that the initiation of translocation proper had been inhibited. The rRNPs accumulated heavily in nucleoplasm, while no or very few rRNPs were recorded within nuclear baskets. Thus, the transport of rRNPs had been blocked prior to the entry into the baskets. Remarkably, the rRNPs had been excluded both from baskets and the space in between the baskets. We propose that normally basket fibrils move freely and repel RNPs from the exclusion zone unless the particles have affinity for and bind to nucleoporins within the baskets.

  3. Gut content weight and clearance rate for three species of freshwater invertebrates

    SciTech Connect

    Brooke, L.T.; Ankley, G.T.; Call, D.J.; Cook, P.M.

    1996-02-01

    There is concern for potential error in the accurate estimation of chemical bioaccumulation in benthic organisms due to xenobiotics associated with gut contents (sediments). In this study the benthic macroinvertebrates Hexagenia limbata, Chironomus tentans, and Lumbriculus variegatus were exposed to five sediments from the Lower Fox River/Green Bay area of Wisconsin to determine the percentage of their weight due to gut contents and the rate at which guts were emptied when the animals were held in clean water. Upon removal from the test sediments, inorganic gut contents in H. limbata, C. tentans, and L. variegatus represented approximately 9, 10, and 10% of their whole body dry weights, respectively. Depuration rates were relatively rapid, with mayflies, midges, and oligochaetes losing approximately 75, 90, and 100% of their gut contents during the first 12 h of depuration. This suggests that a 12--24-h holding period in clean water at the conclusion of sediment bioaccumulation tests with the three species should be sufficient to eliminate potential bias in tissue residue concentrations due to gut contents.

  4. Micro-scale analysis for the determination PAHs in benthic macroinvertebrates

    SciTech Connect

    Sheedy, B.R.; Ankley, G.T.; Kosian, P.A.; Mattson, V.R.; Cox, J.S.; Monson, P.D.

    1995-12-31

    The amount of tissue required for analysis of trace concentrations of non-ionic organic chemicals can be fairly large, e.g., as high as 20 g. However, in order to routinely analyze residues in smaller sediment-dwelling organisms, modified analytical residue techniques are required to accommodate very small sample sizes (e.g., 0.05 to 0.2 g) to achieve desired detection limits. The objective of this study was to optimize analytical techniques for the measurement of polycyclic aromatic hydrocarbon (PAH) residues in two species of freshwater benthic macroinvertebrates, Lumbriculus variegatus and Chironomus tentans. There are several ways of increasing sensitivity for tissue residue analysis, including altering cleanup steps, reducing compound loss, and optimizing instrument detection limits. These techniques were applied to tissue samples from several PAH toxicity and bioaccumulation studies with L. variegatus and C. tentans larvae. Tissues were homogenized and extracted using a micro-homogenizer, and the extracts were analyzed using high pressure liquid chromatography (HPLC) with fluorescence detection. The final method, which will be described in this presentation, provides reproducible data that exceed typical quality assurance requirements and results in detection limits as low as 10 ng/g in sample sizes as small as 0.05 g.

  5. Development and preliminary application of a method to assess river ecological status in the Hai River Basin, north China.

    PubMed

    Shan, Baoqing; Ding, Yuekui; Zhao, Yu

    2016-01-01

    The river ecosystem in the Hai River Basin (HRB), an important economic region in China, is seriously degraded. With the aim of river restoration in the HRB, we developed a method to assess the river's ecological status and conducted a preliminary application of the method. The established method was a predictive model, which used macroinvertebrates as indicator organisms. The river's ecological status was determined by calculating the ratio of observed to expected values (O/E). The method included ecoregionalization according to natural factors, and the selection of reference sites based on combinations of habitat quality and macroinvertebrate community. Macroinvertebrate taxa included Insecta, Crustacea, Gastropoda, and Oligochaeta, with 39 families and 95 genera identified in the HRB. The HRB communities were dominated by pollution tolerant taxa, such as Lymnaeidae, Chironomus, Limnodrilus, Glyptotendipes, and Tubifex. The average Shannon-Wiener index was 1.40±0.5, indicating a low biodiversity. In the river length of 3.31×10(4) km, 55% of the sites were designated poor, with a bad ecological status. Among nine secondary river systems, Luan and Zi-ya had the best and worst river conditions, respectively. Only 17 reference site groups were selected for river management in the 41 ecoregions examined. This study lays the foundation for river restoration and related research in the HRB, and we anticipate further developments of this novel method. PMID:26899653

  6. Effect of zeolite on toxicity of ammonia in freshwater sediments: Implications for toxicity identification evaluation procedures

    USGS Publications Warehouse

    Besser, J.M.; Ingersoll, C.G.; Leonard, E.N.; Mount, D.R.

    1998-01-01

    Techniques for reducing ammonia toxicity in freshwater sediments were investigated as part of a project to develop toxicity identification and evaluation (TIE) procedures for whole sediments. Although ammonia is a natural constituent of freshwater sediments, pollution can lead to ammonia concentrations that are toxic to benthic invertebrates, and ammonia can also contribute to the toxicity of sediments that contain more persistent contaminants. We investigated the use of amendments of a natural zeolite mineral, clinoptilolite, to reduce concentrations of ammonia in sediment pore water. Zeolites have been widely used for removal of ammonia in water treatment and in aqueous TIE procedures. The addition of granulated zeolite to ammonia-spiked sediments reduced pore-water ammonia concentrations and reduced ammonia toxicity to invertebrates. Amendments of 20% zeolite (v/v) reduced ammonia concentrations in pore water by ???70% in spiked sediments with ammonia concentrations typical of contaminated freshwater sediments. Zeolite amendments reduced toxicity of ammonia-spiked sediments to three taxa of benthic invertebrates (Hyalella azteca, Lumbriculus variegatus, and Chironomus tentans), despite their widely differing sensitivity to ammonia toxicity. In contrast, zeolite amendments did not reduce acute toxicity of sediments containing high concentrations of cadmium or copper or reduce concentrations of these metals in pore waters. These studies suggest that zeolite amendments, used in conjunction with toxicity tests with sensitive taxa such as H. azteca, may be an effective technique for selective reduction of ammonia toxicity in freshwater sediments.

  7. Toxicity on aquatic organisms exposed to secondary effluent disinfected with chlorine, peracetic acid, ozone and UV radiation.

    PubMed

    da Costa, Juliana Berninger; Rodgher, Suzelei; Daniel, Luiz Antonio; Espíndola, Evaldo Luiz Gaeta

    2014-11-01

    The toxic potential of four disinfectant agents (chlorine, ozone, peracetic acid and UV radiation), used in the disinfection of urban wastewater, was evaluated with respect to four aquatic organisms. Disinfection assays were carried out with wastewater from the city of Araraquara (São Paulo State, Brazil), and subsequently, toxicity bioassays were applied in order to verify possible adverse effects to the cladocerans (Ceriodaphnia silvestrii and Daphnia similis), midge larvae Chironomus xanthus and fish (Danio rerio). Under the experimental conditions tested, all the disinfectants were capable of producing harmful effects on the test organisms, except for C. xanthus. The toxicity of the effluent to C. silvestrii was observed to increase significantly as a result of disinfection using 2.5 mg L(-1) chlorine and 29.9 mg L(-1) ozone. Ozonation and chlorination significantly affected the survival of D. similis and D. rerio, causing mortality of 60 to 100 % in comparison to the non-disinfected effluent. In experiments with effluent treated with peracetic acid (PAA) and UV radiation, a statistically significant decrease in survival was only detected for D. rerio. This investigation suggested that the study of the ideal concentrations of disinfectants is a research need for ecologically safe options for the treatment of wastewater. PMID:25213288

  8. Inconsistency in the analysis of morphological deformities in chironomidae (Insecta: Diptera) larvae.

    PubMed

    Salmelin, Johanna; Vuori, Kari-Matti; Hämäläinen, Heikki

    2015-08-01

    The incidence of morphological deformities of chironomid larvae as an indicator of sediment toxicity has been studied for decades. However, standards for deformity analysis are lacking. The authors evaluated whether 25 experts diagnosed larval deformities in a similar manner. Based on high-quality digital images, the experts rated 211 menta of Chironomus spp. larvae as normal or deformed. The larvae were from a site with polluted sediments or from a reference site. The authors revealed this to a random half of the experts, and the rest conducted the assessment blind. The authors quantified the interrater agreement by kappa coefficient, tested whether open and blind assessments differed in deformity incidence and in differentiation between the sites, and identified those deformity types rated most consistently or inconsistently. The total deformity incidence varied greatly, from 10.9% to 66.4% among experts. Kappa coefficient across rater pairs averaged 0.52, indicating insufficient agreement. The deformity types rated most consistently were those missing teeth or with extra teeth. The open and blind assessments did not differ, but differentiation between sites was clearest for raters who counted primarily absolute deformities such as missing and extra teeth and excluded apparent mechanical aberrations or deviations in tooth size or symmetry. The highly differing criteria in deformity assignment have likely led to inconsistent results in midge larval deformity studies and indicate an urgent need for standardization of the analysis. PMID:26061223

  9. Cryptic species in the nuisance midge Polypedilum nubifer (Skuse (Diptera: Chironomidae) and the status of Tripedilum Kieffer.

    PubMed

    Cranston, Peter S; Martin, Jon; Spies, Martin

    2016-01-01

    Polypedilum nubifer (Skuse, 1889), originally described from Australia, is an apparently widespread species of Chironomidae (Diptera) that can attain nuisance densities in some eutrophic water bodies. Appropriate management depends upon the identity and ability to distinguish from potential cryptic taxa. A morphological study of larvae, pupae and adults of both sexes confirmed P. nubifer as widely distributed and frequently abundant, but also revealed two previously cryptic species of limited distribution in northern Australia. These species are described as new and illustrated in all stages here. Polypedilum quasinubifer Cranston sp. n. is described from north-west Queensland, Australia and also from Thailand and Singapore. Polypedilum paranubifer Cranston sp. n. is known only from retention ponds of a uranium mine in Northern Territory, Australia. Unusual morphological features of P. nubifer including alternate Lauterborn organs on the larval antenna, cephalic tubules on the pupa and frontal tubercles on the adult head are present in both new species as well. Newly slide-mounted types of Polypedilum pelostolum Kieffer, 1912 (lectotype designated here) confirm synonymy to Chironomus nubifer Skuse, 1889, examined also as newly-slide mounted types. Reviewed plus new evidence does not support recognition of Tripedilum Kieffer, 1921 as a separate taxon; therefore, Tripedilum is returned to junior synonymy with Polypedilum s. str. PMID:27394199

  10. Effects of organic pollution and physical stress on benthic macroinvertebrate communities from two intermittently closed and open coastal lagoons (ICOLLs)

    NASA Astrophysics Data System (ADS)

    Coelho, Susana; Pérez-Ruzafa, Angel; Gamito, Sofia

    2015-12-01

    Benthic macroinvertebrate communities and environmental conditions were studied in two intermittently closed and open coastal lakes and lagoons (ICOLLs), located in southern Algarve (Foz do Almargem e Salgados), with the purpose of evaluating the effects of organic pollution, originated mainly from wastewater discharges, and the physical stress caused by the irregular opening of the lagoons. Most of the year, lagoons were isolated from the sea, receiving the freshwater inputs from small rivers and in Salgados, also from the effluents of a wastewater plant. According to environmental and biotic conditions, Foz do Almargem presented a greater marine influence and a lower trophic state (mesotrophic) than Salgados (hypereutrophic). Benthic macroinvertebrate communities in the lagoons were distinct, just as their relations with environmental parameters. Mollusca were the most abundant macroinvertebrates in Foz do Almargem, while Insecta, Oligochaeta and Crustacea were more relevant in Salgados. Corophium multisetosum occurred exclusively in Salgados stations and, just as Chironomus sp., other Insecta and Oligochaeta, densities were positively related to total phosphorus, clay content and chlorophyll a concentration in the sediment, chlorophyll a concentration in water and with total dissolved inorganic nitrogen. Abra segmentum, Cerastoderma glaucum, Peringia ulvae and Ecrobia ventrosa occurred only in Foz do Almargem, with lower values of the above mentioned parameters. Both lagoons were dominated by deposit feeders and taxa tolerant to environmental stress, although in Salgados there was a greater occurrence of opportunistic taxa associated to pronounced unbalanced situations, due to excess organic matter enrichment.

  11. Acute toxicity of metals and reference toxicants to a freshwater ostracod, Cypris subglobosa Sowerby, 1840 and correlation to EC(50) values of other test models.

    PubMed

    Khangarot, B S; Das, Sangita

    2009-12-30

    The ostracod Cypris subglobosa Sowerby, 1840 static bioassay test on the basis of a 48h of 50% of immobilization (EC(50)) has been used to measure the toxicity of 36 metals and metalloids and 12 reference toxicants. Among the 36 metals and metalloids, osmium (Os) was found to be the most toxic in the test while boron (B), the least toxic. The EC(50) values of this study revealed positive linear relationship with the established test models of cladoceran (Daphnia magna), sludge worm (Tubifex tubifex), chironomid larvae (Chironomus tentans), protozoan (Tetrahymena pyriformis), fathead minnow (Pimephales promelas), bluegill sunfish (Lepomis macrochirus), and aquatic macrophyte duckweed (Lemna minor). Correlation coefficients (r(2)) for 17 physicochemical properties of metals or metal ions and EC(50)s (as pM) were examined by linear regression analysis. The electronegativity, ionization potential, melting point, solubility product of metal sulfides (pK(sp)), softness parameter and some other physicochemical characteristics were significantly correlated with EC(50)s of metals to C. subglobosa. The reproducibility of toxicity test was determined using 12 reference toxicants. The coefficient of variability of the EC(50)s ranged from 6.95% to 55.37% and variability was comparable to that noticed for D. magna and other aquatic test models. The study demonstrated the need to include crustacean ostracods in a battery of biotests to detect the presence of hazardous chemicals in soils, sewage sludges, sediments and aquatic systems. PMID:19683870

  12. Macrobenthic communities of saltpans from the Sado estuary (Portugal)

    NASA Astrophysics Data System (ADS)

    Amaral, Maria José; Costa, Maria Helena

    1999-07-01

    A 1-year study on the evolution of benthic communities of saltpans from the Sado estuary was carried out in order to evaluate its density, biomass and diversity, and to understand its trophic-dynamic structure under harsh environmental conditions. Physical and chemical parameters of the water column and sediments were also studied. Salinity and redox potential fluctuated sharply. Of eighteen taxa observed, a few occurred in significant numbers Chironomus salinarius (99 %) at crystallisation ponds where Artemia is present in the water column at salinities ranging from 23 to 249 g .L -1, Hydrobia (95 %) at evaporation pond (salinities between 29 and 112 g .L -1), while the reservoir, with salinities from 22 to 45 g .L -1, showed higher diversity nevertheless lower than in the estuary itself. It is colonised all year by Abra ovata, Cerastoderma glaucum, Hedistes diversicolor, Capitella sp., Microspio mecznikowianus, Mellina palmata, Polydora ciliata, Capitellidae and Microdeutopus gryllotalpa. The diversity of macrobenthic communities decreases with increasing salinity. Among trophic dynamic groups, surface detritivores burrowers, which are present at 85 % of the samples, are the dominant group at evaporation and crystallisation ponds and appears as an isolated group linked to organic matter of sediments and nutrients.

  13. Sediment-associated pesticides in an urban stream in Guangzhou, China: implication of a shift in pesticide use patterns.

    PubMed

    Li, Huizhen; Sun, Baoquan; Lydy, Michael J; You, Jing

    2013-04-01

    Pesticide use patterns in China have changed in recent years; however, the study of the environmental fate of current-use pesticides (CUPs) and their ecotoxicological significance in aquatic ecosystems is limited. In the present study, sediments were collected from an urban stream in the Chinese city of Guangzhou. Sediment-associated legacy organochlorine pesticides and CUPs-including organophosphates, pyrethroids, fipronil, and abamectin-were analyzed. Additionally, the relative toxicity of the sediments was evaluated with 10-d bioassays using Chironomus dilutus. Fifteen of 16 sediments collected from the stream were acutely toxic to C. dilutus, with 81% of the samples causing 100% mortality. Abamectin, fipronil, and pyrethroids (mainly cypermethrin) were identified as the principal contributors to the noted toxicity in the midges, with median predicted toxic units of 1.63, 1.63, and 1.03, respectively. Sediments taken from downstream sites, where residential and industrial regions were located, had elevated CUP concentrations and sediment toxicity compared with upstream sites. The present study is the first of its kind to link sediment CUPs, fipronil, and abamectin concentrations with toxicity in urban streams in China with a focus on shifting pesticide usage patterns. PMID:23377859

  14. Full-time equivalency tracking system

    USGS Publications Warehouse

    Klesert, Stephen

    1982-01-01

    To help meet the goals of the Surface-Mining Control and Reclamation Act of 1977, the U.S. Geological Survey is assessing the physical, chemical, and biological characteristics of surface water within the coal-mining region of southwestern Indiana. This report discussed benthic-invertebrate and periphytic-algal communities in streams draining homogeneous agricultural, forested, active/reclaimed-mine, and unreclaimed mine watersheds, and relates the biological communities to the physical and chemical characteristics of the streams. Alkalinity and pH were lower and the concentrations of dissolved solids, calcium, magnesium, sodium, potassium, sulfate, iron, manganese, aluminum, and zinc were higher in unreclaimed-mine watersheds than in the other land-use watersheds. Numbers and community diversity of benthic invertebrates were less at sites affected by mining than at agricultural or forested sites, owing to (1) synergistic effects of pH, metals, and unsuitable habitat and (2) lack of colonizing drift organisms because of the small drainage area upstream from the mined area. Only a few organisms , such as the caddisflies Cheumatopsyche and Hydrosyche and the chironomids Chironomus and Cricotopus were found in streams draining mine areas. (USGS)

  15. Toxicity of carbon nanotubes to freshwater aquatic invertebrates

    USGS Publications Warehouse

    Mwangi, Joseph N.; Wang, Ning; Ingersoll, Christopher G.; Hardesty, Doug K.; Brunson, Eric L.; Li, Hao; Deng, Baolin

    2012-01-01

    Carbon nanotubes (CNTs) are hydrophobic in nature and thus tend to accumulate in sediments if released into aquatic environments. As part of our overall effort to examine the toxicity of carbon-based nanomaterials to sediment-dwelling invertebrates, we have evaluated the toxicity of different types of CNTs in 14-d water-only exposures to an amphipod (Hyalella azteca), a midge (Chironomus dilutus), an oligochaete (Lumbriculus variegatus), and a mussel (Villosa iris) in advance of conducting whole-sediment toxicity tests with CNTs. The results of these toxicity tests conducted with CNTs added to water showed that 1.00g/L (dry wt) of commercial sources of CNTs significantly reduced the survival or growth of the invertebrates. Toxicity was influenced by the type and source of the CNTs, by whether the materials were precleaned by acid, by whether sonication was used to disperse the materials, and by species of the test organisms. Light and electron microscope imaging of the surviving test organisms showed the presence of CNTs in the gut as well as on the outer surface of the test organisms, although no evidence was observed to show penetration of CNTs through cell membranes. The present study demonstrated that both the metals solubilized from CNTs such as nickel and the "metal-free" CNTs contributed to the toxicity.

  16. Use of solid phase microextraction to estimate toxicity: relating fiber concentrations to body residues--part II.

    PubMed

    Ding, Yuping; Landrum, Peter F; You, Jing; Harwood, Amanda D; Lydy, Michael J

    2012-09-01

    In the companion paper, solid phase microextraction (SPME) fiber concentrations were used as a dose metric to evaluate the toxicity of hydrophobic pesticides, and concentration-response relationships were found for the hydrophobic pesticides tested in the two test species. The present study extends the use of fiber concentrations to organism body residues to specifically address biotransformation and provide the link to toxic response. Test compounds included the organochlorines p,p'-dichlorodiphenyltrichloroethane (p,p'-DDT), p,p'-dichlorodiphenyldichloroethane (p,p'-DDD), and p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE); two pyrethroids, permethrin and bifenthrin; and an organophosphate, chlorpyrifos. Toxicity, body residues, and biotransformation of the target compounds were determined for the midge Chironomus dilutus and the amphipod Hyalella azteca. Significant regression relationships were found without regard to chemical, extent of biotransformation, or whether the chemical reached steady state in the organisms. The equilibrium SPME fiber concentrations correlated with the parent compound concentration in the biota; however, the regressions were duration specific. Furthermore, the SPME fiber-based toxicity values yielded species-specific regressions with the parent compound-based toxicity values linking the use of SPME fiber as a dose metric with tissue residues to estimate toxic response. PMID:22786796

  17. Use of solid phase microextraction to estimate toxicity: relating fiber concentrations to toxicity--part I.

    PubMed

    Ding, Yuping; Landrum, Peter F; You, Jing; Harwood, Amanda D; Lydy, Michael J

    2012-09-01

    Use of solid-phase microextraction (SPME) fibers as a dose metric for toxicity testing was evaluated for hydrophobic pesticides to the midge Chironomus dilutus and the amphipod Hyalella azteca. Test compounds included p,p'-dichlorodiphenyltrichloroethane (p,p'-DDT), p,p'-dichlorodiphenyldichloroethane (p,p'-DDD), p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE), permethrin, bifenthrin, tefluthrin, and chlorpyrifos. Acute water toxicity tests were determined for 4- and 10-d exposures in both species. Median lethal and sublethal concentrations were expressed both on a water concentration (LC50 and EC50) and on an equilibrium SPME fiber concentration (LC50(fiber) and EC50(fiber)) basis. A significant log dose-response relationship was found between log fiber concentration and organism mortality. It has been shown in the literature that equilibrium SPME fiber concentrations reflect the bioavailable concentrations of hydrophobic contaminants, so these fiber concentrations should be a useful metric for assessing toxic effects from the bioavailable contaminant providing a framework to expand the use of SPME fibers beyond estimation of bioaccumulation. PMID:22767390

  18. Fate and effects of clothianidin in fields using conservation practices.

    PubMed

    de Perre, Chloé; Murphy, Tracye M; Lydy, Michael J

    2015-02-01

    Despite the extensive use of the neonicotinoid insecticide clothianidin, and its known toxicity to beneficial insects such as pollinators, little attention has been given to its fate under agricultural field conditions. The present study investigated the fate and toxicity of clothianidin applied every other year as a corn seed-coating at 2 different rates, 0.25 mg/seed and 0.50 mg/seed, in an agricultural field undergoing a corn-soybean annual rotation, and conservation tillage. Concentrations were measured in soil, surface runoff, infiltration, and groundwater from 2011 to 2013. Clothianidin was detected at low concentrations in soil and water throughout the 2-yr corn and soybean rotation. Low and no-tillage had little or no effect on clothianidin concentrations. Laboratory toxicity bioassays were performed on nontarget species, including Daphnia magna, Hyalella azteca, Chironomus dilutus, Pimephales promelas and Eisenia fetida. Risk quotients were calculated from clothianidin concentrations measured in the field and compared with the laboratory toxicity bioassay results to assess the environmental risk of the insecticide. The risk quotient was found to be lower than the level of concern for C. dilutus, which was the most sensitive species tested; therefore, no short-term environmental risk was expected for the species investigated in the present study. PMID:25376402

  19. Assessing bioavailability and toxicity of permethrin and DDT in sediment using matrix solid phase microextraction.

    PubMed

    Ding, Yuping; Landrum, Peter F; You, Jing; Lydy, Michael J

    2013-01-01

    Matrix solid phase microextraction (matrix-SPME) was evaluated as a surrogate for the absorbed dose in organisms to estimate bioavailability and toxicity of permethrin and dichlorodiphenyltrichloroethane (DDT) in laboratory-spiked sediment. Sediments were incubated for 7, 28, and 90 days at room temperature to characterize the effect of aging on bioavailability and toxicity. Sediment toxicity was assessed using two freshwater invertebrates, the midge Chironomus dilutus and amphipod Hyalella azteca. Disposable polydimethylsiloxane fibers were used to estimate the absorbed dose in organisms and to examine bioavailability and toxicity. The equilibrium fiber concentrations substantially decreased with an increase in sediment aging time, indicating a reduction in bioavailability. Based on median lethal fiber concentrations (fiber LC50), toxicity of permethrin was not significantly different among the different aging times. Due to the substantial degradation of DDT to dichlorodiphenyldichloroethane (DDD) in sediment, sediment toxicity to C. dilutus increased, while it decreased for H. azteca with extended aging times. A toxic unit-based fiber LC50 value represented the DDT mixture (DDT and DDD) toxicity for both species. Significant linear relationships were found between organism body residues and the equilibrium fiber concentrations for each compound, across aging times. The study suggested that the matrix-SPME fibers mimicked bioaccumulation in the organisms, and enabled estimation of body residues, and could potentially be used in environmental risk assessment across matrices (e.g. sediment and water) to measure bioavailability and toxicity of hydrophobic pesticides. PMID:23086182

  20. Effectiveness of a constructed wetland for retention of nonpoint-source pesticide pollution in the Lourens River catchment, South Africa.

    PubMed

    Schulz, R; Peall, S K

    2001-01-15

    Constructed wetlands have been widely used to control both point- and nonpoint-source pollution in surface waters. However, our knowledge about their effectiveness in retaining agricultural pesticide pollution is limited. A 0.44-ha vegetated wetland built along a tributary of the Lourens River, Western Cape, South Africa, was studied to ascertain retention of runoff-related agricultural pollution. Total suspended solids, orthophosphate, and nitrate were retained in the wetland in the proportions 15, 54, and 70%, respectively, during dry weather conditions (with rainfall less than 2 mm/d) and 78, 75, and 84% during wet conditions (with rainfall between 2 and 35 mm/d). Retention of water-diluted azinphos-methyl introduced via runoff at a level of 0.85 microg/L was between 77 and 93%. Chlorpyrifos and endosulfan were measured during runoff in inlet water at 0.02 and 0.2 microg/L, respectively. However, both pesticides were undetectable in the outlet water samples. During a period of 5 months, an increased concentration of various insecticides was detected in the suspended particles at the wetland inlet: azinphos-methyl, 43 microg/kg; chlorpyrifos, 31 microg/kg; and prothiofos, 6 microg/kg. No organophosphorus pesticides were found in the outlet suspended-particle samples, highlighting the retention capability of the wetland. A toxicological evaluation employing a Chironomus bioassay in situ at the wetland inlet and outlet revealed an 89% reduction in toxicity below the wetland during runoff. PMID:11347620

  1. Incipient toxicity of lithium to freshwater organisms representing a salmonid habitat

    SciTech Connect

    Emery, R.; Klopfer, D.C.; Skalski, J.R.

    1981-07-01

    Because the eventual development of fusion power reactors could increase the mining, use and disposal of lithium five-fold by the year 2000, potential effects from unusual amounts of lithium in aquatic environments were investigated. Freshwater oganisms representing a Pacific Northwest salmonid habitat were exposed to elevated conentrations of lithium. Nine parameters were used to determine the incipient toxicity of lithium to rainbow trout (Salmo gairdneri), insect larvae (Chironomus sp.), and Columbia River periphyton. All three groups of biota were incipiently sensitive to lithium at concentrations ranging between 0.1 and 1 mg/L. These results correspond with the incipient toxicity of beryllium, a chemically similar component of fusion reactor cores. A maximum lithium concentration of 0.01 mg/L occurs naturally in most freshwater environments (beryllium is rarer). Therefore, a concentration range of 0.01 to 0.1 mg/L may be regarded as approaching toxic concentrations when assessing the hazards of lithium in freshwaters.

  2. An evaluation of the effectiveness of utilizing bioassays in the assessment of contaminated sites

    SciTech Connect

    Mroz, R.; Carter, J.; Tay, K.L.; Doe, K.

    1995-12-31

    The purpose of this study was to evaluate the battery of biological tests recommended by Environment Canada in the document ``A Review of Whole Organism Bioassays for Assessing the Quality of Soil, Freshwater Sediment and Freshwater in Canada`` for the assessment of contaminated sites. Soil and sediment samples were collected from three contaminated sites in the Atlantic Region and subjected to biological and chemical tests. Four bioassays were conducted on the soil samples: lettuce (Lactuca sativa) seedling emergence, algal (Selenastrum capricornutum) population growth inhibition, earthworm (Eisenia andrel) survival and inhibition of light output in Microtox (Vibrio fischeri). Soil samples collected from Makinsons, Newfoundland had elevated levels of PCBs, total petroleum hydrocarbons (TPH) and heavy metals and showed some toxicity in the algal population growth inhibition test. Samples from the Weldon, New Brunswick site were high in TPH and were marginally toxic to Microtox and lettuce seedlings. The earthworm survival test did not appear sensitive to any of the contaminated soil samples. Freshwater sediment samples, collected from Five Island Lake, Nova Scotia had elevated PCB and heavy metal concentrations. These samples underwent four biological tests: midge (Chironomus tentans) survival, amphipod (Hyalella azteca) survival, algal population growth inhibition and Microtox. At 100% concentration, the sediment was toxic to the first three species, with toxicities ranging from marginal to high. For all samples, the bioassay results were compared to chemical analyses and, in most cases, there was a positive correlation between contaminant concentrations and toxicity.

  3. Using a triad approach in the assessment of hazardous waste site leaching from a Superfund site to an adjacent stream

    SciTech Connect

    Leppanen, C.J.; Blanner, P.M.; Allan, R.S.; Maier, K.J.; Benson, W.H.

    1998-10-01

    A triad approach was used in the evaluation of sediment in the Wolf River adjacent to the North Hollywood Dump, a federally listed Superfund site. Chemical analyses were done for 18 organochlorine pesticides, 21 polychlorinated biphenyl (PCB) congeners, and 10 metals. Sediment toxicity was evaluated with freshwater invertebrates. Chironomus tentans and Hyalella azteca. Benthic macroinvertebrate diversity and abundance were assessed with a family-level biotic index. Mean Al, Ba, Cd, Cu, Fe, Ni, Pb, and Zn concentrations were significantly higher in sediments collected in the spring. Both spring and fall sediments exhibited toxicity downstream from, adjacent to, and upstream from the dump, with toxicity significantly higher in fall sediments; however, a consistent trend was not observed. Toxicity was typically greater in the fall, and metal concentrations were typically higher in spring sediments, suggesting that metals were not responsible for the toxicity. Sediment-associated organochlorine pesticide and PCB congener concentrations were all below detectable limits, suggesting that these potential contaminants are not contributing to the observed toxicity. No differences were found in benthic macroinvertebrate community structure, which was composed of predominantly pollution-tolerant families, among seasons or river reaches, which appear to be limited by the physical characteristics of the river. Sediments in urban reaches of the Wolf River appear to be degraded; the North Hollywood Dump cannot be isolated as a source of toxicity in this study. In situ testing, sediment toxicity identification and evaluation testing, acid-volatile sulfide analyses, or artificial substrate work would be appropriate to follow.

  4. Chronic effects of natural and synthetic oils on freshwater organisms

    SciTech Connect

    Giddings, J.M.; Franco, P.J.

    1986-01-01

    Accidental releases of synthetic oils during storage and transportation may be a major environmental concern for a commercial synthetic fuels industy. To help determine the potential long-term environmental consequence of oil releases in aquatic systems, we measured the chronic toxicity of two synthetic and two natural oils in experiments with four representative aquatic species. The oils selected for study were a direct coal liquefaction product (H-Coal heavy fuel oil), a crude shale oil (Paraho shale oil), and two petroleum crudes (Wilmington and Kern River). Test species were the green alga Selenastrum capricornutum, the crustacean Daphnia magna, the midge Chironomus tentans, and the fathead minnow Pimephales promelas. In this project pelagic organisms (S. capricornutum, D. magna, and P. promelas larvae) were tested in experiments with water-soluble fractions (WSFs) of the oils, and benthic organisms (C. tentans larvae and juvenile P. promelas) were tested with weathered oil residues. In general, WSFs of H-Coal heavy fuel oil and Paraho crude shale oil were more toxic to the test organisms than WSFs of the two petroleum crudes. Residues of H-Coal were more toxic than petroleum residues to C. tentans, but residues of Paraho shale oil were less toxic than petroleum residues. None of the residues had toxic effects on juvenile fathead minnows. 45 refs., 15 figs., 10 tabs.

  5. Dependence of magneto-optical rotatory dispersion and magnetic circular dichroism of deoxy- and methemoglobin on their quaternary structure.

    PubMed

    Sharonov, Y A; Sharonova, N A; Atanasov, B P

    1976-06-15

    Methods of magnetic optical activity, magneto-optical rotatory dispersion (MORD) and magnetic circular dichroism (MCD), were shown to be sensitivie to the quaternary structure of deoxyhemoglobin. The isolated alpha and beta chains, the monomeric hemoglobins (leghemoglobin, fraction III of Chironomus thummi thummi hemoglobin) and hemoglobin in the R state (hemoglobin digested with carboxypeptidases A and B) exhibit in the visible region two MORD minima of equal intensities. In native tetrameric hemoglobins studied (human, horse, porcine, feline, carp, tortoise, frog) the ratio of the intensities of these MORD minima is about 2. The MORD data for deoxy-des Arg-N-ethylsuccinimide-hemoglobin indicate that in solution there is a mixture of the T and R states, the equilibrium between the states being shifted toward the R structure. The identity of the MORD curves for deoxy-bis(N-maleimidoethyl)-ester-hemoglobin and for native deoxyhemoglobin indicates that deoxy-bis(N-maleimidoethyl)ester-hemoglobin has the T structure in solution. Comparison of the MORD curves exhibited by a native methemoglobin, a native metmyoglobin and the modified hemoglobins in the met form in the absence and presence of organic and inorganic phosphates reveals no direct correlation between the MORD changes and methemoglobin quaternary structure. PMID:952896

  6. Distribution and habitat characterization of the recently introduced invasive mosquito Aedes koreicus [Hulecoeteomyia koreica], a new potential vector and pest in north-eastern Italy

    PubMed Central

    2013-01-01

    Background The container breeding species belonging to the genus Aedes (Meigen) are frequently recorded out of their place of origin. Invasive Aedes species are proven or potential vectors of important Arboviruses and their establishment in new areas pose a threat for human and animal health. A new species of exotic mosquito was recorded in 2011 in north-eastern Italy: Aedes (Finlaya) koreicus [Hulecoeteomyia koreica]. The aim of this study was to characterize the biology, the environment and the current distribution of this mosquito in north-eastern Italy. Morphological details useful to discriminate this species from other invasive Aedes mosquitoes are also given (see Additional files). Methods All possible breeding sites for larval development were monitored. In addition, ovitraps and traps for adults were used to collect eggs and adults. The mosquitoes (larvae and adults) were identified morphologically and molecularly. Environmental data and climatic variables during the period of mosquito activity (from April to October) were considered. Results Aedes koreicus was found in 37 municipalities (39.4%) and was detected in 40.2% of places and in 37.3% of larval habitats monitored, in a range of altitude from 173 to 1250 m.a.s.l.. Garden centres were the most common locations (66.7%), followed by streets/squares (57.1%), private gardens (46.4%) and cemeteries (21.1%) (p < 0.01). The main larval habitats were catch basins (48.5%) and artificial water containers (41.8%). As for Aedes albopictus [Stegomyia albopicta], ovitraps were attractive for adult females resulting in the higher rate of positivity (15/21; 71.4%) among breeding sites. The period of Ae. koreicus activity ranged from March 29 to October 29. Conclusion The species is clearly established in the area and is now overlapping with other vectors such as Ae. albopictus and colonizing areas over 800 m.a.s.l, not yet or sporadically reached by the tiger mosquito. The data collected are essential to

  7. Laboratory development and field validation of Phormia regina (Diptera: Calliphoridae).

    PubMed

    Núñez-Vázquez, Carolina; Tomberlin, Jeffery K; Cantú-Sifuentes, Mario; García-Martínez, Oswaldo

    2013-03-01

    Immature blow flies (Diptera: Calliphoridae) collected from decomposing human remains are often used to determine the minimum postmortem interval (PMImin). Phormia regina (Meigen) is a common blow fly of cosmopolitan distribution that is often associated in such cases. P. regina development at two different cyclic temperatures was examined in this study. A field validation study was conducted to determine the accuracy of applying these data to determine the PMImin. Minimal total development time was 32.52 d at cyclic 14.0 +/- 2.0 degrees C and 16.60 d at cyclic 20.5 +/- 3.1 degrees C. The minimal larval development was significantly different (P < 0.05) across temperatures. Larval development needed 15.5 d at 14.0 degrees C and 7.5 d at 20.5 degrees C. For the validation study, instar, mean, and maximum of length and weight data of the larvae collected in the field were analyzed with data generated from the 20.5 degrees C treatment, as it more closely reflected the field conditions experienced. Accuracy in estimating PMImin, was highly variable depending on the unit of measurement used and instar of P. regina collected from the field. Using the oldest instar to estimate a PMImin resulted in ranges that always encompassed the true time of colonization. Accuracy in hours when using measurements units as mean length or weight, and maximal length or weight, varied among the larval instars. In the first instar the greatest overestimation was made with maximal weight while the greatest underestimation was made with mean weight. The most accurate estimate produced with first instars was based on maximal length. In the second instar, there was no overestimation and the greatest underestimation was made with mean weight and the most accurate estimate produced was with maximal length. In the third instar, the greatest overestimation was made with maximal length, and the greatest underestimation was made with mean weight. The estimated time of colonization based on maximal

  8. The Biting Midge Culicoides sonorensis (Diptera: Ceratopogonidae) Is Capable of Developing Late Stage Infections of Leishmania enriettii

    PubMed Central

    Seblova, Veronika; Sadlova, Jovana; Vojtkova, Barbora; Votypka, Jan; Carpenter, Simon; Bates, Paul Andrew; Volf, Petr

    2015-01-01

    Background Despite their importance in animal and human health, the epidemiology of species of the Leishmania enriettii complex remains poorly understood, including the identity of their biological vectors. Biting midges of the genus Forcipomyia (Lasiohelea) have been implicated in the transmission of a member of the L. enriettii complex in Australia, but the far larger and more widespread genus Culicoides has not been investigated for the potential to include vectors to date. Methodology/Principal Findings Females from colonies of the midges Culicoides nubeculosus Meigen and C. sonorensis Wirth & Jones and the sand fly Lutzomyia longipalpis Lutz & Nevia (Diptera: Psychodidae) were experimentally infected with two different species of Leishmania, originating from Australia (Leishmania sp. AM-2004) and Brazil (Leishmania enriettii). In addition, the infectivity of L. enriettii infections generated in guinea pigs and golden hamsters for Lu. longipalpis and C. sonorensis was tested by xenodiagnosis. Development of L. enriettii in Lu. longipalpis was relatively poor compared to other Leishmania species in this permissive vector. Culicoides nubeculosus was not susceptible to infection by parasites from the L. enriettii complex. In contrast, C. sonorensis developed late stage infections with colonization of the thoracic midgut and the stomodeal valve. In hamsters, experimental infection with L. enriettii led only to mild symptoms, while in guinea pigs L. enriettii grew aggressively, producing large, ulcerated, tumour-like lesions. A high proportion of C. sonorensis (up to 80%) feeding on the ears and nose of these guinea pigs became infected. Conclusions/Significance We demonstrate that L. enriettii can develop late stage infections in the biting midge Culicoides sonorensis. This midge was found to be susceptible to L. enriettii to a similar degree as Lutzomyia longipalpis, the vector of Leishmania infantum in South America. Our results support the hypothesis that some

  9. The Importance of Habitat in the Ecology of Decomposition on Rabbit Carcasses in Malaysia: Implications in Forensic Entomology.

    PubMed

    Silahuddin, Siti Aisyah; Latif, Baha; Kurahashi, Hiromu; Walter, David Evans; Heo, Chong Chin

    2015-01-01

    . villenuevi, C. pinguis, H. ligurriens, Hyd. spinigera, Hyd. chalcogaster, F. canicularis, and Boettcherisca highlandica Kurahashi & Tan represented by both adults and larvae, whereas C. nigripes, Chrysomya thanomthini Kurahashi & Tumrasvin, M. domestica, Atherigona sp., Parasarcophaga albiceps Meigen, P. taenionota, Sepsidae, Phoridae, and Millichidae were represented by adults only. Faunal succession followed the sequence of dominant flies, i.e., Calliphoridae, Sarcophagidae, Muscidae, Sepsidae, and lastly Stratiomyidae for jungle, or Sepsidae for rural and highland studies. Mites, from suborders Mesostigmata, Prostigmata, Astigmatina, and Oribatida, were also recovered throughout decomposition, which could be used for future implementation in forensic investigations. The data obtained from this study could provide more accurate indicators for local forensic scientists in solving criminal cases especially on the determination of time and primary location of death. PMID:26336275

  10. Integrated Taxonomy and DNA Barcoding of Alpine Midges (Diptera: Chironomidae)

    PubMed Central

    Montagna, Matteo; Mereghetti, Valeria; Lencioni, Valeria; Rossaro, Bruno

    2016-01-01

    Rapid and efficient DNA-based tools are recommended for the evaluation of the insect biodiversity of high-altitude streams. In the present study, focused principally on larvae of the genus Diamesa Meigen 1835 (Diptera: Chironomidae), the congruence between morphological/molecular delimitation of species as well as performances in taxonomic assignments were evaluated. A fragment of the mitochondrial cox1 gene was obtained from 112 larvae, pupae and adults (Diamesinae, Orthocladiinae and Tanypodinae) that were collected in different mountain regions of the Alps and Apennines. On the basis of morphological characters 102 specimens were attributed to 16 species, and the remaining ten specimens were identified to the genus level. Molecular species delimitation was performed using: i) distance-based Automatic Barcode Gap Discovery (ABGD), with no a priori assumptions on species identification; and ii) coalescent tree-based approaches as the Generalized Mixed Yule Coalescent model, its Bayesian implementation and Bayesian Poisson Tree Processes. The ABGD analysis, estimating an optimal intra/interspecific nucleotide distance threshold of 0.7%-1.4%, identified 23 putative species; the tree-based approaches, identified between 25–26 entities, provided nearly identical results. All species belonging to zernyi, steinboecki, latitarsis, bertrami, dampfi and incallida groups, as well as outgroup species, are recovered as separate entities, perfectly matching the identified morphospecies. In contrast, within the cinerella group, cases of discrepancy arose: i) the two morphologically separate species D. cinerella and D. tonsa are neither monophyletic nor diagnosable exhibiting low values of between-taxa nucleotide mean divergence (0.94%); ii) few cases of larvae morphological misidentification were observed. Head capsule color is confirmed to be a valid character able to discriminate larvae of D. zernyi, D. tonsa and D. cinerella, but it is here better defined as a color

  11. Integrated Taxonomy and DNA Barcoding of Alpine Midges (Diptera: Chironomidae).

    PubMed

    Montagna, Matteo; Mereghetti, Valeria; Lencioni, Valeria; Rossaro, Bruno

    2016-01-01

    Rapid and efficient DNA-based tools are recommended for the evaluation of the insect biodiversity of high-altitude streams. In the present study, focused principally on larvae of the genus Diamesa Meigen 1835 (Diptera: Chironomidae), the congruence between morphological/molecular delimitation of species as well as performances in taxonomic assignments were evaluated. A fragment of the mitochondrial cox1 gene was obtained from 112 larvae, pupae and adults (Diamesinae, Orthocladiinae and Tanypodinae) that were collected in different mountain regions of the Alps and Apennines. On the basis of morphological characters 102 specimens were attributed to 16 species, and the remaining ten specimens were identified to the genus level. Molecular species delimitation was performed using: i) distance-based Automatic Barcode Gap Discovery (ABGD), with no a priori assumptions on species identification; and ii) coalescent tree-based approaches as the Generalized Mixed Yule Coalescent model, its Bayesian implementation and Bayesian Poisson Tree Processes. The ABGD analysis, estimating an optimal intra/interspecific nucleotide distance threshold of 0.7%-1.4%, identified 23 putative species; the tree-based approaches, identified between 25-26 entities, provided nearly identical results. All species belonging to zernyi, steinboecki, latitarsis, bertrami, dampfi and incallida groups, as well as outgroup species, are recovered as separate entities, perfectly matching the identified morphospecies. In contrast, within the cinerella group, cases of discrepancy arose: i) the two morphologically separate species D. cinerella and D. tonsa are neither monophyletic nor diagnosable exhibiting low values of between-taxa nucleotide mean divergence (0.94%); ii) few cases of larvae morphological misidentification were observed. Head capsule color is confirmed to be a valid character able to discriminate larvae of D. zernyi, D. tonsa and D. cinerella, but it is here better defined as a color gradient

  12. Generic revision and species classification of the Microdontinae (Diptera, Syrphidae)

    PubMed Central

    Reemer, Menno; Ståhls, Gunilla

    2013-01-01

    Abstract With 552 species group names available (excluding misspellings), the Microdontinae constitute the smallest of the three subfamilies of Syrphidae. Paradoxically, this subfamily is taxonomically the least organized of the three: 388 species names were previously classified in a single genus, Microdon Meigen, 1803. The present paper introduces a new generic classification of the Microdontinae, relying partly on the results of phylogenetic analyses of morphological and molecular data as published in other papers, and partly on examination of primary type specimens of 347 taxa, plus additional material, and original descriptions. A total number of 67 genus group names (excluding misspellings) are evaluated, redescribed, diagnosed and discussed, with several implications for their taxonomic status. Of these, 43 names are considered as valid genera, 7 as subgenera, 17 as synonyms. Two generic names (Ceratoconcha Simroth, 1907, Nothomicrodon Wheeler, 1924) are left unplaced, because they are known from immature stages only and cannot be reliably associated with taxa known from adults. The following 10 new genera are described by Reemer: Domodon, Heliodon, Laetodon, Menidon, Mermerizon, Metadon, Peradon, Piruwa, Sulcodon and Thompsodon. A key to all genera, subgenera and species groups is given. A total number of 26 new species are described in the following genera: Archimicrodon Hull, 1945, Ceratrichomyia Séguy, 1951, Domodon, Furcantenna Cheng, 2008, Heliodon, Indascia Keiser, 1958, Kryptopyga Hull, 1944, Masarygus Brèthes. 1908, Mermerizon, Metadon, Microdon, Paramixogaster Brunetti, 1923, Piruwa, Pseudomicrodon Hull, 1937, Rhopalosyrphus Giglio-Tos, 1891, and Thompsodon. New lectotypes are designated for Ceratrichomyia behara Séguy, 1951 and Microdon iheringi Bezzi, 1910. A total number of 267 new combinations of species and genera are proposed. New synonyms are proposed for 19 species group names. Three replacement names are introduced for primary and

  13. DNA barcoding of Northern Nearctic Muscidae (Diptera) reveals high correspondence between morphological and molecular species limits

    PubMed Central

    2012-01-01

    Background Various methods have been proposed to assign unknown specimens to known species using their DNA barcodes, while others have focused on using genetic divergence thresholds to estimate “species” diversity for a taxon, without a well-developed taxonomy and/or an extensive reference library of DNA barcodes. The major goals of the present work were to: a) conduct the largest species-level barcoding study of the Muscidae to date and characterize the range of genetic divergence values in the northern Nearctic fauna; b) evaluate the correspondence between morphospecies and barcode groupings defined using both clustering-based and threshold-based approaches; and c) use the reference library produced to address taxonomic issues. Results Our data set included 1114 individuals and their COI sequences (951 from Churchill, Manitoba), representing 160 morphologically-determined species from 25 genera, covering 89% of the known fauna of Churchill and 23% of the Nearctic fauna. Following an iterative process through which all specimens belonging to taxa with anomalous divergence values and/or monophyly issues were re-examined, identity was modified for 9 taxa, including the reinstatement of Phaonia luteva (Walker) stat. nov. as a species distinct from Phaonia errans (Meigen). In the post-reassessment data set, no distinct gap was found between maximum pairwise intraspecific distances (range 0.00-3.01%) and minimum interspecific distances (range: 0.77-11.33%). Nevertheless, using a clustering-based approach, all individuals within 98% of species grouped with their conspecifics with high (>95%) bootstrap support; in contrast, a maximum species discrimination rate of 90% was obtained at the optimal threshold of 1.2%. DNA barcoding enabled the determination of females from 5 ambiguous species pairs and confirmed that 16 morphospecies were genetically distinct from named taxa. There were morphological differences among all distinct genetic clusters; thus, no cases of

  14. Modelling the distributions of Culicoides bluetongue virus vectors in Sicily in relation to satellite-derived climate variables.

    PubMed

    Purse, B V; Tatem, A J; Caracappa, S; Rogers, D J; Mellor, P S; Baylis, M; Torina, A

    2004-06-01

    Surveillance data from 268 sites in Sicily are used to develop climatic models for prediction of the distribution of the main European bluetongue virus (BTV) vector Culicoides imicola Kieffer (Diptera: Ceratopogonidae) and of potential novel vectors, Culicoides pulicaris Linnaeus, Culicoides obsoletus group Meigen and Culicoides newsteadi Austen. The models containing the 'best' climatic predictors of distribution for each species, were selected from combinations of 40 temporally Fourier-processed remotely sensed variables and altitude at a 1 km spatial resolution using discriminant analysis. Kappa values of around 0.6 for all species models indicated substantial levels of agreement between model predictions and observed data. Whilst the distributions of C. obsoletus group and C. newsteadi were predicted by temperature variables, those of C. pulicaris and C. imicola were determined mainly by normalized difference vegetation index (NDVI), a variable correlated with soil moisture and vegetation biomass and productivity. These models were used to predict species presence in unsampled pixels across Italy and for C. imicola across Europe and North Africa. The predicted continuous presence of C. pulicaris along the appenine mountains, from north to south Italy, suggests BTV transmission may be possible in a large proportion of this region and that seasonal transhumance (seasonal movement of livestock between upland and lowland pastures) even in C. imicola-free areas should not generally be considered safe. The predicted distribution of C. imicola distribution shows substantial agreement with observed surveillance data from Greece and Iberia (including the Balearics) and parts of mainland Italy (Lazio, Tuscany and areas of the Ionian coast) but is generally much more restricted than the observed distribution (in Sardinia, Corsica and Morocco). The low number of presence sites for C. imicola in Sicily meant that only a restricted range of potential C. imicola habitats were

  15. The status of toxicity tests with sediment in Brazil

    SciTech Connect

    Araujo, R.P.A.

    1995-12-31

    The earliest studies in Brazil aiming to evaluate sediment quality through toxicity tests started in the beginning of the 80`s. These were developed by the Environmental Sanitation Agency of Sao Paulo State (CETESB) in Cubatao River and Billings Reservoir, which are located in industrialized and populous regions. Elutriate phase sediment toxicity tests were run with Daphnia similis. In the Cubatao River Basin the combination of toxicity, chemistry data and benthic community structure provided clear indications of sites with different levels of pollution. At this time there was a consensus that the study of a complex compartment such as sediment needed improvements in sampling and analysis procedures. Only in the 90`s the investigations involving sediment toxicity assessment were resumed by CETESB, and it was clear that integrative studies were needed in order to make environmental quality assessment. This kind of studies were conducted by CETESB in some highly polluted areas of Sao Paulo State, Ceriodaphnia dubia and Photobacterium phosphoreum interstitial water tests and Hyalella sp whole sediment tests were run, and the results correlated with several sediment organic and inorganic contaminants. The Sediment Quality Triad proposed by Chapman was applied in one of these studies. This approach was extremely useful in interpreting the data. At the same time marine sediment toxicity tests were developed by CETESB in collaboration with Sao Paulo University, and tests were run with the amphipods Tiburonella viscana, Battyporeiapus bisetosus; tanaidacean Kalliapseudes shubarti and the echinoderm Lytechinus variegatus. The embryo test with L. variegatus was the most adequate in these studies. Nowadays there are other groups in some universities developing sediment toxicity tests with Hyalella and Chironomus in response to a growing concern in Brazil to establish adequate sediment quality assessment guidelines.

  16. Chronic toxicity of chloride to freshwater species: effects of hardness and implications for water quality guidelines.

    PubMed

    Elphick, James R F; Bergh, Kelli D; Bailey, Howard C

    2011-01-01

    Toxicity tests using nine freshwater species (Ceriodaphnia dubia, Daphnia magna, Oncorhynchus mykiss, Pimephales promelas, Lumbriculus variegatus, Tubifex tubifex, Chironomus dilutus, Hyallela azteca, and Brachionus calyciflorus) were conducted to evaluate their sensitivity to chloride. Acute-to-chronic ratios (ACRs) from these tests indicate the ACR of 7.59 employed by the United States Environmental Protection Agency (U.S. EPA) in deriving its water quality guideline for chloride may be conservative; a revised ACR of 3.50 is presented here. The endpoints used to calculate the ACR included 24-h to 96-h median lethal concentrations (LC50s) for acute tests, and 48-h to 54-d inhibition concentration (ICx) values for growth or reproduction for chronic exposures. Data from the present chronic toxicity tests, and other investigators, were used to propose a water quality guideline for long-term exposure to chloride using a species sensitivity distribution (SSD) approach. The 5th percentile from the SSD was calculated as 307 mg/L and proposed as the water quality guideline. Cladocerans were the most sensitive species in the dataset. Ceriodaphnia dubia was used to evaluate the relationship between water hardness and sensitivity to chloride. A strong relationship was observed and was used to establish a hardness-related equation to modify the proposed water quality guideline on the basis of water hardness, resulting in values ranging from 64 mg/L chloride at 10 mg/L hardness to 388 mg/L chloride at 160 mg/L hardness (as CaCO₃). These data suggest that current water quality guidelines for chloride may be overly conservative in water with moderate-to-high hardness, and may not be sufficiently protective under soft-water conditions. PMID:20872898

  17. Metal/metalloid accumulation/remobilization during aquatic litter decomposition in freshwater: a review.

    PubMed

    Schaller, Jörg; Brackhage, Carsten; Mkandawire, Martin; Dudel, E Gert

    2011-11-01

    The focus of this article is to combine two main areas of research activities in freshwater ecosystems: the effect of inorganic pollutants on freshwater ecosystems and litter decomposition as a fundamental ecological process in streams. The decomposition of plant litter in aquatic systems as a main energy source in running water ecosystems proceeds in three distinct temporal stages of leaching, conditioning and fragmentation. During these stages metals and metalloids may be fixed by litter, its decay products and the associated organisms. The global-scale problem of contaminated freshwater ecosystems by metals and metalloids has led to many investigations on the acute and chronic toxicity of these elements to plants and animals as well as the impact on animal activity under laboratory conditions. Where sorption properties and accumulation/remobilization potential of metals in sediments and attached microorganisms are quite well understood, the combination of both research areas concerning the impact of higher trophic levels on the modification of sediment sorption conditions and the influence of metal/metalloid pollution on decomposition of plant litter mediated by decomposer community, as well as the effect of high metal load during litter decay on organism health under field conditions, has still to be elucidated. So far it was found that microbes and invertebrate shredder (species of the genera Gammarus and Asellus) have a significant influence on metal fixation on litter. Not many studies focus on the impact of other functional groups affecting litter decay (e.g. grazer and collectors) or other main processes in freshwater ecosystems like bioturbation (e.g. Tubifex, Chironomus) on metal fixation/release. PMID:21907393

  18. Stormwater-related transport of the insecticides bifenthrin, fipronil, imidacloprid, and chlorpyrifos into a tidal wetland, San Francisco Bay, California.

    PubMed

    Weston, Donald P; Chen, Da; Lydy, Michael J

    2015-09-15

    Suisun Marsh, in northern San Francisco Bay, is the largest brackish marsh in California, and provides critical habitat for many fish species. Storm runoff enters the marsh through many creeks that drain agricultural uplands and the urban areas of Fairfield and Suisun City. Five creeks were sampled throughout a major storm event in February 2014, and analyzed for representatives of several major insecticide classes. Concentrations were greatest in creeks with urban influence, though sampling was done outside of the primary season for agricultural pesticide use. Urban creek waters reached maximum concentrations of 9.9 ng/l bifenthrin, 27.4 ng/l fipronil, 11.9 ng/l fipronil sulfone, 1462 ng/l imidacloprid, and 4.0 ng/l chlorpyrifos. Water samples were tested for toxicity to Hyalella azteca and Chironomus dilutus, and while few samples caused mortality, 70% of the urban creek samples caused paralysis of either or both species. Toxic unit analysis indicated that bifenthrin was likely responsible for effects to H. azteca, and fipronil and its sulfone degradate were responsible for effects to C. dilutus. These results demonstrate the potential for co-occurrence of multiple insecticides in urban runoff, each with the potential for toxicity to particular species, and the value of toxicity monitoring using multiple species. In the channels of Suisun Marsh farther downstream, insecticide concentrations and toxicity diminished as creek waters mixed with brackish waters entering from San Francisco Bay. Only fipronil and its degradates remained measurable at 1-10 ng/l. These concentrations are not known to present a risk based on existing data, but toxicity data for estuarine and marine invertebrates, particularly for fipronil's degradates, are extremely limited. PMID:25956145

  19. Interactions among zebra mussel shells, invertebrate prey, and Eurasian ruffe or yellow perch

    USGS Publications Warehouse

    Kolar, C.S.; Fullerton, A.H.; Martin, K.M.; Lamberti, G.A.

    2002-01-01

    The exotic zebra mussel, Dreissena polymorpha, is established in all of the Laurentian Great Lakes and may affect benthivorous fishes by increasing the complexity of benthic substrates and changing energy flow patterns within the food web. Native yellow perch, Perca flavescens, and the nonindigenous Eurasian ruffe, Gymnocephalus cernuus, are benthivores that may compete for limited food resources. As ruffe spread to areas with more dense zebra mussel populations, the zone of interaction among zebra mussels, yellow perch, and ruffe will increase and intensify. In the laboratory, the effect of zebra mussel shells on the ability of these fishes to forage on amphipods (Gammarus pseudolimnaeus) and chironomids (Chironomus plumosus) was examined in light and darkness. In 12 h, ruffe consumed more amphipods than did similar-sized yellow perch, particularly in darkness on bare cobble, and in light within zebra mussels. Amphipods decreased activity more in the presence of ruffe than yellow perch. More amphipods were found in zebra mussel shells than in bare cobble, whether or not fish were present. In darkness, when ruffe consumed more amphipods on bare cobble, amphipods became more associated with zebra mussel shells. Although ruffe consumed more amphipods than yellow perch, perch consumed more chironomids than ruffe on bare cobble. The presence of zebra mussel shells altered the relative consumption of invertebrates in some substrate-light combinations. Experiments such as these help to improve understanding of the direct and indirect effects of predation between and among native and nonindigenous species that may exert structuring forces on the nearshore communities of the Great Lakes currently or in the future.

  20. Mosquito larvicidal and antimicrobial activity of synthesized nano-crystalline silver particles using leaves and green berry extract of Solanum nigrum L. (Solanaceae: Solanales).

    PubMed

    Rawani, Anjali; Ghosh, Anupam; Chandra, Goutam

    2013-12-01

    Silver nanoparticles (AgNPs) that are synthesized by using aqueous extracts of Solanum nigrum L., is a simple, non-toxic and ecofriendly green material. The present study is based on assessments of the larvicidal and antimicrobial activities of the synthesized AgNPs from fresh leaves, dry leaves and green berries of S. nigrum against larvae of Culex quinquefasciatus and Anopheles stephensi and four human pathogenic and five fish pathogenic bacteria respectively. The synthesized nanoparticles are characterized with UV-vis spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscope (TEM) analysis. The nanoparticles are spherical to polyhedral in shape with size of 50-100nm (average size of 56.6nm). In larvicidal bioassay with synthesized AgNPs, highest mortality are observed at 10ppm against An. stephensi with LC50 values of 1.33, 1.59, 1.56ppm and LC90 values of 3.97, 7.31, 4.76ppm for dry leaves, fresh leaves and berries respectively. Antibacterial activity test reveals better results against fish pathogenic bacteria than human pathogenic bacteria. Non target organism like Toxorhynchites larvae (mosquito predator), Diplonychus annulatum (predatory water-bug) and Chironomus circumdatus larvae (chironomid) are also exposed to respective lethal concentrations (to mosquito larvae) of dry nanoparticles and no abnormality in the non target organisms are recorded. These results suggest that the synthesized AgNPs of S. nigrum have the potential to be used as an ideal eco-friendly compound for the control of the mosquito larvae and harmful bacteria. PMID:24055718

  1. Use of chironomid mentum deformities to assess environmental degradation: A perspective

    SciTech Connect

    Bird, G.A.

    1995-12-31

    The frequency of chironomid mentum deformities was used to assess environmental degradation (ED) at 12 sites in the Yamaska River (YR), Quebec, that were known to be either impacted by agriculture or urban centers, or were relatively clean. Higher frequencies of deformities were associated with the level of pollution at the sites and were in general agreement with the total biotic index of ED. Temporal variation occurred in the incidence of deformities (a difficulty also encountered with other bioassays), including those at a clean site. In the laboratory, Chironomus tentans larvae reared in YR sediment had substantial wear of their mentum teeth compared to larvae reared in four reference substrates. Mentum deformities were observed in the cultured larvae, presumably because of inbreeding and not the effect of treatment. A subsequent study investigated whether exposure to ionizing radiation or a heavy metal would induce deformities. C. tentans larvae were exposed to {sup 210}Pb at 100, 1,000 and 2,000 Bq{center_dot}g{sup {minus}1} dry sediment. No effect was observed on survival, growth or frequency of deformities. Exposure to stable Pb at 0.5 and 5.0 mg{center_dot}g{sup {minus}1} dry sediment also had no effect, but higher concentrations resulted in 100% mortality. However, deformities were present in each treatment, including controls (1 to 8% deformed), and were confined to the median tooth. Similar deformities, as high as 16% of the population, were observed in five remote Canadian Shield lakes at the Experimental Lakes Area, northwestern Ontario. These deformities can be considered natural abnormalities and are of common occurrence. Natural abnormalities must be considered when using this system as an index of environmental degradation.

  2. Toxicity of brominated volatile organics to freshwater biota.

    PubMed

    Binet, Monique T; Stauber, Jenny L; Adams, Merrin S; Rhodes, Stuart; Wech, Janine

    2010-09-01

    As part of a larger study investigating the fate and effects of brominated volatile organic compounds (VOCs) in contaminated groundwaters discharging to surface waters, the toxicity of 1,2 dibromoethene (DBE) and 1,1,2-tribromoethene (TriBE) to freshwater aquatic biota was investigated. Their toxicity to bacteria (Microtox(R)), microalgae (Chlorella sp.), cladocerans (Ceriodaphnia dubia), duckweed (Lemna sp.) and midges (Chironomus tepperi) was determined after careful optimization of the test conditions to minimize chemical losses throughout the tests. In addition, concentrations of DBE and TriBE were carefully monitored throughout the bioassays to ensure accurate calculation of toxicity values. 1,2-Dibromoethene showed low toxicity to most species, with concentrations to cause 50% lethality or effect (LC/EC50 values) ranging from 28 to 420 mg/L, 10% lethality or effect (LC/EC10 values) ranging from 18 to 94 mg/L and no-observed-effect concentrations (NOECs) ranging from 22 to 82 mg/L. 1,1,2-Tribromoethene was more toxic than DBE, with LC/EC50 values of 2.4 to 18 mg/L, LC/EC10 values of 0.94 to 11 mg/L and NOECs of 0.29 to 13 mg/L. Using these limited data, together with data from the only other published study on TriBE, moderate-reliability water quality guidelines (WQGs) were estimated from species sensitivity distributions. The proposed guideline trigger values for 95% species protection with 50% confidence were 2 mg/L for DBE and 0.03 mg/L for TriBE. The maximum concentrations of DBE and TriBE in nearby surface waters (3 and 1 microg /L, respectively) were well below these WQGs, so the risk to the freshwater environment receiving contaminated groundwater inflows was considered to be low, with hazard quotients <1 for both VOCs. Environ. PMID:20821656

  3. Toxicity of silicon carbide nanowires to sediment-dwelling invertebrates in water or sediment exposures

    USGS Publications Warehouse

    Mwangi, Joseph N.; Wang, Ning; Ritts, Andrew; Kunz, James L.; Ingersoll, Christopher G.; Li, Hao; Deng, Baolin

    2011-01-01

    Silicon carbide nanowires (SiCNW) are insoluble in water. When released into an aquatic environment, SiCNW would likely accumulate in sediment. The objective of this study was to assess the toxicity of SiCNW to four freshwater sediment-dwelling organisms: amphipods (Hyalella azteca), midges (Chironomus dilutus), oligochaetes (Lumbriculus variegatus), and mussels (Lampsilis siliquoidea). Amphipods were exposed to either sonicated or nonsonicated SiCNW in water (1.0 g/L) for 48 h. Midges, mussels, and oligochaetes were exposed only to sonicated SiCNW in water for 96 h. In addition, amphipods were exposed to sonicated SiCNW in whole sediment for 10 d (44% SiCNW on dry wt basis). Mean 48-h survival of amphipods exposed to nonsonicated SiCNW in water was not significantly different from the control, whereas mean survival of amphipods exposed to sonicated SiCNW in two 48-h exposures (0 or 15% survival) was significantly different from the control (90 or 98% survival). In contrast, no effect of sonicated SiCNW was observed on survival of midges, mussels, or oligochaetes. Survival of amphipods was not significantly reduced in 10-d exposures to sonicated SiCNW either mixed in the sediment or layered on the sediment surface. However, significant reduction in amphipod biomass was observed with the SiCNW either mixed in sediment or layered on the sediment surface, and the reduction was more pronounced for SiCNW layered on the sediment. These results indicated that, under the experimental conditions, nonsonicated SiCNW in water were not acutely toxic to amphipods, sonicated SiCNW in water were acutely toxic to the amphipods, but not to other organisms tested, and sonicated SiCNW in sediment affected the growth but not the survival of amphipods.

  4. Evaluation of freshwater sediment quality values including apparent effects thresholds of Hyalella azteca and Microtox{reg_sign}

    SciTech Connect

    Cubbage, J.; Batts, D.

    1995-12-31

    Data from 36 studies in Washington State were merged into a single database to derive Apparent Effects Thresholds (AETS) for freshwater sediments and to evaluate other sediment quality values. Sediments from 235 sites were analyzed for several contaminants, Bioassays tested at 30 or more of these sites included Hyalella azteca, Daphnia magna and Chironomus tentans mortality, Ceriodaphnia dubia reproduction and growth, and Microtox{reg_sign} luminescence reduction. Adequate sample size (n > 50) and wide range of response were available for Hyalella (n = 235) and Microtox{reg_sign} (n = 61) to determine AETs for organic carbon normalized PAHs, pesticides, and PCBs, and dry weight normalized metals, phenols and chlorinated phenols. The ability of these AETs to predict response in any bioassay at the sites in the database was compared with Ontario Ministry Environment and Energy (OMEE) Sediment Quality Guidelines and the Environment Canada (EC) Interim Sediment Quality Values. Measures of sensitivity (number correctly predicted/number impacted) and efficiency (number correctly predicted/number predicted) were compared. The EC Threshold Effects Level (TEL) was the most sensitive (fewest Type 2 errors) at 92%, but the least efficient (most Type 1 errors) at 35%. The lowest AET (LAET) of Hyalella and Microtox{reg_sign}, derived from the current study, was the next most sensitive (77%) and more efficient (44%). The OMEE Severe Effects Level was the least sensitive (59%) and the most efficient (53%). The EC Probable Effects Level (PEL) was 50% efficient and 72% sensitive. Of the four sets of sediment quality values, the OMEE Severe Effects Level had the highest overall reliability (number of correct predictions of effects and non-effects/number of sites examined) in predicting bioassay effects in the Washington State freshwater sediment database.

  5. Assessing the potential toxicity of resuspended sediment

    SciTech Connect

    Bonnet, C.; Babut, M.; Ferard, J.F.; Martel, L.; Garric, J.

    2000-05-01

    Two moderately contaminated freshwater sediments (Sorel Harbour, St. Lawrence River, Canada) were subjected to a suspension event. The objective was to assess the environmental impact of the disposal of dredged material in water, in particular, the short-term effects of dumping on the water column and the long-term effects of dredged sediment deposits. In a series of microcosms, the sediments were left to stand for 25 d under flow-through conditions. In a second series of microcosms, sediments were vigorously suspended for 15 min before being left to settle and were submitted to the same treatment as reference sediments during the following 25 d. Physicochemical and biological parameters (Daphnia magna and Hydra attenuata survival) were measured in overlying water throughout the experiment. Sediment toxicity was assessed with Chironomus tentans and Hyalella azteca exposed to sediments collected at both the beginning and end of the 25-d period. Pore-water toxicity was evaluated with D. magna. During the suspension process, in the Sorel Harbour mixed sediment overlying water, the authors observed effects on H. attenuata survival and ammonia and metals (chromium, copper, and zinc) releases. Meanwhile, in reference (nonmixed) and mixed sediments as well as in associated pore waters, there were no significant chemical modifications no biological effects after the 25-d experiments. The developed approach, which attempts to simulate a dumping process, aims at allowing the assessment of the short- and long-term hazards resulting from a resuspension process in overlying water and in resettled sediments using both chemical and biological measurements.

  6. Sediment and water toxicity evaluations for the Clinch River ecological risk assessment

    SciTech Connect

    Gonzalez, A.M.; Phipps, T.L.; Kszos, L.A.

    1995-12-31

    The sediment and surface water at three sites in the Clinch River and six sites in Poplar Creek were evaluated by means of toxicity tests with aquatic organisms. The results of these tests were used as one of the lines of evidence in an assessment of ecological risk due to contaminants, transported from the Oak Ridge Reservation, to the off-site sediment and water environment. Results from a suite of six whole sediment, elutriate and pore water toxicity tests were summarized in terms of survival (Hyalella azteca, Daphnia magna, Anodonta imbecillis, Ceriodaphnia dubia), fecundity (Daphnia magna) or light output reduction (Microtox{reg_sign}). Results from the water toxicity tests were summarized in terms of reduction in survival or fecundity of C. dubia, and survival or growth of Pimephales promelas. Toxicity test results (covering a period of about 1 6 months) showed little difference between reference site media and media from sites of concern. They also showed no strong spatial or temporal response pattern. These results are further supported by the presence of indigenous Chironomus and Hexagenia spp. in the sediment samples. Toxicity results will be discussed with respect to three issues. Two criteria were used to define significant differences between reference sites and sites of concern: a difference of 20%, and statistical significance at a = 0.05. Secondly, the relevance of comparing mean responses to control vs. reference site will be discussed. Lastly, toxicity results are consistent with site characterization information which suggest that contaminants of concern in sediment are buried under clean sediment, effectively isolating the material from potential human or ecological exposure.

  7. Advection around ventilated U-shaped burrows: A model study

    NASA Astrophysics Data System (ADS)

    Brand, Andreas; Lewandowski, JöRg; Hamann, Enrico; Nützmann, Gunnar

    2013-05-01

    Advective transport in the porous matrix of sediments surrounding burrows formed by fauna such as Chironomus plumosus has been generally neglected. A positron emission tomography study recently revealed that the pumping activity of the midge larvae can indeed induce fluid flow in the sediment. We present a numerical model study which explores the conditions at which advective transport in the sediment becomes relevant. A 0.15 m deep U-shaped burrow with a diameter of 0.002 m within the sediment was represented in a 3-D domain. Fluid flow in the burrow was calculated using the Navier-Stokes equation for incompressible laminar flow in the burrow, and flow in the sediment was described by Darcy's law. Nonreactive and reactive transport scenarios were simulated considering diffusion and advection. The pumping activity of the model larva results in considerable advective flow in the sediment at reasonable high permeabilities with flow velocities of up to 7.0 × 10-6 m s-1 close to the larva for a permeability of 3 × 10-12 m2. At permeabilities below 7 × 10-13 m2 advection is negligible compared to diffusion. Reactive transport simulations using first-order kinetics for oxygen revealed that advective flux into the sediment downstream of the pumping larva enhances sedimentary uptake, while the advective flux into the burrow upstream of the larvae inhibits diffusive sedimentary uptake. Despite the fact that both effects cancel each other with respect to total solute uptake, the advection-induced asymmetry in concentration distribution can lead to a heterogeneous solute and redox distribution in the sediment relevant to complex reaction networks.

  8. Development and application of freshwater sediment-toxicity benchmarks for currently used pesticides.

    PubMed

    Nowell, Lisa H; Norman, Julia E; Ingersoll, Christopher G; Moran, Patrick W

    2016-04-15

    Sediment-toxicity benchmarks are needed to interpret the biological significance of currently used pesticides detected in whole sediments. Two types of freshwater sediment benchmarks for pesticides were developed using spiked-sediment bioassay (SSB) data from the literature. These benchmarks can be used to interpret sediment-toxicity data or to assess the potential toxicity of pesticides in whole sediment. The Likely Effect Benchmark (LEB) defines a pesticide concentration in whole sediment above which there is a high probability of adverse effects on benthic invertebrates, and the Threshold Effect Benchmark (TEB) defines a concentration below which adverse effects are unlikely. For compounds without available SSBs, benchmarks were estimated using equilibrium partitioning (EqP). When a sediment sample contains a pesticide mixture, benchmark quotients can be summed for all detected pesticides to produce an indicator of potential toxicity for that mixture. Benchmarks were developed for 48 pesticide compounds using SSB data and 81 compounds using the EqP approach. In an example application, data for pesticides measured in sediment from 197 streams across the United States were evaluated using these benchmarks, and compared to measured toxicity from whole-sediment toxicity tests conducted with the amphipod Hyalella azteca (28-d exposures) and the midge Chironomus dilutus (10-d exposures). Amphipod survival, weight, and biomass were significantly and inversely related to summed benchmark quotients, whereas midge survival, weight, and biomass showed no relationship to benchmarks. Samples with LEB exceedances were rare (n=3), but all were toxic to amphipods (i.e., significantly different from control). Significant toxicity to amphipods was observed for 72% of samples exceeding one or more TEBs, compared to 18% of samples below all TEBs. Factors affecting toxicity below TEBs may include the presence of contaminants other than pesticides, physical/chemical characteristics

  9. Comparative responses of freshwater organisms to exposures of a commercial naphthenic acid.

    PubMed

    Kinley, Ciera M; McQueen, Andrew D; Rodgers, John H

    2016-06-01

    Comparative toxicity studies using unconfounded exposures can prioritize the selection of sensitive sentinel test species and refine methods for evaluating ecological risks of complex mixtures like naphthenic acids (NAs), a group of organic acids associated with crude oils and energy-derived waters that have been a source of aquatic toxicity. The objectives of this study were to compare responses of freshwater aquatic organisms (vertebrate, invertebrates, and a macrophyte; in terms of acute toxicity) to Fluka commercial NAs and to compare measured toxicity data with peer-reviewed toxicity data for other commercial NA sources and energy-derived NA sources. Exposures were confirmed using high performance liquid chromatography. Responses (7-d LC50s/EC50) ranged from 1.9 mg L(-1) for Pimephales promelas to 56.2 mg L(-1) for Typha latifolia. Following P. promelas in order of decreasing sensitivity were Ceriodaphnia dubia (7-d LC50 = 2.8 mg L(-1)), Hyalella azteca (7-d LC50 = 4.1 mg L(-1)), Chironomus dilutus (7-d LC50 = 6.5 mg L(-1)), and T. latifolia (7-d EC50 = 56.2 mg L(-1)), indicating that in terms of sensitivities, fish > invertebrates > plant for Fluka NAs in this study. Factors that affect exposures and measurements of exposures differ among commercial and energy-derived NAs and constrain comparisons. Despite differences in exposures, fish and invertebrates were relatively sensitive to both commercial and energy-derived NA sources (based on laboratory measurements and peer-reviewed data) and could be appropriate sentinel species for risk evaluations. PMID:27016812

  10. Risk assessment of Magnacide H herbicide at Río Colorado irrigation channels (Argentina). Tier 3: studies on native species.

    PubMed

    Venturino, Andrés; Montagna, Cristina Mónica; de D'Angelo, Ana María Pechen

    2007-01-01

    We evaluated the potential environmental risk of the herbicide Magnacide (Baker Petrolite, TX, USA) using native species from Argentina, representing the ecosystem at the Irrigation Corporation (CORFO) channels at the Colorado River mouth, Buenos Aires, Argentina. Six species including fish, toads, snails, crustaceans, and insects were selected to perform studies on acute toxicity and repeated exposure effects. Magnacide H susceptibility ranking was Bufo arenarum (lethal concentration 50 [LC50] = 0.023 mg/L), Onchorhynchus mykiss (LC50 = 0.038 mg/L), Heleobia parchappii (LC50 = 0.21 mg/L), Hyalella curvispina (LC50 = 0.24 mg/L), Simulium spp. (LC50 = 0.60 mg/L), and Chironomus spp. (LC50 = 2.83 mg/L). The risk limit of 10th percentile (0.013 mg/L) determined by probit analysis on sensitivity distribution was similar to the one calculated from literature data. Risk assessment based on field application data suggested lethal exposures for more than 70 to 90% of the species up to 20 km downstream from the application point. Repeated exposures to Magnacide H of amphibian larvae at the lowest-observed-effect concentration caused some effects during the first exposure, but without cumulative effects. Amphipods were insensitive to repeated exposures, showing no cumulative effects. Whether short-term exposures may result in long-term sublethal effects on the organism's life history was not addressed by these laboratory tests. In conclusion, tier 3 studies indicate that Magnacide H application schedule is extremely toxic for most native species at CORFO-Rio Colorado channels, representing a high potential risk in the environment. The real environmental impact must be addressed by field studies at tier 4 giving more information on population effects and communities. PMID:17269476

  11. Identification of two RNA-binding proteins in Balbiani ring premessenger ribonucleoprotein granules and presence of these proteins in specific subsets of heterogeneous nuclear ribonucleoprotein particles.

    PubMed Central

    Wurtz-T; Kiseleva, E; Nacheva, G; Alzhanova-Ericcson, A; Rosén, A; Daneholt, B

    1996-01-01

    Balbiani ring (BR) granules are premessenger ribonucleoprotein particles (RNPs) generated in giant chromosomal puffs, the BRs, in the larval salivary glands of the dipteran chironomus tentans. Monoclonal antibodies were raised against nuclear proteins collected on a single-stranded-DNA-agarose affinity column, and two of them were used to identify RNA-binding proteins in BR granules. First, in Western blots (immunoblots), one of the antibodies recognized a 36-kDa protein and the other recognized a 45-KDa protein. Second, both antibodies bound to the BRs in immunocytological experiments. It was shown in cross-linking experiments that the two proteins are associated with heterogeneous nuclear RNP (hnRNP) complexes extracted from C. tentans nuclei. By immunoelectron microscopy of isolated and partly unfolded BR RNPs, it was specifically demonstrated that the BR granules contain the two proteins and, in addition, that both proteins are distributed frequently along the RNP fiber of the particles. Thus, the 36- and 45-KDa proteins are likely to be abundant, RNA-binding proteins in the BR particles. To elucidate to what extent the two proteins are also present in other hnRNPs, we studied the binding of the antibodies to chromosomal puffs in general. It was observed that many puffs in addition to the BRs harbor the two proteins, but there are also puffs containing only one of the components, either the 36- or the 45-kDa protein. We conclude that the two proteins are not randomly bound to all hnRNPs but that each of them seems to be linked to a specific subset of the particles. PMID:8657116

  12. Biological and chemical characterization of metal bioavailability in sediments from Lake Roosevelt, Columbia River, Washington, USA

    USGS Publications Warehouse

    Besser, J.M.; Brumbaugh, W.G.; Ivey, C.D.; Ingersoll, C.G.; Moran, P.W.

    2008-01-01

    We studied the bioavailability and toxicity of copper, zinc, arsenic, cadmium, and lead in sediments from Lake Roosevelt (LR), a reservoir on the Columbia River in Washington, USA that receives inputs of metals from an upstream smelter facility. We characterized chronic sediment toxicity, metal bioaccumulation, and metal concentrations in sediment and pore water from eight study sites: one site upstream in the Columbia River, six sites in the reservoir, and a reference site in an uncontaminated tributary. Total recoverable metal concentrations in LR sediments generally decreased from upstream to downstream in the study area, but sediments from two sites in the reservoir had metal concentrations much lower than adjacent reservoir sites and similar to the reference site, apparently due to erosion of uncontaminated bank soils. Concentrations of acid-volatile sulfide in LR sediments were too low to provide strong controls on metal bioavailability, and selective sediment extractions indicated that metals in most LR sediments were primarily associated with iron and manganese oxides. Oligochaetes (Lumbriculus variegatus) accumulated greatest concentrations of copper from the river sediment, and greatest concentrations of arsenic, cadmium, and lead from reservoir sediments. Chronic toxic effects on amphipods (Hyalella azteca; reduced survival) and midge larvae (Chironomus dilutus; reduced growth) in whole-sediment exposures were generally consistent with predictions of metal toxicity based on empirical and equilibrium partitioning-based sediment quality guidelines. Elevated metal concentrations in pore waters of some LR sediments suggested that metals released from iron and manganese oxides under anoxic conditions contributed to metal bioaccumulation and toxicity. Results of both chemical and biological assays indicate that metals in sediments from both riverine and reservoir habitats of Lake Roosevelt are available to benthic invertebrates. These findings will be used as

  13. An estimation of radiation doses to benthic invertebrates from sediments collected near a Canadian uranium mine.

    PubMed

    Thomas, P; Liber, K

    2001-10-01

    A new method is described for calculating radiation doses to benthic invertebrates from radionuclide concentrations in freshwater sediment. Both internal and external radiation doses were estimated for all 14 principal radionuclides of the uranium-238 decay series. Sediments were collected from three sites downstream of a uranium mining operation in northern Saskatchewan, Canada. Sediments from two sites, located approximately 1.6 and 4.4 km downstream from mining operations, yielded absorbed doses to both larval midges, Chironomus tentans, and adult amphipods, Hyalella azteca, of 59-60 and 19 mGy/year, respectively, compared to 3.2 mGy/year for a nearby control site. External beta radiation from protactinium-234 (234Pa) and alpha radiation from uranium (U) contributed most of the dose at the impacted sites, whereas polonium-210 (210Po) was most important at the control site. If a weighting factor of 20 was employed for the greater biological effect of alpha vs. beta and gamma radiation, then total equivalent doses rose to 540-560 mGy/year at the site closest to uranium operations. Such equivalent doses are above the 360-mGy/year no-observed-effect level for reproductive effects in vertebrates from gamma radiation exposure. Data are not available to determine the effect of such doses on benthic organisms, but they are high enough to warrant concern. Detrimental effects have been observed in H. azteca at similar uranium concentration in laboratory toxicity tests, but it remains unclear whether the radiotoxicity or the chemotoxicity of uranium is responsible for these effects. PMID:11686646

  14. Acute and chronic toxicity of sodium sulfate to four freshwater organisms in water-only exposures

    USGS Publications Warehouse

    Wang, Ning; Consbrock, Rebecca A.; Ingersoll, Christopher G.; Hardesty, Douglas K.; Brumbaugh, William G.; Hammer, Edward J.; Bauer, Candice R.; Mount, David R.

    2015-01-01

    The acute and chronic toxicity of sulfate (tested as sodium sulfate) was determined in diluted well water (hardness of 100 mg/L and pH 8.2) with a cladoceran (Ceriodaphnia dubia; 2-d and 7-d exposures), a midge (Chironomus dilutus; 4-d and 41-d exposures), a unionid mussel (pink mucket, Lampsilis abrupta; 4-d and 28-d exposures), and a fish (fathead minnow, Pimephales promelas; 4-d and 34-d exposures). Among the 4 species, the cladoceran and mussel were acutely more sensitive to sulfate than the midge and fathead minnow, whereas the fathead minnow was chronically more sensitive than the other 3 species. Acute-to-chronic ratios ranged from 2.34 to 5.68 for the 3 invertebrates but were as high as 12.69 for the fish. The fathead minnow was highly sensitive to sulfate during the transitional period from embryo development to hatching in the diluted well water, and thus, additional short-term (7- to 14-d) sulfate toxicity tests were conducted starting with embryonic fathead minnow in test waters with different ionic compositions at a water hardness of 100 mg/L. Increasing chloride in test water from 10 mg Cl/L to 25 mg Cl/L did not influence sulfate toxicity to the fish, whereas increasing potassium in test water from 1mg K/L to 3mg K/L substantially reduced the toxicity of sulfate. The results indicate that both acute and chronic sulfate toxicity data, and the influence of potassium on sulfate toxicity to fish embryos, need to be considered when environmental guidance values for sulfate are developed or refined.

  15. Applicability of subchronic toxicity test with Hyalella azteca for toxicity identification evaluation programs

    SciTech Connect

    Putt, A.E.; Jop, K.M.

    1995-12-31

    A series of screening tests including the short-term chronic exposure of Ceriodaphnia dubia to sediment pore waters, 10-day exposures of Chironomus tentans and Hyalella azteca to bulk sediments and a bioaccumulation study with Lumbriculus variegatus were performed as part of an ecological risk assessment of Plow Shop Pond, Fort Devens, Massachusetts. Chronic endpoints such as reproduction and growth indicated sediment toxicity, however, a toxicity identification evaluation program was initiated to further define the source and extent of the toxicity. A short-term chronic exposure with C. dubia was a logical choice for the TIE, however, since amphipods are epibenthic organisms, they are a better surrogate of sediment dwelling organisms than a water column species such as C. dubia. Observations performed during H. azteca culture suggested that this species of amphipod could thrive in the water column for up to three weeks. Therefore, 7-day old H. azteca were exposed to pore water samples under static-renewal conditions for 10 days. Survival and growth (i.e., dry weight) were determined at the termination of each exposure. Laboratory control group performance consistently averaged a {>=}90% survival and {>=}43 {micro}g of dry weight per amphipod. Growth of amphipods used in each exposure generally exceeded two times the initial body weight after 10 days of exposure. Previous studies have indicated that the growth and reproductive response of H. azteca are positively correlated for a given set of exposure conditions. The results of these 10-day subchronic exposures with H. azteca provide a consistent and reliable measure of the chronic sediment toxicity with a benthic invertebrate for toxicity identification evaluation programs.

  16. Diverse circular replication-associated protein encoding viruses circulating in invertebrates within a lake ecosystem.

    PubMed

    Dayaram, Anisha; Galatowitsch, Mark L; Argüello-Astorga, Gerardo R; van Bysterveldt, Katherine; Kraberger, Simona; Stainton, Daisy; Harding, Jon S; Roumagnac, Philippe; Martin, Darren P; Lefeuvre, Pierre; Varsani, Arvind

    2016-04-01

    Over the last five years next-generation sequencing has become a cost effective and efficient method for identifying known and unknown microorganisms. Access to this technique has dramatically changed the field of virology, enabling a wide range of environmental viral metagenome studies to be undertaken of organisms and environmental samples from polar to tropical regions. These studies have led to the discovery of hundreds of highly divergent single stranded DNA (ssDNA) virus-like sequences encoding replication-associated proteins. Yet, few studies have explored how viruses might be shared in an ecosystem through feeding relationships. Here we identify 169 circular molecules (160 CRESS DNA molecules, nine circular molecules) recovered from a New Zealand freshwater lake, that we have tentatively classified into 51 putatively novel species and five previously described species (DflaCV-3, -5, -6, -8, -10). The CRESS DNA viruses identified in this study were recovered from molluscs (Echyridella menzeisii, Musculium novaezelandiae, Potamopyrgus antipodarum and Physella acuta) and insect larvae (Procordulia grayi, Xanthocnemis zealandica, and Chironomus zealandicus) collected from Lake Sarah, as well as from the lake water and benthic sediments. Extensive diversity was observed across most CRESS DNA molecules recovered. The putative capsid protein of one viral species was found to be most similar to those of members of the Tombusviridae family, thus expanding the number of known RNA-DNA hybrid viruses in nature. We noted a strong association between the CRESS DNA viruses and circular molecules identified in the water and browser organisms (C. zealandicus, P. antipodarum and P. acuta), and between water sediments and undefended prey species (C. zealandicus). However, we were unable to find any significant correlation of viral assemblages to the potential feeding relationships of the host aquatic invertebrates. PMID:26873065

  17. Toxicity of sediments from lead-zinc mining areas to juvenile freshwater mussels (Lampsilis siliquoidea) compared to standard test organisms.

    PubMed

    Besser, John M; Ingersoll, Christopher G; Brumbaugh, William G; Kemble, Nile E; May, Thomas W; Wang, Ning; MacDonald, Donald D; Roberts, Andrew D

    2015-03-01

    Sediment toxicity tests compared chronic effects on survival, growth, and biomass of juvenile freshwater mussels (28-d exposures with Lampsilis siliquoidea) to the responses of standard test organisms-amphipods (28-d exposures with Hyalella azteca) and midges (10-d exposures with Chironomus dilutus)-in sediments from 2 lead-zinc mining areas: the Tri-State Mining District and Southeast Missouri Mining District. Mussel tests were conducted in sediments sieved to <0.25 mm to facilitate recovery of juvenile mussels (2-4 mo old). Sediments were contaminated primarily with lead, zinc, and cadmium, with greater zinc and cadmium concentrations in Tri-State sediments and greater lead concentrations in southeast Missouri sediments. The frequency of highly toxic responses (reduced 10% or more relative to reference sites) in Tri-State sediments was greatest for amphipod survival (25% of samples), midge biomass (20%), and mussel survival (14%). In southeast Missouri sediments, the frequency of highly toxic samples was greatest for mussel biomass (25%) and amphipod biomass (13%). Thresholds for metal toxicity to mussels, expressed as hazard quotients based on probable effect concentrations, were lower for southeast Missouri sediments than for Tri-State sediments. Southeast Missouri sites with toxic sediments had 2 or fewer live mussel taxa in a concurrent mussel population survey, compared with 7 to 26 taxa at reference sites. These results demonstrate that sediment toxicity tests with juvenile mussels can be conducted reliably by modifying existing standard methods; that the sensitivity of mussels to metals can be similar to or greater than standard test organisms; and that responses of mussels in laboratory toxicity tests are consistent with effects on wild mussel populations. PMID:25545632

  18. Toxicity and bioavailability of heavy metal mixtures in natural and synthetic sediments

    SciTech Connect

    Frugis, M.; Clements, W.H.

    1994-12-31

    Toxicity tests were conducted to compare differences in bioavailability of a metal mixture (zinc, copper, cadmium and lead) in natural and synthetic sediments to Chironomus tentans and Ceriodaphnia dubia. Preliminary tests were conducted with sediment collected at five stations from the Arkansas River (Leadville, CO) and one from the La Cache Poudre River (Fort Collins, CO). After seven days of exposure, mortality on C. tentans in sediment from the most contaminated station (AR3) was significantly different from the reference station (PDR). Bioaccumulation in these insects showed significant correlation with abiotic factors: particle size, organic matter, total carbon and cation exchange capacity. During a second experiment, particle size and carbon contents of synthetic sediment were modified to reflect composition of natural sediment. Two types of artificial sediments were spiked with 0X, 0.085X, 0.175X and 0.35X of metal mixture measured in AR3. After ten days, mortality of C. tentans in the 0.35X and AR3 treatments were similar. In a final experiment, synthetic and natural sediments were spiked at 0X, 0.175X, 0.35X, and 0.70X. Again, mortality of contents in 0.35X and AR3 were not significantly different. A 48hrs-acute test conducted with C. dubia showed that interstitial water from AR3 and AR5 stations had higher toxicity than other stations. In addition, toxicity of interstitial water from synthetic sediment was greater than from spiked natural sediment or sediments collected from the Arkansas River. These results indicate that heavy metals are more bioavailable in synthetic sediments than in natural substrates.

  19. Deriving Freshwater Quality Criteria for Iron, Lead, Nickel, and Zinc for Protection of Aquatic Life in Malaysia

    PubMed Central

    Shuhaimi-Othman, M.; Nadzifah, Y.; Nur-Amalina, R.; Umirah, N. S.

    2012-01-01

    Freshwater quality criteria for iron (Fe), lead (Pb), nickel (Ni), and zinc (Zn) were developed with particular reference to aquatic biota in Malaysia, and based on USEPA's guidelines. Acute toxicity tests were performed on eight different freshwater domestic species in Malaysia which were Macrobrachium lanchesteri (prawn), two fish: Poecilia reticulata and Rasbora sumatrana, Melanoides tuberculata (snail), Stenocypris major (ostracod), Chironomus javanus (midge larvae), Nais elinguis (annelid), and Duttaphrynus melanostictus (tadpole) to determine 96 h LC50 values for Fe, Pb, Ni, and Zn. The final acute value (FAV) for Fe, Pb, Ni, and Zn were 74.5, 17.0, 165, and 304.9 μg L−1, respectively. Using an estimated acute-to-chronic ratio (ACR) of 8.3, the value for final chronic value (FCV) was derived. Based on FAV and FCV, a criterion maximum concentration (CMC) and a criterion continuous concentration (CCC) for Fe, Pb, Ni, and Zn that are 37.2, 8.5, 82.5, and 152.4 μg L−1 and 9.0, 2.0, 19.9, and 36.7 μg L−1, respectively, were derived. The results of this study provide useful data for deriving national or local water quality criteria for Fe, Pb, Ni, and Zn based on aquatic biota in Malaysia. Based on LC50 values, this study indicated that N. elinguis, M. lanchesteri, N. elinguis, and R. sumatrana were the most sensitive to Fe, Pb, Ni, and Zn, respectively. PMID:22919358

  20. Deriving freshwater quality criteria for iron, lead, nickel, and zinc for protection of aquatic life in Malaysia.

    PubMed

    Shuhaimi-Othman, M; Nadzifah, Y; Nur-Amalina, R; Umirah, N S

    2012-01-01

    Freshwater quality criteria for iron (Fe), lead (Pb), nickel (Ni), and zinc (Zn) were developed with particular reference to aquatic biota in Malaysia, and based on USEPA's guidelines. Acute toxicity tests were performed on eight different freshwater domestic species in Malaysia which were Macrobrachium lanchesteri (prawn), two fish: Poecilia reticulata and Rasbora sumatrana, Melanoides tuberculata (snail), Stenocypris major (ostracod), Chironomus javanus (midge larvae), Nais elinguis (annelid), and Duttaphrynus melanostictus (tadpole) to determine 96 h LC(50) values for Fe, Pb, Ni, and Zn. The final acute value (FAV) for Fe, Pb, Ni, and Zn were 74.5, 17.0, 165, and 304.9 μg L(-1), respectively. Using an estimated acute-to-chronic ratio (ACR) of 8.3, the value for final chronic value (FCV) was derived. Based on FAV and FCV, a criterion maximum concentration (CMC) and a criterion continuous concentration (CCC) for Fe, Pb, Ni, and Zn that are 37.2, 8.5, 82.5, and 152.4 μg L(-1) and 9.0, 2.0, 19.9, and 36.7 μg L(-1), respectively, were derived. The results of this study provide useful data for deriving national or local water quality criteria for Fe, Pb, Ni, and Zn based on aquatic biota in Malaysia. Based on LC(50) values, this study indicated that N. elinguis, M. lanchesteri, N. elinguis, and R. sumatrana were the most sensitive to Fe, Pb, Ni, and Zn, respectively. PMID:22919358