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Sample records for chironomus riparius meigen

  1. Assessment of thiamethoxam toxicity to Chironomus riparius.

    PubMed

    Saraiva, Althiéris S; Sarmento, Renato A; Rodrigues, Andreia C M; Campos, Diana; Fedorova, Ganna; Žlábek, Vladimír; Gravato, Carlos; Pestana, João L T; Soares, Amadeu M V M

    2017-03-01

    The insecticide thiamethoxam (TMX) is a systemic neonicotinoid widely used for pest control in several agricultural crops. TMX mimics the action of acetylcholine causing uncontrolled muscular contraction eventually leading to insect death. TMX is being found in freshwater ecosystems at concentrations of up to 225µg/L. Still, chronic toxicity data for freshwater invertebrates is limited. Therefore, the aim of this study was to evaluate the acute and chronic effects (at organismal and biochemical levels) of TMX on the freshwater insect Chironomus riparius. C. riparius life history responses were significantly affected by TMX exposure, namely with a decrease in growth and delay in emergence. Concerning the biochemical responses, after a short exposure (48h) to TMX, our results showed that low concentrations of TMX significantly reduced CAT activity and LPO levels of C. riparius. No effects were observed in AChE, GST and ETS activities. Effects in terms of survival, development rates and biochemical responses of C. riparius exposed to low concentrations of TMX observed in this study suggest potential deleterious effects of this neonicotinoid on aquatic insects inhabiting freshwaters environments near agricultural areas.

  2. Karyotypes of Chironomus Meigen (Diptera: Chironomidae) species from Africa

    PubMed Central

    Wülker, Wolfgang F.; Kiknadze, I.I.; Istomina, A.G.

    2011-01-01

    Abstract The karyotypes of six African Chironomus species (Chironomus alluaudi Kieffer, 1913, Chironomus transvaalensis Kieffer, 1923, Chironomus sp. Nakuru, Chironomus formosipennis Kieffer, 1908, Chironomus prope pulcher Wiedemann, 1830, Chironomus sp. Kisumu) were investigated; four of these karyotypes were described for the first time (Chironomus sp. Nakuru, Chironomus formosipennis, Chironomus prope pulcher, Chironomus sp. Kisumu). Of the six Chironomus karyotypes, three had “pseudothummi” cytocomplex chromosome arms combinations AE CD BF G (Chironomus alluaudi, Chironomus transvaalensis, Chironomus sp. Nakuru), two had “thummi”cytocomplex arms combinations AB CD EF G (Chironomus formosipennis, Chironomus prope pulcher), and one had “parathummi”armcombinations AC BF DE G (Chironomus sp. Kisumu). Thus, three of the ten main cytocomplexes known were detected in Africa. Detailed photomaps of all chromosome arms, with the exception of arms B and G, were prepared for the karyotypes of Chironomus alluaudi, Chironomus transvaalensis, Chironomus sp. Nakuru, Chironomus prope pulcher; the karyotypes of Chironomus formosipennis, Chironomus sp. Kisumucould only be fragmentarily mapped. Endemic African banding sequences were characteristic for most of the chromosomal arms in all species studied. However, basic sequences, which can be present in different Chironomus species on different continents (Wülker, 1980; Kiknadze et al. 2008), were also detected also in several African species (Chironomus alluaudi, Chironomus sp. Nakuru, and Chironomus formosipennis). The banding sequences of African species studied allow discussion of the derivation of modern banding patterns from hypothetical species, living before separation of cytocomplexes and continents. PMID:24260617

  3. Ecotoxicological multilevel-evaluation of the effects of fenbendazole exposure to Chironomus riparius larvae.

    PubMed

    Park, Kiyun; Bang, Hyun Woo; Park, Jungan; Kwak, Inn-Sil

    2009-10-01

    Veterinary antibiotics may find their way into the aquatic environment through direct or indirect pathways due to their widespread use. Fenbendazole is a benzimidazole anthelmintic that is widely used in veterinary medicine. To evaluate the potential ecological risk of fenbendazole, we examined the molecular and biochemical responses of biomarker genes such as heat shock proteins (HSPs), cytochrome P450 (CYP450), glutathione S-transferases (GSTs) and hemoglobins (Hbs) in Chironomus riparius for long periods. The expression of HSP70, HSP40, HSP90 and CYP450 in C. riparius increased significantly after exposure to all concentrations of fenbendazole evaluated, while the levels of GST and HbA only increased in C. riparius exposed to relatively high concentrations of fenbendazole (30 microg L(-1)). HbB expression did not differ significantly between the control and treatment groups. Exposure to 30 microg L(-1) fenbendazole had significant effects on the survival, growth, sex balance of emergent adults and development of mouthpart deformity in C. riparius. These results should constitute an important contribution to the understanding of the toxicology of fenbendazole in C. riparius. Moreover, the responses of the biomarker genes also provide valuable information that will aid in understanding the effects of fenbendazole in aquatic ecosystems.

  4. Influence of heavy metals on glyceraldehyde-3-phosphate dehydrogenase interactions in Chironomus riparius larvae.

    PubMed

    Wai, Isaac; Chong, King; Ho, Wing Shing

    2013-08-01

    Some aquatic organisms can live in contaminated environment due to their adaptable defense mechanism related to their inducible detoxification and excretion. A recent study showed glyceraldehyde-3-phosphate dehydrogenase (GAPDH) can modulate different cellular activities including transcription activation and detoxification. In the present study, the authors report on experiments to test the GAPDH activity of Chironomus riparius toward heavy metals. Glyceraldehyde-3-phosphate dehydrogenase was isolated and purified from C. riparius. The kinetics of the enzyme was measured. The results showed that GAPDH was inhibited by heavy metals including Co(2+) , Cu(2+) , Fe(2+) , Ni(2+) , Pb(2+) , but was activated by zinc ions. The kinetics study of the enzyme showed maximum initial velocity (Vmax) of GAPDH increased by 50%. In addition, the substrate and cofactor affinity increased in the presence of zinc. The GAPDH from C. riparius had maximum activities at pH 8.5 and 37 °C. The protein sequence analysis shows that there are 2 additional cysteine and histidine residues in the conserved region of GAPDH from C. riparius, which is believed to play an important role in the interactions with heavy metals. The results suggest that exposure to zinc could modulate GAPDH, which could be related to response of antioxidant defense to other heavy metals.

  5. 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.

  6. Chironomus riparius (Diptera) genome sequencing reveals the impact of minisatellite transposable elements on population divergence.

    PubMed

    Oppold, Ann-Marie; Schmidt, Hanno; Rose, Marcel; Hellmann, Sören Lukas; Dolze, Florian; Ripp, Fabian; Weich, Bettina; Schmidt-Ott, Urs; Schmidt, Erwin; Kofler, Robert; Hankeln, Thomas; Pfenninger, Markus

    2017-03-18

    Active transposable elements (TEs) may result in divergent genomic insertion and abundance patterns among conspecific populations. Upon secondary contact, such divergent genetic backgrounds can theoretically give rise to classical Dobzhansky-Muller incompatibilities (DMI), thus contributing to the evolution of endogenous genetic barriers and eventually cause population divergence. We investigated differential TE abundance among conspecific populations of the non-biting midge Chironomus riparius and evaluated their potential role in causing endogenous genetic incompatibilities between these populations. We focussed on a Chironomus-specific TE, the minisatellite-like Cla-element, whose activity is associated with speciation in the genus. Using a newly generated and annotated draft genome for a genomic study with five natural C. riparius populations, we found highly population-specific TE insertion patterns with many private insertions. A significant correlation of the pairwise FST estimated from genome-wide single nucleotide polymorphisms (SNPs) and the FST estimated from TEs, is consistent with drift as the major force driving TE population differentiation. However, the significantly higher Cla-element FST level due to a high proportion of differentially fixed Cla-element insertions also indicates selection against segregating (i.e. heterozygous) insertions. With reciprocal crossing experiments and fluorescent in-situ hybridisation of Cla-elements to polytene chromosomes, we documented phenotypic effects on female fertility and chromosomal mispairings. We propose that the inferred negative selection on heterozygous Cla-element insertions may cause endogenous genetic barriers and therefore acts as DMI among C. riparius populations. The intrinsic genomic turnover exerted by TEs may thus have a direct impact on population divergence that is operationally different from drift and local adaptation. This article is protected by copyright. All rights reserved.

  7. 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.

  8. 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.

  9. Effects of sediment contamination by artisanal gold mining on Chironomus riparius in Mabubi River, Tanzania

    NASA Astrophysics Data System (ADS)

    Chibunda, R. T.; Pereka, A. E.; Tungaraza, C.

    The contamination of sediments by mercury from in artisanal gold mining has been only assessed through bulk chemical analysis and subsequent comparison with reference values from uncontaminated areas. However, measurement of contaminant levels alone has a limited ability to predict adverse effects on living resources. This study investigated the possible effects of contamination of sediments in Mabubi River by mercury drained from Mugusu artisanal gold mine on the survival, growth and emergency of the benthic midge Chironomus riparius. Sediments collected downstream from the Mugusu Mine impaired growth and delayed emergence of the midges but did not impair survival. Mean dry body weight of larvae from sediments collected 3 km down stream (1012 μg) was significantly lower than those from the control sediment ( p < 0.05). Compared to the control sediment, the emergence of the midges from sediments collected up to 6 km downstream of the mining activity were delayed for four days. In conclusion, chemistry and ecotoxicity results from this study suggest that sediments collected in the Mabubi River downstream of the Mugusu mine adversely affect C. riparius and probably other fauna and as such present a considerable local environmental risk.

  10. Interacting effects of toxicants and organic matter on the midge Chironomus riparius in polluted river water.

    PubMed

    Stuijfzand, S C; Helms, M; Kraak, M H; Admiraal, W

    2000-07-01

    Toxicants and organic matter in river water have contrasting impacts on macrofauna. Through manipulations of both factors, their interactive effects on organisms were evaluated. This way, an attempt was made to clarify the presence or absence of pollution-"tolerant" and -"sensitive" species in rivers affected by mixed sources of pollution. Under controlled conditions, larval growth of the "tolerant" midge Chironomus riparius was measured in different types of river water containing varying levels of particles (obtained by selective filtration) and toxicants (either complex mixtures or metals). Exposure of first-instar larvae to water from the polluted rivers Meuse and Dommel revealed that growth was less inhibited by toxicant levels in river water than expected based on laboratory toxicity tests. Factors present in polluted river water stimulated growth of midges to such an extent that inhibiting effects of high toxicant concentrations were neutralized, and at low toxicant levels, were overcompensated for. It was found that particulate matter has great potential to reduce inhibiting effects of toxicants on C. riparius, not (only) by reducing the bioavailability of toxicants, but by serving as a supplementary, superior food source. The success of the "pollution-tolerant" midge was not explained by tolerance of this species to toxicants, but by its ability to take advantage of coinciding organic enrichment. It is hypothesized that the extent to which beneficial effects of organic compounds on organisms occur is species specific.

  11. Characterization of cholinesterases in Chironomus riparius and the effects of three herbicides on chlorpyrifos toxicity.

    PubMed

    Pérez, Joanne; Monteiro, Marta S; Quintaneiro, Carla; Soares, Amadeu M V M; Loureiro, Susana

    2013-11-15

    In this study, the toxicities of four pesticides (the herbicides atrazine, terbuthylazine, metolachlor and the insecticide chlorpyrifos) previously detected in the Alqueva reservoir/dam (south of Portugal) were evaluated individually and in binary combinations of the herbicides and the insecticide using fourth-instar larvae of the aquatic midge Chironomus riparius. Chlorpyrifos induced toxicity to midges in all the 48 h toxicity bioassays performed. The swimming behaviour of the larvae was impaired, with EC50 values ranging from 0.15 to 0.17 μg/L. However, neither s-triazine (atrazine and terbuthylazine) herbicides nor metolachlor alone at concentrations up to 200 μg/L caused significant toxicity to C. riparius. When combined with both s-triazine herbicides, chlorpyrifos toxicity was enhanced by approximately 2-fold when tested in a binary mixture experimental setup, at the 50% effective concentration levels. To evaluate how chlorpyrifos toxicity was being increased, the cholinesterases (ChE) were characterized biochemically using different substrates and selective inhibitors. The results obtained suggested that the main enzyme present in this species is acetylcholinesterase (AChE) and therefore it was assayed upon C. riparius exposures to all pesticides individually and as binary mixtures. Although atrazine and terbuthylazine are not effective inhibitors of AChE, the potentiation of chlorpyrifos toxicity by the two s-triazine herbicides was associated with a potentiation in the inhibition of AChE in midges; both s-triazine herbicides at 200 μg/L increased the inhibition of the AChE activity by 7 and 8-fold, respectively. A strong correlation was observed between swimming behaviour disturbances of larvae and the inhibition of the AChE activity. In contrast, metolachlor did not affect chlorpyrifos toxicity at any of the concentrations tested. Therefore, the herbicides atrazine and terbuthylazine can act as synergists in the presence of chlorpyrifos, increasing

  12. 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.

  13. Expression of Chironomus riparius serine-type endopeptidase gene under di-(2-ethylhexyl)-phthalate (DEHP) exposure.

    PubMed

    Park, Kiyun; Kwak, Inn-Sil

    2008-11-01

    Environmental stressors can induce changes in gene expression that can be useful as biomarkers. To identify potential biomarkers of water quality, we characterized full-length cDNA sequences of the serine-type endopeptidase (SP) gene from Chironomus riparius. Their expression was analyzed during different life-history stages and in response to treatment with various concentrations of di(2-ethylhexyl) phthalate (DEHP) for short and long periods of time. A comparative molecular and phylogenetic investigation was then conducted among different orders of insects using sequence database analysis. The sequence of the C. riparius SP gene was found to be most closely related to the sequence of SPs isolated from Aedes aegypti. In addition, the basal level of C. riparius SP mRNA was more highly expressed in larvae than in other life-history stages. However, the expression of C. riparius SP was primarily limited to the gut in larvae. When the effects of short-term exposure to DEHP were evaluated, C. riparius SP gene expression decreased within 1 h of treatment, regardless of dose. We also investigated expression of the C. riparius SP gene following long-term DEHP exposure (10 days) and found that it decreased significantly across all DEHP dosages. Finally, the response of the SP gene was more sensitive in C. riparius that were exposed to low concentrations of DEHP than in those that were exposed to high concentrations. These results show that suppression of the C. riparius SP gene by DEHP is as a potential biomarker that could be useful for monitoring aquatic quality.

  14. 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

  15. Cadmium alters the expression of small heat shock protein genes in the aquatic midge Chironomus riparius.

    PubMed

    Martín-Folgar, Raquel; Martínez-Guitarte, José-Luis

    2017-02-01

    Cadmium (Cd) is a widespread and highly toxic heavy metal of particular ecotoxicological relevance for aquatic ecosystems. It occurs naturally in the environment but is also an industrial pollutant with extensively researched carcinogenic potentials. Heat shock proteins (HSPs) are chaperones that play an important role in maintaining protein homeostasis under stress conditions. Small heat shock proteins (sHSPs) comprise the most diverse group of the HSPs family. They are expressed both constitutively and by stress-induction. The midge Chironomus riparius is widely used as a test species in aquatic toxicology. In the present study, Reverse Transcription Polymerase Chain Reaction (RT-PCR) was used to evaluate the effects of acute Cd exposure to the expression profile of seven shsp genes (hsp17, hsp21, hsp22, hsp23, hsp24, hsp27, and hsp34) in C. riparius larvae. Results show a specific pattern of response with a rapid response by hsp27, which was downregulated at 2-6 h, while the rest of the shsp genes remained unaltered except for hsp17 at 2 h, which was upregulated. However, at 24 h of exposure are observed high levels of hsp23, hsp24, hsp27, and hsp34 transcription while hsp22 mRNA levels were downregulated and hsp17 and hsp21 remained unaltered. These changes in gene expression suggest a functional diversity between the sHSPs in the cellular response to heavy metal stress. The differential pattern in comparison with heat shock supports a specific profile depending on the stress supporting the use of shsp genes as suitable biomarkers for ecotoxicological studies on aquatic systems.

  16. 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.

  17. Bioconcentration and acute toxicity of polycyclic musks in two benthic organisms (Chironomus riparius and Lumbriculus variegatus).

    PubMed

    Artola-Garicano, Elsa; Sinnige, Theo L; van Holsteijn, Ineke; Vaes, Wouter H J; Hermens, Joop L M

    2003-05-01

    In the current study, the bioconcentration behavior and acute toxicity of two polycyclic musks, Tonalide 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene (AHTN) and Galaxolide 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexa-methylcyclopenta[gamma]-2-benzopyran (HHCB), were studied in two benthic organisms. Polycyclic musks are frequently used fragrances, and they have been detected in different compartments of the environment. The aim of this study was to fill some empirical data gaps for AHTN and HHCB for benthic organisms. Results show that differences exist between both organisms. Chironomus riparius exhibited bioconcentration factors (BCFs) for AHTN and HHCB substantially lower than predicted for nontransformed organics. The BCFs for both chemicals increased after coexposure of the organism to the cytochrome P450 inhibitor piperonyl butoxide. Thus, the low BCF values were the result of rapid biotransformation of AHTN and HHCB in the midge larvae. Bioconcentration kinetics indicated that both chemicals induced their own cytochrome P450-mediated metabolism. Acute toxicity of AHTN to midge larvae was reduced compared to predicted baseline toxicity and was similar for HHCB. Bioconcentration of AHTN and HHCB in the worm (Lumbriculus variegatus) is in agreement with predictions based on the octanol-water partition coefficients of these chemicals. Acute toxicity was found to be similar to predicted values for baseline toxicity. Summarizing, for AHTN and HHCB, acute toxicity and bioconcentration behavior in L. variegatus was in accordance with predicted data for nontransformed organics. In C. riparius, bioconcentration as well as toxicity were reduced.

  18. Telomeric transcriptome from Chironomus riparius (Diptera), a species with noncanonical telomeres.

    PubMed

    Martínez-Guitarte, J L; de la Fuente, M; Morcillo, G

    2014-06-01

    Although there are alternative telomere structures, most telomeres contain DNA arrays of short repeats (6-26 bp) maintained by telomerase. Like other diptera, Chironomus riparius has noncanonical telomeres and three subfamilies, TsA, TsB and TsC, of longer sequences (176 bp) are found at their chromosomal ends. Reverse transcription PCR was used to show that different RNAs are transcribed from these sequences. Only one strand from TsA sequences seems to render a noncoding RNA (named CriTER-A); transcripts from both TsB strands were found (CriTER-B and αCriTER-B) but no TsC transcripts were detected. Interestingly, these sequences showed a differential transcriptional response upon heat shock, and they were also differentially affected by inhibitors of RNA polymerase II and RNA polymerase III. A computer search for transcription factor binding sites revealed putative regulatory cis-elements within the transcribed sequence, reinforcing the experimental evidence which suggests that the telomeric repeat might function as a promoter. This work describes the telomeric transcriptome of an insect with non-telomerase telomeres, confirming the evolutionary conservation of telomere transcription. Our data reveal differences in the regulation of telomeric transcripts between control and stressful environmental conditions, supporting the idea that telomeric RNAs could have a relevant role in cellular metabolism in insect cells.

  19. Endocrine-related genes are altered by antibacterial agent triclosan in Chironomus riparius aquatic larvae.

    PubMed

    Martínez-Paz, Pedro; Morales, Mónica; Urien, Josune; Morcillo, Gloria; Martínez-Guitarte, José Luis

    2017-06-01

    Triclosan (TCS) is an antibacterial agent widely used in personal care and consumer products and commonly detected in aquatic ecosystems. In the present study, the effects of TCS on endocrine-related genes of Chironomus riparius aquatic larvae, a reference organism in aquatic toxicology, were evaluated. Twenty-four-hour in vivo exposures at 10µg/L, 100µg/L, and 1000µg/L TCS revealed that this xenobiotic was able to alter the transcriptional activity of ecdysone receptor gene (EcR), the ultraspiracle gene (usp), the estrogen-related receptor gene (ERR), and the E74 early ecdysone-inducible gene, as measured by real-time RT-PCR. Moreover, the hsp70 gene, a heat shock protein gene, was upregulated after exposure to TCS. The results of the present work provide the first evidence of the potential disruptive effects of TCS in endocrine-related genes suggesting a mode of action that mimics ecdysteroid hormones in insects.

  20. Transcriptional changes induced by in vivo exposure to pentachlorophenol (PCP) in Chironomus riparius (Diptera) aquatic larvae.

    PubMed

    Morales, Mónica; Martínez-Paz, Pedro; Martín, Raquel; Planelló, Rosario; Urien, Josune; Martínez-Guitarte, José Luis; Morcillo, Gloria

    2014-12-01

    Pentachlorophenol (PCP) has been extensively used worldwide as a pesticide and biocide and is frequently detected in the aquatic environment. In the present work, the toxicity of PCP was investigated in Chironomus riparius aquatic larvae. The effects following short- and long-term exposures were evaluated at the molecular level by analyzing changes in the transcriptional profile of different endocrine genes, as well as in genes involved in the stress response and detoxification. Interestingly, although no differences were found after 12- and 24-h treatments, at 96-h exposures PCP was able to induce significant increases in transcripts from the ecdysone receptor gene (EcR), the early ecdysone-inducible E74 gene, the estrogen-related receptor gene (ERR), the Hsp70 gene and the CYP4G gene. In contrast, the Hsp27 gene appeared to be downregulated, while the ultraspiracle gene (usp) (insect ortholog of the retinoid X receptor) was not altered in any of the conditions assayed. Moreover, Glutathione-S-Transferase (GST) activity was not affected. The results obtained show the ability of PCP to modulate transcription of different biomarker genes from important cellular metabolic activities, which could be useful in genomic approaches to monitoring. In particular, the significant upregulation of hormonal genes represents the first evidence at the genomic level of the potential endocrine disruptive effects of PCP on aquatic invertebrates.

  1. Toxicity of inorganic and organic selenium to Daphnia magna (cladocera) and Chironomus riparius (diptera)

    USGS Publications Warehouse

    Ingersoll, Christopher G.; Dwyer, F.J.; May, T.W.

    1990-01-01

    Elevated concentrations of selenium (Se) have been previously measured in biota sampled from the Kesterson National Wildlife Refuge (KNWR) in the San Joaquin Valley of central California. We conducted acute and chronic toxicity tests with the cladoceran Daphnia magna and the midge Chironomus riparius to determine the toxicity or bioaccumulation of waterborne Se in a reconstituted water similar to the San Joaquin River. Daphnids were more acutely sensitive than midges to the toxic effects of inorganic Se. An organic form of Se (seleno-[L]-methionine) was extremely toxic to daphnids, but was relatively nontoxic to midges. In long-term exposure to a 6:1 mixture of selenate to selenite (a mixture representative of KNWR), the emergence time of adult midges was delayed at Se concentrations ≥ 837 μg/L. Daphnid reproduction and intrinsic rate of natural increase (r) were reduced at Se concentrations ≥ 348 μg/L and growth of adults was reduced at ≥ 156 μg/L. Whole body Mg, K and Na concentrations in daphnids were not affected by chronic Se exposure; however, whole body Ca concentration increased at intermediate Se exposure concentrations. In addition, whole body Cl concentration was reduced at 711 μg Se/L. Daphnids accumulated potentially toxic concentrations of Se from water that may adversely affect fish or waterfowl through the food chain.

  2. 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.

  3. Calculation of sediment effect concentrations (SECs) for Hyalella azteca and Chironomus riparius

    SciTech Connect

    Haverland, P.S.; Brunson, E.L.; Canfield, T.J.; Dwyer, F.J.; Henke, C.E.; Ingersoll, C.G.; Kemble, N.E.; Mount, D.R.

    1994-12-31

    A data base for sediment toxicity and chemistry was generated with field-collected sediments using 10 to 32 d tests with the amphipod Hyalella azteca and the midge Chironomus riparius. Physical characterizations of sediment included organic carbon, percentage water, and particle size. Chemical characterizations of sediment included total metals, butyltins, methyl-mercury, acid volatile sulfide, (AVS) and simultaneously extracted metals, chlorinated pesticides, total polychlorinated biphenyls (PCBs), polychlorinated dioxins and furans, or polycyclic aromatic hydrocarbons (PAHs). Samples which significantly reduced survival, length, or maturation of test organisms relative to the control were classified as ``toxic``. A 10-fold difference in concentration for at least one chemical among the samples at each site was checked. If the concentration of a chemical measured in a toxic sample was less than or equal to the mean concentration of the chemical in the non-toxic samples at a site, then the chemical in this toxic sample was classified as ``no concordance`` (and then designated as a non-toxic in the calculations of SECs). The authors will discuss how the data base was created and the criteria used to calculate SECs (three types of SECs were calculated: (1) ERL and MM, (2) TEL and PEL, and (3) AET).

  4. Evaluation of sediment effect concentrations (SECs) for Hyalella azteca and Chironomus riparius

    SciTech Connect

    Ingersoll, C.G.; Brunson, E.L.; Canfield, T.J.; Dwyer, F.J.; Haveriand, P.S.; Henke, C.E.; Kemble, N.E.; Mount, D.R.

    1994-12-31

    A data base for sediment toxicity and chemistry was generated for field-collected sediments from sites across the United States. Toxicity tests were conducted for 10 to 32 d with Hyalella azteca and Chironomus riparius. Characterizations of sediment included organic carbon, percentage water, particle size, metals, AVS, chlorinated pesticides, PCBs, dioxins and furans, or PAHs. Three types of SECs were calculated: (1) Effect Ranges Low and Median (ERL and ERM), (2) Threshold and Probable Effect Levels (TEL and PEL), and (3) Apparent Effect Threshold (AET). SECs were normalized to: (1) dry weight, (2) total organic carbon, or (3) AVS. SECs were generated primarily for metals and PAHs. Ranges of concentrations were typically too narrow to adequately evaluate SECs for butyltins, methyl mercury, dioxins and furans, chlorinated pesticides, or PCBs. Use of ERLs or TELs to predict the toxicity of samples minimized Type 2 error (toxic sample predicted to be non-toxic), but resulted in a relatively high Type 1 error (non-toxic sample predicted to be toxic). In contrast, use of AETs to predict toxicity resulted in higher Type 2 error and lower Type 1 error. Use of ERMs or PELs resulted in moderate Type 1 and 2 error when predicting the toxicity of samples. Selection of appropriate SECs requires decisions regarding the acceptability of incorrectly classifying the toxicity of sediment samples.

  5. 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. PMID:27879923

  6. Bioaccumulation and toxicity of sediment associated herbicides (ioxynil, pendimethalin, and bentazone) in Lumbriculus variegatus (Oligochaeta) and Chironomus riparius (Insecta).

    PubMed

    Mäenpää, Kimmo A; Sormunen, Arto J; Kukkonen, Jussi V K

    2003-11-01

    The benthic macroinvertebrates Lumbriculus variegatus and Chironomus riparius were used in toxicity and bioaccumulation tests to determine the toxic concentrations and accumulation potential of sediment associated herbicides. The tested chemicals were ioxynil, bentazone, and pendimethalin. The bioaccumulation tests with L. variegatus were performed in four different sediments, each having different characteristics. Water-only LC(50) tests were performed with both L. variegatus and C. riparius. A sublethal effect of model compounds in sediments was assessed by a C. riparius larvae growth-inhibition test. Of the model compounds, ioxynil appeared to be the most toxic, with LC(50) values 1.79 and 2.79 mgL(-1) for L. variegatus and C. riparius, respectively. The LC(50) water concentrations for bentazone were 79.11 and 62.31 mgL(-1) for L. variegatus and C. riparius, respectively. Similarly, ioxynil revealed the highest bioaccumulation potential in bioaccumulation tests. The most important characters affecting chemical fate in the sediment seemed to be the organic matter content and the particle size fraction. The sediments with low organic material and coarse particle size consistently showed high bioaccumulation potential and vice versa. In C. riparius growth tests bentazone had a statistically significant effect on larval growth at sediment concentrations of 1160 and 4650 mgkg(-1) (P<0.05). It is noteworthy that standard deviations tend to be greater at high chemical concentrations, which addresses the fact that part of the individuals started to suffer. Ioxynil had an effect on the larval growth in other test sediment at the highest concentration (15.46 mgkg(-1)dw), in which head capsule length correlated with larval weight, decreasing toward higher exposure concentrations. The current results show the importance of sediment organic matter as a binding site of xenobiotics.

  7. 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.

  8. FLUID AND ION SECRETION BY MALPIGHIAN TUBULES OF LARVAL CHIRONOMIDS, Chironomus riparius: EFFECTS OF REARING SALINITY, TRANSPORT INHIBITORS, AND SEROTONIN.

    PubMed

    Zadeh-Tahmasebi, Melika; Bui, Phuong; Donini, Andrew

    2016-10-01

    Larvae of Chironomus riparius respond to ion-poor and brackish water (IPW, BW) conditions by activating ion uptake mechanisms in the anal papillae and reducing ion absorption at the rectum, respectively. The role that the Malpighian tubules play in ion and osmoregulation under these conditions is not known in this species. This study examines rates of fluid secretion and major cation composition of secreted fluid from tubules of C. riparius reared in IPW, freshwater (FW) and BW. Fluid secretion of tubules from FW and BW larvae was similar but tubules from IPW larvae secrete fluid at higher rates, are more sensitive to serotonin stimulation, and the secreted fluid contains less Na(+) . Therefore in IPW, tubules work in concert with anal papillae to eliminate excess water while conserving Na(+) in the hemolymph. Tubules do not appear to play a significant role in ion/osmoregulation under BW. Serotonin immunoreactivity in the nervous system and gastrointestinal tract of larval C. riparius was similar to that seen in mosquito larvae with the exception that the hindgut was devoid of staining. Hemolymph serotonin titer was similar in FW and IPW; hence, serotonin is not responsible for the observed high rates of fluid secretion in IPW. Instead, it is suggested that serotonin may work in a synergistic manner with an unidentified hormonal factor in IPW. Ion transport mechanisms in the tubules of C. riparius are pharmacologically similar to those of other insects.

  9. 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)).

  10. Acute toxicity of selected herbicides and surfactants to larvae of the midge Chironomus riparius

    USGS Publications Warehouse

    Buhl, Kevin J.; Faerber, Neil L.

    1989-01-01

    The acute toxicities of eight commercial herbicides and two surfactants to early fourth instar larvae of the midgeChironomus riparius were determined under static conditions. The formulated herbicides tested were Eradicane® (EPTC), Fargo® (triallate), Lasso® (alachlor), ME4 Brominal® (bromoxynil), Ramrod® (propachlor), Rodeo® (glyphosate), Sencor®(metribuzin), and Sutan (+)® (butylate); the two surfactants were Activator N.F.® and Ortho X-77®. In addition, technical grade alachlor, metribuzin, propachlor, and triallate were tested for comparison with the formulated herbicides. The relative toxicity of the commercial formulations, based on percent active ingredient, varied considerably. The EC50 values ranged from 1.23 mg/L for Fargo® to 5,600 mg/L for Rodeo®. Fargo®, ME4 Brominal®, and Ramrod®were moderately toxic to midge larvae; Lasso®, Sutan (+)®, and Eradicane® were slightly toxic; and Sencor® and Rodeo® were practically non-toxic. The 48-hr EC50 values of the two surfactants were nearly identical and were considered moderately toxic to midges. For two of the herbicides in which the technical grade material was tested, the inert ingredients in the formulations had a significant effect on the toxicity of the active ingredients. Fargo® was twice as toxic as technical grade triallate, whereas Sencor® was considerably less toxic than technical grade metribuzin. A comparison of the slope function values indicated that the toxic action of all the compounds occurred within a relatively narrow range. Published acute toxicity data on these compounds for other freshwater biota were tabulated and compared with our results. In general, the relative order of toxicity toC. riparius was similar to those for other freshwater invertebrates and fish. Maximum concentrations of each herbicide in bulk runoff during a projected “critical” runoff event were calculated as a percentage of the application rate lost in a given volume of runoff. A comparison

  11. 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.

  12. 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.

  13. Hazard evaluation of ten organophosphorous insecticides against the midge, Chironomus riparius via QSAR

    USGS Publications Warehouse

    Landrum, Peter F.; Fisher, Susan W.; Hwang, Haejo; Hickey, James P.

    1999-01-01

    Toxicities of ten organophosphorus (OP) insecticides were measured against midge larvae (Chironomus riparius) under varying temperature (11, 18, and 25°C) and pH (6, 7, and 8) conditions and with and without sediment. Toxicity usually increased with increasing temperature and was greater in the absence of sediment. No trend was found with varying pH. A series of unidimensional parameters and multidimensional models were used to describe the changes in toxicity. Log Kow was able to explain about 40–60% of the variability in response data for aqueous exposures while molecular volume and aqueous solubility were less predictive. Likewise, the linear solvation energy relationship (LSER) model only explained 40–70% of the response variability, suggesting that factors other than solubility were most important for producing the observed response. Molecular connectivity was the most useful for describing the variability in the response. In the absence of sediment, 1χv and 3κ were best able to describe the variation in response among all compounds at each pH (70–90%). In the presence of sediment, even molecular connectivity could not describe the variability until the partitioning potential to sediment was accounted for by assuming equilibrium partitioning. After correcting for partitioning, the same molecular connectivity terms as in the aqueous exposures described most of the variability, 61–87%, except for the 11°C data where correlations were not significant. Molecular connectivity was a better tool than LSER or the unidimensional variables to explain the steric fitness of OP insecticides which was crucial to the toxicity.

  14. 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.

  15. 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.

  16. Investigating heritability of cadmium tolerance in Chironomus riparius natural populations: A physiological approach.

    PubMed

    Pedrosa, João; Gravato, Carlos; Campos, Diana; Cardoso, Paulo; Figueira, Etelvina; Nowak, Carsten; Soares, Amadeu M V M; Barata, Carlos; Pestana, João L T

    2017-03-01

    Physiological responses allow populations to cope with metal contamination and can be involved in the evolution of tolerance under historical metal contamination scenarios. Here we investigate physiological aspects that might be underlying the heritable high tolerance to cadmium (Cd) in two Chironomus riparius populations collected from historically metal contaminated sites in comparison to two populations from reference sites. To evaluate differences in the physiological response to short-term Cd exposure, protein expression profiles, metallothioneins [MTs] and several antioxidant defences such as total glutathione (GSHt), catalase (CAT) and glutathione-S-transferases [GSTs], were measured in all four populations reared for at least 8 generations under laboratory clean conditions. Cd-induced oxidative damage in lipids and energy related parameters (energy consumption and energy reserves) were also assessed. Results showed two major gradients of protein profiles according to Cd concentration and population tolerance. Furthermore, Cd-tolerant populations showed higher baseline levels of MTs and GSHt while Cd-sensitive populations, collected from reference sites, showed significant induction of GSHt levels with Cd exposure that were nonetheless insufficient to avoid increased oxidative damage to lipids. Cd exposure had no clear effects on the antioxidant enzymes or energy reserves but triggered a general increase in energy consumption. Finally, energy consumption was higher in Cd-tolerant populations across experimental conditions. Altogether, results demonstrate that inherited Cd-tolerance in these midge populations is related, at least in part, with different constitutive levels and plasticity of different defence mechanisms confirming the validity of using multiple physiological traits when studying evolution of tolerance.

  17. Acute toxicity of ammonia (NH3-N) in sewage effluent to Chironomus riparius: II. Using a generalized linear model

    USGS Publications Warehouse

    Monda, D.P.; Galat, D.L.; Finger, S.E.; Kaiser, M.S.

    1995-01-01

    Toxicity of un-ionized ammonia (NH3-N) to the midge, Chironomus riparius was compared, using laboratory culture (well) water and sewage effluent (≈0.4 mg/L NH3-N) in two 96-h, static-renewal toxicity experiments. A generalized linear model was used for data analysis. For the first and second experiments, respectively, LC50 values were 9.4 mg/L (Test 1A) and 6.6 mg/L (Test 2A) for ammonia in well water, and 7.8 mg/L (Test 1B) and 4.1 mg/L (Test 2B) for ammonia in sewage effluent. Slopes of dose-response curves for Tests 1A and 2A were equal, but mortality occurred at lower NH3-N concentrations in Test 2A (unequal intercepts). Response ofC. riparius to NH3 in effluent was not consistent; dose-response curves for tests 1B and 2B differed in slope and intercept. Nevertheless, C. riparius was more sensitive to ammonia in effluent than in well water in both experiments, indicating a synergistic effect of ammonia in sewage effluent. These results demonstrate the advantages of analyzing the organisms entire range of response, as opposed to generating LC50 values, which represent only one point on the dose-response curve.

  18. Consequences of inbreeding and reduced genetic variation on tolerance to cadmium stress in the midge Chironomus riparius.

    PubMed

    Nowak, Carsten; Jost, Daniel; Vogt, Christian; Oetken, Matthias; Schwenk, Klaus; Oehlmann, Jörg

    2007-12-30

    Inbreeding and loss of genetic variation are considered to be major threats to small and endangered populations. The reduction of fitness due to inbreeding is believed to be more severe under stressful environmental conditions. We generated nine strains of the ecotoxicological model organism Chironomus riparius of different inbreeding levels in order to test the hypothesis that the inbreeding level and thus the degree of genome-wide homozygosity influences the life-history under cadmium exposure. Therefore, midge populations were exposed to a gradient of sediment-bound cadmium. The level of genetic variation in the used strains was assessed using microsatellite markers. In the life-cycle tests, inbreeding reduced fitness within C. riparius populations both under control and stressed conditions. However, differences between genetically diverse and impoverished strains were greatest at high cadmium exposure. Overall, inbreeding effects were not only dependent on cadmium concentrations in the sediment, but also on the life-history trait investigated. While some parameters where only affected by inbreeding, others were altered by both, inbreeding and cadmium. For the larval developmental time, a significant interaction was found between inbreeding and cadmium stress. While all strains showed a similar developmental time under control conditions, high rates of inbreeding led to a significantly delayed emergence time under high cadmium concentrations, resulting in longer generation periods and reduced population growth rates as population-relevant effects. The results show, that bioassays with C. riparius are affected by the level of inbreeding within Chironomus test strains. Pollution stress is therefore likely to affect the survival of rare and endangered populations more severe than that of large and genetically diverse ones.

  19. 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.

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

    PubMed

    Planelló, R; Martínez-Guitarte, J L; Morcillo, G

    2007-02-01

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

  1. Combining Next-Generation Sequencing and Microarray Technology into a Transcriptomics Approach for the Non-Model Organism Chironomus riparius

    PubMed Central

    Marinković, Marino; de Leeuw, Wim C.; de Jong, Mark; Kraak, Michiel H. S.; Admiraal, Wim; Breit, Timo M.; Jonker, Martijs J.

    2012-01-01

    Whole-transcriptome gene-expression analyses are commonly performed in species that have a sequenced genome and for which microarrays are commercially available. To do such analyses in species with no or limited genome data, i.e. non-model organisms, necessary transcriptomics resources, i.e. an annotated transcriptome and a validated gene-expression microarray, must first be developed. The aim of the present study was to establish an advanced approach for developing transcriptomics resources for non-model organisms by combining next-generation sequencing (NGS) and microarray technology. We applied our approach to the non-biting midge Chironomus riparius, an ecologically relevant species that is widely used in sediment ecotoxicity testing. We sampled extensively covering all C. riparius developmental stages as well as toxicant exposed larvae and obtained from a normalized cDNA library 1.5 M NGS reads totalling 501 Mbp. Using the NGS data we developed transcriptomics resources in several steps. First, we designed 844 k probes directly on the NGS reads, as well as 76 k probes targeting expressed sequence tags of related species. These probes were tested for their affinity to C. riparius DNA and mRNA, by performing two biological experiments with a 1 M probe-selection microarray that contained the entire probe-library. Subsequently, the 1.5 M NGS reads were assembled into 23,709 isotigs and 135,082 singletons, which were associated to ∼55 k, respectively, ∼61 k gene ontology terms and which corresponded together to 22,593 unique protein accessions. An algorithm was developed that took the assembly and the probe affinities to DNA and mRNA into account, what resulted in 59 k highly-reliable probes that targeted uniquely 95% of the isotigs and 18% of the singletons. Concluding, our approach allowed the development of high-quality transcriptomics resources for C. riparius, and is applicable to any non-model organism. It is expected, that these resources will advance

  2. 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.

  3. Encaged Chironomus riparius larvae in assessment of trace metal bioavailability and transfer in a landfill leachate collection pond.

    PubMed

    Gimbert, Frédéric; Petitjean, Quentin; Al-Ashoor, Ahmed; Cretenet, Céline; Aleya, Lotfi

    2017-01-09

    Household wastes may constitute a vector of environmental contamination when buried, in particular through degradation and production of leachates containing significant trace metal (TM) concentrations that may constitute a serious risk to biota. The objectives of this study were to assess the bioavailability and transfer potential of various TMs present in water and sediments in a reservoir receiving landfill leachates. An active biomonitoring approach was adopted consisting of exposing naive laboratory organisms in cages deployed in the field. Aquatic insects such as Chironomus riparius larvae are good candidates since they represent key organisms in the trophic functioning of aquatic ecosystems. The results show that water, suspended particles, and sediments were significantly contaminated by various TMs (As, Cd, Cu, Ni, Pb, and Zn). Their contribution to the transfer of TMs depends, however, on the specific element considered, e.g., Cd in sediments or Pb in both suspended particles and sediments. The internal fate of TMs was investigated according to their fractionation between an insoluble and a cytosolic fraction. This approach revealed different detoxification strategies capable of preventing the induction of deleterious effects at the individual scale. However, the accumulation of several TMs in C. riparius larvae tissues may also represent a significant load potentially transferable to higher trophic levels.

  4. The use of Chironomus riparius larvae to assess effects of pesticides from rice fields in adjacent freshwater ecosystems.

    PubMed

    Faria, Mafalda S; Nogueira, António J A; Soares, Amadeu M V M

    2007-06-01

    A bioassay with Chironomus riparius larvae, using larval development and growth as endpoints, was carried out inside a rice field and in the adjacent wetland channel in Portugal, during pesticide treatments (molinate, endosulfan and propanil) to determine impact caused by pesticide contamination in freshwater ecosystems. The bioassay was also performed under laboratory conditions, to assess whether in situ and laboratory bioassays demonstrated comparable results. Growth was inhibited by concentrations of endosulfan (2.3 and 1.9 microgL(-1) averages) in water from rice field in both the field and laboratory, and by concentrations of endosulfan (0.55 and 0.76 microgL(-1) averages) in water from the wetland channel in the laboratory bioassay, while development was not affected. C. riparius larvae were not affected by molinate and propanil concentrations. The results indicate that endosulfan treatments in rice fields may cause an ecological impairment in adjacent freshwater ecosystems. The results also indicate that laboratory testing can be used to assess in situ toxicity caused by pesticide contamination.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. Genotoxic effects of environmental endocrine disruptors on the aquatic insect Chironomus riparius evaluated using the comet assay.

    PubMed

    Martínez-Paz, Pedro; Morales, Mónica; Martínez-Guitarte, José Luis; Morcillo, Gloria

    2013-12-12

    Genotoxicity is one of the most important toxic endpoints in chemical toxicity testing and environmental risk assessment. The aim of this study was to evaluate the genotoxic potential of various environmental pollutants frequently found in aquatic environments and characterized by their endocrine disrupting activity. Monitoring of DNA damage was undertaken after in vivo exposures of the aquatic larvae of the midge Chironomus riparius, a model organism that represents an abundant and ecologically relevant macroinvertebrate, widely used in freshwater toxicology. DNA-induced damage, resulting in DNA fragmentation, was quantified by the comet assay after short (24 h) and long (96 h) exposures to different concentrations of the selected toxicants: bisphenol A (BPA), nonylphenol (NP), pentachlorophenol (PCP), tributyltin (TBT) and triclosan (TCS). All five compounds were found to have genotoxic activity as demonstrated by significant increases in all the comet parameters (%DNA in tail, tail length, tail moment and Olive tail moment) at all tested concentrations. Persistent exposure did not increase the extent of DNA damage, except for TCS at the highest concentration, but generally there was a reduction in DNA damage thought to be associated with the induction of the detoxification processes and repairing mechanisms. Comparative analysis showed differences in the genotoxic potential between the chemicals, as well as significant time and concentration-dependent variations, which most likely reflect differences in the ability to repair DNA damage under the different treatments. The present report demonstrates the sensitivity of the benthic larvae of C. riparius to these environmental genotoxins suggesting its potential as biomonitor organism in freshwater ecosystems. The results obtained about the DNA-damaging potential of these environmental pollutants reinforce the need for additional studies on the genotoxicity of endocrine active substances that, by linking genotoxic

  10. DNA damage and translational response during detoxification from copper exposure in a wild population of Chironomus riparius.

    PubMed

    Bernabò, Paola; Gaglio, Matteo; Bellamoli, Francesco; Viero, Gabriella; Lencioni, Valeria

    2017-04-01

    Copper is one of the predominant components of pesticides employed in agriculture and known to be highly toxic once it reaches aquatic organisms. The impact of sublethal concentrations of this metal on wild insects is not yet completely understood. Studies addressing alterations in different levels of gene expression are still lacking. We previously demonstrated that in a wild population of Chironomus riparius, HSP and CYP families of genes were up-regulated at the transcriptional level after copper exposure. Here, we analyse the impact of copper at the genomic, translational and protein functional level, obtaining a comprehensive picture of the molecular reply to this metal. We studied genotoxicity in C. riparius larvae by Comet Assay, the translational response by polysomal profiling and the detoxification capacity by the CYP450 enzymes activity. Fourth-instar larvae from a mountain stream polluted by agricultural land run-off (NE-Italy) were exposed for 3 h copper concentrations ≤ LC50. We report DNA damage induced by copper, even at sublethal levels, as demonstrated by significant increases in all the comet parameters at concentrations ≥1 mg L(-1). By estimating the transcript-specific translational efficiency, we observe a specific up-regulation of CYP4G. Furthermore, the enzymatic activity of CYP450 enzymes is increased at all sublethal copper concentrations, confirming the role of this protein family in the detoxification processes. Surprisingly, the HSP transcripts are up-regulated at the transcriptional level, but these changes are buffered at the translational level suggesting the existence of still unknown post-transcriptional controls that may be connected to survival processes.

  11. Calculation and evaluation of sediment effect concentrations for the amphipod Hyalella azteca and the midge Chironomus riparius

    USGS Publications Warehouse

    Ingersoll, Christopher G.; Haverland, Pamela S.; Brunson, Eric L.; Canfield, Timothy J.; Dwyer, F. James; Henke, Chris; Kemble, Nile E.; Mount, David R.; Fox, Richard G.

    1996-01-01

    Procedures are described for calculating and evaluating sediment effect concentrations (SECs) using laboratory data on the toxicity of contaminants associated with field-collected sediment to the amphipod Hyalella azteca and the midge Chironomus riparius. SECs are defined as the concentrations of individual contaminants in sediment below which toxicity is rarely observed and above which toxicity is frequently observed. The objective of the present study was to develop SECs to classify toxicity data for Great Lake sediment samples tested with Hyalella azteca and Chironomus riparius. This SEC database included samples from additional sites across the United States in order to make the database as robust as possible. Three types of SECs were calculated from these data: (1) Effect Range Low (ERL) and Effect Range Median (ERM), (2) Threshold Effect Level (TEL) and Probable Effect Level (PEL), and (3) No Effect Concentration (NEC). We were able to calculate SECs primarily for total metals, simultaneously extracted metals, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). The ranges of concentrations in sediment were too narrow in our database to adequately evaluate SECs for butyltins, methyl mercury, polychlorinated dioxins and furans, or chlorinated pesticides. About 60 to 80% of the sediment samples in the database are correctly classified as toxic or not toxic depending on type of SEC evaluated. ERMs and ERLs are generally as reliable as paired PELs and TELs at classifying both toxic and non-toxic samples in our database. Reliability of the SECs in terms of correctly classifying sediment samples is similar between ERMs and NECs; however, ERMs minimize Type I error (false positives) relative to ERLs and minimize Type II error (false negatives) relative to NECs. Correct classification of samples can be improved by using only the most reliable individual SECs for chemicals (i.e., those with a higher percentage of correct classification). SECs

  12. 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.

  13. DNA damage and transcriptional changes induced by tributyltin (TBT) after short in vivo exposures of Chironomus riparius (Diptera) larvae.

    PubMed

    Morales, Mónica; Martínez-Paz, Pedro; Ozáez, Irene; Martínez-Guitarte, José Luis; Morcillo, Gloria

    2013-08-01

    Tributyltin (TBT) is a widespread environmental contaminant in aquatic systems whose adverse effects in development and reproduction are related to its well-known endocrine-disrupting activity. In this work, the early molecular effects of TBT in Chironomus riparius (Diptera) were evaluated by analyzing its DNA damaging potential and the transcriptional response of different endocrine-related genes. Twenty-four-hour in vivo exposures of the aquatic larvae, at environmentally relevant doses of TBT, revealed genotoxic activity as shown by significant increases in DNA strand breaks quantified with the comet assay. TBT was also able to induce significant increases in transcripts from the ecdysone receptor gene (EcR), the ultraspiracle gene (usp) (insect ortholog of the retinoid X receptor), the estrogen-related receptor (ERR) gene and the E74 early ecdysone-inducible gene, as measured by real-time RT-PCR. In contrast, the expression of the vitellogenin (vg) gene remained unaltered, while the hsp70 gene appeared to be down-regulated. The ability of TBT to up-regulate hormonal target genes provides the first evidence, at genomic level, of its endocrine disruptive effects and also suggests a mechanism of action that mimics ecdysteroid hormones in insects. These data reveal for the first time the early genomic effects of TBT on an insect genome.

  14. Transcriptional deregulation of genetic biomarkers in Chironomus riparius larvae exposed to ecologically relevant concentrations of di(2-ethylhexyl) phthalate (DEHP).

    PubMed

    Herrero, Óscar; Morcillo, Gloria; Planelló, Rosario

    2017-01-01

    Di(2-ethylhexyl) phthalate (DEHP) is a ubiquitous environmental pollutant used worldwide as a plasticizer and solvent in many formulations. Based on available toxicological data, it has been classified as toxic for reproduction and as an endocrine disruptor. Despite this, ecotoxicological studies in aquatic wildlife organisms are still scarce. In the present work, the toxic molecular alterations caused by DEHP in aquatic larvae of the midge Chironomus riparius have been studied, by analyzing the transcriptional activity of genes related to some vital cellular pathways, such as the ribosomal machinery (rpL4, rpL13), the cell stress response (hsc70, hsp70, hsp40, hsp27), the ecdysone hormone pathway (EcR), the energy metabolism (GAPDH), and detoxication processes (CYP4G). Environmentally relevant concentrations (10-3 to 105 μg/L) and exposure conditions (24 to 96 h) have been tested, as well as the toxic effects after DEHP withdrawal. Although the compound caused no mortality, significant changes were detected in almost all the studied biomarkers: e.g. strong repression of hsp70; general inhibition of EcR; GAPDH activity loss in long exposures; among others. Our data show a general transcriptional downregulation that could be associated with an adaptive response to cell damage. Besides, the activity of the compound as an ecdysone antagonist and its delayed effects over almost all the biomarkers analyzed are described as novel toxic targets in insects.

  15. Transcriptional deregulation of genetic biomarkers in Chironomus riparius larvae exposed to ecologically relevant concentrations of di(2-ethylhexyl) phthalate (DEHP)

    PubMed Central

    Morcillo, Gloria; Planelló, Rosario

    2017-01-01

    Di(2-ethylhexyl) phthalate (DEHP) is a ubiquitous environmental pollutant used worldwide as a plasticizer and solvent in many formulations. Based on available toxicological data, it has been classified as toxic for reproduction and as an endocrine disruptor. Despite this, ecotoxicological studies in aquatic wildlife organisms are still scarce. In the present work, the toxic molecular alterations caused by DEHP in aquatic larvae of the midge Chironomus riparius have been studied, by analyzing the transcriptional activity of genes related to some vital cellular pathways, such as the ribosomal machinery (rpL4, rpL13), the cell stress response (hsc70, hsp70, hsp40, hsp27), the ecdysone hormone pathway (EcR), the energy metabolism (GAPDH), and detoxication processes (CYP4G). Environmentally relevant concentrations (10−3 to 105 μg/L) and exposure conditions (24 to 96 h) have been tested, as well as the toxic effects after DEHP withdrawal. Although the compound caused no mortality, significant changes were detected in almost all the studied biomarkers: e.g. strong repression of hsp70; general inhibition of EcR; GAPDH activity loss in long exposures; among others. Our data show a general transcriptional downregulation that could be associated with an adaptive response to cell damage. Besides, the activity of the compound as an ecdysone antagonist and its delayed effects over almost all the biomarkers analyzed are described as novel toxic targets in insects. PMID:28166271

  16. Molecular cloning of soluble trehalase from Chironomus riparius larvae, its heterologous expression in Escherichia coli and bioinformatic analysis.

    PubMed

    Forcella, Matilde; Mozzi, Alessandra; Bigi, Alessandra; Parenti, Paolo; Fusi, Paola

    2012-10-01

    Trehalase is involved in the control of trehalose concentration, the main blood sugar in insects. Here, we describe the molecular cloning of the cDNA encoding for the soluble form of the trehalase from the midge larvae of Chironomus riparius, a well-known bioindicator of the quality of freshwater environments. Molecular cloning was achieved through multiple alignment of Diptera trehalase sequences, allowing the synthesis of internal homology-based primers; the complete open reading frame(ORF) was subsequently obtained through RACE-PCR(where RACE is rapid amplification of cDNA ends). The cDNA contained the 5' untranslated region (UTR), the 3' UTR including a poly(A) tail and the ORF of 1,725 bp consisting of 574 amino acid residues with a predicted molecular mass of 65,778 Da. Recombinant trehalase was successfully expressed in Escherichia coli as a His-tagged protein and purified on Ni-NTA affinity chromatography. Primary structure analysis showed a series of characteristic features shared by all insect trehalases, while three-dimensional structure prediction yielded the typical glucosidase fold, the two key residues involved in the catalytic mechanism being conserved. Production of recombinant insect trehalases opens the way to structural characterizations of the catalytic site, which might represent, among others, an element for reconsidering the enzyme as a target in pest insects' control.

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

    PubMed Central

    Pedrosa, João A. M.; Bálint, Miklós; Diogo, João B.; Ilkova, Julia; Pestana, João L. T.; Pfenninger, Markus

    2016-01-01

    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

  18. The role of genetic diversity and past-history selection pressures in the susceptibility of Chironomus riparius populations to environmental stress.

    PubMed

    Pedrosa, João A M; Cocchiararo, Berardino; Bordalo, Maria D; Rodrigues, Andreia C M; Soares, Amadeu M V M; Barata, Carlos; Nowak, Carsten; Pestana, João L T

    2017-01-15

    Natural populations experiencing intense selection and genetic drift may exhibit limited potential to adapt to environmental change. The present study addresses the following aspects of the "genetic erosion" hypothesis in the midge Chironomus riparius: does long-term mercury (Hg) contamination affect the Hg tolerance of midge populations inhabiting such impacted areas? If so, is there any fitness cost under changing environmental conditions? And does genetic impoverishment influence the susceptibility of C. riparius to cope with environmental stressful conditions? For this end, we tested the acute and chronic tolerance to Hg and salinity in four C. riparius populations differing in their levels of genetic diversity (assessed through microsatellite markers) and past-histories of Hg exposure. Results showed that the midge population collected from a heavily Hg-contaminated site had higher Hg tolerance compared to the population collected from a closely-located reference site suggesting directional selection for Hg-tolerant traits in its native environment despite no genetic erosion in the field. No increased susceptibility under changing environmental conditions of salinity stress was observed. Moreover, results also showed that populations with higher genetic diversity performed better in the partial life-cycle assays providing evidence on the key role that genetic diversity plays as mediator of populations' susceptibility to environmental stress. Our findings are discussed in terms of the suitability of C. riparius as a model organism in evolutionary toxicology studies as well as the validity of ecotoxicological assessments using genetically eroded laboratory populations.

  19. Predictions of sediment toxicity using a database for Hyalella azteca and Chironomus riparius

    SciTech Connect

    Haverland, P.S.; Dwyer, F.J.; Henke, C.E.; Ingersoll, C.G.; Mount, D.R.; Field, J.; MacDonald, D.D.; Smith, S.L.

    1995-12-31

    A database was developed for calculating sediment effect concentrations (SECS) for various contaminants Associated with field-collected sediment using laboratory toxicity data for the amphipod H. azteca and the midge C. riparius. Three types of SECs were calculated: (1) Effect Range Low (ERL) and Effect Range Median (ERM), (2) Threshold Effect Level (TEL) and Probable Effect Level (PEL), and (3) No Effect Concentration (NEC). The predictive abilities of SECs were evaluated using independent toxicity data sets. For example, the predictive ability of ERMs was evaluated by first calculating ERMs using just the Great Lakes (GL) portion of the database. These GL ERMs were then used to predict responses in independent H. azteca 28-d tests and C. riparius 1 4-d tests with Clark Fork River sediments. About 70 to 90% of the samples were correctly classified at 1 to 2 exceedances of GL ERMS. At 1 to 2 exceedances of GL ERMS, Type 2 error (false negatives) was < 10% and Type 1 error (false positives) was 10 to 30%. Evaluations using GL PELs and GL NECs resulted in similar predictive ability compared to GL ERMS. When SECs are used to conduct a preliminary screening to predict the potential for toxicity in the absence of actual toxicity testing, a low number of SEC exceedances should be used to minimize the potential for false negatives; however, the risk of accepting higher false positives is increased. The authors are currently using SECs calculated from the entire database to predict the response of H. azteca and C. riparius in a variety of independent data sets generated by other laboratories.

  20. 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.

  1. 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.

  2. 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.

  3. Overexpression of long non-coding RNAs following exposure to xenobiotics in the aquatic midge Chironomus riparius.

    PubMed

    Martínez-Guitarte, José-Luis; Planelló, Rosario; Morcillo, Gloria

    2012-04-01

    Non-coding RNAs (ncRNAs) represent an important transcriptional output of eukaryotic genomes. In addition to their functional relevance as housekeeping and regulatory elements, recent studies have suggested their involvement in rather unexpected cellular functions. The aim of this work was to analyse the transcriptional behaviour of non-coding RNAs in the toxic response to pollutants in Chironomus riparius, a reference organism in aquatic toxicology. Three well-characterized long non-coding sequences were studied: telomeric repeats, Cla repetitive elements and the SINE CTRT1. Transcription levels were evaluated by RT-PCR after 24-h exposures to three current aquatic contaminants: bisphenol A (BPA), benzyl butyl phthalate (BBP) and the heavy metal cadmium (Cd). Upregulation of telomeric transcripts was found after BPA treatments. Moreover, BPA significantly activated Cla transcription, which also appeared to be increased by cadmium, whereas BBP did not affect the transcription levels of these sequences. Transcription of SINE CTRT1 was not altered by any of the chemicals tested. These data are discussed in the light of previous studies that have shown a response by long ncRNAS (lncRNAs) to cellular stressors, indicating a relationship with environmental stimuli. Our results demonstrated for the first time the ability of bisphenol A to activate non-coding sequences mainly located at telomeres and centromeres. Overall, this study provides evidence that xenobiotics can induce specific responses in ncRNAs derived from repetitive sequences that could be relevant in the toxic response, and also suggests that ncRNAs could represent a novel class of potential biomarkers in toxicological assessment.

  4. 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

  5. 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.

  6. Bioaccumulation and toxicity of 4-nonylphenol (4-NP) and 4-(2-dodecyl)-benzene sulfonate (LAS) in Lumbriculus variegatus (Oligochaeta) and Chironomus riparius (Insecta).

    PubMed

    Mäenpää, K; Kukkonen, J V K

    2006-05-10

    The discharge of surfactants, such as 4-nonylphenol (4-NP) and linear alkylbenzene sulfonates (LAS), into water bodies leads to accumulation of the chemicals in the sediments and may thus pose a problem to benthic organisms. To study the bioaccumulation of surfactants, Oligochaeta worm Lumbriculus variegatus was exposed to sediment-spiked, [14C]-labeled 4-NP and 4-(2-dodecyl)-benzene sulfonate (C12-LAS) in three different sediments (S1-S3). The sediments were characterized for organic carbon (OC) content and particle size distribution. The acute toxicity was examined by exposing L. variegatus and three to four instar Chironomus riparius (Insecta) larvae in water-only exposure to 4-NP and LAS at different concentrations. After 48-h exposure, lethal water concentrations (LC50) and lethal body residues (LBR50) were estimated using liquid scintillation counting. Chronic toxicity was evaluated in two different sediments by exposing first instar C. riparius larvae to sediment-spiked chemicals at different concentrations. After 10 days, the sublethal effects of surfactants were observed by measuring wet weight and head capsule length. Finally, another 10-day test was set up in order to measure the LAS body residues associated with sublethal effects in C. riparius in S2 sediment. The bioaccumulation test revealed that the bioaccumulation of both 4-NP and LAS increased as the sediment organic matter content decreased. It is assumed that the chemical binding to organic material decreased chemical bioavailability. The acute toxicity tests showed that L. variegatus was more tolerant of 4-NP, and C. riparius was more tolerant of LAS when based on water exposure concentration. The LBR-estimates revealed, however, that L. variegatus tolerated clearly higher tissue residues of both chemicals compared with C. riparius. Both chemicals had sublethal effects on C. riparius growth in sediment exposure, reducing larvae wet weight and head capsule size. 4-NP, however, showed an irregular

  7. The UV filter benzophenone 3 (BP-3) activates hormonal genes mimicking the action of ecdysone and alters embryo development in the insect Chironomus riparius (Diptera).

    PubMed

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

    2014-09-01

    Numerous studies have evaluated the endocrine effects of UV filters in vertebrates, but little attention has been paid to their possible hormonal activity in invertebrates. We examined the effects of benzophenone-3 (BP-3), one of the most common sunscreen agents, in Chironomus riparius (Insecta), a reference organism in aquatic toxicology. Salivary glands from larvae were treated with either the hormone ecdysone or BP-3 to compare the response of endocrine genes. It was found that BP-3 elicits the same effects as the natural hormone activating the expression of a set of ecdysone responsive genes. BP-3 also activated the stress gene hsp70. Interestingly, similar effects have been confirmed in vivo in embryos. Moreover, BP-3 also altered embryogenesis delaying hatching. This is the first demonstration of hormonal activity of UV filters in invertebrates, showing a mode of action similar to ecdysteroid hormones. This finding highlights the potential endocrine disruptive effects of these emergent pollutants.

  8. 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.

  9. Use of whole-body and subcellular Cu residues of Lumbriculus variegatus to predict waterborne Cu toxicity to both L. variegatus and Chironomus riparius in fresh water.

    PubMed

    Ng, Tania Y T; Pais, Nish M; Dhaliwal, Tarunpreet; Wood, Chris M

    2012-06-01

    We tested the use of whole-body and subcellular Cu residues (biologically-active (BAM) and inactive compartments (BIM)), of the oligochaete Lumbriculus variegatus to predict Cu toxicity in fresh water. The critical whole-body residue associated with 50% mortality (CBR(50)) was constant (38.2-55.6 μg g(-1) fresh wt.) across water hardness (38-117 mg L(-1) as CaCO(3)) and exposure times during the chronic exposure. The critical subcellular residue (CSR(50)) in metal-rich granules (part of BIM) associated with 50% mortality was approximately 5 μg g(-1) fresh wt., indicating that Cu bioavailability is correlated with toxicity:subcellular residue is a better predictor of Cu toxicity than whole-body residue. There was a strong correlation between the whole-body residue of L. variegatus (biomonitor) and survival of Chironomus riparius (relatively sensitive species) in a hard water Cu co-exposure. The CBR(50) in L. variegatus for predicting mortality of C. riparius was 29.1-45.7 μg g(-1) fresh wt., which was consistent within the experimental period; therefore use of Cu residue in an accumulator species to predict bioavailability of Cu to a sensitive species is a promising approach.

  10. Identification, characterization and expression profiles of Chironomus riparius glutathione S-transferase (GST) genes in response to cadmium and silver nanoparticles exposure.

    PubMed

    Nair, Prakash M Gopalakrishnan; Choi, Jinhee

    2011-02-01

    In this study, we report the identification and characterization of 13 cytosolic GST genes in Chironomus riparius from Expressed Sequence Tags (ESTs) database generated using pyrosequencing. Comparative and phylogenetic analyses were undertaken with Drosophila melanogaster and Anopheles gambiae GSTs and 3 Delta, 4 Sigma, 1 each in Omega, Epsilon, Theta, Zeta and 2 unclassified classes of GSTs were identified and characterized. The relative mRNA expression levels of all of the C. riparius GSTs (CrGSTs) genes under different developmental stages were varied with low expression in the larval stage. The antioxidant role of CrGSTs was studied by exposing fourth instar larvae to a known oxidative stress inducer Paraquat and the relative mRNA expression to different concentrations of cadmium (Cd) and silver nanoparticles (AgNPs) for various time intervals were also studied. All the CrGSTs showed up- or down regulation to varying levels based upon the concentration, and duration of exposure. The highest mRNA expression was noticed in Delta3, Sigma4 and Epsilon1 GST class in all treatments. These results show the role of CrGST genes in defense against oxidative stress and its potential as a biomarker to Cd and AgNPs exposure.

  11. Characterization of the small heat shock protein Hsp27 gene in Chironomus riparius (Diptera) and its expression profile in response to temperature changes and xenobiotic exposures.

    PubMed

    Martínez-Paz, Pedro; Morales, Mónica; Martín, Raquel; Martínez-Guitarte, José Luis; Morcillo, Gloria

    2014-07-01

    Small heat shock proteins constitute the most diverse and least conserved group within the large family of heat shock proteins, which play a crucial role in cell response to environmental insults. Chironomus riparius larvae are widely used in environmental research for testing pollutant toxicity in sediments and freshwater environments. Different genes, such as Hsp70, Hsc70, Hsp90, and Hsp40, have been identified in this species as sensitive biomarkers for xenobiotics, but small Hsps genes remain largely unknown. In this study, the Hsp27 has been characterized in C. riparius and its transcriptional response evaluated under several environmental stimuli. The Hsp27 gene was mapped by FISH on polytene chromosomes at region I-C4 and was found to encode a 195 aa protein, which contains an α-crystallin domain bounded by three conserved regions. This protein shows homology with Drosophila melanogaster HSP27, Ceratitis capitata HSP27, and Sarcophaga crassipalpis HSP25. Real-time reverse transcriptase-polymerase chain reaction analysis showed that heat shock (35 °C) and cadmium dramatically upregulate this gene. Moreover, exposures to triclosan and bisphenol A were able to significantly increase mRNA levels. However, neither nonylphenol nor tributyltin altered Hsp27 gene expression. The transcriptional activity of Hsp27 gene was modulated during cold stress. Interestingly, cold shock (4 °C) significantly reduced Hsp27 transcripts, but this gene was significantly overexpressed during the recovery time at the normal growing temperature. These results show that the Hsp27 gene is sensitive to different environmental stimuli, including endocrine-disrupting pollutants, suggesting its potential as a suitable biomarker for ecotoxicological studies in aquatic systems.

  12. Characterization of Hsp70 gene in Chironomus riparius: expression in response to endocrine disrupting pollutants as a marker of ecotoxicological stress.

    PubMed

    Morales, Mónica; Planelló, Rosario; Martínez-Paz, Pedro; Herrero, Oscar; Cortés, Estrella; Martínez-Guitarte, José Luis; Morcillo, Gloria

    2011-01-01

    We characterized the Hsp70 cDNA in Chironomus riparius and evaluated its expression profile under different environmental stressors. It is highly conserved, at both DNA and protein levels, displaying many of the hallmarks of Hsps and sharing 80-96% of overall amino acid identities with homologous sequences from other diptera. The changes are mainly concentrated in the C-terminal domain of the protein. Phylogenetic analysis was consistent with the known classification of insects. The Hsp70 gene was located by in situ hybridization in region III-3A at the third polytene chromosome, a locus activated upon heat shock as shown by RNA pol II binding. As C. riparius is widely used in aquatic ecotoxicology testing, we studied Hsp70 gene induction in fourth instar aquatic larvae submitted to heat shock and selected environmental pollutants classified as potential endocrine disruptors. RT-PCR analysis showed that Hsp70 mRNA levels increased significantly (p<0.05) after short-term acute exposures to a temperature shift (HS), cadmium chloride (Cd), butyl benzyl phthalate (BBP), diethylhexyl phthalate (DEHP), bisphenol A (BPA), 4-nonylphenol (NP) and ethinylestradiol (EE). However, neither pentachlorophenol (PCP) nor tributyltin (TBTO) treatments were able to activate the Hsp70 gene. The cognate form, Hsc70, was also analysed and, unlike Hsp70, was not altered by any of the different treatments assayed. Moreover, at the times tested, there was no significant mortality of the larvae. The rapid upregulation of the Hsp70 gene suggests that it is sensitive and selective for different environmental pollutants, and could be used as an early molecular endpoint in ecotoxicological studies.

  13. 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.

  14. Characterization and expression during development and under environmental stress of the genes encoding ribosomal proteins L11 and L13 in Chironomus riparius.

    PubMed

    Martínez-Guitarte, J L; Planelló, R; Morcillo, G

    2007-08-01

    The Chironomus riparius gene sequences encoding ribosomal proteins L11 and L13 were characterized and their expression analysed during development, and under different types of cellular stress. A comparative and phylogenetic study among different orders of insects was carried out by analysis of sequence databases. L11 is highly conserved, both at the level of DNA and protein, and it shares over 90% amino acid identity with homologous sequences from other insects. Interestingly, the changes are mainly concentrated in the C-terminal domain of the protein. Conversely, L13 shows a lower degree of homology, around 60% amino acid identity, and the changes were dispersed throughout the length of the polypeptide. Surprisingly, when comparing L13 nucleotide sequences, only a very low or no homology was found even among diptera. These results are helpful for defining the structural and, therefore, evolutionary constraints of these proteins. Studies of gene expression by RT-PCR showed that they are differentially expressed in distinct stages of development. Both L11 and L13 were significantly upregulated during embryogenesis. The expression profiles of the transcripts were also analysed after a general stress, such as heat shock, as well as after a specific stress, such as acute cadmium treatment. In both conditions, no significant differences to controls were detected in L11 and L13 transcripts, in spite of the drastic changes observed in the stress-induced gene HSP70, and the inhibitory effect on rRNA transcription. These data confirm that both genes are equally robust against harmful environmental conditions, suggesting that they could be used as a control for environmentally responsive genes in Chironomus. Overall, our results show a coordinated expression of both the L11 and the L13 genes, but not a coordinated regulation of rRNA and ribosomal protein production.

  15. 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.

  16. 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.

  17. Life-cycle changes and zinc shortage in cadmium-tolerant midges, Chironomus riparius (Diptera), reared in the absence of cadmium

    SciTech Connect

    Postma, J.F.; Mol, S.; Larsen, H.; Admiraal, W. . Section of Aquatic Ecotoxicology)

    1995-01-01

    Adaptation to selected metals is known to modify life-cycle characteristics of some invertebrates and can modify the response to other metals. The reverse process, i.e., adaptation to nonpolluted conditions in a metal-tolerant strain, was studied here for a cadmium-tolerant population of the midge Chironomus riparius to detect whether this backward adaptation followed the same lines. It appeared that cadmium-tolerant populations, reared in the absence of cadmium, continued to suffer from high mortality rates and lowered larval growth rates and reproductive success. Also, some cadmium-tolerant populations accumulated more zinc than did nontolerant populations. Successive experiments in which both cadmium-tolerant and nontolerant populations were exposed to zinc indicated that the reduced growth rate and reproduction were a direct consequence of zinc shortage in tolerant midges reared in the absence of cadmium. Mortality among cadmium-tolerant midges was, however, not lowered by zinc exposure and, judged by their high mortality rates, these midges were even more sensitive to zinc than were nontolerant chironomids. It was concluded that cadmium-tolerant chironomid populations recovering from prolonged exposure are affected by an increased need for zinc as well as by an increased mortality rate as a direct consequence of their earlier adaptation process.

  18. 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.

  19. 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.

  20. Characterization of a cytochrome P450 gene (CYP4G) and modulation under different exposures to xenobiotics (tributyltin, nonylphenol, bisphenol A) in Chironomus riparius aquatic larvae.

    PubMed

    Martínez-Paz, Pedro; Morales, Mónica; Martínez-Guitarte, José Luis; Morcillo, Gloria

    2012-03-01

    Cytochrome P450 family members participate in xenobiotic transformation as a detoxification mechanism. We have characterized a CYP gene, assigned to the 4G family, in Chironomus riparius, a reference organism in aquatic toxicology. Due to the potential interest of CYP genes and P450 proteins for monitoring pollution effects at the molecular level, the alterations in the pattern of expression of this gene, induced by different xenobiotics, were analyzed. Different compounds, such as the biocide tributyltin (TBTO) and two other well-known endocrine disruptors, nonylphenol (NP) and bisphenol A (BPA), were tested at different concentrations and acute exposures. Upregulation of the CrCYP4G gene was found after exposures to TBTO (1 ng/L 24h-0.1 ng/L 96 h) and, as measured by RT-PCR mRNA quantification, its level was up to twofold that of controls. However, in contrast, NP (1, 10, 100 μg/L, 24h) and BPA (0.5mg/L 24h-3mg/L 96 h) downregulated the gene (by around a half of the control level) suggesting that this gene responds specifically to particular chemicals in the environment. Glutathione-S-transferase (GST) enzymatic activity was also evaluated for each condition. A fairly good correlation was found with CYP4G gene behavior, as it was activated by TBTO (96 h), but inhibited by NP and BPA (24h). Only the higher concentration of BPA tested activated GST, whereas it inhibited CYP4G activity. The results show that different xenobiotics can induce distinct responses in the detoxification pathway, suggesting multiple xenobiotic transduction mechanisms. This work confirms that specific P450 codifying genes, as well as GST enzyme activities, could be suitable biomarkers for ecotoxicological studies.

  1. 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

  2. The endocrine disruptor bisphenol A increases the expression of HSP70 and ecdysone receptor genes in the aquatic larvae of Chironomus riparius.

    PubMed

    Planelló, R; Martínez-Guitarte, J L; Morcillo, G

    2008-05-01

    Bisphenol A (BPA) is an endocrine disruptor that can mimic the action of estrogens by interacting with hormone receptors and is, therefore, potentially able to influence reproductive functions in vertebrates. Although information about the interaction with the endocrine systems in invertebrates is limited, it has also been shown its effect on reproductive and developmental parameters in these organisms. As little is known about its mechanism of action in aquatic invertebrates, we have examined the effects of BPA on the expression of some selected genes, including housekeeping, stress-induced and hormone-related genes in Chironomus riparius larvae, a widely used organism in aquatic ecotoxicology. The levels of different gene transcripts were measured by Northern blot or by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). Exposure to BPA (3 mgl(-1), 12-24h) did not affect the levels of rRNA or those of mRNAs for both L11 or L13 ribosomal proteins, selected as examples of housekeeping genes involved in ribosome biogenesis. Nevertheless, BPA treatment induced the expression of the HSP70 gene. Interestingly, it was found that BPA significantly increases the mRNA level of the ecdysone receptor (EcR). These results show for the first time that exposure to endocrine disrupting chemicals, such as BPA, can selectively affect the expression of the ecdysone receptor gene suggesting a direct interaction with the insect endocrine system. Furthermore, this finding suggests a common way of BPA action, shared by vertebrates and invertebrates, through interaction with steroid hormone receptors. Our study adds a new element, the EcR, which may be a useful tool for the screening of environmental xenoestrogens in insects.

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

    PubMed

    Planelló, R; Martínez-Guitarte, J L; Morcillo, G

    2010-03-01

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

  4. 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.

  5. 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.

  6. Acute toxicity, critical body residues, Michaelis-Menten analysis of bioaccumulation, and ionoregulatory disturbance in response to waterborne nickel in four invertebrates: Chironomus riparius, Lymnaea stagnalis, Lumbriculus variegatus and Daphnia pulex.

    PubMed

    Leonard, Erin M; Wood, Chris M

    2013-06-01

    We investigated the bioaccumulation and acute toxicity (48 h or 96 h) of Ni in four freshwater invertebrate species in two waters with hardness of 40 (soft water) and 140 mg L(-1) as CaCO(3) (hard water). Sensitivity order (most to least) was Lymnaea stagnalis > Daphnia pulex > Lumbriculus variegatus > Chironomus riparius. In all cases water hardness was protective against acute Ni toxicity with LC(50) values 3-3.5× higher in the hard water vs. soft water. In addition, higher water hardness significantly reduced Ni bioaccumulation in these organisms suggesting that competition by Ca and Mg for uptake at the biotic ligand may contribute to higher metal resistance. CBR50 values (Critical Body Residues) were less dependent on water chemistry (i.e. more consistent) than LC(50) values within and across species by ~2 fold. These data support one of the main advantages of the Tissue Residue Approach (TRA) where tissue concentrations are generally less variable than exposure concentrations with respect to toxicity. Whole body Ni bioaccumulation followed Michaelis-Menten kinetics in all organisms, with greater hardness tending to decrease B(max) with no consistent effect on K(d). Across species, acute Ni LC(50) values tended to increase with both K(d) and B(max) values - i.e. more sensitive species exhibited higher binding affinity and lower binding capacity for Ni, but there was no correlation with body size. With respect to biotic ligand modeling, log K(NiBL) values derived from Ni bioaccumulation correlated well with log K(NiBL) values derived from toxicity testing. Both whole body Na and Mg levels were disturbed, suggesting that disruption of ionoregulatory homeostasis is a mechanism of acute Ni toxicity. In L. stagnalis, Na depletion was a more sensitive endpoint than mortality, however, the opposite was true for the other organisms. This is the first study to show the relationship between Na and Ni.

  7. Comparative effects of butyl benzyl phthalate (BBP) and di(2-ethylhexyl) phthalate (DEHP) on the aquatic larvae of Chironomus riparius based on gene expression assays related to the endocrine system, the stress response and ribosomes.

    PubMed

    Planelló, Rosario; Herrero, Oscar; Martínez-Guitarte, José Luis; Morcillo, Gloria

    2011-09-01

    In this work, the effects of butyl benzyl phthalate (BBP) and di(2-ethylhexyl) phthalate (DEHP), two of the most extensively used phthalates, were studied in Chironomus riparius under acute short-term treatments, to compare their relative toxicities and identify genes sensitive to exposure. The ecotoxicity of these phthalates was assessed by analysis of the alterations in gene expression profiles of selected inducible and constitutive genes related to the endocrine system, the cellular stress response and the ribosomal machinery. Fourth instar larvae, a model system in aquatic toxicology, were experimentally exposed to five increasing concentrations (0.01, 0.1, 1, 10, and 100mg/L) of DEHP and BBP for 24h. Gene expression was analysed by the changes in levels of transcripts, using RT-PCR techniques with specific gene probes. The exposures to DEHP or BBP were able to rapidly induce the hsp70 gene in a concentration-dependent manner, whereas the cognate form hsc70 was not altered by either of these chemicals. Transcription of ribosomal RNA as a measure of cell viability, quantified by the levels of ITS2, was not affected by DEHP, but was slightly, yet significantly, downregulated by BBP at the highest concentrations tested. Finally, as these phthalates are classified as endocrine disruptor chemicals (EDCs), their potential effect on the ecdysone endocrine system was studied by analysing the two genes, EcR and usp, of the heterodimeric ecdysone receptor complex. It was found that BBP provoked the overexpression of the EcR gene, with significant increases from exposures of 0.1mg/L and above, while DEHP significantly decreased the activity of this gene at the highest concentration. These data are relevant as they show for the first time the ability of phthalates to interfere with endocrine marker genes in invertebrates, demonstrating their potential capacity to alter the ecdysone signalling pathway. Overall, the study clearly shows a differential gene-toxin interaction

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

    PubMed Central

    Gunderina, Larisa; Golygina, Veronika; Broshkov, Andrey

    2015-01-01

    Abstract Chromosomal localization of ribosomal RNA coding genes has been studied by using FISH (fluorescence in situ hybridization) in 21 species from the genus Chironomus Meigen, 1803. Analysis of the data has shown intra- and interspecific variation in number and location of 5.8S rDNA hybridization sites in 17 species from the subgenus Chironomus and 4 species from the subgenus Camptochironomus Kieffer, 1914. In the majority of studied species the location of rDNA sites coincided with the sites where active NORs (nucleolus organizer regions) were found. The number of hybridization sites in karyotypes of studied chironomids varied from 1 to 6. More than half of the species possessed only one NOR (12 out of 21). Two rDNA hybridization sites were found in karyotypes of five species, three – in two species, and five and six sites – in one species each. NORs were found in all chromosomal arms of species from the subgenus Chironomus with one of them always located on arm G. On the other hand, no hybridization sites were found on arm G in four studied species from the subgenus Camptochironomus. Two species from the subgenus ChironomusChironomus balatonicus Devai, Wuelker & Scholl, 1983 and Chironomus “annularius” sensu Strenzke, 1959 – showed intraspecific variability in the number of hybridization signals. Possible mechanisms of origin of variability in number and location of rRNA genes in the karyotypes of species from the genus Chironomus are discussed. PMID:26140162

  9. Comparative analysis of karyotypes of Chironomus solitus Linevich & Erbaeva, 1971 and Chironomus anthracinus Zetterstedt, 1860 (Diptera, Chironomidae) from East Siberia

    PubMed Central

    Proviz, Valentina

    2015-01-01

    Abstract A comparative chromosome banding analysis of Chironomus solitus Linevich & Erbaeva, 1971 and Chironomus anthracinus Zetterstedt, 1860 from East Siberia (Lakes Baikal, Gusinoe, Arakhley and Irkutsk Reservoir) showed close similarity of banding sequences. Chironomus solitus differs from Chironomus anthracinus in one species-specific sequence of arm B. Arms C (43%) and D (30%) had inversion banding sequences previously reported in Chironomus anthracinus The similarity of karyotypic features of Chironomus solitus and Chironomus anthracinus in combination with morphological features of larvae provide evidence in favour of including Chironomus solitus in the Chironomus anthracinus group of sibling species long with Chironomus reservatus Shobanov, 1997. PMID:26140165

  10. 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

  11. Six new species of Microdon Meigen from Madagascar (Diptera: Syrphidae).

    PubMed

    Reemer, Menno; Bot, Sander

    2015-10-28

    Six new species of the myrmecophilous hoverfly genus Microdon Meigen (Diptera: Syrphidae) are described from Madagascar. Redescriptions are given for the three other Madagascan species of this genus. Keys are presented to the Madagascan genera of the subfamily Microdontinae and to the Madagascan species of Microdon.

  12. The ultrastructure of the non-neurosecretory components in the brain of the midge, Chironomus riparious Mg. (diptera: nematocera).

    PubMed

    Scales, M D; Credland, P F

    1978-02-24

    The ultrastruct of the neural sheath, glial cells and neurons in the brain of the neoimaginal male Chironomus riparius is described. The neural sheath comprises a neural lamella and underlying perineurium. The neural lamella consists of an amorphous matrix in which fine fibrils occur. The perineurium is composed of two cell types forming a continuous layer around the brain. The subjacent cortical layer, composed of the cell bodies of neurons and glial cells, varies considerably in thickness and surrounds the centrally located neuropiles. Three types of glial cells are distinguished on the basis of their positions and appearances. Five types of neurons are described which differ in size and relative frequency of organelles. Four types of axons, including those of neurosecretory cells, are distinguished by their size and content.

  13. [The correct writing and pronunciation of the generic name Aedes Meigen, 1818].

    PubMed

    Zamburlini, R

    1995-12-01

    The generic name Aedes Meigen, 1818 (Diptera, Culicidae) is derived from the latinisation of the ancient Greek word [symbol: see text] which means unpleasant, annoying, irritant. The correct latin pronunciation is "a-edes".

  14. 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)

  15. Chironomus calligraphus (Diptera: Chironomidae), a new pest species in Georgia.

    PubMed

    Gray, Elmer W; Royals, Candace; Epler, John H; Wyatt, Roger D; Brewer, Ben; Noblet, Ray

    2012-09-01

    Chironomid midges are ubiquitous and ecologically important aquatic insects. However, some species can become pests when they occur in extremely high numbers, particularly those that colonize man-made habitats. Chironomus calligraphus is a Neotropical, pan-American species that has recently been found in the Nearctic region. This paper represents the 1st reported occurrence of C. calligraphus in Georgia. Extensive larval populations were found in the leaf sheaths and root masses of cattails and in the firm sandy substrates of a wastewater lake at an industrial site in coastal Georgia. Chironomus calligraphus was causing a significant economic impact at this site.

  16. On the identity of Prochyliza nigrimana (Meigen) and Prochyliza nigricornis (Meigen) (Diptera: Piophilidae), with a synopsis of Prochyliza Walker and description of a new species.

    PubMed

    Martín-Vega, Daniel

    2014-12-08

    With representatives distributed throughout the Holarctic and Neotropical regions, the genus Prochyliza Walker (Diptera: Piophilidae) is known from eight species. There has been, however, considerable controversy over the identity of two of them: the common, synanthropic species Prochyliza nigrimana (Meigen), and the rarely collected Prochyliza nigricornis (Meigen). The described differences between both species were only based on body colouration but, since a wide colour variation has been documented among P. nigrimana individuals, several authors had suggested that both taxa might be just extreme colour variants of the same species. Recent collections from central Spain showed that the colouration characters described for P. nigricornis certainly apply to dark P. nigrimana individuals, but also to other Prochyliza specimens showing distinct morphological characters and genitalia. In order to solve this controversy, the holotypes of both P. nigrimana and P. nigricornis were studied, concluding that both specimens are conspecific and instating P. nigricornis as a subjective junior synonym (syn. nov.). A new species, Prochyliza georgekaplani sp. nov., is described from specimens collected in central Spain. A synopsis and an updated identification key to the known species of the genus Prochyliza are also provided.

  17. Redescription of Chironomus javanus and Chironomus kiiensis (Diptera: Chironomidae) Larvae and Adults Collected from a Rice Field in Pulau Pinang, Malaysia

    PubMed Central

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

    2012-01-01

    Chironomus javanus (Kieffer) and Chironomus kiiensis Tokunaga were redescribed from materials collected from a rice field in Pulau Pinang, Malaysia. The larvae can only be distinguished after careful preparation and examination using a compound microscope, but the pupae were not useful to differentiate C. javanus from C. kiiensis. The adult specimens showed clear body and wing characteristics for rapid and accurate identification. PMID:24575227

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

    PubMed

    Polevoi, Alexei; Salmela, Jukka

    2016-04-15

    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.

  19. 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

    2014-07-29

    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. 

  20. Comparative evaluation of the sensitivity of Hyallela azteca and Chironomus tentans for use in freshwater toxicity tests

    SciTech Connect

    Cappellino, S.; Brix, K.V.; Andreasen, E.

    1994-12-31

    Laboratory studies were conducted to assess the bioavailability of contaminants in a creek located in western Washington. Bioassays were conducted on eighteen sediment samples using the amphipod Hyallela azteca and the midge Chironomus tentans. The Hyallela test was a standard 10-day acute test with survival as the test endpoint. The Chironomus test was a 30-day chronic test evaluating both survival and adult emergence. Results from these bioassays showed Chironomus emergence to be the most sensitive endpoint, followed by Chironomus survival and Hyallela survival, respectively.

  1. A review of the genus Drymeia Meigen, 1826 (Diptera: Muscidae) in Russia.

    PubMed

    Sorokina, Vera S; Pont, Adrian C

    2015-08-14

    A key is provided to the 26 species of the genus Drymeia Meigen, 1826 known from Russia and four additional species that may be found in Russia (D. brumalis (Rondani, 1866), D. cantabrigensis (Huckett, 1965), D. gymnophthalma (Hennig, 1963), D. similis (Malloch, 1918)). The key includes the 10 new species here described from the mountains of South Siberia (D. acrostichalis sp. nov., D. aristata sp. nov., D. cilitarsis sp. nov., D. glabra sp. nov., D. grandis sp. nov., D. grisea sp. nov., D. longiseta sp. nov., D. phaonina sp. nov., D. puchokana sp. nov., D. triseta sp. nov.,) and other two new species from the Russian Arctic (D. cristata sp. nov., D. taymirensis sp. nov.). Five species (D. fasciculata (Stein, 1916), D. firthiana (Huckett, 1965), D. groenlandica (Lundbeck, 1901), D. quadrisetosa (Malloch, 1919), D. neoborealis (Snyder, 1949)) are newly recorded from Russia. Three new synonymies are proposed: D. pribilofensis (Malloch, 1921) (syn: D. inaequalis (Malloch, 1922)), D. setibasis (Huckett, 1965) (syn: D. gymnophthalma sibirica (Lavčiev, 1971, unavailable junior secondary homonym) and D. quadrisetosa (Malloch, 1919) (syn: D. amurensis (Lavčiev, 1971)). The male terminalia and the female ovipositors of the new species are illustrated. New faunistic data are given for some previously described species of Russian Drymeia.

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

    PubMed

    Shamshev, Igor; Grootaert, Patrick; Kustov, Semen

    2015-03-23

    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.

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

    PubMed

    Cumming, Heather J; Wheeler, Terry A

    2016-05-18

    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.

  4. Fine structure of Delia platura (Meigen) (Diptera: Anthomyiidae) revealed by scanning electron microscopy.

    PubMed

    Wang, Qi-Ke; Yang, Yan-Zhi; Liu, Mei-Qin; Zhang, Dong

    2014-08-01

    Delia platura (Meigen) is a phytophagous fly that can cause significant crop losses. To obtain a better understanding of the external morphology of this species, adult D. platura is studied using scanning electron microscopy. Organs or structures that are important for taxonomy, such as the compound eyes, spiracles, pulvilli, wings, and genitalia are highlighted to complement previous description based on light microscope. Mesothoracic and metathoracic spiracles of D. platura that provide efficiency in preventing entrance of fine materials or dust into the tracheal system are morphologically different. In addition, the elongate-oval pulvillus is densely covered with tenent setae with spoon-like tip, which can increase the number of contact points for attachment to a surface. Four types of sensilla are observed on the male genitalia of D. platura including: trichoid sensilla, chaetic sensilla, three subtypes of campaniform sensilla, and basiconic sensilla. Long bristles and microtrichiae are observed on the female genitalia of D. platura. The possible function of sensilla located in the genitalia of D. platura is discussed. Microsc. Res. Tech. 77:619-630, 2014. © 2014 Wiley Periodicals, Inc.

  5. Mechanical transmission of porcine reproductive and respiratory syndrome virus by mosquitoes, Aedes vexans (Meigen)

    PubMed Central

    Otake, Satoshi; Dee, Scott A.; Rossow, Kurt D.; Moon, Roger D.; Pijoan, Carlos

    2002-01-01

    The objective of this study was to determine whether porcine reproductive and respiratory syndrome virus (PRRSV) could be transmitted to naïve pigs by mosquitoes following feeding on infected pigs. During each of 4 replicates, mosquito-to-pig contact took place on days 5, 6, and 7 after PRRSV infection of the donor pig. A total of 300 mosquitoes [Aedes vexans (Meigen)] were allowed to feed on each viremic donor pig, housed in an isolation room. After 30 to 60 s, feeding was interrupted, and the mosquitoes were manually transferred in small plastic vials and allowed to feed to repletion on a naïve recipient pig housed in another isolation room. Prior to contact with the recipient pig, the mosquitoes were transferred to clean vials. Swabs were collected from the exterior surface of all vials, pooled, and tested for PRRSV. Separate personnel handled the donor pig, the recipient pig, and the vial-transfer procedure. Transmission of PRRSV from the donor to the recipient pig occurred in 2 out of 4 replicates. The PRRSV isolated from the infected recipient pigs was nucleic-acid-sequenced and found to be 100% homologous with the virus used to infect the donor pigs. Homogenates of mosquito tissues collected in all replicates were positive by either polymerase chain reaction or swine bioassay. All control pigs remained PRRSV negative, and PRRSV was not detected on the surface of the vials. This study indicates that mosquitoes (A. vexans) can serve as mechanical vectors of PRRSV. PMID:12146891

  6. Mechanical transmission of porcine reproductive and respiratory syndrome virus by mosquitoes, Aedes vexans (Meigen).

    PubMed

    Otake, Satoshi; Dee, Scott A; Rossow, Kurt D; Moon, Roger D; Pijoan, Carlos

    2002-07-01

    The objective of this study was to determine whether porcine reproductive and respiratory syndrome virus (PRRSV) could be transmitted to naive pigs by mosquitoes following feeding on infected pigs. During each of 4 replicates, mosquito-to-pig contact took place on days 5, 6, and 7 after PRRSV infection of the donor pig. A total of 300 mosquitoes [Aedes vexans (Meigen)] were allowed to feed on each viremic donor pig, housed in an isolation room. After 30 to 60 s, feeding was interrupted, and the mosquitoes were manually transferred in small plastic vials and allowed to feed to repletion on a naïve recipient pig housed in another isolation room. Prior to contact with the recipient pig, the mosquitoes were transferred to clean vials. Swabs were collected from the exterior surface of all vials, pooled, and tested for PRRSV. Separate personnel handled the donor pig, the recipient pig, and the vial-transfer procedure. Transmission of PRRSV from the donor to the recipient pig occurred in 2 out of 4 replicates. The PRRSV isolated from the infected recipient pigs was nucleic-acid-sequenced and found to be 100% homologous with the virus used to infect the donor pigs. Homogenates of mosquito tissues collected in all replicates were positive by either polymerase chain reaction or swine bioassay. All control pigs remained PRRSV negative, and PRRSV was not detected on the surface of the vials. This study indicates that mosquitoes (A. vexans) can serve as mechanical vectors of PRRSV.

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

    PubMed

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

    2014-07-29

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

  8. 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.

  9. Possible genetic basis of pederin polymorphism in rove beetles (Paederus riparius).

    PubMed

    Kellner, R L

    2000-01-01

    In Paederus riparius, (+) females able to biosynthesize the unique hemolymph toxin pederin and (-) females lacking this ability co-occur in natural populations. Larvae descended from both types of females were reared in the laboratory and the imagoes were crossed in order to get information about a possible genetic basis of this polymorphism. The daughters of (+) mothers become (+) females or (-) females, while the progeny of (-) mothers comprises only (-) females. This suggests a matrilineal trait because pederin biosynthesis cannot be inherited from the father. The rather stable proportion of nearly 90% (+) females in collected females is not maintained, however, when the beetles are reared in the laboratory. This observation is discussed with regard to artificial rearing conditions, where individuals are kept separate and cannot prey on conspecifics.

  10. 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

    2015-07-03

    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.

  11. 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...

  12. 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...

  13. Ceriodaphnia and Chironomus in situ toxicity tests assessing the wastewater treatment efficacy of constructed wetlands

    SciTech Connect

    Barjaktarovic, L.; Nix, P.; Gulley, J.

    1995-12-31

    In situ toxicity tests were designed for Ceriodaphnia dubia and Chironomus tentans as part of a larger study designed to assess the effectiveness of constructed wetlands for the treatment of wastewater produced by oil production at Suncor OSG. The artificial wetlands were 50m long by 3m wide, with three replicates of the control and the treatment. Each wetland had four sample sites equidistant along its length, creating a gradient of treatment from site A being the most toxic to site D being the least toxic. Each test was conducted twice during the summer of 1994. Both the Ceriodaphnia and Chironomus test cages were a flow through design to allow for maximal exposure to the water within the wetlands. Mortality and reproduction were used as endpoints for Ceriodaphnia, whereas mortality and growth were used as endpoints for the Chironomus test. Test durations were fifteen and ten days respectively. Chironomus had very high mortality along the entire wetlands whereas Ceriodaphnia survival and fecundity increased along the length of the treatment wetlands. Both organisms had low mortality and high growth/fecundity in the control wetlands.

  14. 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...

  15. 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 ...

  16. Gastromermis kolleonis n. sp. (Nematoda: Mermithidae), a Parasite of Midges (Chironomus sp. Chironomidae) from Argentina

    PubMed Central

    de Doucet, Maria M. A.; Poinar, George O.

    1984-01-01

    Gastromermis kolleonis n. sp. (Nematoda: Mermithidae) is described from the Arroyo Saldan River in Córdoba, Argentina. This species parasitizes midges of the genus Chironomus (Chironomidae: Diptera). It is distinguished from other members of the genus by the presence of six longitudinal chords, vulval flaps, degree of ventral displacement of the mouth, and size and shape of the spicule and amphids. PMID:19294020

  17. Using Frons Width to Differentiate Blow Fly Species (Diptera: Calliphoridae) Phormia regina (Meigen) and Protophormia terraenovae (Robineau-Desvoidy).

    PubMed

    Langer, Sarah V; Kyle, Christopher J; Beresford, David V

    2017-03-01

    Protophormia terraenovae (Robineau-Desvoidy) (Diptera: Calliphoridae) and Phormia regina (Meigen) (Diptera: Calliphoridae) are morphologically similar blow fly species commonly used for estimating postmortem intervals. Field collection and storage of adults can result in color changes, in particular on calypters and palps; often collected specimens show damage such as wing fray or fungal growth. We measured the frons width: total head width ratio using photographs (ImageJ version 1.49) to differentiate these two species. Both sexes were distinguishable to species, with the greatest difference between males: 12.34% P. terraenovae versus 1.62% P. regina, less so for females: 40.25% P. terraenovae, versus 33.65% P. regina. Incorporating this feature into future blow fly keys would help with distinguishing field-caught specimens when other features are obstructed.

  18. Changes in the morphology and presumptive chemistry of impact and pooled bloodstain patterns by Lucilia sericata (Meigen) (Diptera: Calliphoridae).

    PubMed

    Fujikawa, Amanda; Barksdale, Larry; Higley, Leon G; Carter, David O

    2011-09-01

    Bloodstain pattern analysis can be critical to accurate crime scene reconstruction. However, bloodstain patterns can be altered in the presence of insects and can confound crime scene reconstruction. To address this problem, we conducted a series of controlled laboratory experiments to investigate the effect of Lucilia sericata (Meigen) on impact bloodstains and pooled bloodstains in association with three combinations of common surfaces (linoleum/painted drywall, wood floor/wallpaper, and carpet/wood paneling). L. sericata fed from the pooled bloodstains and added insect stains through regurgitation and defecation of consumed blood. L. sericata formed defecatory trails of insect stains that indicated directionality. Defecatory stains fluoresced when viewed at 465 nm with an orange filter. These observations differed from Calliphora vicina insect stains because feeding on blood spatter was not observed and trails of insect stains were formed by L. sericata. The fluorescence of defecatory stains can be used as a method to detect insect stains and discriminate them from real bloodstains.

  19. Mineral deposition in bacteria-filled and bacteria-free calcium bodies in the crustacean Hyloniscus riparius (Isopoda: Oniscidea).

    PubMed

    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.

  20. 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.

  1. 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.

  2. A revision of the genus Pelecocera Meigen with the description of the male of pelecocera persiana Kuznetzov from Iran (Diptera: Syrphidae).

    PubMed

    Mengual, Ximo; Kazerani, Farzaneh; Talebi, Ali Asghar; Gilasian, Ebrahim

    2015-04-14

    The genus Pelecocera Meigen (Diptera: Syrphidae) is revised. Type material of most species was studied to describe, illustrate and delimit the male of Pelecocera persiana Kuznetzov, recently discovered from Iran. This is the first known specimen of this species since 1914, when the type female was collected. The diagnostic characters of P. persiana are provided, along with an identification key for Pelecocera species. The lectotype of Pelecocera latifrons Loew is designated.

  3. Novel oligonucleotide probes for in situ detection of pederin-producing endosymbionts of Paederus riparius rove beetles (Coleoptera: Staphylinidae).

    PubMed

    Kador, Matthias; Horn, Marcus A; Dettner, Konrad

    2011-06-01

    Bacterial endosymbionts from female Paederus rove beetles are hitherto uncultured, phylogenetically related to Pseudomonas sp., and produce the polyketide pederin, which exhibits strong cytotoxic effects and antitumoral activities. The location of such endosymbionts inside beetles and on beetles' eggs is hypothesized based on indirect evidence rather than elucidated. Thus, an endosymbiont-specific and a competitor oligonucleotide probe (Cy3-labelled PAE444 and unlabelled cPAE444, respectively) were designed and utilized for FISH with semi-thin sections of Paederus riparius eggs. Cy3-PAE444-positive cells were densely packed and covered the whole eggshell. Hundred percent of EUB338-Mix-positive total bacterial cells were PAE444 positive, indicating a biofilm dominated by Paederus endosymbionts. Analysis of different egg deposition stadiums by electron microscopy and pks (polyketide synthase gene, a structural gene associated with pederin biosynthesis)-PCR supported results obtained by FISH and revealed that the endosymbiont-containing layer is applied to the eggshell inside the efferent duct. These findings suggest that P. riparius endosymbionts are located inside unknown structures of the female genitalia, which allow for a well-regulated release of endosymbionts during oviposition. The novel oligonucleotide probes developed in this study will facilitate (1) the identification of symbiont-containing structures within genitalia of their beetle hosts and (2) directed cultivation approaches in the future.

  4. New insight into the Delia platura Meigen caused alteration in nutrient content of soybean (Glycine max L. Merill).

    PubMed

    Bosnyákné, Helga Egri; Kerepesi, Ildikó; Keszthelyi, Sándor

    2016-09-01

    Climate change has brought about an increasing level of seedcorn maggot (Delia platura Meigen, 1826) (Diptera: Anthomyiidae) damage in Hungary. In order to have a more accurate understanding of the effects of these plant injuries induced by the larvae of D. platura, the nutrient content of soybean (Glycine max L. Merill.) was studied. Our results show that the moisture, raw fat, raw fibre, and raw ash content of the batches damaged by D. platura were significantly less in comparison with that of the control samples. In response to the deleterious effect of the insect, the infected soybean plants showed forced ripening (P = 0.004) (P > 0.05). The difference of moisture content between damaged and control samples was 2.30% on average. The fact of nutritional value loss was also reflected by the alteration of sugar mobilisation. As the result of this experiment the sucrose breakdown to glucose and fructose during the germination was significantly slower in the damaged seeds than that of the control ones. Overall, this late and surprising damage caused by D. platura led to the forced ripening of the affected soybean plants and a significant change in their nutritional values. Based on the herein reported results, it is presumable that in cases when the current climatic extremities, which are envisaged to occur more frequently in the future, and effects of agricultural practices will be coincided in the future a qualitative change of the produced soybean batches can be expected through the damage caused by this fly species.

  5. Localization of chromosomal protein HMG-1 in polytene chromosomes of Chironomus thummi

    PubMed Central

    1981-01-01

    The distribution of accessible antigenic sites in the chromosomal protein high mobility group one (HMG-1) in Chironomus thummi polytene chromosomes is visualized by immunofluorescence. The results indicate that (a) HMG-1 is distributed in a distinct banding pattern along the entire length of the chromosomes; (b) the banding pattern obtained with fluorescent antibody does not strictly correspond to that observed by phase-contrast microscopy; and (c) the amount of HMG-1 increases, and the fluorescent banding pattern changes, during the development of the organism. Our findings suggest that the protein may be involved in the modulation of the structure of selected loci in the chromosome. PMID:6453126

  6. Origin and development of the tergotrochanteral muscle in Chironomus (Diptera: Nematocera).

    PubMed

    Lebart-Pedebas, M C

    1992-01-01

    The origin and the development of the tubular tergo-trochanteral muscle (TTD) was studied by light and electron microscopy in Chironomus (Diptera: Nematocera). Unlike the flight muscles, the TTD was found to develop from myoblasts located around a larval axon, without contribution from a larval muscle. The myoblasts fuse together to form myotubes. Innervation of the TTD arises from the larval axon. The myotubes send out sarcoplasmic extensions towards the axon branches issued from the larval axon. The first differentiated synapses are described. The TTD begins to grow later than the flight muscles. The implications of this developmental lag are discussed.

  7. 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

  8. Acute and chronic effects of magnetic microparticles potentially used in lake restoration on Daphnia magna and Chironomus sp.

    PubMed

    Álvarez-Manzaneda, I; Ramos-Rodríguez, E; López-Rodríguez, M J; Parra, G; Funes, A; de Vicente, I

    2017-01-15

    Magnetic microparticles (MPs) have been recently proposed as a new and promising tool for restoring eutrophicated waters. In this study, we analyzed the acute (immobilization) and chronic effects of iron (Fe) MPs on Daphnia magna and on the benthic macroinvertebrate Chironomus sp. In the chronic toxicity tests the offspring production (male and female) in D. magna and the mortality of larvae and pupae, and adult emergence in Chironomus sp. experiments were used as the endpoints. The concentration of MPs that caused 50% of immobilized individuals (EC50) in the acute toxicity test was much higher in D. magna (0.913g MPs l(-1)) than in Chironomus sp. (0.445g MPs l(-1)). The results of chronic toxicity tests in D. magna showed that in presence of dissolved Fe (dFe), parthenogenetic reproduction was significantly affected, while no significant effect on mortality of larvae and pupae and on adult emergence was detected in Chironomus sp. test. Taking into account both that long-term exposure is not likely to occur and the regular dose of MPs potentially used in a restoration plan, we conclude that MPs is a riskless (no toxic effect on planktonic and benthic organisms) and efficient (high P adsorption capacity) tool for lake restoration.

  9. Origin and development of the dorso-ventral flight muscles in Chironomus (Diptera; Nematocera).

    PubMed

    Lebart-Pedebas, M C

    1990-01-01

    The origin and development of the dorso-ventral flight muscles (DVM) was studied by light and electron microscopy in Chironomus (Diptera; Nematocera). Chironomus was chosen because unlike Drosophila, its flight muscles develop during the last larval instar, before the lytic process of metamorphosis. Ten fibrillar DVM were shown to develop from a larval muscle associated with myoblasts. This muscle is connected to the imaginal leg disc so that its cavity communicates with the adepithelial cells present in the disc; but no migration of myoblasts seems to take place from the imaginal leg disc towards the larval muscle or vice versa. At the beginning of the last larval instar, the myoblasts were always present together with the nerves in the larval muscle. In addition, large larval muscle cells incorporated to the imaginal discs were observed to border on the area occupied by adepithelial cells, and are probably involved in the formation of 4 other fibrillar DVM with adepithelial cells. Three factors seem to determine the number of DVM fibres: the initial number of larval fibres in the Anlage, the fusions of myoblasts with these larval fibres and the number of motor axons in the Anlage. The extrapolation of these observations to Drosophila, a higher dipteran, is discussed.

  10. 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...

  11. 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.

  12. A repetitive DNA sequence associated with the centromeres of Chironomus pallidivittatus.

    PubMed Central

    Rovira, C; Beermann, W; Edström, J E

    1993-01-01

    A clone containing centromere-associated DNA from Chironomus pallidivittatus was obtained by microdissection-microcloning. It hybridizes to the centromeric end of one chromosome and exclusively to regions in the three remaining, metacentric chromosomes to which centromeres have previously been localized on cytological grounds. In the metacentric positions the hybridization can be assigned to thin bands. The clone contains 155bp tandem repeats and short flanking regions represented in all of the centromeres. Titration experiments show that the four centromeres together contain 200kb of 155bp repeat per genome. In a line of tissue culture cells the amounts are increased by a factor 1.5-2, resulting in proportionately extended arrays of tandem repeats. Each repeat contains two invertrepeats surrounding a region containing only AT base pairs, a feature with some similarity to functionally essential elements in the Saccharomyces cerevisiae centromere. Images PMID:8493096

  13. Genotoxicity of heavy metals to the larvae of Chironomus kiiensis Tokunaga after short-term exposure.

    PubMed

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

    2012-09-01

    The genotoxic effects of increasing concentrations (below lethal concentration [LC₅₀]) of cadmium ([Cd] 0.1, 1 and 10 mg/L), copper ([Cu] 0.2, 2 and 20 mg/L) and zinc ([Zn] 0.5, 5 and 50 mg/L) on Chironomus kiiensis were evaluated using alkaline comet assay after exposure for 24 h. Both the tail moment and the olive tail moment showed significant differences between the control and different concentrations of Cd, Cu and Zn (Kruskal-Wallis, p < 0.05). The highest concentration of Cd was associated with higher DNA damage to C. kiiensis larvae compared with Cu and Zn. The potential genotoxicity of these metals to C. kiiensis was Cd > Cu > Zn.

  14. 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).

  15. Toxicity of hexachlorobenzene to Hyalella azteca and Chironomus tentans in spiked sediment bioassays

    SciTech Connect

    Barber, T.R.; Fuchsman, P.C.; Chappie, D.J.; Sferra, J.C.; Sheehan, P.J.

    1997-08-01

    Fourteen-day, whole-sediment toxicity tests using the amphipod Hyalella azteca and the midge Chironomus tentans were conducted on spiked sediment samples representing a range of hexachlorobenzene (HCB) concentrations. High rates of survival and growth relative to controls were observed in both test species. No observed effects concentrations (NOECs) were equal to the highest HCB concentration tested (42 mg/kg, normalized to 1% total organic carbon). Available literature on the aquatic toxicity of this hydrophobic chemical shows an absence of lethal and sublethal effects from exposure to HCB or below water solubility concentrations, and toxicity from exposure to dissolved HCB in sediment porewater therefore would not be expected. Because whole-sediment toxicity tests integrate exposure to HCB dissolved in porewater and adsorbed to particles, it was considered possible that exposure via sediment ingestion could cause toxicity; however, no such effect was observed in this study.

  16. 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.

  17. Heat shock regulatory elements are present in telomeric repeats of Chironomus thummi.

    PubMed

    Martinez, J L; Sanchez-Elsner, T; Morcillo, G; Diez, J L

    2001-11-15

    As in other Diptera, the telomeres of Chironomus thummi lack canonical short telomerase-specified repeats and instead contain complex sequences. They react to heat shock and other stress treatments by forming giant puffs at some chromosome termini, which are visible in polytene cells. All telomeres, except the telocentric end of chromosome four (4L), consist of large blocks of repeats, 176 bp in length. Three subfamilies of telomeric sequences have been found to show different distribution patterns between chromosome ends. TsA and TsC are characteristic of telomeres 3R and 4R, respectively, whereas TsB is present in the other non-telocentric telomeres. Heat shock transcription regulatory elements have been identified in the telomeric sequences, appearing differentially represented in the three subfamilies, but otherwise rather similar in size and sequence. Interestingly, TsA and TsB repeats share the well-conserved heat shock element (HSE) and GAGA motif, while the TATA box is only present in the former. Neither a HSE nor a TATA box appear in TsC repeats. Moreover, experimental data indicate that the HSE is functionally active in binding heat shock transcription factor (HSF). These results provide, for the first time, a molecular basis for the effect of heat shock on C.thummi telomeres and might also explain the different behaviour they show. A positive correlation between the presence of HSE and telomeric puffing and transcription under heat shock was demonstrated. This was also confirmed in the sibling species Chironomus piger. The significance of heat shock activation of telomeric repeats in relation to telomeric function is unknown at present, but it might be compared to the behaviour of other non-heat shock protein coding sequences, such as SINE-like and LINE-like retroelements, which have been reported to be activated by stress.

  18. A case of auricular, anal and umbilical myiasis caused by the larvae of Phormia regina (Meigen) (Diptera: Calliphoridae) in neonatal kittens.

    PubMed

    Pekmezci, Didem; Pekmezci, Gökmen Zafer; Açıcı, Mustafa; Gökalp, Güvenç; Tütüncü, Mehmet

    2014-01-01

    The occurrence of feline myiasis is rare. Massive infestations of dipteran larvae can lead to death if not treated at an early stage. Auricular, anal and umbilical myiasis was detected in three neonatal kittens. The dipteran larvae were collected, fixed in 70% alcohol and clarified with 10% KOH for a few days. Later, larvae were dissected under the stereomicroscope, mounted on slides and then identified as the third instar of the black blowfly, Phormia regina (Meigen) (Diptera: Calliphoridae), according to their stigmatic and cephaloskeleton structures. Original measurements and figures are presented. Treatment included mechanical removal of larvae and cleansing of the area by applying polyvinylpyrrolidone-iodine complex. The presence of P. regina in cats has been reported here for the first time in Turkey.

  19. Prevalence of vector-borne bacterial pathogens in riparian brush rabbits (Sylvilagus bachmani riparius) and their ticks.

    PubMed

    Schmitz, Kelly M; Foley, Janet E; Kasten, Rickie W; Chomel, Bruno B; Larsen, R Scott

    2014-04-01

    From June to October 2010, 48 endangered riparian brush rabbits (Sylvilagus bachmani riparius) were trapped at a captive propagation site in central California with the intention of release into re-established habitats. During prerelease examinations, ticks and blood samples were collected for surveillance for Rickettsia spp., Anaplasma phagocytophilum, Borrelia burgdorferi, and Bartonella spp. Ticks were identified, and DNA was extracted for PCR analysis. Serology was performed to detect exposure to Rickettsia spp., B. burgdorferi, and A. phagocytophilum. DNA was extracted from blood samples and analyzed for A. phagocytophilum using PCR assays. Rabbit blood samples were also cultured for Bartonella spp. Haemaphysalis leporispalustris ticks were detected on all rabbits except one. A total of 375 ticks were collected, with 48% of the rabbits (23 rabbits) having a burden ranging from 0 to 5 ticks, 15% (seven rabbits) from 6 to 10 ticks, 25% (12 rabbits) from 11 to 15 ticks, and 12% (six rabbits) with >15 ticks. There was no evidence of B. burgdorferi or R. rickettsii in tick or rabbit samples. There was also no evidence of Bartonella spp. in the rabbit samples. Four tick samples and 14 rabbits were weakly PCR positive for A. phagocytophilum, and six rabbits were antibody positive for A. phagocytophilum. These results suggest that there may be little risk of these tick-borne diseases in riparian brush rabbits or to the people in contact with them.

  20. Reduced chromosomal puffing in Chironomus tentans as a biomarker for potentially genotoxic substances

    SciTech Connect

    Bentivegna, C.S. . Dept. of Environmental Sciences); Cooper, K.R. . Joint Graduate Program in Toxicology)

    1993-06-01

    Chromosomal puffing in the salivary glands of larval Chironomus tentans was developed as a biomarker for genotoxic substances. Reduced chromosomal puffing was considered an indication of decreased RNA synthesis. Third- or fourth-instar larvae were exposed to test chemicals in an artificial substrate under static conditions. Chromosomes from glands of individual larvae were stained with methyl green and pyronin Y. The widths of Balbiani rings 1 and 2 were measured. Three carcinogens with different mechanisms of action were tested, benzo[a] pyrene(BaP), actinomycin D(Act D), and dimethylnitrosamine (DMN). Puff size was statistically reduced by all three chemicals with varying potency. Lowest-observable-effect levels were 0.5 nmol BaP, 6.0 nmol Act D, and 24443,000 nmol DMN. The degree of response was influenced by exposure time, applied dose, individual sensitivity, and possibly chemical hydrophobicity. Biomarker specificity was determined by testing a weak carcinogen, benzo[e]pyrene(BeP), and an acutely toxic noncarcinogen, naphthalene(NP). The effective dose of BaP was four orders of magnitude higher than that of BaP. Only lethal doses of NP had statistically significant effects on puff size, LD50 = 25,000 nmol. Approximately 40% of the larvae in the laboratory population appeared tolerant to the effects of BaP. Advantages of this biomarker were its association with a known mechanism of action and measurement of the whole-organism integrated response.

  1. 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.

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

    PubMed

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

    2011-11-01

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

  3. SOURCES OF LARVAL SALIVARY GLAND SECRETION IN THE DIPTERAN CHIRONOMUS TENTANS

    PubMed Central

    Doyle, D.; Laufer, H.

    1969-01-01

    The soluble proteins in the hemolymph, the salivary gland, and the salivary secretion of fourth instar Chironomus tentans were examined by disc electrophoresis in acrylamide gels. Of the 11 protein fractions detected in buffered saline extracts of the gland, 10 are present also in the hemolymph. Amino acid isotope incorporation experiments indicate that the protein fractions shared by the salivary gland and the hemolymph are not synthesized in the gland but are synthesized in other larval tissues. Immunochemical studies show that most of these proteins eventually are secreted from the gland. The salivary gland in vivo and in vitro is active in de novo protein synthesis. The protein synthesized tends to form large molecular weight aggregates. As demonstrated by radioautography, at least 80% of this protein is secreted from the 30 large cells forming most of the gland. The proteins synthesized in the salivary gland cannot be detected in the hemolymph. The results of this investigation are consistent with a mechanism of secretion formation involving both de novo synthesis of some secretion proteins and the selective uptake, transport, and secretion of hemal proteins by the salivary gland. PMID:5782452

  4. Transcription and activation under environmental stress of the complex telomeric repeats of Chironomus thummi.

    PubMed

    Martínez-Guitarte, J L; Díez, J L; Morcillo, G

    2008-01-01

    In contrast to their traditional role, telomeres seem to behave as transcriptionally active regions. RNAs complementary to the short DNA repeats characteristic of telomerase-maintained telomeres have recently been identified in various mammalian cell lines, representing a new and unexpected element in telomere architecture. Here, we report the existence of transcripts complementary to telomeric sequences characteristic of Chironomus thummi telomeres. As in other Diptera, the non-canonical telomeres of chironomids lack the simple telomerase repeats and have instead more complex repetitive sequences. Northern blots of total RNA hybridized with telomere probes and RT-PCR with telomere-specific tailed primers confirm the existence of small non-coding RNAs of around 200 bp, the size of the DNA repeated telomeric unit. Telomere transcripts are heterogeneous in length, and they appear as a ladder pattern that probably corresponds to multimers of the repeat. Moreover, telomeres are activated under conditions of environmental stress, such as heat shock, appearing highly decondensed and densely labelled with acetylated H4 histone, as well as with RNA polymerase II antibodies, both marks of transcriptional activity. Changes in the expression levels of telomeric RNA were detected after heat shock. These findings provide evidence that transcriptional activity of the repetitive telomere sequences is an evolutionarily conserved feature, not limited to telomerase telomeres. The functional significance of this non-coding RNA as a new additional element in the context of telomere biology remains to be explained.

  5. 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.

  6. Comparison of the 10-day freshwater sediment toxicity tests using Hyalella azteca and Chironomus tentans

    SciTech Connect

    Becker, D.S.; Bigham, G.N.; Rose, C.D.

    1995-12-01

    Comparisons were made of the performance of the 10-d freshwater sediment toxicity tests using the amphipod Hyalella azteca and midge Chironomus tentans. Sediments were collected from eight stations in Onondaga Lake, New York, and represented a wide range of toxicity. The biological end points were survival, biomass, and body length. The two tests were compared on the basis of correspondence among relative values of the end points and ability to statistically discriminate adverse effects relative to control responses (i.e., discriminatory ability). Minimum detectable differences (MDDs) and adverse response ranges of the end points were used to further evaluate the discriminatory ability of the end points. Relative responses and discriminatory abilities of the end points of both tests were similar, despite numerous differences that exist among characteristics of the test species and end points. Significant concordance was found among all end points with respect to relative toxicity of sediments from the eight stations. Although MDDs and adverse response ranges of the various end points differed substantially, the observed positive correlation between those two variables resulted in all end points having similar discriminatory ability. Although amphipod biomass and body length have rarely been used as end points in 10-d tests, both end points provided results comparable to those of the other end points evaluated in the present study.

  7. 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.

  8. A revision of chromosome II (CD) mapping in Chironomus plumosus (Linnaeus, 1758) group (Diptera, Chironomidae)

    PubMed Central

    Golygina, Veronika V.; Kiknadze, I. I.

    2012-01-01

    Abstract A revision of the main and alternative banding sequences in chromosome II (CD) has been made for all 14 species of the Chironomus plumosus (Linnaeus, 1758)group. A new version of mapping has been suggested for 10 out of 18 banding sequences of arm C and 12 out of 22 banding sequences of arm D. Mapping of 7 banding sequences has been done for the first time according to the Keyl-Devai system. Phylogenetic relationships of banding sequences of chromosome II have been discussed. PMID:24260666

  9. 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.

  10. Chronic toxicity of the synthetic hormone 17alpha-ethinylestradiol to Chironomus tentans and Hyalella azteca.

    PubMed

    Dussault, Eve B; Balakrishnan, Vimal K; Solomon, Keith R; Sibley, Paul K

    2008-12-01

    The chronic toxicity of the synthetic hormone 17alpha-ethinylestradiol (EE2) was investigated in two benthic invertebrates, the midge Chironomus tentans and the freshwater amphipod Hyalella azteca, in life-cycle water-only assays. In C. tentans, a 50% decrease in emergence was observed at a concentration of 1.5 mg/L; emergence was a more sensitive endpoint than survival, growth, or biomass. Reproduction was not significantly affected by EE2 exposure until a concentration of 3.1 mg/L, where emergence, and therefore reproduction, did not occur. In contrast, reproduction was the most sensitive endpoint in H. azteca (50% decrease in reproduction observed at a concentration of 0.36 mg/L). The sensitivity of the F1 generation to EE2 was also investigated with H. azteca, but was not different from the F0 generation. The data from the present study were combined with those from previous 10-d toxicity assays, to derive acute to chronic toxicity ratios (ACRs) for EE2. The ACRs calculated for EE2 were 13 for C. tentans and 16 for H. azteca, indicating that the application factors currently used in ecological risk assessment for the derivation of chronic toxicity are protective and conservative for these organisms. The results of the present study suggest that chronic toxicity was not mediated by disruption of endocrine pathways. Using a hazard quotient approach, the risk associated with sublethal exposure to EE2 was <1 for H. azteca and C. tentans, indicating that adverse effects are not expected, and that environmental exposure to EE2 likely poses a low risk to benthic invertebrates.

  11. [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.

  12. 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.

  13. 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.

  14. 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.

  15. 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

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

    USGS Publications Warehouse

    Burton, G.A.; 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.

  17. 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

  18. Field validation of 10-day freshwater sediment toxicity tests using Hyalella azteca and Chironomus tentans

    SciTech Connect

    Becker, D.S.; Bigham, G.N.

    1995-12-31

    Two of the toxicity tests commonly used to evaluate freshwater sediments are the 10-day amphipod (Hyalella azteca) and chironomid (Chironomus tentans) tests. EPA and ASTM have recently developed standardized protocols for these tests. Although both tests are considered sensitive indicators of sediment toxicity, little information exists on how well test results correspond to adverse biological effects in the field. In this study, the lethal and sublethal (i.e., biomass) responses of the two toxicity tests were compared with alterations of benthic macroinvertebrate assemblages (i.e., benthic effects) at 56 stations in Onondaga Lake, New York. The lake has received municipal and industrial discharges for more than 100 years, and sediment chemical concentrations range widely throughout the lake. Toxicity results for Onondaga Lake were compared with reference conditions using the t-test, and benthic effects were determined using classification analysis of log-transformed taxa abundances. In general, a relatively high level of agreement was found between results of the toxicity tests and alterations of benthic assemblages. Significant (P < 0.05) correlations were found between all toxicity test endpoints and taxa richness of benthic assemblages. In addition, significant concordance (P {le} 0.01, binomial test) was found between toxicity designations for the 56 stations based on toxicity tests and toxicity designations based on benthic effects. Despite the general level of agreement among the various biological indicators, chironomid biomass and benthic effects were found to be the most sensitive indicators of toxicity, whereas amphipod survival and biomass were the least sensitive indicators. This study suggests that results of the 10-day amphipod and chironomid toxicity tests are highly predictive of adverse biological effects in the field.

  19. Population variability in Chironomus (Camptochironomus) species (Diptera, Nematocera) with a Holarctic distribution: evidence of mitochondrial gene flow.

    PubMed

    Martin, J; Guryev, V; Blinov, A

    2002-10-01

    Phylogenetic analysis of DNA sequences from mitochondrial (mt) genes (Cytochrome b and Cytochrome oxidase I) and one nuclear gene (globin 2b) was used for the investigation of Nearctic and Palearctic populations representing four Chironomus species of the subgenus Camptochironomus, namely C. biwaprimus, C. pallidivittatus, C. tentans sensu stricto and C. dilutus (the last two species constitute Holarctic C. tentans sensu lato). Phenograms constructed on the basis of mt sequences were not congruent with trees based on nuclear genes, or with morphological and cytological data. The mt tree divided the populations by continental region, rather than by the species groupings recognized by the other data sets. The incongruence is explained by mt gene flow resulting from hybridization between the sympatric species on each continent. Calculation of divergence times, based on the sequence data, suggest that C. tentans (s.l.) and C. pallidivittatus have both been in North America for about 2.5 My.

  20. 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.

  1. [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.

  2. Review and Synthesis of Bioassessment Methodologies for Freshwater Contaminated Sediments

    DTIC Science & Technology

    1990-01-01

    treatment effects, and safety considerations. The authors recommend three test species; Hyalella azteca, Chironomus tentans, and Chironomus riparius...given below. a. Hyalella azteca. Provide exposure at 200 C in I-L beakers or 20- aquaria for ᝺ days (short-term partial life cycle) or >10 days...benthic invertebrate bioassays. Three test species are recommended: Chironomus tentans, Hyalella azteca, and Hexa- genia limbata. See earlier discussions

  3. Effects of phenol on metabolic activities and transcription profiles of cytochrome P450 enzymes in Chironomus kiinensis larvae.

    PubMed

    Cao, C W; Sun, L L; Niu, F; Liu, P; Chu, D; Wang, Z Y

    2016-02-01

    Phenol, also known as carbolic acid or phenic acid, is a priority pollutant in aquatic ecosystems. The present study has investigated metabolic activities and transcription profiles of cytochrome P450 enzymes in Chironomus kiinensis under phenol stress. Exposure of C. kiinensis larvae to three sublethal doses of phenol (1, 10 and 100 µM) inhibited cytochrome P450 enzyme activity during the 96 h exposure period. The P450 activity measured after the 24 h exposure to phenol stress could be used to assess the level (low or high) of phenol contamination in the environment. To investigate the potential of cytochrome P450 genes as molecular biomarkers to monitor phenol contamination, the cDNA of ten CYP6 genes from the transcriptome of C. kiinensis were identified and sequenced. The open reading frames of the CYP6 genes ranged from 1266 to 1587 bp, encoding deduced polypeptides composed of between 421 and 528 amino acids, with predicted molecular masses from 49.01 to 61.94 kDa and isoelectric points (PI) from 6.01 to 8.89. Among the CYP6 genes, the mRNA expression levels of the CYP6EW3, CYP6EV9, CYP6FV1 and CYP6FV2 genes significantly altered in response to phenol exposure; therefore, these genes could potentially serve as biomarkers in the environment. This study shows that P450 activity combined with one or multiple CYP6 genes could be used to monitor phenol pollution.

  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. Rapid reformation of the thick chromosome fiber upon completion of RNA synthesis at the Balbiani ring genes in Chironomus tentans.

    PubMed

    Andersson, K; Mähr, R; Björkroth, B; Daneholt, B

    1982-01-01

    We have studied the ultrastructure of the Balbiani ring genes in Chironomus tentans during treatment with the RNA synthesis inhibitor DRB (5,6-dichloro-1-beta-D-ribofuranosyl-benzimidazole). This nucleoside analogue blocks transcription at or near the initiation site but does not interfere with the elongation and termination processes. In the ordinary active state the Balbiani ring genes display a 5 nm chromosome fiber, carrying densely distributed, growing ribonucleoprotein particles (Andersson et al., 1980). When the transcriptional activity declines, a 10 nm fiber can be observed between sparsely distributed RNA polymerases. Furthermore, after passage of the last RNA polymerase the 10 nm fiber can be seen as well as its gradual packing into a 25 nm thick fiber. Thus, the active chromosome fiber is rapidly packed into higher order structures when the fiber is not directly involved in transcription. The formation of the thick fiber does not require that the gene along its entire length is devoid of active RNA polymerases. The thick fiber can again be mobilized for transcription, since in reversion experiments the BR genes appear as ordinary active genes with an extended nucleofilament and densely packed nascent transcription products. The dynamic behaviour of the chromosome fiber during transcription is discussed as well as the packing and unpacking of a gene into higher order structures.

  6. 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.

  7. 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.

  8. Large-sized polysomes in Chironomus tentans salivary glands and their relation to Balbiani ring 75S RNA

    PubMed Central

    1977-01-01

    Polysomes from the salivary glands of Chironomus tentans were investigated to determine whether Balbiani ring 75S RNA is incorporated into polysomal structures, and thus probably acts as messenger RNA. A new extraction technique for obtaining ribonucleoproteins was applied that gives a high yield of polysomes with only moderate degradation of the cytoplasmic, high molecular weight RNA. The polysomes sedimented in a broad region (200-2,000S) with a peak value of about 700S, which suggested that they were partly of very large sizes. This was confirmed by visualization of the polysomes in the electron microscope: 400S polysomes contained mainly 11-16 ribosomes, and 1,500S polysomes about 60 ribosomes per polysome. However, polysomes containing 100 or more ribosomes were also observed. It was further established that most of the cytoplasmic 75S RNA was located in polysomes, preferentially in the most rapidly sedimenting ones. From the available information on Balbiani ring RNA in cytoplasm and the present demonstration of 75S RNA molecules in polysomes, it was concluded that at least some Balbiani ring RNA, generated as 75S RNA within the Balbiani rings, eventually enters polysomes without being measurably changed in size. The present information on the potential amino acid coding sequences in 75S RNA is discussed in relation to the large size of the polysomes observed. PMID:856829

  9. 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.

  10. Expression of heat shock protein and hemoglobin genes in Chironomus tentans (Diptera, chironomidae) larvae exposed to various environmental pollutants: a potential biomarker of freshwater monitoring.

    PubMed

    Lee, Soon-Mi; Lee, Se-Bum; Park, Chul-Hwi; Choi, Jinhee

    2006-11-01

    To identify a sensitive biomarker of freshwater monitoring, we evaluated pollutant-induced expression of heat shock proteins (HSPs) and hemoglobins (Hbs) genes in the larvae of the aquatic midge Chironomus tentans (Diptera, Chironomidae). As pollutants, we examined nonylphenol, bisphenol-A, 17alpha-ethynyl estradiol, bis(2-ethylhexyl) phthalate, endosulfan, paraquat dichloride, chloropyriphos, fenitrothion, cadmium chloride, lead nitrate, potassium dichromate, benzo[a]pyrene and carbon tetrachloride. We also investigated larval growth as a physiological descriptor by measuring changes in the body fresh weight and dry weight after chemical exposure. The response of the HSPs gene expression by chemical exposure was rapid and sensitive to low chemical concentrations but it was not stressor specific. Interestingly, an increase in the expression of HSPs genes was observed not only in a stress inducible form (HSP70), but also in a constitutively (HSC70) expressed form. The expression of Hb genes showed chemical-specific responses: that is, alkyl phenolic compounds increased the expression of hemoglobin genes, whereas pesticides decreased the expression. As expected, molecular-level markers were more sensitive than physiological endpoints, suggesting that gene expression could be developed as an early warning biomarker in this animal. The overall results suggest that the expression of HSP and Hb genes in Chironomus could give useful information for diagnosing general health conditions in fresh water ecosystem. The expression of Hb genes, in particular, seems to be a promising biomarker, especially in view of the potential of Chironomus larvae as a biomonitoring species and of the physiological particularities of their respiratory pigments.

  11. 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.

  12. [DNA reduplication cycle during chromosome polytenization in the salivary gland cells of Chironomus thummi larvae. III. The determination of the duration of the DNA synthesis period].

    PubMed

    Gundrina, L I; Sherudilo, A I; Mitina, R L

    1984-08-01

    The duration of DNA synthesis in the salivary gland cells of Chironomus thummi larvae of the IV instar was determined by means of autoradiography and cytophotometry. Cells of different levels of ploidy differ in the duration of their DNA synthesis period. The tS of 2(10)c and 2(11)c cells was equal to 17 and 22 hours, respectively. The doubling of DNA content of the chironomid salivary gland cells leads to a 1.3 time increase in the duration of S-phase.

  13. 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.

  14. 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

  15. Two secretory protein genes in Chironomus tentans have arisen by gene duplication and exhibit different developmental expression patterns.

    PubMed

    Galli, J; Wieslander, L

    1993-05-20

    The salivary gland cells in the dipteran Chironomus tentans produce approximately 15 different secretory proteins, with relative molecular masses ranging between 1 x 10(4) and 1 x 10(6). Together these proteins form two types of extra corporal tubes, a larval protective housing and feeding tube or a pupation tube. The developmental change in tube formation is accompanied by a switch in production from one combination of secretory proteins to another. Here we characterize two genes, the sp38-40.A and B genes, which encode secretory proteins with relative molecular masses of 38,000 to 40,000. The two genes are located 346 base-pairs apart in the same orientation and have presumably arisen by gene duplication as the result of an illegitimate recombination event. Both genes contain two regions with cysteine codons, surrounded by regions with short repeats coding for proline and charged amino acid residues. The two genes and alleles of the genes differ in their number of repeats. This structure resembles the structure of the Balbiani ring (BR) genes, which encode the four largest salivary gland secretory proteins. The sp38-40.A and B genes are therefore likely to belong to a BR multigene family containing all or most of the 15 salivary gland secretory protein genes. The expression of the sp38-40.A and B genes are different: the A gene is expressed throughout the larval fourth instar but considerably less in the prepupal stage, while the B gene shows the opposite expression pattern. The developmental regulation of the expression of the two genes has therefore diverged after the gene duplication event.

  16. Selenium bioaccumulation and speciation in Chironomus dilutus exposed to water-borne selenate, selenite, or seleno-DL-methionine.

    PubMed

    Franz, Eric D; Wiramanaden, Cheryl I E; Janz, David M; Pickering, Ingrid J; Liber, Karsten

    2011-10-01

    The objective of the present study was to describe the uptake and elimination kinetics of selenium (Se) administered in the forms of selenate, selenite, and selenomethionine (seleno-DL-methionine) in different life stages of the midge Chironomus dilutus, and to determine the relationship between Se bioavailability and Se speciation using X-ray absorption spectroscopy (XAS). Midge larvae exposed to 4.3 µg/L as dissolved selenate for 10 d of had negligible accumulation of Se (indistinguishable from control organisms). However, larvae rapidly accumulated Se over 10 d of exposure to 3.8 and 1.8 µg/L selenite and seleno-DL-methionine (Se-met), respectively. Most Se accumulated by larvae exposed to selenite or Se-met was retained after 10 d of elimination in clean water. When additional midge larvae were exposed to Se until emergence, Se accumulated during the larval stage was largely retained in the adults. Although a strong correlation was found between the adult whole-body Se concentration and the Se concentration in the exuvia after emergence, only a minor loss of Se occurred in the shed exuvia compared with larvae and adult whole-body concentrations. X-ray absorption spectroscopy analysis showed that organic selenides and diselenides, modeled as Se-met and selenocystine, respectively, were the dominant forms of Se in both the larval and adult insect stages. The proportion and concentration of organic selenides (selenomethionine) increased in larvae and adults exposed to Se-met and selenite compared with larvae exposed to selenate, whereas the concentration of diselenides (selenocystine) remained relatively constant for all treatments.

  17. Bioaccumulation of the synthetic hormone 17alpha-ethinylestradiol in the benthic invertebrates Chironomus tentans and Hyalella azteca.

    PubMed

    Dussault, Eve B; Balakrishnan, Vimal K; Borgmann, Uwe; Solomon, Keith R; Sibley, Paul K

    2009-09-01

    The present study investigated the bioaccumulation of the synthetic hormone 17alpha-ethinylestradiol (EE2) in the benthic invertebrates Chironomus tentans and Hyalella azteca, in water-only and spiked sediment assays. Water and sediment residue analysis was performed by LC/MS-MS, while biota extracts were analyzed using both LC/MS-MS and a recombinant yeast estrogen receptor assay. At the lowest exposure concentration, C. tentans accumulated less EE2 than H. azteca in the water-only assays (p=0.0004), but due to different slopes, this difference subsided with increasing concentrations; at the exposure concentration of 1mg/L, C. tentans had a greater body burden than H. azteca (p=0.02). In spiked sediments, C. tentans had the greatest EE2 accumulation (1.2+/-0.14 vs. 0.5+/-0.05 microg/gdw, n=4). Measurements in H. azteca indicated a negligible contribution from the sediments to the uptake of EE2 in this species. These differences were likely due to differences in the behavior and life history of the two species (epibenthic vs. endobenthic). Water-only bioaccumulation factors (BAFs) calculated at the lowest exposure concentration were significantly smaller in C. tentans than in H. azteca (31 vs. 142, respectively; p<0.0001). In contrast, the sediment bioaccumulation factor (BSAF) of C. tentans was larger than that of H. azteca (0.8 vs. 0.3; p<0.0001). Extracts of the exposed animals caused a response in a recombinant yeast estrogen receptor assay, thus confirming the estrogenic activity of the samples, presumably from EE2 and its estrogenic metabolites. The results of the present study suggest that consumption of invertebrate food items could provide an additional source of exposure to estrogenic substances in vertebrate predators.

  18. 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.

  19. Unexpected homology between inducible cell wall protein QID74 of filamentous fungi and BR3 salivary protein of the insect Chironomus

    PubMed Central

    Rey, Manuel; Ohno, Susumu; Pintor-Toro, Jose A.; Llobell, Antonio; Benitez, Tahia

    1998-01-01

    A gene, qid74, of mycoparasitic filamentous fungus Trichoderma harzianum and its allies encodes a cell wall protein that is induced by replacing glucose in the culture medium with chitin (simulated mycoparasitism conditions). Because no trace of this gene can be detected in related species such as Gibberella fujikuroi and Saccharomyces cerevisiae, the qid74 gene appears to have arisen de novo within the genus Trichoderma. Qid74 protein, 687 residues long, is now seen as highly conserved tandem repeats of the 59-residue-long unit. This unit itself, however, may have arisen as tandem repeats of the shorter 13-residue-long basic unit. Within the genus Trichoderma, the amino acid sequence of Qid74 proteins has been conserved in toto. The most striking is the fact that Qid74 shares 25.3% sequence identity with the carboxyl-terminal half of the 1,572-residue-long BR3 protein of the dipteran insect Chironomus tentans. BR3 protein is secreted by the salivary gland of each aquatic larva of Chironomus to form a tube to house itself. Furthermore, the consensus sequence derived from these 59-residue-long repeating units resembles those of epidermal growth factor-like domains found in divergent invertebrate and vertebrate proteins as to the positions of critical cysteine residues and homology of residues surrounding these cysteines. PMID:9600944

  20. 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

  1. Comparative chronic toxicity of imidacloprid, clothianidin, and thiamethoxam to Chironomus dilutus and estimation of toxic equivalency factors.

    PubMed

    Cavallaro, Michael C; Morrissey, Christy A; Headley, John V; Peru, Kerry M; Liber, Karsten

    2017-02-01

    Nontarget aquatic insects are susceptible to chronic neonicotinoid insecticide exposure during the early stages of development from repeated runoff events and prolonged persistence of these chemicals. Investigations on the chronic toxicity of neonicotinoids to aquatic invertebrates have been limited to a few species and under different laboratory conditions that often preclude direct comparisons of the relative toxicity of different compounds. In the present study, full life-cycle toxicity tests using Chironomus dilutus were performed to compare the toxicity of 3 commonly used neonicotinoids: imidacloprid, clothianidin, and thiamethoxam. Test conditions followed a static-renewal exposure protocol in which lethal and sublethal endpoints were assessed on days 14 and 40. Reduced emergence success, advanced emergence timing, and male-biased sex ratios were sensitive responses to low-level neonicotinoid exposure. The 14-d median lethal concentrations for imidacloprid, clothianidin, and thiamethoxam were 1.52 μg/L, 2.41 μg/L, and 23.60 μg/L, respectively. The 40-d median effect concentrations (emergence) for imidacloprid, clothianidin, and thiamethoxam were 0.39 μg/L, 0.28 μg/L, and 4.13 μg/L, respectively. Toxic equivalence relative to imidacloprid was estimated through a 3-point response average of equivalencies calculated at 20%, 50%, and 90% lethal and effect concentrations. Relative to imidacloprid (toxic equivalency factor [TEF] = 1.0), chronic (lethality) 14-d TEFs for clothianidin and thiamethoxam were 1.05 and 0.14, respectively, and chronic (emergence inhibition) 40-d TEFs were 1.62 and 0.11, respectively. These population-relevant endpoints and TEFs suggest that imidacloprid and clothianidin exert comparable chronic toxicity to C. dilutus, whereas thiamethoxam induced comparable effects only at concentrations an order of magnitude higher. However, the authors caution that under field conditions, thiamethoxam readily degrades to

  2. Metabolite localization by atmospheric pressure high-resolution scanning microprobe matrix-assisted laser desorption/ionization mass spectrometry imaging in whole-body sections and individual organs of the rove beetle Paederus riparius.

    PubMed

    Bhandari, Dhaka Ram; Schott, Matthias; Römpp, Andreas; Vilcinskas, Andreas; Spengler, Bernhard

    2015-03-01

    Mass spectrometry imaging provides for non-targeted, label-free chemical imaging. In this study, atmospheric pressure high-resolution scanning microprobe matrix-assisted laser desorption/ionization mass spectrometry imaging (AP-SMALDI MSI) was used for the first time to describe the chemical distribution of the defensive compounds pederin, pseudopederin, and pederon in tissue sections (16 μm thick) of the rove beetle Paederus riparius. The whole-insect tissue section was scanned with a 20-μm step size. Mass resolution of the orbital trapping mass spectrometer was set to 100,000 at m/z 200. Additionally, organ-specific compounds were identified for brain, nerve cord, eggs, gut, ovaries, and malpighian tubules. To confirm the distribution of the specific compounds, individual organs from the insect were dissected, and MSI experiments were performed on the dissected organs. Three ganglia of the nerve cord, with a dimension of 250-500 μm, were measured with 10-μm spatial resolution. High-quality m/z images, based on high spatial resolution and high mass accuracy were generated. These features helped to assign mass spectral peaks with high confidence. Mass accuracy of the imaging experiments was <3 ppm root mean square error, and mapping of different compound classes from a single experiment was possible. This approach improved the understanding of the biochemistry of P. riparius. Concentration differences and distributions of pederin and its analogues could be visualized in the whole-insect section. Without any labeling, we assigned key lipids for specific organs to describe their location in the body and to identify morphological structures with a specificity higher than with staining or immunohistology methods.

  3. [Hemoglobins, XXXVII. The primary structure of a monomeric insect hemoglobin (Erythrocruorin), component CTT IIIa of Chironomus thummi thummi. An anomalous Heme complex: E7 Gln, E11 Ile].

    PubMed

    Steer, W; Braunitzer, G

    1981-01-01

    The primary structure of the monomeric hemoglobin CTT IIIa of the midge larva of Chironomus thummi thummi is presented. Cyanogenbromide peptides and tryptic peptides were used for sequence analysis. The primary structure was established with a small number of large peptides. The complete sequencing of the cyanogen bromide peptides was enabled by the C-terminal fixation of arginine. The primary structure of CTT IIIa is compared to the beta-chains of human and to the monomeric component CTT III: CTT IIIa possesses a "tail" of 9 amino acids on the N-terminus, and shows only a small number of identical residues compared to the number that other CTT hemoglobins share with each other. Also the heme complex is unusual: E7 Gln and E11 Ile.

  4. Responses of Hyalella azteca and Chironomus tentans to particle-size distribution and organic matter content of formulated and natural freshwater sediments

    SciTech Connect

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

    1994-10-01

    The freshwater amphipod, Hyalella azteca (Saussure), and midge, Chironomus tentans (Fabricius), were exposed to formulated sediments and nontoxic field-collected sediments for 10 d to determine their responses to varying sediment particle sizes and organic matter content of freshwater sediments. In experiments with formulated sediments, H. azteca survival was >80% when exposed for 10 d to all particle-size regimes examined. Subsequent exposures of H. azteca to field-collected sediments resulted in >80% H. azteca survival in all sediments. Field-collected sediments with organic matter content ranging from 0.12 to 7.8% yielded no observed effects on amphipod survival, which ranged from 84 to 100%. Survival of C. tentans ranged from 4 to 56% when exposed to formulated sediments for 10 d with 0% particulate organic matter content. A threshold organic matter content between 0.76 and 0.91% was observed for C. tentans exposed to formulated and field-collected sediments. Chironomus tentans survival was >80% in all cases when exposed to various particle-size regimes in formulated sediments containing 2.5% particulate organic matter. Formulated sediments were suitable for determining H. azteca and C. tentans responses to particle-size regimes and organic matter content of sediments, as test results using formulated and natural sediments were in agreement. Except for C. tentans observed intolerance of <0.76 to 0.91% organic matter content of sediments, C. tentans and H. azteca are suitable benthic toxicity testing organisms for determining the potential toxicity of sediments with a wide range of particle-size regimes and organic matter content.

  5. The ability of the blowflies Calliphora vomitoria (Linnaeus), Calliphora vicina (Rob-Desvoidy) and Lucilia sericata (Meigen) (Diptera: Calliphoridae) and the muscid flies Muscina stabulans (Fallén) and Muscina prolapsa (Harris) (Diptera: Muscidae) to colonise buried remains.

    PubMed

    Gunn, Alan; Bird, Jerry

    2011-04-15

    The blowflies Calliphora vomitoria (Linnaeus), Calliphora vicina (Rob-Desvoidy) and Lucilia sericata (Meigen) exhibited a limited ability to colonise pig liver baits buried in loose soil. Calliphora vomitoria colonised baits buried at 5 cm but no deeper whilst C. vicina and L. sericata colonised remains at 10 cm but not at 20 cm. The baits were colonised by larvae hatching from eggs laid on the surface of the soil. Both C. vomitoria and L. sericata were able to develop from eggs through to adulthood on baits that were infested before being buried and the larvae developed at similar rates and pupariated at similar depths to larvae developing on baits on the soil surface. The muscid flies Muscina stabulans (Fallén) and Muscina prolapsa (Harris) colonised remains buried in loose soil at a depth of 40 cm and even when presented with baits on the soil surface their larvae tended to remain in the soil beneath the baits. In compacted soil, M. stabulans colonised baits buried at 10 cm but M. prolapsa only colonised those buried at 5 cm. In both muscid species, the adult flies were instantly attracted to feed on fresh blood and laid eggs in the soil above buried baits within 30min of them being introduced into the cages. The adult muscid flies did not attempt to burrow into the soil and their larvae colonised the baits from eggs laid on the soil surface. This information could be useful in determining whether a body was stored above ground before being buried and/or the time since burial occurred.

  6. 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.

  7. 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.

  8. 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.

  9. Toxicokinetics of sediment-sorbed benzo[a]pyrene and hexachlorobiphenyl using the freshwater invertebrates Hyalella azteca, Chironomus tentans, and Lumbriculus variegatus.

    PubMed

    Schuler, Lance J; Wheeler, Matthew; Bailer, A John; Lydy, Michael J

    2003-02-01

    This study investigated the effect of long-term sediment aging on the toxicokinetics of benzo[a]pyrene (BaP) and hexachlorobiphenyl (HCBP) using three freshwater benthic invertebrates. Hyalella azteca, Chironomus tentans, and Lumbriculus variegatus were exposed to BaP- and HCBP-spiked sediments that were aged for 7 d or 1.5 years. The toxicokinetics of the two compounds were determined for each test organism using a two-compartment model. The modeling of BaP was more complex because biotransformation was included within the model. The results of this study showed that the HCBP uptake clearance rates (k(s)) for each species were generally an order of magnitude greater than those determined for BaP and this difference was most likely due to preferential and rapid binding of BaP to sediment particles. Overall, the bioavailability of HCBP in spiked sediments tended to decrease with duration of aging, based on k(s) values and bioaccumulation factors (BAFs). However, the decreases in bioavailability appear to be species specific. Benzo[a]pyrene did not decline in bioavailability for the species tested because it may resist movement into the micropores of the sediment due to its large size. In addition to the bioassays, this article outlines a method for toxicokinetic modeling of biotransformed compounds and methods for statistical comparisons of kinetic parameters (i.e., k(s), k(d)...) and BAF values.

  10. 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.

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

    PubMed

    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

    Relationships between sediment toxicity and sediment chemistry were evaluated for 98 samples collected from seven metropolitan study areas across the United States. Sediment-toxicity tests were conducted with the amphipod Hyalella azteca (28 day exposures) and with the midge Chironomus dilutus (10 day exposures). Overall, 33 % of the samples were toxic to amphipods and 12 % of the samples were toxic to midge based on comparisons with reference conditions within each study area. Significant correlations were observed between toxicity end points and sediment concentrations of trace elements, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), or organochlorine (OC) pesticides; however, these correlations were typically weak, and contaminant concentrations were usually below sediment-toxicity thresholds. Concentrations of the pyrethroid bifenthrin exceeded an estimated threshold of 0.49 ng/g (at 1 % total organic carbon) in 14 % of the samples. Of the samples that exceeded this bifenthrin toxicity threshold, 79 % were toxic to amphipods compared with 25 % toxicity for the samples below this threshold. Application of mean probable effect concentration quotients (PECQs) based on measures of groups of contaminants (trace elements, total PAHs, total PCBs, OC pesticides, and pyrethroid pesticides [bifenthrin in particular]) improved the correct classification of samples as toxic or not toxic to amphipods compared with measures of individual groups of contaminants.

  12. 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.

  13. 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; 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 United States Environmental Protection Agency 2000; ASTM American Society for Testing and Materials International 2012). Toxicity end points evaluated in the amphipod and midge exposures included the effects of these field-collected sediments on survival, weight, or biomass of the test organisms.

  14. 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.

  15. 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

  16. Acute and chronic toxicity of imidacloprid to the aquatic invertebrates Chironomus tentans and Hyalella azteca under constant- and pulse-exposure conditions.

    PubMed

    Stoughton, Sarah J; Liber, Karsten; Culp, Joseph; Cessna, Allan

    2008-05-01

    The toxicity of imidacloprid, a nicotinic mimic insecticide, to the aquatic invertebrates Chironomus tentans and Hyalella azteca, was first evaluated in static 96-hour tests using both technical material (99.2% pure) and Admire, a commercially available formulated product (240 g a.i. L(-1)). The 96-h lethal concentration (LC)50 values for technical imidacloprid and Admire were 65.43 and 17.44 microg/L, respectively, for H. azteca, and 5.75 and 5.40 microg/L, respectively, for C. tentans. Admire was subsequently used in 28-day chronic tests with both species. Exposure scenarios consisted of a constant- and a pulse-exposure regime. The pulse exposure lasted for four days, after which time the animals were transferred to clean water for the remaining 24 days of the study. Assessments were made on both day 10 and day 28. In the C. tentans under constant exposure, larval growth on day 10 was significantly reduced at 3.57 microg/L imidacloprid, the lowest-observed-effect concentration (LOEC). The no-observed-effect concentration (NOEC) and LOEC for the 28-day exposure duration (adult survival and emergence) were 1.14 and greater than 1.14 mug/L, respectively; the associated LC50 and LC25 were 0.91 and 0.59 microg/L, respectively. The LOEC for the pulse treatment was greater than 3.47 microg/L, but the day 10 LC25 was 3.03 microg/L. In the H. azteca tests, the day 10 and 28 constant exposure, as well as the day 28 pulse exposure, LOEC (survival) values were similar at 11.95, 11.46, and 11.93 microg/L, respectively. The day 10 and 28 constant exposure effective concentration (EC)25s (dry weight) were also similar, at 6.22 and 8.72 microg/L, respectively, but were higher than the pulse-exposure day 10 LOEC and EC25 (dry weight) values of 3.53 and 2.22 microg/L, respectively. Overall, C. tentans was more sensitive to acute and chronic imidacloprid exposure, but less sensitive to a single pulse, than H. azteca. Chronic, low-level exposure to imidacloprid may therefore reduce

  17. Separating the effects of water physicochemistry and sediment contamination on Chironomus tepperi (Skuse) survival, growth and development: a boosted regression tree approach.

    PubMed

    Hale, Robin; Marshall, Stephen; Jeppe, Katherine; Pettigrove, Vincent

    2014-07-01

    More comprehensive ecological risk assessment procedures are needed as the unprecedented rate of anthropogenic disturbances to aquatic ecosystems continues. Identifying the effects of pollutants on aquatic ecosystems is difficult, requiring the individual and joint effects of a range of natural and anthropogenic factors to be isolated, often via the analysis of large, complicated datasets. Ecotoxicologists have traditionally used multiple regression to analyse such datasets, but there are inherent problems with this approach and a need to consider other potentially more suitable methods. Sediment pollution can cause a range of negative effects on aquatic animals, and these are used as the basis for toxicity bioassays to measure the biological impact of pollution and the success of remediation efforts. However, experimental artefacts can also lead to sediments being incorrectly classed as toxic in such studies. Understanding the influence of potentially confounding factors will help more accurate assessments of sediment pollution. In this study, we analysed standardised sediment bioassays conducted using the chironomid Chironomus tepperi, with the aim of modelling the impact of sediment toxicants and water physico-chemistry on four endpoints (survival, growth, median emergence day, and number of emerging adults). We used boosted regression trees (BRT), a method that has a number of advantages over multiple regression, to model bioassay endpoints as a function of water chemistry, sediment quality and underlying geology. Endpoints were generally influenced most strongly by water quality parameters and nutrients, although some metals negatively influenced emergence endpoints. Sub-lethal endpoints were generally better predicted than lethal endpoints; median emergence day was the most sensitive endpoint examined in this study, while the number of emerging adults was the least sensitive. We tested our modelling results by experimentally manipulating sediment and

  18. Toxicity of uranium, molybdenum, nickel, and arsenic to Hyalella azteca and Chironomus dilutus in water-only and spiked-sediment toxicity tests.

    PubMed

    Liber, Karsten; Doig, Lorne E; White-Sobey, Suzanne L

    2011-07-01

    A series of laboratory spiked-sediment toxicity tests with the amphipod Hyalella azteca and the midge Chironomus dilutus were undertaken to determine acute and chronic toxicity thresholds for uranium (U), molybdenum (Mo), nickel (Ni), and arsenic (As) based on both whole-sediment (total) and pore water exposure concentrations. Water-only toxicity data were also generated from separate experiments to determine the toxicities of these metals/metalloids under our test conditions and to help evaluate the hypothesis that pore water metal concentrations are better correlated with sediment toxicity to benthic organisms than whole-sediment metal concentrations. The relative toxicity of the four elements tested differed depending on which test species was used and whether whole-sediment or pore water metal concentrations were correlated with effects. Based on measured whole-sediment concentrations, Ni and As were the two most acutely toxic elements to H. azteca with 10-d LC50s of 521 and 532 mg/kg d.w., respectively. Measured pore water concentrations indicated that U and Ni were the two most acutely toxic elements, with 10-d LC50s to H. azteca of 2.15 and 2.05 mg/L, respectively. Based on pore water metal concentrations, the no-observed-effect concentrations (NOECs) for growth were (H. azteca and C. dilutus, respectively) 0.67 and 0.21 mg/L for U, <0.37 and 0.60 mg/L for Ni, and 16.43 and <0.42 mg/L for As. Pore-water lowest-observed-effect concentrations (LOECs) for growth were (H. azteca and C. dilutus, respectively) 2.99 and 0.48 mg/L for U, 0.37 and 2.33 mg/L for Ni, and 58.99 and 0.42 mg/L for As. For U and Ni, results from 96-h water-only acute toxicity tests correlated well with pore water metal concentrations in acutely toxic metal-spiked sediment. This was not true for As where metalloid concentrations in overlying water (diffusion from sediment) may have contributed to toxicity. The lowest whole-sediment LOEC reported here for As was 6.6- and 4-fold higher than

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

    PubMed

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

    2010-02-01

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

  20. [Ecological imprinting and protein biosynthesis. Experiments with Drosophila melanogaster Meigen].

    PubMed

    Laudien, H; Iken, H H

    1977-06-01

    According to the "host selection principle", butterflies and other herbivorous insects preferentially lay their eggs on those plant races that they fed on when young. This is also true for karpophagic and parasitic insects. The selection of specific chemical conditions could be either inherited or acquired. If learned information determines host selection, we have a case of imprinting, as a) reception and use of the information are not simultaneous, b) there is no reward. In experiments with Drosophila melanogaster we marked the egg deposition medium with ethanol, acetic acid, peppermint oil, or benzaldehyd. The flies spontaneously prefer mediums with ethanol and acetic acid, and reject peppermint oil and benzaldehyd. If they are reared in one of these media, the preference for it is increased, or the rejection rate lowered. Rearing with actinomycin C neutralizes the effect of the other markers. It is concluded that actinomycin C blocks imprinting on the egg deposition substrate in Drosophila melanogaster.

  1. Mass rearing of Lucilia sericata Meigen (Diptera: Calliphoridae)

    PubMed Central

    Firoozfar, F; Moosa-Kazemi, H; Baniardalani, M; Abolhassani, M; Khoobdel, M; Rafinejd, J

    2011-01-01

    Objective To carry out an experimental study with the main objective of mass rearing of sheep flies (Lucilia sericata). Methods Hand collection and beef- or cattle liver-baited net traps were used for field fly sampling from April, 2010 to November, 2010. The samples collected from different places were placed in properly labeled tubes and sent to the Entomology Laboratory. Since maggot identification is important in inducing mortality, they were kept under insectary condition to develop to adult stage and identified using systematic keys. Results A total of 218 flies were collected in three rounds of sampling from the field of Tehran and Karaj Counties. In the first generation, 433 flies including 135 (31.17%) male, and 298 (68.82%) female were yielded. The female/male of parent ratio was calculated as 1.72 in Tehran and in Karaj areas, whereas it was 2.20% and 1.81%, respectively in F1 and F2 generations, respectively. Conclusions During this study, the mass rearing of sheep blow fly has been established at the School of Public Health, Tehran University of Medical Sciences and can be used for producing flies for maggot therapy. PMID:23569725

  2. 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.

  3. 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.; Ingersoll, Christopher G.; Steevens, Jeffery A.; MacDonald, Donald D.

    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

  4. 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.

  5. 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.

  6. 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.

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

    USGS Publications Warehouse

    Kemble, Nile E.; Brumbaugh, William G.; Brunson, Eric L.; Dwyer, F. James; Ingersoll, Christopher G.; Monda, Dave P.; Woodward, Daniel F.

    1994-01-01

    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 (48-h exposure), rainbow trout (96-h exposure), and Microtox®. 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 (28-d exposure), Chironomus riparius (14-d exposure), rainbow trout (Oncorhynchus mykiss) 21- to 28-d exposure and Daphnia magna (2- to 22-d exposure). 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.

  8. 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).

  9. 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.

  10. Descriptions of three new species of the genus Cheilosia Meigen from China (Diptera, Syrphidae).

    PubMed

    Barkalov, Anatolij V; Ståhls, Gunilla

    2015-06-11

    Three species of genus Cheilosia (Diptera, Syrphidae: Eristalinae) from China are described as new to science, Cheilosia bullabucca Barkalov & Ståhls sp. n., C. lamproptera Barkalov & Ståhls sp. n. and C. yunnanensis Barkalov & Ståhls sp. n. We provide species descriptions and keys for their identification. The phylogenetic placements of the taxa was estimated based on their morphological characteristics and by analysing the taxa under parsimony using a mtDNA COI sequence dataset including a comprehensive set of Palaearctic previously generated Cheilosia spp. sequences representing all major subgenera. Based on both their morphological affinities and the molecular data. The Chinese taxa were placed in the subgenera Eucartosyrphus (C. bullabucca), Cheilosia s. str. (C. oblonga), Floccocheila (C. versicolor) while C. yunnanensis was not resolved as member of Cheilosia s. str. based on DNA despite sharing morphological characteristics with the subgenus. As the name Cheilosia (Nephocheila) prima Barkalov & Cheng from China is a junior homonym of Cheilosia (Cartosyrphus) prima Hunter, 1896 from the Nearctic region, for the Chinese species the new name Cheilosia (Nephocheila) primaria Barkalov & Ståhls nomen nov. is proposed.

  11. Albuginosus, A New Subgenus of Aedes Meigen (Diptera: Culicidae) Described from the Afrotropical Region

    DTIC Science & Technology

    1986-01-01

    from a discarded tin (Hopkins 1952) ; rot hole in a mangrove (Mattingly in Hopkins 1952); tree holes in Mangifera indica, Parkia filicoidea...Afrique occidentale. Ecologic , repartition, frequence et controle des vecteurs, et observations concernant l’epidemiologie de la fievre jaune. Cah...Entomol. Res. 33: 181-193. I Ronald Press Co., New York, 723 p. Hopkins, G. H. E. 1952. Mosquitoes of bionomics of mosquitoes and taxonomy notes

  12. On the tensile strength of insect swarms

    NASA Astrophysics Data System (ADS)

    Ni, Rui; Ouellette, Nicholas T.

    2016-08-01

    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.

  13. 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.

  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. Sesquiterpenes of the geosmin-producing cyanobacterium Calothrix PCC 7507 and their toxicity to invertebrates.

    PubMed

    Höckelmann, Claudia; Becher, Paul G; von Reuss, Stephan H; Jüttner, Friedrich

    2009-01-01

    The occurrence of sesquiterpenes was investigated with the geosmin-producing cyanobacterium Calothrix PCC 7507. The essential oil obtained by vacuum destillation was studied in more detail by GC-MS methods and superposition with authentic compounds. Geosmin was the dominating compound while the other sesquiterpenes were minor components. Sesquiterpenes that have not been described before in cyanobacteria were isodihydroagarofuran, eremophilone and 6,11-epoxyisodaucane. Closed-loop stripping analysis revealed that most of the sesquiterpenes were found in the biomass of Calothrix, while eremophilone was mainly observed in the medium of the axenic culture. Eremophilone showed acute toxicity (LC50) against Chironomus riparius (insecta) at 29 microM and against Thamnocephalus platyurus (crustacea) at 22 microM. The compound was not toxic for Plectus cirratus (nematoda). 6,11-Epoxyisodaucane and isodihydroagarofuran exhibited no toxicity to invertebrates when applied in concentrations up to 100 microM.

  16. 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.

  17. 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.

  18. 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.

  19. 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?

  20. 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.

  1. Field assessment of reproduction-related traits of chironomids using a newly developed emergence platform (E-Board).

    PubMed

    Ferrari, Benoît J D; Faburé, Juliette

    2017-03-01

    Further progress in the development of reliable biomonitoring strategies requires to better link effects in aquatic ecological systems to ambient concentrations of chemical contaminants. Among existing tools, in situ bioassays using caging method represent an interesting way to achieve this challenge. However, elaboration of adapted exposure chambers and suitable operating procedures is still required, particularly to assess ecological relevant traits such as those related to the reproduction. In such context, we developed a new device (Emergence board - E-Board) which allows assessing in rivers the development of the Chironomus riparius species from the early fourth instar larvae to the adult stage. The system acts as a suspended matter trap floating in the subsurface of the water equipped of an emergence trap for catching adults. The system was tested in actual field conditions. Its easy handling allowed obtaining data which demonstrated its applicability for assessing the development of the chironomids. Moreover, by adapting energy-based models (DEB) specifically developed in the laboratory for the species C. riparius, we were able to predict the growth pattern and the emergence of chironomids in real environmental conditions. The E-Board represents thus a promising new in situ tool in perspective of evaluation of the quality of the ecosystems.

  2. Fluoxetine effects assessment on the life cycle of aquatic invertebrates.

    PubMed

    Péry, A R R; Gust, M; Vollat, B; Mons, R; Ramil, M; Fink, G; Ternes, T; Garric, J

    2008-09-01

    Fluoxetine is a serotonin re-uptake inhibitor, generally used as an antidepressant. It is suspected to provoke substantial effects in the aquatic environment. This study reports the effects of fluoxetine on the life cycle of four invertebrate species, Daphnia magna, Hyalella azteca and the snail Potamopyrgus antipodarum exposed to fluoxetine spiked-water and the midge Chironomus riparius exposed to fluoxetine-spiked sediments. For D. magna, a multi-generational study was performed with exposition of newborns from exposed organisms. Effects of fluoxetine could be found at low measured concentrations (around 10microgl(-1)), especially for parthenogenetic reproduction of D. magna and P. antipodarum. For daphnids, newborns length was impacted by fluoxetine and the second generation of exposed individuals showed much more pronounced effects than the first one, with a NOEC of 8.9microgl(-1). For P. antipodarum, significant decrease of reproduction was found for concentrations around 10microgl(-1). In contrast, we found no effect on the reproduction of H. azteca but a significant effect on growth, which resulted in a NOEC of 33microgl(-1), expressed in nominal concentration. No effect on C. riparius could be found for measured concentrations up to 59.5mgkg(-1). General mechanistic energy-based models showed poor relevance for data analysis, which suggests that fluoxetine targets specific mechanisms of reproduction.

  3. Folded gastrulation and T48 drive the evolution of coordinated mesoderm internalization in flies

    PubMed Central

    Urbansky, Silvia; González Avalos, Paula; Wosch, Maike; Lemke, Steffen

    2016-01-01

    Gastrulation constitutes a fundamental yet diverse morphogenetic process of metazoan development. Modes of gastrulation range from stochastic translocation of individual cells to coordinated infolding of an epithelial sheet. How such morphogenetic differences are genetically encoded and whether they have provided specific developmental advantages is unclear. Here we identify two genes, folded gastrulation and t48, which in the evolution of fly gastrulation acted as a likely switch from an ingression of individual cells to the invagination of the blastoderm epithelium. Both genes are expressed and required for mesoderm invagination in the fruit fly Drosophila melanogaster but do not appear during mesoderm ingression of the midge Chironomus riparius. We demonstrate that early expression of either or both of these genes in C.riparius is sufficient to invoke mesoderm invagination similar to D.melanogaster. The possible genetic simplicity and a measurable increase in developmental robustness might explain repeated evolution of similar transitions in animal gastrulation. DOI: http://dx.doi.org/10.7554/eLife.18318.001 PMID:27685537

  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. Gene expression patterns and life cycle responses of toxicant-exposed chironomids.

    PubMed

    Marinković, Marino; de Leeuw, Wim C; Ensink, Wim A; de Jong, Mark; Breit, Timo M; Admiraal, Wim; Kraak, Michiel H S; Jonker, Martijs J

    2012-11-20

    Cellular stress responses are frequently presumed to be more sensitive than traditional ecotoxicological life cycle end points such as survival and growth. Yet, the focus to reduce test duration and to generate more sensitive end points has caused transcriptomics studies to be performed at low doses during short exposures, separately and independently from traditional ecotoxicity tests, making comparisons with life cycle end points indirect. Therefore we aimed to directly compare the effects on growth, survival, and gene expression of the nonbiting midge Chironomus riparius. To this purpose, we simultaneously analyzed life cycle and transcriptomics responses of chironomid larvae exposed to four model toxicants. We observed that already at the lowest test concentrations many transcripts were significantly differentially expressed, while the life cycle end points of C. riparius were hardly affected. Analysis of the differentially expressed transcripts showed that at the lowest test concentrations substantial and biologically relevant cellular stress was induced and that many transcripts responded already maximally at these lowest test concentrations. The direct comparison between molecular end life cycle responses after fourteen days of exposure revealed that gene expression is more sensitive to toxicant exposure than life cycle end points, underlining the potential of transcriptomics for ecotoxicity testing and environmental risk assessment.

  7. Effects of pharmaceuticals on aquatic invertebrates. Part II: the antidepressant drug fluoxetine.

    PubMed

    Nentwig, Gerrit

    2007-02-01

    Fluoxetine, a selective serotonin reuptake inhibitor antidepressant and high-prescription-volume drug, is excreted unchanged or as a glucuronide from the human organism. Little is known about its fate in sewage treatment plants. Effects of fluoxetine on life-cycle parameters of the midge Chironomus riparius, especially development (mean emergence time), emergence, sex ratio, and fecundity, were assessed, as well as effects on reproduction of the oligochaete Lumbriculus variegatus and of the freshwater mudsnail Potamopyrgus antipodarum. Due to the moderate lipophilic properties of the compound with a log P (OW) of 4.05, C. riparius and L. variegatus were exposed to fluoxetine via spiked artificial sediment at a nominal concentration range between 0.15 and 5.86 mg/kg (dry weight). Additionally, a test was performed exposing P. antipodarum via water in a nominal concentration range between 0.64 and 400 mug/L. As endpoints, emergence rate and timing, sex ratio, clutch numbers and clutch size of the midges, the number of worms in the oligochaete test, as well as the number of embryos in the snail test were monitored. For C. riparius, no clear substance-related effects were observed; for L. variegatus, the results indicated a slight increase in reproduction, which was statistically significant at nominal fluoxetine concentrations of 0.94 and 2.34 mg/kg. In P. antipodarum, the antidepressant reduced reproduction significantly. No observed effect concentration (NOEC) and 10% effect concentration (EC(10)) were determined to be 0.47 and 0.81 mug/L, respectively, based on measured fluoxetine concentrations in water. These low values indicate that P. antipodarum and possibly other aquatic mollusks are sensitive to fluoxetine and that the drug might pose a risk to gastropod populations in the field.

  8. Coupling geochemical and biological approaches to assess the availability of cadmium in freshwater sediment.

    PubMed

    Dabrin, Aymeric; Durand, Cyrielle L; Garric, Jeanne; Geffard, Olivier; Ferrari, Benoit J D; Coquery, Marina

    2012-05-01

    Sediments are considered as a sink for metals, and the assessment of metal bioavailability for benthic organisms represents a great challenge. Diffusive Gradient in Thin films (DGT), developed to measure labile metals in aquatic media, have more recently been applied to sediment. Nevertheless, few studies have determined the relation between measurements from DGT and bioaccumulation in different benthic organisms. The aim of our work was to determine if labile metal measured by DGT in sediment is representative of bioavailable metal for benthic organisms. We focused our work on Cd and chose to use the diversity of ecological traits from different organisms to better understand the measurement given by DGT. We exposed simultaneously DGT and 3 macroinvertebrates species (the chironomid, Chironomus riparius; the amphipod, Gammarus fossarum; the mudsnail, Potamopyrgus antipodarum) to a natural sediment Cd-spiked at environmental relevant concentrations. The nature of sediment-bound Cd was also determined by means of sequential extractions in order to better interpret DGT measurements. Cadmium concentrations were determined in DGT and in the 3 organisms after one week of exposure. Results provided by DGT indicated that Cd was poorly released from particulate phase to pore water, suggesting that Cd measured by DGT was representative of the pore water labile fraction. Sequential extractions showed that the percentage of Cd bound to carbonate fraction increased simultaneously with Cd-spiking level; hence, this Cd fraction was poorly reactive to supply DGT demand. Cadmium accumulation rates were similar between DGT measurements and P. antipodarum, suggesting that labile Cd in pore waters was representative of bioavailable Cd for this species. Cadmium accumulation rates in C. riparius were higher than in DGT, demonstrating that C. riparius can mobilize Cd bound to carbonate phase. G. fossarum showed the lowest Cd accumulation rates, suggesting that they were mainly exposed

  9. Fear and loathing in the benthos: Responses of aquatic insect larvae to the pesticide imidacloprid in the presence of chemical signals of predation risk.

    PubMed

    Pestana, João L T; Loureiro, Susana; Baird, Donald J; Soares, Amadeu M V M

    2009-06-28

    The influence of interactions between pesticide exposure and perceived predation risk on the lethal and sub-lethal responses of two aquatic insects was investigated using the pesticide imidacloprid, and a combination of predator-release kairomones from trout and alarm substances from conspecifics. Laboratory experiments examined feeding and respiration rates of the caddisfly Sericostoma vittatum as well as the growth, emergence and respiration rates of the midge Chironomus riparius, exposed to sub-lethal concentrations of imidacloprid. The effects of the two stressors on burrowing behaviour of both species were also assessed. The results show significant effects of environmentally relevant concentrations of imidacloprid on all endpoints studied. Perceived predation risk also elicited sub-lethal effects in C. riparius and S. vittatum, the latter species being less responsive to predation cues. The effects of simultaneous exposure to both types of stressors were assessed using two different approaches: analysis of variance and conceptual models [concentration addition (CA) and independent action (IA)] normally used for the evaluation of contaminant mixture exposure. Both statistical approaches showed no significant interactions on responses in simultaneous exposures in the majority of parameters assessed with only a signification deviation from the reference CA and IA models being found for C. riparius respiration data contrary to the ANOVA results. Exposure to imidacloprid also compromised antipredator behavioural responses of both insect species, with potential negative consequences in terms of mortality from predation in the field. The results obtained demonstrate that natural and anthropogenic stressors can be treated within the same framework providing compatible data for modelling. For an improved interpretation of ecological effects it will be important to expand the mechanistic study of effects of combined exposure to pesticides and perceived predation risk

  10. 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.

  11. A comparison of sediment toxicity test methods at three Great Lake Areas of Concern

    USGS Publications Warehouse

    Burton, G. Allen; Ingersoll, Christopher G.; Burnett, LouAnn C.; Henry, Mary; Hinman, Mark L.; Klaine, Stephen J.; Landrum, Peter F.; Ross, Phillipe; Tuchman, Marc

    1996-01-01

    The significance of sediment contamination is often evaluated using sediment toxicity (bioassay) testing. There are relatively few “standardized” test methods for evaluating sediments. Popular sediment toxicity methods examine the extractable water (elutriate), interstitial water, or whole (bulk) sediment phases using test species spanning the aquatic food chain from bacteria to fish. The current study was designed to evaluate which toxicity tests were most useful in evaluations of sediment contamination at three Great Lake Areas of Concern. Responses of 24 different organisms including fish, mayflies, amphipods, midges, cladocerans, rotifers, macrophytes, algae, and bacteria were compared using whole sediment or elutriate toxicity assays. Sediments from several sites in the Buffalo River, Calumet River (Indiana Harbor), and Saginaw River were tested, as part of the U.S. Environmental Protection Agency's (USEPA) Assessment and Remediation of Contaminated Sediments (ARCS) Project. Results indicated several assays to be sensitive to sediment toxicity and able to discriminate between differing levels of toxicity. Many of the assay responses were significantly correlated to other toxicity responses and were similar based on factor analysis. For most applications, a test design consisting of two to three assays should adequately detect sediment toxicity, consisting of various groupings of the following species: Hyalella azteca, Ceriodaphnia dubia, Chironomus riparius, Chironomus tentans, Daphnia magna, Pimephales promelas, Hexagenia bilineata, Diporeia sp., Hydrilla verticillata, or Lemna minor.

  12. An evaluation of benthic community measures using laboratory-derived sediment effect concentrations

    SciTech Connect

    Dwyer, F.J.; Canfield, T.J.; Ingersoll, C.G.; Kemble, N.E.; Mount, D.R.

    1995-12-31

    Sediment effect concentrations (SECs) are contaminant sediment concentrations which are frequently associated with sediment toxicity. Recently, a number of different SECs have been calculated from laboratory toxicity tests with field collected sediments using Chironomus tentans, Chironomus riparius, and Hyalella azteca. Toxicity endpoints included (depending upon species) lethality, growth and sexual maturation. The authors selected the Effect Range Median (ERM) calculated for 28-d Hyalella azteca as an SEC for evaluating six different benthic community measures as indicators of contaminated sediment. The benthic measures included: taxa richness, chironomid genera richness, percent chironomid deformity, chironomid biotic index, ratio of chironomids/oligochaetes, and oligochaete biotic index. Benthic measures were obtained for 31 stations from the Great Lakes and 13 stations from Milltown Reservoir and Clark Fork River, MT. Each benthic measure was ranked from 1 to 100 and individual ranks and various combinations of ranks were plotted against the ratio of chemical concentration at the site/ERM calculated for that chemical (similar to a toxic unit approach) and the sum of the ERM ratios (sum of toxic units). Preliminary analysis indicates that, in general, benthic measures varied widely in relatively uncontaminated stations, confounding any underlying relationship that may have existed. The absence of chironomids, in areas with suitable habitat, seems to be indicative of grossly contaminated stations, but not an endpoint useful for discriminating stations with contaminant concentrations closer to the SEC. The usefulness of benthic measures as diagnostic tools for contaminated sediments and potential ways to improve these measures will be discussed.

  13. Lucilia silvarum Meigen, 1826 (Diptera: Calliphoridae)--a new species of interest for forensic entomology in Europe.

    PubMed

    Fremdt, Heike; Szpila, Krzysztof; Huijbregts, Johannes; Lindström, Anders; Zehner, Richard; Amendt, Jens

    2012-10-10

    In Europe, the blowfly genus Lucilia is represented in Forensic Entomology mainly by the species L. ampullacea, L. caesar, L. illustris and L. sericata. In the US, Lucilia silvarum is rarely recorded as a carrion breeding species but usually as a more or less exclusive parasite of frogs and toads. We present three forensic cases from different European countries reporting, for the first time, L. silvarum on human bodies that were found close to lakes, wetlands, or riversides. To use this species for post-mortem interval estimations, thermal development data is needed. The first step is accurate identification by morphological and molecular means. Therefore, we analysed a 611 bp part of the mitochondrial COI region for 23 specimens of L. silvarum from 9 different geographical regions, all of which give the same haplotype. Differences within the haplotype varied by up to 0.2%. Comparison between the haplotype found and those published on GenBank showed up to 1.2% variance. Moreover, we present an updated key for the morphological identification of the third larval instars of European Lucilia spp. of forensic importance, adding not only L. silvarum, but also L. cuprina which was recorded in Europe for the first time about 20 years ago.

  14. 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

  15. Efficacy of fenvalerate as contact poison against the larval development and viability of mutant form (Sepia) of Drosophila melanogaster (Meigen).

    PubMed

    Choudhary, Shamim

    2004-01-01

    Fenvalerate, a synthetic pyrethroid, was analysed for its toxic effects on Drosophila melanogaster. It has been estimated that LC50 0.0166 micro 1/100 ml food is threshold of lethality. These studies have also revealed that fenvalerate is toxic as it had a pronounced effect on the rate of development and viability.

  16. 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.

  17. Two new species of Chrysotus Meigen (Diptera, Dolichopodidae) from Siberia, with a key to the Siberian species.

    PubMed

    Negrobov, Oleg P; Barkalov, Anatolij V; Selivanova, Olga V

    2014-06-16

    Two new species from the southern tundra of the Taimyr Peninsula (Russia) are described. Chrysotus tricaudatus Negrobov, Barkalov & Selivanova sp. nov. is similar to C. albibarbus Loew, but can be distinguished by its brown palpus with black setae, yellow hind tibia and base of hind tarsus, and features of the male genitalia. Chrysotus komovi Negrobov, Barkalov & Selivanova sp. nov. is similar to C. obscuripes Zetterstedt, but can be distinguished by features of the male genitalia. A key to all Siberian species of the genus is also presented along with figures of diagnostic morphological characters. 

  18. The Organization of Extrinsic Neurons and Their Implications in the Functional Roles of the Mushroom Bodies in Drosophila melanogaster Meigen

    PubMed Central

    Ito, Kei; Suzuki, Kazumi; Estes, Patricia; Ramaswami, Mani; Yamamoto, Daisuke; Strausfeld, Nicholas J.

    1998-01-01

    Although the importance of the Drosophila mushroom body in olfactory learning and memory has been stressed, virtually nothing is known about the brain regions to which it is connected. Using Golgi and GAL4–UAS techniques, we performed the first systematic attempt to reveal the anatomy of its extrinsic neurons. A novel presynaptic reporter construct, UAS-neuronal synaptobrevin–green fluorescent protein (n-syb–GFP), was used to reveal the direction of information in the GAL4-labeled neurons. Our results showed that the main target of the output neurons from the mushroom body lobes is the anterior part of the inferior medial, superior medial, and superior lateral protocerebrum. The lobes also receive afferents from these neuropils. The lack of major output projections directly to the deutocerebrum’s premotor pathways discourages the view that the role of the mushroom body may be that of an immediate modifier of behavior. Our data, as well as a critical evaluation of the literature, suggest that the mushroom body may not by itself be a “center” for learning and memory, but that it can equally be considered as a preprocessor of olfactory signals en route to “higher” protocerebral regions. PMID:10454372

  19. 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

  20. 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.

  1. 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

  2. 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)

  3. 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...

  4. 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.

  5. 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...

  6. Responses of Chironomus tentans and Hyalella azteca to polycyclic aromatic hydrocarbons

    SciTech Connect

    Hatch, A.C.; Burton, G.A. Jr.

    1995-12-31

    The toxicity of polycyclic aromatic hydrocarbons (PAHs) is affected by ultraviolet (UV) light and a number of interacting environmental variables. The effect of two photoinduced PAHs, anthracene and fluoranthene, was studied with the midge, C. tentans, and the amphipod H. azteca in water-only and sediment exposures. Reduced growth was observed in the presence of UV light at low (ug/L) concentrations. Mixtures showed approximately additive responses. The amphipod was slightly more sensitive to photoinduced toxicity. Responses were modified by exposure differences due to behavior patterns, which altered UV exposures. Results suggest natural factors such as inorganic and organic particulates, in combination with behavior, have a significant role in determining the ecological relevance of photoinduced PAH toxicity.

  7. 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.

  8. Chronic toxicity of copper to five benthic invertebrates in laboratory-formulated sediment: sensitivity comparison and preliminary risk assessment.

    PubMed

    Roman, Yblin E; De Schamphelaere, Karel A C; Nguyen, Lien T H; Janssen, Colin R

    2007-11-15

    Five benthic organisms commonly used for sediment toxicity testing were chronically (28 to 35 days) exposed to copper in standard laboratory-formulated sediment (following Organization for Economic Cooperation and Development guidelines) and lethal and sub-lethal toxicities were evaluated. Sub-lethal endpoints considered were reproduction and biomass production for Lumbriculus variegatus, growth and reproduction for Tubifex tubifex, growth and emergence for Chironomus riparius, and growth for Gammarus pulex and Hyalella azteca. Expressed on whole-sediment basis the observed lethal sensitivity ranking (from most to least sensitive) was: G. pulex>L. variegatus>H. azteca=C. riparius=T. tubifex, with median chronic lethal concentrations (LC50) between 151 and 327 mg/kg dry wt. The sub-lethal sensitivity ranking (from most to least sensitive, with the most sensitive endpoint between parentheses): C. riparius (emergence)>T. tubifex (reproduction)=L. variegatus (reproduction)>G. pulex (growth)>H. azteca (growth), with median effective concentrations (EC50) between 59.2 and 194 mg/kg dry wt. No observed effect concentrations (NOEC) or 10% effective concentrations (EC10) for the five benthic invertebrates were used to perform a preliminary risk assessment for copper in freshwater sediment by means of (a) the "assessment factor approach" or (b) the statistical extrapolation approach (species sensitivity distribution). Depending on the data (NOEC or EC10) and the methodology used, we calculated a Predicted No Effect Concentration (PNEC) for sediment between 3.3 and 47.1 mg Cu/dry wt. This range is similar to the range of natural (geochemical) background concentrations of copper in sediments in Europe, i.e. 90% of sediments have a concentration between 5 and 49 mg Cu/kg dry wt. A detailed analysis of the outcome of this preliminary exercise highlighted that multiple issues need to be explored for achieving a scientifically more sound risk assessment and for the development of

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

    USGS Publications Warehouse

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

    2013-01-01

    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.

  10. 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

  11. 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.

  12. First record in South Asia of deer throat bot fly larvae Pharyngomyia picta (Meigen, 1824) (Diptera: Oesteridae) from Sambar deer (Rusa unicolor), a new host record.

    PubMed

    Sreejith, Radhakrishnan; Ajithkumar, K G; Reghu, Ravindran; Kavitha, Rajagopal

    2012-06-01

    The Bot fly larvae, identified to be the third instars of the deer throat bot fly Pharyngomyia picta were recovered from the lumen of trachea and secondary bronchi during the necropsy of a female sambar deer (Rusa unicolor) in Kerala, India. This forms the first report of P. picta from India and the whole of South Asia. Sambar deer is a new host record for the larvae of this fly. Morphological description of the third stage larvae with supporting figures are presented.

  13. Contributions to the Mosquito Fauna of Southeast Asia. XVI. Genus Aedes Meigen, Subgenus Aedimorphus Theobald in Southeast Asia (Contributions of the American Entomological Institute. Volume 9, Number 5)

    DTIC Science & Technology

    1973-01-01

    Biological data recorded in the literature are also given and the sources are cited. The nomenclature and chaetotaq used for females, female genitalia...North America. In most instances, however, comprehensive data on other biological factors which determine vector status are not available. Aedes...genitalia, and pupal and larval chae- totaxy of vexans vexans from the remainder of its distribution. In the absence of sufficient biological

  14. Ecotoxicological effect characterisation of widely used organic UV filters.

    PubMed

    Kaiser, D; Sieratowicz, A; Zielke, H; Oetken, M; Hollert, H; Oehlmann, J

    2012-04-01

    Chemical UV filters are used in sun protection and personal care products in order to protect consumers from skin cancer induced by ultraviolet (UV) radiation. The present study aims to evaluate the effects of three common UV filters butyl-methoxydibenzoylmethane (B-MDM) ethylhexyl-methoxycinnamate (EHMC) and octocrylene (OCR) on aquatic organism, focussing particularly on infaunal and epibentic invertebrates (Chironomus riparius, Lumbriculus variegatus, Melanoides tuberculata and Potamopyrgus antipodarum). Due to their life habits, these organism are especially affected by lipophilic substances. Additionally, two direct sediment contact assays utilising zebra fish (Danio rerio) embryos and bacteria (Arthrobacter globiformis) were conducted. EHMC caused a toxic effect on reproduction in both snails with lowest observed effect concentrations (LOEC) of 0.4 mg/kg (Potamopyrgus antipodarum) and 10 mg/kg (Melanoides tuberculata). At high concentrations sublethal effects could be observed for D. rerio after exposure to EHMC (NOEC 100 mg/kg). B-MDM and OCR showed no effects on any of the tested organism.

  15. 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.

  16. 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.

  17. 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

  18. Comparison of a test battery for assessing the toxicity of a bleached-kraft pulp mill effluent before and after secondary treatment implementation.

    PubMed

    Rosa, R; Moreira-Santos, M; Lopes, I; Silva, L; Rebola, J; Mendonça, E; Picado, A; Ribeiro, R

    2010-02-01

    Pulp and paper mill effluents may cause harmful effects to the aquatic environment due to the combined influence of physical factors, toxic compounds, and nutrient enrichment. In the present study, the effectiveness of secondary treatment in reducing the toxicity of an elemental chlorine-free bleached-kraft pulp mill effluent was evaluated. To characterize the toxicity of the effluent, before and after the implementation of secondary treatment, a battery of tests with organisms bearing different functions at the ecosystem level was used, namely Vibrio fischeri (5-min luminescence), Pseudokirchneriella subcapitata (72-h growth), Lemna minor (7-day growth), Daphnia magna (21-day reproduction and 24-h postexposure feeding), Chironomus riparius (9-day growth), and Danio rerio (28-day growth). For the effluent sample collected before the implementation of secondary treatment, P. subcapitata was the most sensitive organism followed by V. fischeri and D. magna, and no toxic effects were observed toward the other organisms. For the effluent sample collected after the implementation of secondary treatment, the effluent caused no toxic effects on any of the tested species. The present results demonstrated not only that secondary treatment efficaciously reduced effluent toxicity toward the selected test organisms but also the usefulness of a battery of tests to characterize the toxicity of pulp mill effluents.

  19. Chironomidae bloodworms larvae as aquatic amphibian food.

    PubMed

    Fard, Mojdeh Sharifian; Pasmans, Frank; Adriaensen, Connie; Laing, Gijs Du; Janssens, Geert Paul Jules; Martel, An

    2014-01-01

    Different species of chironomids larvae (Diptera: Chironomidae) so-called bloodworms are widely distributed in the sediments of all types of freshwater habitats and considered as an important food source for amphibians. In our study, three species of Chironomidae (Baeotendipes noctivagus, Benthalia dissidens, and Chironomus riparius) were identified in 23 samples of larvae from Belgium, Poland, Russia, and Ukraine provided by a distributor in Belgium. We evaluated the suitability of these samples as amphibian food based on four different aspects: the likelihood of amphibian pathogens spreading, risk of heavy metal accumulation in amphibians, nutritive value, and risk of spreading of zoonotic bacteria (Salmonella, Campylobacter, and ESBL producing Enterobacteriaceae). We found neither zoonotic bacteria nor the amphibian pathogens Ranavirus and Batrachochytrium dendrobatidis in these samples. Our data showed that among the five heavy metals tested (Hg, Cu, Cd, Pb, and Zn), the excess level of Pb in two samples and low content of Zn in four samples implicated potential risk of Pb accumulation and Zn inadequacy. Proximate nutritional analysis revealed that, chironomidae larvae are consistently high in protein but more variable in lipid content. Accordingly, variations in the lipid: protein ratio can affect the amount and pathway of energy supply to the amphibians. Our study indicated although environmentally-collected chironomids larvae may not be vectors of specific pathogens, they can be associated with nutritional imbalances and may also result in Pb bioaccumulation and Zn inadequacy in amphibians. Chironomidae larvae may thus not be recommended as single diet item for amphibians.

  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. 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.

  2. Assessment of the use of the AVS concept for the routine toxicity monitoring of contaminated freshwater sediments

    SciTech Connect

    Vangheluwe, M.L.; Janssen, C.R.; Goyvaerts, M.P.; Cooman, P.

    1995-12-31

    Acid volatile sulfides (AVS) have been shown to be an important factor mediating the bioavailability of heavy metals in sediments and have consequently been suggested as a possible predictive tool for toxicity assessment of these matrices. The potential use and limitations of the AVS method for predictive toxicity screening and priority setting was assessed in a large scale sediment monitoring study (Flanders, Belgium). The acute toxicity of 50 metal contaminated freshwater sediments, with varying metal concentrations and sediment characteristics, were tested using the Microtox{reg_sign} Solid Phase test and the 10 day test with Chironomus riparius and Hyalella azteca. Uni and multivariate statistical techniques were used to asses the relations between acute toxicity and SEM/AVS ratio`s and to evaluate the influence of sediment characteristics on metal bioavailability and toxicity. In general, the results of this study indicate that the AVS-toxicity relationship proposed in literature does have certain limitations. Finally, the potential use of a concentration-addition model for predicting metal-mixture toxicity in sediments will be presented and discussed.

  3. 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.

  4. 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...

  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. Using aquatic macroinvertebrate species traits to build test batteries for sediment toxicity assessment: accounting for the diversity of potential biological responses to toxicants.

    PubMed

    Ducrot, Virginie; Usseglio-Polatera, Philippe; Péry, T Alexandre R R; Mouthon, Jacques; Lafont, Michel; Roger, Marie-Claude; Garric, Jeanne; Férard, Jean-François

    2005-09-01

    An original species-selection method for the building of test batteries is presented. This method is based on the statistical analysis of the biological and ecological trait patterns of species. It has been applied to build a macroinvertebrate test battery for the assessment of sediment toxicity, which efficiently describes the diversity of benthic macroinvertebrate biological responses to toxicants in a large European lowland river. First, 109 potential representatives of benthic communities of European lowland rivers were selected from a list of 479 taxa, considering 11 biological traits accounting for the main routes of exposure to a sediment-bound toxicant and eight ecological traits providing an adequate description of habitat characteristics used by the taxa. Second, their biological and ecological trait patterns were compared using coinertia analysis. This comparison allowed the clustering of taxa into groups of organisms that exhibited similar life-history characteristics, physiological and behavioral features, and similar habitat use. Groups exhibited various sizes (7-35 taxa), taxonomic compositions, and biological and ecological features. Main differences among group characteristics concerned morphology, substrate preferendum and habitat utilization, nutritional features, maximal size, and life-history strategy. Third, the best representatives of the mean biological and ecological characteristics of each group were included in the test battery. The final selection was composed of Chironomus riparius (Insecta: Diptera), Branchiura sowerbyi (Oligochaeta: Tubificidae), Lumbriculus variegatus (Oligochaeta: Lumbriculidae), Valvata piscinalis (Gastropoda: Valvatidae), and Sericostoma personatum (Trichoptera: Sericostomatidae). This approach permitted the biological and ecological variety of the battery to be maximized. Because biological and ecological traits of taxa determine species sensitivity, such maximization should permit the battery to better account

  8. 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.

  9. Toxicity of CeO2 nanoparticles at different trophic levels--effects on diatoms, chironomids and amphibians.

    PubMed

    Bour, Agathe; Mouchet, Florence; Verneuil, Laurent; Evariste, Lauris; Silvestre, Jérôme; Pinelli, Eric; Gauthier, Laury

    2015-02-01

    The aim of the present work is to provide wider information on the toxicity of cerium dioxide nanoparticles (CeO2 NPs) in aquatic environments, by studying the toxicity of two types of CeO2 NPs for four species (diatoms Nitzschia palea, the sediment-dwelling invertebrate Chironomus riparius, and the amphibian larvae Xenopus laevis and Pleurodeles waltl.). The two types of CeO2 NPs have different intrinsic properties: some of them are small citrate-coated spheres (2-5 nm), and the others are larger uncoated plates (20-60 nm). Acute toxicity (mortality at 48 or 96 h, depending on the test-organism) was assessed for the four species, from 0.1 to 100 mg L(-1) of NPs. Sub-lethal effects were assessed on chironomids exposed between 0.01 and 1 mg L(-1) of NPs. Mortality, growth inhibition and genotoxic effects were evaluated on amphibian larvae from 0.1 to 10 mg L(-1). Results reveal that no acute toxicity occurs on any species after short exposures, even at the highest concentrations. Mortality (35%) is observed on Xenopus larvae after 12d of exposure at the highest concentration of one type of NPs. No significant effects were observed on chironomids during chronic exposure. Xenopus larvae growth was inhibited from 1 mg L(-1) of both NPs while growth inhibition is observed on Pleurodeles only at the highest concentration of one type of NPs. No genotoxicity was observed on Xenopus but Pleurodeles exhibited dose-dependent genotoxic effects when exposed to one type of NPs. Observed differences in toxicity are discussed focusing on the studied compartment, routes of exposure, species and NPs.

  10. Toxicity risk assessment of mercury, DDT and arsenic legacy pollution in sediments: A triad approach under low concentration conditions.

    PubMed

    Marziali, L; Rosignoli, F; Drago, A; Pascariello, S; Valsecchi, L; Rossaro, B; Guzzella, L

    2017-03-31

    The determination of sediment toxicity is challenging due to site-specific factors affecting pollutants distribution and bioavailability, especially when contamination levels are close to expected non-effect concentrations. Different lines of evidence and sensitive tools are necessary for a proper toxicity risk assessment. We examined the case study of the Toce River (Northern Italy), where past industrial activities determined Hg, DDT and As enrichment in sediments. A triad approach comprising chemical, ecotoxicological and ecological analyses (benthic invertebrates) was carried out for risk assessment of residual contamination in river sediments. A "blank" site upstream from the industrial site was selected to compare the other sites downstream. Sediment, water and benthic invertebrate samplings were carried out following standard protocols. Results emphasized that despite the emissions of the industrial site ceased about 20years ago, sediments in the downstream section of the river remain contaminated by Hg, DDT and As with concentrations exceeding Threshold Effect Concentrations. A chronic whole-sediment test with Chironomus riparius showed decreased development rate and a lower number of eggs per mass in the contaminated sediments. Benthic community was analyzed with the calculation of integrated (STAR_ICMi) and stressor-specific metrics (SPEARpesticide and mean sensitivity to Hg), but no significant differences were found between upstream and downstream sites. On the other hand, multivariate analysis (partial Redundancy Analysis and variation partitioning) emphasized a slight impact on invertebrate community, accounting for 5% variation in taxa composition. Results show that legacy contaminants in sediments, even at low concentrations, may be bioavailable and possibly toxic for benthic invertebrates. At low concentration levels, sensitive and site-specific tools need to be developed for a proper risk analysis.

  11. 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

  12. Multi-residue analysis of emerging pollutants in benthic invertebrates by modified micro-quick-easy-cheap-efficient-rugged-safe extraction and nanoliquid chromatography-nanospray-tandem mass spectrometry analysis.

    PubMed

    Berlioz-Barbier, Alexandra; Buleté, Audrey; Faburé, Juliette; Garric, Jeanne; Cren-Olivé, Cécile; Vulliet, Emmanuelle

    2014-11-07

    Aquatic ecosystems are continuously contaminated by agricultural and industrial sources. Although the consequences of this pollution are gradually becoming visible, their potential impacts on aquatic ecosystems are poorly known, particularly regarding the risk of bioaccumulation in different trophic levels. To establish a causality relationship between bioaccumulation and disease, experiments on biotic matrices must be performed. In this context, a multi-residue method for the analysis of 35 emerging pollutants in three benthic invertebrates (Potamopyrgus antipodarum, Gammarus fossarum, and Chironomus riparius) has been developed. Because the variation in response of each individual must be taken into account in ecotoxicological studies, the entire analytical chain was miniaturised, thereby reducing the required sample size to a minimum of one individual and scaling the method accordingly. A new extraction strategy based on a modified, optimised and miniaturised "QuEChERS" approach is reported. The procedure involves salting out liquid-liquid extraction of approximately 10-20mg of matrix followed by nano-liquid chromatography-nano electospray ionisation coupled with tandem mass spectrometry. The validated analytical procedure exhibited recoveries between 40 and 98% for all the target compounds and enabled the determination of pollutants on an individual scale in the ng g(-1) concentration. The method was subsequently applied to determine the levels of target analytes in several encaged organisms which were exposed upstream and downstream of an effluent discharge. The results highlighted a bioaccumulation of certain targeted emerging pollutants in three freshwater invertebrates, as well as inter-species differences. 18 out of 35 compounds were detected and eight were quantified. The highest concentrations were measured for ibuprofen in G. fossarum, reaching up to 105 ng g(-1).

  13. 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

  14. Comparison of whole-sediment, elutriate and pore-water exposures for use in assessing sediment-associated organic contaminants in bioassays

    SciTech Connect

    Harkey, G.A. Clemson Univ., Pendleton, SC ); Landrum, P.F. ); Klaine, S.J. )

    1994-08-01

    Bioassays have frequently been used as tools to simulate exposure of benthos to sediment-associated contaminants in hazard assessments. Due to the problems involved with estimating bioavailability in whole-sediment bioassays, aqueous fractions such as elutriates and pore water have been substituted for whole-sediment exposures. The objective of this research was to compare and evaluate the bioavailability of representative neutral hydrophobic contaminants in whole sediments and in aqueous extracts of whole sediment in simultaneous bioassays, using three representative indicator species, Diporeia spp., Chironomus riparius larvae, and Lumbriculus variegatus. Aqueous extracts of whole sediment did not accurately represent the exposure observed in whole sediment. Generally, the aqueous extracts underexposed organisms compared to whole sediment, even after adjusting accumulation to the fraction of organic carbon in the test media. Accumulation comparisons among whole-sediment, elutriate, and pore-water exposures depended on sampling time. At some sampling times for some contaminants, differences in accumulation between a particular aqueous extract and whole sediment were not significant; however, these similarities were not observed for all species at the particular sampling time. Bioaccumulation and contaminant clearance data suggest that a number of factors such as the indicator species, exposure media, and chemical/physical properties of individual contaminants are responsible for the accumulation differences observed among the tested media. Normalizing bioaccumulation to the amount of organic carbon in a source compartment adjusted for bioavailability differences of only some contaminants. The authors suggest that the bioavailability of contaminants such as those tested cannot be accurately predicted in bioassays that expose organisms to aqueous representations of whole sediment.

  15. 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.

  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

    2016-01-01

    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.

  17. 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

  18. 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.

  19. 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.

  20. 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 intoxicity testing. Ingredients used to prepare formulated sediments included commercially available silt, clay, sand, humic acid, dolomite, and α-cellulose (as a source of organic carbon). α-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 α-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

  1. 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...

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

    PubMed

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

    2015-01-01

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

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

    PubMed

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

    2015-01-01

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

  4. 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

  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 Brachymonas chironomi AIMA4T (DSM 19884T) isolated from a Chironomus sp. egg mass

    DOE PAGES

    Laviad, Sivan; Lapidus, Alla; Han, James; ...

    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

  7. 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.

  8. Toxicity of bed sediments from the Niagara River Area of Concern and tributaries, New York, to Chironomus dilutus and Hyalella azteca, 2014-15

    USGS Publications Warehouse

    George, Scott D.; Baldigo, Barry P.; Duffy, Brian T.

    2016-09-20

    The Niagara River was designated as an Area of Concern in 1987 on both the United States and Canadian sides of the international boundary line because past industrial discharges and hazardous waste sites had caused extensive degradation of aquatic habitats. The degradation of the “benthos”, or the benthic macroinvertebrate community, was identified as one of seven beneficial use impairments caused by contaminated bed sediments. The U.S. Geological Survey and the New York State Department of Environmental Conservation, in cooperation with the U.S. Environmental Protection Agency, conducted a study in 2014 and 2015 to gather more extensive data on (a) the toxicity of bed sediments and (b) the status of macroinvertebrate communities on the main stem and tributaries of the Niagara River. This report addresses the first component of that study (toxicity of bed sediments), and summarizes results from laboratory toxicity tests that compare the survival and growth of two macroinvertebrate species between bed sediments from study sites and laboratory controls. Sediment toxicity was negligible at most sites, however poor performance of one or both test species in bed sediments from several tributary sites suggests that the quality of sediments may be adversely affecting benthic macroinvertebrate communities in some tributaries to the Niagara River.

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

    DOE PAGES

    Laviad, Sivan; Lapidus, Alla; Copeland, Alex; ...

    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

  10. 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.

  11. 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.

  12. 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

  13. The chronic toxicity of molybdate to freshwater organisms. I. Generating reliable effects data.

    PubMed

    De Schamphelaere, K A C; Stubblefield, W; Rodriguez, P; Vleminckx, K; Janssen, C R

    2010-10-15

    The European Union regulation on Registration, Evaluation, Authorization and Restriction of Chemical substances (REACH) (EC, 2006) requires the characterization of the chronic toxicity of many chemicals in the aquatic environment, including molybdate (MoO(4)(2-)). Our literature review on the ecotoxicity of molybdate revealed that a limited amount of reliable chronic no observed effect concentrations (NOECs) for the derivation of a predicted no-effect concentration (PNEC) existed. This paper presents the results of additional ecotoxicity experiments that were conducted in order to fulfill the requirements for the derivation of a PNEC by means of the scientifically most robust species sensitivity distribution (SSD) approach (also called the statistical extrapolation approach). Ten test species were chronically exposed to molybdate (added as sodium molybdate dihydrate, Na(2)MoO(4)·2H(2)O) according to internationally accepted standard testing guidelines or equivalent. The 10% effective concentrations (EC10, expressed as measured dissolved molybdenum) for the most sensitive endpoint per species were 62.8-105.6 (mg Mo)/L for Daphnia magna (21day-reproduction), 78.2 (mg Mo)/L for Ceriodaphnia dubia (7day-reproduction), 61.2-366.2 (mg Mo)/L for the green alga Pseudokirchneriella subcapitata (72h-growth rate), 193.6 (mg Mo)/L for the rotifer Brachionus calyciflorus (48h-population growth rate), 121.4 (mg Mo)/L for the midge Chironomus riparius (14day-growth), 211.3 (mg Mo)/L for the snail Lymnaea stagnalis (28day-growth rate), 115.9 (mg Mo)/L for the frog Xenopus laevis (4day-larval development), 241.5 (mg Mo)/L for the higher plant Lemna minor (7day-growth rate), 39.3 (mg Mo)/L for the fathead minnow Pimephales promelas (34day-dry weight/biomass), and 43.2 (mg Mo)/L for the rainbow trout Oncorhynchus mykiss (78day-biomass). These effect concentrations are in line with the few reliable data currently available in the open literature. The data presented in this study can

  14. Predictions of sediment toxicity using consensus-based freshwater sediment quality guidelines

    USGS Publications Warehouse

    Ingersoll, C.G.; MacDonald, D.D.; Wang, N.; Crane, J.L.; Field, L.J.; Haverland, P.S.; Kemble, N.E.; Lindskoog, R.A.; Severn, C.; Smorong, D.E.

    2001-01-01

    The objectives of this study were to compare approaches for evaluating the combined effects of chemical mixtures on the toxicity in field-collected sediments and to evaluate the ability of consensus-based probable effect concentrations (PECs) to predict toxicity in a freshwater database on both a national and regional geographic basis. A database was developed from 92 published reports, which included a total of 1,657 samples with high-quality matching sediment toxicity and chemistry data from across North America. The database was comprised primarily of 10- to 14-day or 28- to 42-day toxicity tests with the amphipod Hyalella azteca (designated as the HA10 or HA28 tests) and 10- to 14-day toxicity tests with the midges Chironomus tentans or C. riparius (designated as the CS10 test). Mean PEC quotients were calculated to provide an overall measure of chemical contamination and to support an evaluation of the combined effects of multiple contaminants in sediments. There was an overall increase in the incidence of toxicity with an increase in the mean quotients in all three tests. A consistent increase in the toxicity in all three tests occurred at a mean quotient > 0.5, however, the overall incidence of toxicity was greater in the HA28 test compared to the short-term tests. The longer-term tests, in which survival and growth are measured, tend to be more sensitive than the shorter-term tests, with acute to chronic ratios on the order of six indicated for H. azteca. Different patterns were observed among the various procedures used to calculate mean quotients. For example, in the HA28 test, a relatively abrupt increase in toxicity was associated with elevated polychlorinated biphenyls (PCBs) alone or with elevated polycyclic aromatic hydrocarbons (PAHs) alone, compared to the pattern of a gradual increase in toxicity observed with quotients calculated using a combination of metals, PAHs, and PCBs. These analyses indicate that the different patterns in toxicity may be

  15. 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

  16. Bioassessment Methodologies for the Regulatory Testing of Freshwater Dredged Material. Phase 2

    DTIC Science & Technology

    1990-03-01

    assessments. Phase II comment: Recommended animals for acute and life cycle testing are the daphnid Daphnia magna , the midge Chironomus tentans, and the... Daphnia magna , represents organisms inhabiting the near-bottom and water-column environment; the other species, Chironomus tentans, represents the...sediments using Daphnia magna and Chironomus tentans in a 48- hr period. Each treatment would be replicated four times using five D. magna and five C

  17. Toxicological Effects of Military Smokes and Obscurants on Aquatic Threatened and Endangered Species

    DTIC Science & Technology

    2004-12-01

    of these S&O on two potential prey of TE fish, Daphnia magna (a filter feeding, planktonic crustacean) and Chironomus tentans (a benthic midge), using...field toxicity testing is an essential component. Acute field toxicity data obtained for Daphnia magna and Chironomus tentans exposed to fog oil, fog

  18. 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 ...

  19. 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...

  20. 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...

  1. 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,...

  2. The National Shipbuilding Research Program: Contaminated Sediment Management Guide for NSRP Shipyards

    DTIC Science & Technology

    1999-10-22

    acute test methods are: l Ten-day freshwater acute toxicity tests using Hyalella azteca (amphipod or scud) and Chironomus tentans (midge). l...toxicity tests using the ampipods Ampelisca abdita, Rhepoxynius abronius, Hyalella azteca, Eohaustorius estuarius, and Leptocherius plumulosus. l Twenty...bioaccumulation method published in 1994 and two new long-term sediment toxicity test methods for chironomus tentans and Hyalella azteca. The final

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

    PubMed

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

    2016-07-07

    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.

  4. A new species of the genus Polyodaspis Duda, 1933 (Diptera: Acalyptratae: Chloropidae) from Central Asia with a key to the Palaearctic species.

    PubMed

    Nartshuk, E P

    2016-01-28

    A new species, Polyodaspis ferulae n. sp., from Central Asia (Uzbekistan) is described. The species was collected on inflorescences of Ferula foetida (Apiaceae). Siphonella levicola Becker in Becker and Stein, 1913 described from Iran is synonymized with Polyodaspis sulcicollis (Meigen, 1838) based on investigation of the holotype. A key to 9 species of the genus Polyodaspis Duda, 1933 is proposed with illustrations of male genitalia. Polyodaspis and Anacamptoneurum Becker, 1903 are treated as separate genera. New localities of P. sulcicollis (Meigen, 1838) from Kazakhstan and Central Asia are given.

  5. 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...

  6. The Mosquitoes of the Subgenus Culex in Southwestern Asia and Egypt (Diptera: Culicidae) (Contributions of the American Entomological Institute. Volume 24, Number 1, 1988)

    DTIC Science & Technology

    1988-01-01

    Synonymy with pipiens by Edwards, 1932a: 210. luteus Meigen, 1804: 6. Type locality: Europe. Type(s) (female) non-extant. Synonymy with pipiens by...lividocostalis (Culex),45,48, 236 longefurcatus (Culex) , 23, 230 longiareolata (Culiseta), 71,81, 228 luteoannula tus (Cu lex) , 233 luteus (Culex

  7. 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...

  8. First record of Lucilia bufonivora Moniez, 1876 (Diptera: Calliphoridae) from North America and key to North American species of the L. bufonivora species group.

    PubMed

    Tantawi, Tarek I; Whitworth, Terry

    2014-11-04

    The obligate anuran myiasis blow fly Lucilia bufonivora Moniez is reported from North America for the first time. The L. bufonivora species group is defined on the basis of the aedeagus and the history and biology of the North American species (L. bufonivora, L. elongata Shannon and L. silvarum (Meigen)) are discussed. A key is provided to separate the three North American species of this group. The North American species L. thatuna Shannon, a member of the L. sericata (Meigen) species group, is also treated because it is likely a parasite of anurans and is poorly known. The male abdominal sternites, aedeagus (L. elongata only), pregonites, postgonites, bacilliform sclerites, ejaculatory sclerites, and female ovipositors and spermathecae of L. elongata and L. thatuna are illustrated for the first time. 

  9. Seasonal and habitat abundance and distribution of some forensically important blow flies (Diptera: Calliphoridae) in Central California.

    PubMed

    Brundage, Adrienne; Bros, Shannon; Honda, Jeffrey Y

    2011-10-10

    Seasonal and habitat calliphorid abundance and distribution were examined weekly for two years (2001-2003) in Santa Clara County, California, using sentinel traps baited with bovine liver. Of the 34,389 flies examined in three defined habitats (rural, urban, and riparian), 38% of the total catch represented Compsomyiops callipes (Bigot) and 23% represented Phormia regina (Meigen). Other flies collected in this survey included Calliphora vomitoria (Linnaeus), Calliphora latifrons (Hough), Lucilia sericata (Meigen), Lucilia cuprina (Wiedemann), and Lucilia mexicana (Macquart), which is a new record for the area. Multivariate MANOVA and ANOVA (P ≤ 0.05) analysis indicate significant seasonal habitat preference for all fly species examined. This information may be used to identify potentially forensically impo rtant fly species within Santa Clara County, California.

  10. 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

  11. Morphology and identification of first instars of the European and Mediterranean blowflies of forensic importance. Part II. Luciliinae.

    PubMed

    Szpila, K; Hall, M J R; Pape, T; Grzywacz, A

    2013-12-01

    First instars of Lucilia ampullacea Villeneuve, Lucilia caesar Linnaeus, Lucilia cuprina Weidemann, Lucilia richardsi Collin, Lucilia sericata Meigen and Lucilia silvarum Meigen (Diptera: Calliphoridae) are thoroughly documented with scanning electron microscopy images, light microscopy photographs and line drawings. The following morphological structures are documented: pseudocephalon, antennal complex, maxillary palpus, facial mask, cephaloskeleton, thoracic and abdominal spinulation, spiracular field, and posterior spiracles. New diagnostic features of the cephaloskeleton are presented and the spinulation of the abdominal segments is described. Earlier descriptions are summarized and major discrepancies with the current study are discussed. The present results allow for the clarification, correction and, especially, complementing existing information provided by numerous authors. The first instar larva of L. richardsi is described for the first time and an identification key to the first instars of European species of Lucilia Robineau-Desvoidy of forensic importance is presented.

  12. 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] ...

  13. 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.

  14. Bioaccumulation and Food Chain Transfer of Polycyclic Aromatic Hydrocarbons and Heavy Metals: A Laboratory and Field Investigation.

    DTIC Science & Technology

    1992-10-14

    toxicity (96 h test with Ceriodaphnia dubia) has been observed from stations located 30 Km downstream from California Gulch (Clements, unpublished data...Chronic effects of Cd on the reproduction of the guppy (Poecillia reticulata) through Cd-accumulated midge larvae (Chironomus yQshimatsui). Ecotox

  15. 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.

  16. Cold Spring Brook Site Investigation Work Plan

    DTIC Science & Technology

    1994-11-01

    obtain laboratory data to evaluate adverse effects associated with exposure of the freshwater invertebrate species Chironomus tentans and Hyalella azteca...To provide additional characterization of potential sediment toxicity, the Army will perform 10-day survival tests using Hyalella azteca, an amphipod

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

    PubMed

    Podenas, Sigitas; Byun, Hye-Woo

    2016-06-30

    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.

  18. [Description and key to the main species of Calliphoridae (Diptera) larvae of forensic importance from Colombia].

    PubMed

    Florez, Eliana; Wolff, Marta

    2009-01-01

    Larvae of 13 blowfly species from Colombia are described and an illustrated key for all them is presented. All larval instars of Calliphora nigribasis Macquart, Cochliomyia macellaria (Fabricius), Chrysomya albiceps (Wiedemann), Chrysomya megacephala (Fabricius), Hemilucilia segmentaria (Fabricius), Hemilucilia semidiaphana (Rondani), Lucilia eximia (Weidemann) are described, but the second and third instars of Compsomyiops verena (Walter), and only the third instar of Calliphora vicina Robineau-Desvoidy, Cochliomyia hominivorax (Coquerel), Lucilia peruviana Robineau-Desvoidy, Lucilia sericata (Meigen) and Sarconesiopsis magellanica (Le Guillou).

  19. Description of the Egg of Aedes (Aedimorphus) domesticus (Theobald) (Diptera: Culicidae)

    DTIC Science & Technology

    1972-01-01

    Theobald) are herein des- cribed for the first time. Aedes vexans (Meigen) is the only other species in the subgenus Aedimorphus which has the eggs ...1972 2. REPORT TYPE 3. DATES COVERED 00-00-1972 to 00-00-1972 4. TITLE AND SUBTITLE Description of the Egg of Aedes (Aedimorphus) domesticus...ANSI Std Z39-18 60 Description of the Egg of Aedes (Aedimorphus) domesticus (Theobald) (Diptera: Culicidae)l John F. Reinert* Department of

  20. Transcriptional Analysis of Four Family 4 P450s in a Puerto Rico Strain of Aedes aegypti (Diptera: Culicidae) Compared With an Orlando Strain and Their Possible Functional Roles in Permethrin Resistance

    DTIC Science & Technology

    2014-05-01

    With an Orlando Strain and Their Possible Functional Roles in Permethrin Resistance WILLIAM R. REID,1 ANNE THORNTON,2,3 JULIA W. PRIDGEON,4,5,6 JAMES J...resistance of the Puerto Rico strain to permethrin. To determine the cytochrome P450s that might play a role in the resistance to permethrin, the...the four cytochrome P450s had any functional role in permethrin resistance, transgenicDrosophilamelanogasterMeigen linesoverexpressing the four family

  1. New Record and Updated Checklists of the Mosquitoes of Afghanistan and Iraq

    DTIC Science & Technology

    2008-08-12

    claviger (Meigen). Although Buck et al. (1972), Ward (1972), Danilov (1985a, 1985b) reported Cx. univittatus Theobald from Afghanistan, it actually...refers to Cx. perexiguus Theobald according to Harbach (1988). Danilov (1978) stated that Ae. versicolor (Barraud) “may be expected in the mountain...K Ae.(Och. pulcritarsis (Rondani) D - Ae. (Stegomyia) aegypti (Linnaeus) - Anopheles (Anopheles) algeriensis Theobald A3, D, G, W, X A2, G, P An

  2. Evaluation of potential confounding factors in sediment toxicity tests with three freshwater benthic invertebrates

    SciTech Connect

    Ankley, G.T.; Benoit, D.A. ); Balogh, J.C. ); Reynoldson, T.B.; Day, K.E. ); Hoke, R.A. )

    1994-04-01

    The authors examined the effects of natural sediment physicochemical properties on the results of lab tests with the amphipod Hyalella azteca, the midge Chironomus tentans, and the oligochaete Lumbriculus variegatus. Ten-day exposures with the three species were conducted with 50 uncontaminated sediment samples from Lakes Erie, Huron, Superior, and Ontario, which differed markedly with regard to characteristics such as grain-size distribution, organic carbon content, and mineralogical composition. Tests were conducted both with and without the addition of exogenous food. Survival of Hyalella azteca, survival and growth of Chironomus tentans, and survival/reproduction and growth of Lumbriculus variegatus were significantly greater in tests in which the animals were fed vs, those in which they were not. Approximately 10% of the tests in which Hyalella azteca was not fed and 80% of tests in which the amphipods were fed resulted in >80% survival, a common criterion for defining the acceptability of tests with Hyalella azteca in clean control sediments. Similarly, a relatively high percentage of the tests in which Chironomus tentans was not fed would have failed a control survival criterion of 70% for the midge. Hence, there is significant potential for false positive results if Hyalella azteca or Chironomus tentans is not fed during sediment tests. Predictive modeling of the assay results in relationship to sediment physicochemical characteristics failed to reveal any additional factors that influenced survival of Hyalella azteca and Chrionomus tentans, or reproduction and growth of Lumbriculus variegatus in tests in which the organisms were fed. However, linear modeling did suggest that growth of fed as well as unfed Chironomus tentans may have been influenced by grain-size distribution of the test sediments.

  3. Aquatic Plant Control Research Program: Proceedings Annual Meeting (28th) Held in Baltimore, Maryland on November 15-18, 1993

    DTIC Science & Technology

    1994-06-01

    administration of a corn - Corps of Engineers (HQUSACE) as the prelmsive Corp-wide APC progrm Aquatic Plant Control Operations Support Center (APCOSC) in...and staff at the Diptera. Chironomid larvae were corn - Sino American Biological Control Laboratory, monly associated with the plants . A Chironomus...Miscellaneous Paper A9-ý June 1994 US Army Corps AD-A283 599 of Engineers Waterways Experiment Station Aquatic Plant Control Resarch Program

  4. Histone acetylation in insect chromosomes.

    PubMed

    Allfrey, V G; Pogo, B G; Littau, V C; Gershey, E L; Mirsky, A E

    1968-01-19

    Acetylation of histones takes place along the salivary gland chromosomes of Chironomus thummi when RNA synthesis is active. It can be observed but not measured quantitatively by autoradiography of chromosome squashes. The "fixatives" commonly used in preparing squashes of insect chromosomes preferentially extract the highly acetylated "arginine-rich" histone fractions; the use of such fixatives may explain the reported absence of histone acetylation in Drosophila melanogaster.

  5. Laboratory Evaluation of the Toxicity of Cyclotrimethylene Trinitramine (RDX) to Aquatic Organisms

    DTIC Science & Technology

    1977-12-01

    concentrations of RDX in water during chronic exposures of Daphnia magna and Chironomus tentans. 75 17 -, Weekly mean (standard deviation) percent survival...of the water flea ( Daphnia magna ) exposed t) RDX up to 42 days. 76 .TABLE NO. PAGE 18 - Mean (standard deviation) number of young water flea produced...per parthenogenetic female Daphnia magna exposed to RDX during the 42-day exposure. 77 19 - Mean (standard deviation) percent survival of the Po midges

  6. Plow Shop Pond Supplemental Investigation Work Plan

    DTIC Science & Technology

    1994-09-01

    Ceriodaphnia dubia to sediment elutriate, and Chironomus tentans and Hyallella azteca to whole sediment. Twenty-two short-term chronic toxicity tests with C...in the proposed short-term chronic test include survival, growth, and reproduction . Twenty-two sediment samples for screening level bioassay will be...collected concurrently and from the same locations as the sediment samples collected for3 analytical chemical analyses. Ceriodaphnia dubia or water

  7. Chromatin structure in bands and interbands of polytene chromosomes imaged by atomic force microscopy.

    PubMed

    de Grauw, C J; Avogadro, A; van den Heuvel, D J; vd Werf, K O; Otto, C; Kraan, Y; van Hulst, N F; Greve, J

    1998-01-01

    Polytene chromosomes from Drosophila melanogaster, observed from squash preparations, and chromosomes from Chironomus thummi thummi, investigated under physiological conditions, are imaged using an Atomic Force Microscope. Various chromatin fiber structures can be observed with high detail in fixed chromosomes and correspond to structures which are also observed in chromosomes of diploid cells. Unfixed chromosomes can be imaged in buffer and show less fiber-like details because of the inherent soft nature of the chromatin material.

  8. 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.

  9. 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.

  10. Detection of eastern equine encephalitis virus antibodies in moose (Alces americana), Maine, 2010.

    PubMed

    Lubelczyk, Charles; Elias, Susan P; Kantar, Lee; Albert, Jennifer; Hansen, Stephen; Saxton-Shaw, Kali; MacMillan, Katharine; Smith, Leticia B; Eisen, Rebecca; Swope, Bethany; Smith, Robert Pease; Mutebi, John-Paul

    2014-01-01

    Moose sera were collected from harvested animals during the 2010 hunting season in Maine. Of the 145 serum samples screened by plaque reduction neutralization test (PRNT), 16 (11%) had antibodies to eastern equine encephalitis virus (EEEV). Positive samples were collected from Aroostook County (n=13), Somerset County (n=2), and Piscataquis County (n=1) in northern and central Maine. Preliminary mosquito surveillance revealed the presence of enzootic and bridge vectors mosquitoes, including Culiseta (Climacura) melanura (Coquillett), Aedes (Aedimorphus) vexans (Meigen), and Coquillettidia (Coquillettidia) perturbans (Walker). Select mosquito species were tested by RT-PCR for the presence of EEEV. None were positive. This is the first report of EEEV in moose from Maine.

  11. Arthropods of forensic importance on pig carrion in the Coahuilan semidesert, Mexico.

    PubMed

    Valdes-Perezgasga, Ma Teresa; Sanchez-Ramos, Francisco Javier; Garcia-Martinez, Oswaldo; Anderson, Gail S

    2010-07-01

    This is the first report of an ongoing research to establish a sarcosaprophagous arthropod database in the Coahuilan semidesert. Seven pigs (Sus scrofa L.) were used as human models to determine succession in an open urban area during the 2007 winter-spring period. Arthropods were collected manually and from pitfall traps. Carcass biomass loss, as well as arthropod colonization, was recorded during 71 days postmortem. Five decomposition stages were identified during which most abundant orders were found to be Diptera, Coleoptera, and Hymenoptera. Lucilia sericata (Meigen), Chrysomya rufifacies (Macquart), Necrobia rufipes (DeGeer), Dermestes maculatus (DeGeer), Pheidole hyatti Emery, and Pogonomyrmex rugosus Emery stood out as dominant species.

  12. 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.

  13. 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.

  14. Taxonomy and immature stages of the Platystomatidae (Diptera: Tephritoidea) of Israel.

    PubMed

    Bodner, L; Freidberg, A

    2016-09-28

    The Platystomatidae fauna of Israel is reviewed. Eleven species in two genera, Platystoma Meigen and Rivellia Robineau-Desvoidy, are recognized. Ten of the eleven species are recorded from Israel for the first time, and six of them are described as new: Platystoma dalia n. sp., P. elizabethae n. sp., P. geula n. sp., P. torridum n. sp., P. trigonum n. sp., and Rivellia israelica n. sp. Detailed descriptions, redescriptions, illustrations, and keys to all local platystomatid taxa are provided. The complete life-cycle of P. torridum n. sp. is reported, with descriptions and illustrations of egg, 3rd instar larva, and puparium.

  15. Biting midges of the subfamily Forcipomyiinae (Diptera: Ceratopogonidae) from the Middle East, with keys and descriptions of new species.

    PubMed

    Alwin-Kownacka, Alicja; Szadziewski, Ryszard; Szwedo, Jacek

    2016-10-05

    Middle East biting midges of the genera Atrichopogon Kieffer and Forcipomyia Meigen, subfamily Forcipomyiinae Lenz, covering 41 species are reviewed. Two new species are described and illustrated: Forcipomyia (F.) siverekensis Alwin & Szadziewski sp. nov. and Forcipomyia (Microhelea) borkenti Alwin & Szadziewski sp. nov. The list includes 16 species of Atrichopogon and 25 of Forcipomyia. Nine species previously described by Vimmer and Kieffer from the Middle East are treated as nomina dubia and not included in the list.        Keys to identification of Atrichopogon and Forcipomyia species of the Middle East are also provided.

  16. Impact of freezing on the emergence of Culicoides chiopterus and Culicoides dewulfi from bovine dung.

    PubMed

    Steinke, S; Lühken, R; Kiel, E

    2015-04-15

    The emergence of Culicoides chiopterus (Meigen), 1830 and C. dewulfi Goetghebuer, 1936 (Diptera: Ceratopogonidae) from cowpats in northwestern Germany was investigated. In order to investigate the survival of both species at low temperatures, cowpat subsamples were frozen for 48h at -18 and -21°C. Emergence from frozen and non-frozen samples was compared. The number of emerging adults of C. chiopterus from samples frozen at -18°C was greatly reduced and no emergence was observed from samples frozen at -21°C. No adult C. dewulfi emerged from frozen samples, suggesting this species is less resistant to these temperatures, compared to C. chiopterus.

  17. Seasonal and Daily Activity Patterns of Mosquito (Diptera: Culicidae) Vectors of Pathogens in Northeastern Italy.

    PubMed

    Montarsi, Fabrizio; Mazzon, Luca; Cazzin, Stefania; Ciocchetta, Silvia; Capelli, Gioia

    2015-01-01

    The seasonal and daily activity of mosquito vectors of pathogens affecting animals and humans were studied in northeastern Italy at a site within the Po River Delta Park. A CDC-CO2 trap and a gravid trap were operated at 2-h intervals for 24 h every 15 d from May to October 2010. Overall, 5,788 mosquitoes comprising six species were collected, namely Culex pipiens L. (75.1% of total), Aedes caspius (Pallas) (15.2%), Aedes vexans (Meigen) (6.9%), Anopheles maculipennis s.l. Meigen (2.6%), Culiseta annulata (Schrank) (0.2%), and Culex modestus Ficalbi (<0.1%). The relative abundance of these species increased from May until the beginning of July and then decreased, disappearing at the beginning of October. The diel host-seeking patterns and oviposition site-seeking patterns were species specific and were differentially affected by the ecological variables recorded at the day and hour of mosquito collection or two weeks before collection. Knowledge of the seasonal and daily host-seeking patterns of mosquitoes highlights the time periods of the day and the seasons of potential exposure for animals and humans to mosquito-borne pathogens, therefore delineating the best time for the application of preventive measures. Furthermore, knowledge of the oviposition site-seeking activity of the mosquitoes optimizes the capture of gravid females, thereby enhancing the likelihood of detecting pathogens.

  18. Landscape and land cover factors influence the presence of Aedes and Anopheles larvae.

    PubMed

    Vanwambeke, Sophie O; Somboon, Pradya; Harbach, Ralph E; Isenstadt, Mark; Lambin, Eric F; Walton, Catherine; Butlin, Roger K

    2007-01-01

    The objective of this study was to test for associations between land cover data and the presence of mosquito larvae of the genera Aedes Meigen and Anopheles Meigen in northern Thailand at the landscape scale. These associations were compared with associations between larval habitat variables and the presence of mosquito larvae at a finer spatial scale. Collection data for the larvae of one Aedes species and three species-groups of Anopheles, all of which are involved in pathogen transmission, were used. A variety of northern Thai landscapes were included, such as upland villages, lowland villages and peri-urban areas. Logistic regression was used to evaluate associations. Generally, land cover and landscape variables explained the presence of larvae as well as did larval habitat variables. Results were best for species/species-groups with specific habitat requirements. Land cover variables act as proxies for the types of habitat available and their attributes. Good knowledge of the habitat requirements of the immature stages of mosquitoes is necessary for interpreting the effects of land cover.

  19. Larval Distribution and Behavior of Chrysomya rufifacies (Macquart) (Diptera: Calliphoridae) Relative to Other Species on Florida Black Bear (Carnivora: Ursidae) Decomposing Carcasses.

    PubMed

    Swiger, S L; Hogsette, J A; Butler, J F

    2014-02-01

    Larval interactions of dipteran species, blow flies in particular, were observed and documented daily over time and location on five black bear carcasses in Gainesville, FL, USA, from June 2002 - September 2004. Cochliomyia macellaria (Fabricius) or Chrysomya megacephala (Fabricius) larvae were collected first, after which Chrysomya rufifacies (Macquart) oviposited on the carcasses in multiple locations (i.e., neck, anus, and exposed flesh) not inhabited already by the other blow fly larvae. Within the first week of decomposition, C. rufifacies larvae grew to ≥12 mm, filling the carcasses with thousands of larvae and replacing the other calliphorid larvae either through successful food source competition or by predation. As a result, C. macellaria and C. megacephala were not collected past their third instar feeding stage. The blow fly species, C. megacephala, C. macellaria, Lucilia caeruleiviridis (Macquart), Phormia regina (Meigen), Lucilia sericata (Meigen), and C. rufifacies, completed two developmental cycles in the 88.5-kg carcass. This phenomenon might serve to complicate or prevent the calculation of an accurate postmortem interval.

  20. Phenotypic differentiation and phylogenetic signal of wing shape in western European biting midges, Culicoides spp., of the subgenus Avaritia.

    PubMed

    Muñoz-Muñoz, F; Talavera, S; Carpenter, S; Nielsen, S A; Werner, D; Pagès, N

    2014-09-01

    In the past decade biting midges of the subgenus Avaritia (Diptera: Ceratopogonidae) have been popular subjects of applied entomological studies in Europe owing to their implication as biological vectors in outbreaks of bluetongue and Schmallenberg viruses. This study uses a combination of cytochrome oxidase subunit I barcode sequencing and geometric morphometric analyses to investigate wing shape as a means to infer species identification within this subgenus. In addition the congruence of morphological data with different phylogenetic hypotheses is tested. Five different species of the subgenus Avaritia were considered in the study (C. obsoletus (Meigen); C. scoticus Kettle and Lawson; C. chiopterus (Meigen); C. dewulfi Goetghebuer and C. imicola (Kieffer)). The study demonstrated that over 90% of individuals could be separated correctly into species by their wing shape and that patterns of morphological differentiation derived from the geometric morphometric analyses were congruent with phylogenies generated from sequencing data. Morphological data produced are congruent with monophyly of the subgenus Avaritia and the exclusion of C. dewulfi from the group containing C. obsoletus, C. scoticus and C. chiopterus. The implications of these results and their importance in a wider context of integrating multiple data types to interpret both phylogeny and species characterization is discussed.

  1. 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

  2. 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.

  3. Biting Midges (Diptera: Ceratopogonidae) from Cambay Amber Indicate that the Eocene Fauna of the Indian Subcontinent Was Not Isolated

    PubMed Central

    Stebner, Frauke; Szadziewski, Ryszard; Singh, Hukam; Gunkel, Simon; Rust, Jes

    2017-01-01

    India’s unique and highly diverse biota combined with its unique geodynamical history has generated significant interest in the patterns and processes that have shaped the current distribution of India’s flora and fauna and their biogeographical relationships. Fifty four million year old Cambay amber from northwestern India provides the opportunity to address questions relating to endemism and biogeographic history by studying fossil insects. Within the present study seven extant and three fossil genera of biting midges are recorded from Cambay amber and five new species are described: Eohelea indica Stebner & Szadziewski n. sp., Gedanohelea gerdesorum Stebner & Szadziewski n. sp., Meunierohelea cambayana Stebner & Szadziewski n. sp., Meunierohelea borkenti Stebner & Szadziewski n. sp., and Meunierohelea orientalis Stebner & Szadziewski n. sp. Fossils of species in the genera Leptoconops Skuse, 1889, Forcipomyia Meigen, 1818, Brachypogon Kieffer, 1899, Stilobezzia Kieffer, 1911, Serromyia Meigen, 1818, and Mantohelea Szadziewski, 1988 are recorded without formal description. Furthermore, one fossil belonging to the genus Camptopterohelea Wirth & Hubert, 1960 is included in the present study. Our study reveals faunal links among Ceratopogonidae from Cambay amber and contemporaneous amber from Fushun, China, Eocene Baltic amber from Europe, as well as the modern Australasian and the Oriental regions. These findings imply that faunal exchange between Europe, Asia and India took place before the formation of Cambay amber in the early Eocene. PMID:28076427

  4. 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.

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

    PubMed

    Podeniene, Virginija; Naseviciene, Nijole; Podenas, Sigitas

    2014-02-10

    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. 

  6. Horse-, bird-, and human-seeking behavior and seasonal abundance of mosquitoes in a West Nile virus focus of southern France.

    PubMed

    Balenghien, T; Fouque, F; Sabatier, P; Bicout, D J

    2006-09-01

    After 35 yr of disease absence, West Nile virus (family Flaviviridae, genus Flavivirus, WNV) circulation has been regularly detected in the Camargue region (southern France) since 2000. WNV was isolated from Culex modestus Ficalbi, which was considered the main vector in southern France after horse outbreaks in the 1960s. Recent WNV transmissions outside of the Cx. modestus distribution suggested the existence of other vectors. To study potential WNV vectors, horse- and bird-baited traps and human landing collections of mosquitoes were carried out weekly from May to October 2004 at two Camargue sites: one site in a wet area and the other site in a dry area, both chosen for their past history of WNV transmission. At the wet site, the most abundant species in bird-baited traps were Culex pipiens L. and Cx. modestus; both species also were found in lower proportions on horses and humans. The most abundant species in horse-baited traps and human landing collections were Aedes caspius (Pallas), Aedes vexans (Meigen), and Anopheles hyrcanus (Pallas) sensu lato; some of these species were occasionally collected with avian blood at the end of the summer. Anopheles maculipennis Meigen sensu lato was an abundant horse feeder, but it was rarely collected landing on human bait and never contained avian blood. At the dry site, Cx. pipiens was the most abundant species in bird- and horse-baited traps. The seasonal and circadian dynamics of these species are analyzed, and their potential in WNV transmission in Camargue discussed.

  7. Field evaluation against mosquitoes of regular and polymer-based deet formulations in Manitoba, Canada, with comment on methodological issues.

    PubMed

    Schofield, Steven; Tepper, Martin; Gadawski, Randy

    2007-05-01

    Studies were carried out in Manitoba, Canada, to evaluate the efficacy of three repellent products for protection of human subjects against mosquito bites. All test substances contained the active ingredient N,N-diethyl-3-methylbenzamide (deet); two were polymer-based creams (3M Ultrathon Insect Repellent and Morflex DEET Insect Repellent 30) and the third (Muskol Insect Repellent) was an alcohol-based pump spray formulation. Application of repellent was to the forearm and lower legs of subjects at 0.75 or 0.83 mg deet/cm2. Exposure to mosquito attack was continuous, and efficacy was determined by measuring complete protection time (CPT). Regardless of whether delivered as a polymer cream or in alcohol, mean CPT was similar for the tested repellents at 623 +/- 107 to 644 +/- 163 min. By contrast, mean CPT for the different test subjects showed significant variation, ranging from 531 +/- 42 to 756 +/- 54 min. Mosquito collections from untreated human test subjects, Centers for Disease Control and Prevention (CDC) light traps and sweep-netting consisted primarily of Ochlerotatus sticticus (Meigen) and Aedes vexans (Meigen). Relative catch of these two species was similar for different sampling methods through much of the day, but not in the evening, when CDC light traps oversampled Ae. vexans relative to untreated human subjects. Results are used to highlight the need to account for intersubject variation when designing repellent studies, and also are used as a basis to discuss limitations associated with using relatively few subjects when testing repellents.

  8. Egg morphology of nine species of Pollenia Robineau-Desvoidy, 1830 (Diptera: Calliphoridae).

    PubMed

    Grzywacz, Andrzej; Szpila, Krzysztof; Pape, Thomas

    2012-07-01

    Egg morphology of nine species of the cluster fly genus Pollenia Robineau-Desvoidy was studied with scanning electron microscopy. Funnel-shaped micropylar area, chorion covered with centrally depressed hexagons, well developed hatching pleats on the dorsal surface encompassing the median area were found in eggs of all species: P. amentaria (Scopoli), P. angustigena Wainwright, P. atramentaria (Meigen), P. labialis Robineau-Desvoidy, P. mayeri Jacentkovsky, P. pediculata Macquart, P. rudis (Fabricius), P. similis (Jacentkovsky), and P. vagabunda (Meigen). Untypical for Calliphoridae, a dual morphological structure of plastron-bearing area is described here for the first time. On the basis of our observations, all species studied share the presence of a plastron respiratory function on the entire surface between the hatching lines. Differences between species were found in the shape of the longitudinal hatching pleats and the proportion between 'island pattern' and 'hexagonal pattern' of their chorionic surface, and in the intensity of perforation of hexagons of the median area. Comparisons of Pollenia egg morphology with that of other representatives of Calliphoridae revealed its unique structure, allowing easy differentiation from other representatives of the family.

  9. Identification of forensically important sarcophagid flies (Diptera: Sarcophagidae) in China, based on COI and 16S rDNA gene sequences.

    PubMed

    Guo, Yadong; Cai, Jifeng; Chang, Yunfeng; Li, Xiang; Liu, Qinlai; Wang, Xinghua; Wang, Xiang; Zhong, Ming; Wen, Jifang; Wang, Jiangfeng

    2011-11-01

    Insects attracted to cadavers may provide important indications of the postmortem interval (PMI). However, use of the flesh flies (Diptera: Sarcophagidae) for PMI estimation is limited as the species are often not morphologically distinct, especially as immatures. In this study, 23 forensically important flesh flies were collected from 13 locations in 10 Chinese provinces. Then, a 278-bp segment of the cytochrome oxidase subunits one (COI) gene and a 289-bp segment of the 16S rDNA gene of all specimens were successfully sequenced. Phylogenetic analysis of the sequenced segments showed that all sarcophagid specimens were properly assigned into four species (Boerttcherisca peregrina [Robineau-Desvoidy, 1830], Helicophagella melanura [Meigen, 1826], Parasarcophaga albiceps [Meigen, 1826], and Parasarcophaga dux [Thompson, 1869]) with relatively strong supporting values, thus indicating that the COI and 16S rDNA regions are suitable for identification of sarcophagid species. The difference between intraspecific threshold and interspecific divergence confirmed the potential of the two regions for sarcophagid species identification.

  10. Biting Midges (Diptera: Ceratopogonidae) from Cambay Amber Indicate that the Eocene Fauna of the Indian Subcontinent Was Not Isolated.

    PubMed

    Stebner, Frauke; Szadziewski, Ryszard; Singh, Hukam; Gunkel, Simon; Rust, Jes

    2017-01-01

    India's unique and highly diverse biota combined with its unique geodynamical history has generated significant interest in the patterns and processes that have shaped the current distribution of India's flora and fauna and their biogeographical relationships. Fifty four million year old Cambay amber from northwestern India provides the opportunity to address questions relating to endemism and biogeographic history by studying fossil insects. Within the present study seven extant and three fossil genera of biting midges are recorded from Cambay amber and five new species are described: Eohelea indica Stebner & Szadziewski n. sp., Gedanohelea gerdesorum Stebner & Szadziewski n. sp., Meunierohelea cambayana Stebner & Szadziewski n. sp., Meunierohelea borkenti Stebner & Szadziewski n. sp., and Meunierohelea orientalis Stebner & Szadziewski n. sp. Fossils of species in the genera Leptoconops Skuse, 1889, Forcipomyia Meigen, 1818, Brachypogon Kieffer, 1899, Stilobezzia Kieffer, 1911, Serromyia Meigen, 1818, and Mantohelea Szadziewski, 1988 are recorded without formal description. Furthermore, one fossil belonging to the genus Camptopterohelea Wirth & Hubert, 1960 is included in the present study. Our study reveals faunal links among Ceratopogonidae from Cambay amber and contemporaneous amber from Fushun, China, Eocene Baltic amber from Europe, as well as the modern Australasian and the Oriental regions. These findings imply that faunal exchange between Europe, Asia and India took place before the formation of Cambay amber in the early Eocene.

  11. Mosquito and West Nile virus surveillance in northeast Montana, U.S.A., 2005 and 2006.

    PubMed

    Friesen, K M; Johnson, G D

    2014-03-01

    Mosquito and West Nile virus (WNV) surveillance was conducted on a national wildlife refuge in northeast Montana in 2005 and 2006, during which outbreaks of WNV in a colony of American white pelicans (Pelecanus erythrorhynchos Gmelin) (Pelecaniformes: Pelecanidae) resulted in juvenile mortality rates of ∼ 31%. Both years, floodwater species Ochlerotatus dorsalis (Meigen) (Diptera: Culicidae), Aedes vexans (Meigen) (Diptera: Culicidae) and Ochlerotatus flavescens (Muller) (Diptera: Culicidae) comprised 78% of the total collection and heightened host-seeking activity was observed from mid-June to mid-July. Culex tarsalis Coquillett (Diptera: Culicidae) was most active from mid-July to mid-August and comprised 18% of the collection in 2005 and 20% in 2006. However, fewer than 10% of the Cx. tarsalis females collected in 2006 were obtained adjacent to the pelicans' nesting grounds. Minimum infection rates per 1000 Cx. tarsalis tested for WNV were 1.36 in 2005 and 1.41 in 2006. All pools in which WNV was detected in 2006 were composed of females collected 10 km from the nesting grounds. Substantial juvenile pelican mortality in 2006 despite reductions in the population of the primary vector and in mosquito infection rates near the colony suggests that the methods used to detect the introduction of WNV were too coarse and that amplification of the virus within the colony may reflect causes other than mosquito infection.

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

    PubMed

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

    2014-03-17

    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.

  13. 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.

  14. Evaluation of a polyacrylamide soil additive to reduce agricultural-associated contamination.

    PubMed

    Krauth, D M; Bouldin, J L; Green, V S; Wren, P S; Baker, W H

    2008-08-01

    Polyacrylamide is an effective water treatment product used to reduce suspended sediment and associated contaminants. An anionic polyacrylamide-containing product was tested for sediment and associated contaminant reduction and potential toxicity in agricultural irrigation and rainfall runoff. The product effectively reduced turbidity, total suspended solids, and phosphate concentrations in the field when compared to the untreated runoff waters. Acute survival of Ceriodaphnia dubia and Pimephales promelas was not decreased compared to laboratory controls. No significant increases in toxicity were measured in 10-d sediment toxicity tests with Chironomus dilutus. Product applications were effective in controlling sediment and nutrient contamination without increasing measured toxicity.

  15. Use of sediment serial dilution series to establish biological effect levels and clean-up goals

    SciTech Connect

    Timmer, E.; DeLong, T.; Millard, J.; Dobroski, C.

    1995-12-31

    A sediment serial dilution study was used to determine biological effect levels for two freshwater invertebrates, Chironomus tentans and Hyalella azteca. The sediments for the test were collected from a New England brook which contained elevated levels of lead and polychlorinated aromatic hydrocarbons. The objective of the sediment dilution study was two-fold: (1 ) to provide a site-specific estimation of biological effect levels, thus reducing uncertainties associated with using literature-based values, and (2) to establish clean-up goals specific to this freshwater system.

  16. 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.

  17. A new method based on branch length similarity (BLS) entropy to characterize time series

    NASA Astrophysics Data System (ADS)

    Lee, Sang-Hee

    2016-10-01

    In previous studies, branch length similarity (BLS) entropy was suggested to characterize spatial data, such as an object's shape and poses. The entropy was defined on a simple network consisting of a single node and branches. The simple network was referred to as the "unit branching network" (UBN). In the present study, I applied the BLS entropy concept to temporal data (e.g., time series) by forming UBNs on the data. The temporal data were obtained from the logistic equation and the movement behavior of Chironomid riparius. Using the UBNs, I calculated a variable, γ, defined as the ratio of the mean entropy value to the standard deviation for the difference values of the sets of two UBNs connected with each other along a given direction. Consequently, I found that ? could be effectively used to characterize temporal data.

  18. 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.

  19. 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

  20. The blowflies of the Madeira Archipelago: species diversity, distribution and identification (Diptera, Calliphoridae s. l.)

    PubMed Central

    Prado e Castro, Catarina; Szpila, Krzysztof; Martínez-Sánchez, Anabel; Rego; Silva, Isamberto; Serrano, Artur R.M.; Boieiro, Mário

    2016-01-01

    Abstract Knowledge on the taxonomic diversity and distribution of blowflies from the Madeira Archipelago is updated. New and interesting findings are reported for poorly studied islands and islets of this archipelago, together with a brief analysis of the diversity of Macaronesian Calliphoridae s. l. Seven blowfly species were collected during this study, including the first records of Calliphora vicina Robineau-Desvoidy, 1830, Chrysomya albiceps (Wiedemann, 1819), Lucilia sericata (Meigen, 1826), Pollenia rudis (Fabricius, 1794) and Stomorhina lunata (Fabricius, 1805) from Porto Santo, and of Calliphora vicina, Lucilia sericata and Stomorhina lunata from Desertas Islands. The presence of Calliphora loewi Enderlein, 1903 in Madeira Laurisilva forest is discussed and its first instar larva is redescribed, revealing important differences in relation to its original description. An identification key to the adult Madeiran blowflies is provided for the first time. PMID:27917052

  1. Insect Visitors and Potential Pollinators of Orchis militaris (Orchidaceae) in Southern Belgium.

    PubMed

    Henneresse, Thomas; Tyteca, Daniel

    2016-01-01

    As part of a research project on the food deception strategy in Orchis militaris (L.), the objective of this study was to identify insect visitors and potential pollinators of this orchid species in Belgium. In 2013, insects were collected over 2 d per site in five localities distributed in Southern Belgium (Wallonia). A total of 104 insects belonging to 49 species were caught. Dipterans were the most abundant visitors (50% of total specimens), followed by Hymenopterans (32%). Rhingia campestris Meigen, Bombylius venosus Mikan, Apis mellifera (L.), and Bombus lapidarius (L.) were the most abundant species. Only five specimens bore one to more than 10 pollinia: four honeybees (A. mellifera) and one bumblebee worker (B. lapidarius). These two species should be considered as potential pollinators in the study area, but probably not confirmed ones.

  2. Limonia crane flies (Diptera: Limoniidae) of Korea.

    PubMed

    Podenas, Sigitas; Podeniene, Virginija

    2017-02-09

    The Korean species of Limonia Meigen, 1803 crane flies (Diptera: Limoniidae) are taxonomically revised. Species L. annulata Lackschewitz, 1940 (Lackschewitz, Pagast, 1940), L. bidens Savchenko, 1979, L. episema Alexander, 1924, L. fusciceps fusciceps Alexander, 1924, L. juvenca Alexander, 1935, L. messaurea messaurea Mendl, 1971, L. nemoralis Savchenko, 1983 are new records for the Korean peninsula and L. pia n. sp. is described. Synonymy of L. venerabilis Alexander, 1938 with L. macrostigma (Schummel, 1829) is confirmed. L. tanakai (Alexander, 1921) is not confirmed for the Korean Peninsula. An identification key, redescriptions and illustrations of all species and both sexes of adults, if they were found in Korea, are presented. Descriptions, illustrations and habitat characteristics are given for the previously unknown larva and pupa of L. parvipennis Alexander, 1940. Distinguishing morphological characters of the last instar larvae of Korean Limonia are discussed. Keys to the known Korean Limonia larvae and pupae are compiled.

  3. 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.

  4. Field studies on Culicoides (Diptera: Ceratopogonidae) activity and response to deltamethrin applications to sheep in northeastern Spain.

    PubMed

    Mullens, Bradley A; Gerry, Alec C; Monteys, Victor Sarto I; Pinna, M; González, A

    2010-01-01

    An enclosure trapping experiment compared numbers and engorgement of Culicoides spp. taken from treated sheep (7.5% deltamethrin) to Culicoides from untreated sheep. Attack rates were low (0.2/min), but 58% of Culicoides obsoletus s.l. and 67% of Culicoides parroti Kieffer engorged on untreated sheep, and no engorgement occurred on treated sheep on 0 and 4 d posttreatment. A UV light trap in a livestock barn collected eight Culicoides spp. (510 individuals), dominated by C. obsoletus (Meigen) (68%), Culicoides imicola Kieffer (19%), Culicoides circumscriptus Kieffer (8%), and Culicoides alazanicus Dzhafarov (4%). A more powerful but nonattractive fan trap collected five species (121 individuals) dominated by C. obsoletus (48%), C. imicola (36%), C. alazanicus (8%), and C. circumscriptus (7%). Parity of C. obsoletus and C. imicola did not vary between the light and fan traps. Engorged Culicoides in the barn (33 C. obsoletus and three C. imicola) had fed on sheep or goats (precipitin test).

  5. Insect Visitors and Potential Pollinators of Orchis militaris (Orchidaceae) in Southern Belgium

    PubMed Central

    Henneresse, Thomas; Tyteca, Daniel

    2016-01-01

    As part of a research project on the food deception strategy in Orchis militaris (L.), the objective of this study was to identify insect visitors and potential pollinators of this orchid species in Belgium. In 2013, insects were collected over 2 d per site in five localities distributed in Southern Belgium (Wallonia). A total of 104 insects belonging to 49 species were caught. Dipterans were the most abundant visitors (50% of total specimens), followed by Hymenopterans (32%). Rhingia campestris Meigen, Bombylius venosus Mikan, Apis mellifera (L.), and Bombus lapidarius (L.) were the most abundant species. Only five specimens bore one to more than 10 pollinia: four honeybees (A. mellifera) and one bumblebee worker (B. lapidarius). These two species should be considered as potential pollinators in the study area, but probably not confirmed ones. PMID:27694346

  6. 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

  7. 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

  8. 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.

  9. 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

  10. 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

    2016-05-30

    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.

  11. 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

  12. The complete mitochondrial genome of Dixella aestivalis (Diptera: Nematocera: Dixidae).

    PubMed

    Briscoe, Andrew G; Sivell, Duncan; Harbach, Ralph E

    2017-01-01

    Dixidae, meniscus midges, belong to the suborder Nematocera of the order Diptera. The family includes 197 known species classified in nine genera. The complete mitochondrial genome of the Dixella aestivalis (Meigen) from the United Kingdom is reported here, along with its annotation and comparison with the genome of an unidentified species of Dixella from China. The circular genome consists of 16 465 bp and has a gene content consisting of 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes and a non-coding, A + T-rich, control region. The mitochondrial genome of D. aestivalis can be used to identify genetic markers for species identification, and will be valuable for resolving phylogenetic relationships within the genus, family Dixidae and suborder Nematocera.

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

    PubMed

    Zhang, Xiao; Kang, Zehui; Mao, Meng; Li, Xuankun; Cameron, Stephen L; Jong, Herman de; 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.

  14. Development of the Oriental Latrine Fly, Chrysomya megacephala (Diptera: Calliphoridae), at Five Constant Temperatures.

    PubMed

    Gruner, S V; Slone, D H; Capinera, J L; Turco, M P

    2016-11-04

    Chrysomya megacephala (Fabricius) is a forensically important fly that is found throughout the tropics and subtropics. We calculated the accumulated development time and transition points for each life stage from eclosion to adult emergence at five constant temperatures: 15, 20, 25, 30, and 35 °C. For each transition, the 10th, 50th, and 90th percentiles were calculated with a logistic linear model. The mean transition times and % survivorship were determined directly from the raw laboratory data. Development times of C. megacephala were compared with that of two other closely related species, Chrysomya rufifacies (Macquart) and Phormia regina (Meigen). Ambient and larval mass temperatures were collected from field studies conducted from 2001-2004. Field study data indicated that adult fly activity was reduced at lower ambient temperatures, but once a larval mass was established, heat generation occurred. These development times and durations can be used for estimation of a postmortem interval (PMI).

  15. The Biochemical Adaptations of Spotted Wing Drosophila (Diptera: Drosophilidae) to Fresh Fruits Reduced Fructose Concentrations and Glutathione-S Transferase Activities.

    PubMed

    Nguyen, Phuong; Kim, A-Young; Jung, Jin Kyo; Donahue, Kelly M; Jung, Chuleui; Choi, Man-Yeon; Koh, Young Ho

    2016-04-01

    Spotted wing drosophila, Drosophila suzukii Matsumura, is an invasive and economically damaging pest in Europe and North America. The females have a serrated ovipositor that enables them to infest almost all ripening small fruits. To understand the physiological and metabolic basis of spotted wing drosophila food preferences for healthy ripening fruits, we investigated the biological and biochemical characteristics of spotted wing drosophila and compared them with those of Drosophila melanogaster Meigen. We found that the susceptibility to oxidative stressors was significantly increased in spotted wing drosophila compared with those of D. melanogaster. In addition, we found that spotted wing drosophila had significantly reduced glutathione-S transferase (GST) activity and gene numbers. Furthermore, fructose concentrations found in spotted wing drosophila were significantly lower than those of D. melanogaster. Our data strongly suggest that the altered food preferences of spotted wing drosophila may stem from evolutionary adaptations to fresh foods accompanied by alterations in carbohydrate metabolism and GST activities.

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

    PubMed

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

    2015-08-01

    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.

  17. Stimulation of blowfly feeding behavior by octopaminergic drugs

    PubMed Central

    Long, Thomas F.; Murdock, Larry L.

    1983-01-01

    Adult blowflies (Phormia regina Meigen) injected with the octopaminergic drug demethylchlordimeform (10 μg per fly) exhibited enhanced proboscis extension responses when their tarsae were touched to water or aqueous sucrose. They drank more water than saline-injected control flies did but the quantity imbibed was within the normal fluid intake capacity. They became grossly hyperphagic when offered 1 M sucrose, doubling (and in some cases even tripling) their initial body weights. Three other drugs enhanced tarsal responsiveness and induced hyperphagia: DL-octopamine, clonidine (which is known to stimulate octopaminergic receptors in insects), and pargyline, a monoamine oxidase inhibitor. Yohimbine, an antagonist of one class of octopaminergic receptor in insects, prevented the hyperphagia induced by all four drugs. Dopamine, 5-hydroxytryptamine, and DL-norepinephrine failed to cause hyperphagia. These results suggest that octopaminergic receptors in the nervous system of the blowfly positively modulate feeding and drinking behavior. Images PMID:16593335

  18. Slow and stepped re-warming after acute low temperature exposure do not improve survival of Drosophila melanogaster larvae.

    PubMed

    Sinclair, Brent J; Rajamohan, Arun

    2008-01-01

    We tested that hypothesis that slow re-warming rates would improve the ability of Drosophila melanogaster Meigen larvae to survive acute low temperature exposure. Four larval stages (1(st), 2(nd), 3(rd) instars and wandering stage 3(rd) instars) of four wild-type strains were exposed to -7 degrees C for periods of time expected to result in 90 % mortality. Larvae were then either directly transferred to their rearing temperature (21 degrees C), or returned to this temperature in a stepwise fashion (pausing at 0 and 15 degrees C) or by slow warming at 1 or 0.1 degrees C/min. We observed a reduced rapid cold-hardening effect and no general increase in survival of acute chilling in larvae re-warmed in a stepwise or slow fashion, and hypothesise that slow re-warming may result in accumulation of further chill injuries.

  19. Attempted mechanical transmission of lumpy skin disease virus by biting insects.

    PubMed

    Chihota, C M; Rennie, L F; Kitching, R P; Mellor, P S

    2003-09-01

    The mosquitoes Anopheles stephensi Liston and Culex quinquefasciatus Say (Diptera: Culicidae), the stable fly Stomoxys calcitrans Linnaeus (Diptera: Muscidae) and the biting midge Culicoides nubeculosus Meigen (Diptera: Ceratopogonidae) were allowed to feed on either lumpy skin disease (LSD) infected animals or through a membrane on a bloodmeal containing lumpy skin disease virus (LSDV). These arthropods were then allowed to refeed on susceptible cattle at various intervals after the infective feed. Virus was detected in the insects by polymerase chain reaction immediately after feeding and at sufficiently high titre to enable transmission to occur. However, no transmission of virus from infected to susceptible animals by An. stephensi, S. calcitrans, C. nubeculosus and Cx. quinquefasciatus was observed.

  20. Identification of the forensically important sarcophagid flies Boerttcherisca peregrina, Parasarcophaga albiceps and Parasarcophaga dux (Diptera: Sarcophagidae) based on COII gene in China.

    PubMed

    Guo, Y D; Cai, J F; Li, X; Xiong, F; Su, R N; Chen, F L; Liu, Q L; Wang, X H; Chang, Y F; Zhong, M; Wang, X; Wen, J F

    2010-12-01

    Accurate species identication is a crucial step in forensic entomology, as the insect collected on a corpse can provide useful information for estimation of postmortem interval (PMI). The utility of the forensically important Sarcophagidae (Diptera) for crime scene investigation has been severely restricted, as morphological identification is difficult, especially the identification of females and larvae. In this study, a method for using mitochondrial DNA (mtDNA) sequence data and phylogenetic analysis was performed to distinguish the three Chinese sarcophagid species: Boerttcherisca peregrina (Robineau-Desvoidy, 1830) Parasarcophaga albiceps (Meigen, 1826) and Parasarcophaga dux (Thompson, 1869) (Diptera: Sarcophagidae). DNA was extracted and analyzed by a 189 bp fragment of cytochrome coxidase subunit II (COII) gene. The monophyletic branches of the phylogenetic tree reveal that this marker is suitable for discrimination between these species, providing high support for separation on congeneric species. Therefore, the molecular method applied to the sarcophagid species identification is feasible.

  1. 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

  2. Toward development of neem-based repellents against the Scottish Highland biting midge Culicoides impunctatus.

    PubMed

    Blackwell, A; Evans, K A; Strang, R H C; Cole, M

    2004-12-01

    Oil of neem, from the tree Azadirachta indica A. Juss (Meliaceae), was evaluated for repellent and antifeedant activity against Culicoides biting midges (Diptera: Ceratopogonidae), by three complementary methods with serial dilutions. Electroantennograms revealed the sensitivity of Culicoides nubeculosus (Meigen) females to neem > or = 0.10%. Culicoides impunctatus Goetghebuer females were repelled by > or = 1% in a Y-tube olfactometer, Using a membrane feeder for wild-caught parous females of C. impunctatus, the proportion blood-feeding was significantly reduced by topical applications of neem oil > or = 0.10% concentrations, with blood-feeding completely prevented by > or =1%. On the basis of these response data, we developed 2% neem-based formulations for personal protection against biting midges.

  3. History of tachinid classification (Diptera, Tachinidae)

    PubMed Central

    O’Hara, James E.

    2013-01-01

    Abstract The history of the classification of the Tachinidae (Diptera) is traced from Meigen to the present. The contributions of Robineau-Desvoidy, Townsend, Villeneuve, Mesnil, Herting, Wood and many others are discussed within a chronological, taxonomic, and geographic context. The gradual development of the Tachinidae into its modern concept as a family of the Oestroidea and the emergence of the classificatory scheme of tribes and subfamilies in use today are reviewed. Certain taxa that have in the past been difficult to place, or continue to be of uncertain affinity, are considered and some are given in a table to show their varied historical treatments. The more significant systematic works published on the Tachinidae in recent decades are enumerated chronologically. PMID:23878512

  4. Development of the oriental latrine fly, Chrysomya megacephala (Diptera: Calliphoridae), at five constant temperatures

    USGS Publications Warehouse

    Gruner, S. V.; Slone, D.H.; Capinera, J.L.; Turco, M. P.

    2017-01-01

    Chrysomya megacephala (Fabricius) is a forensically important fly that is found throughout the tropics and subtropics. We calculated the accumulated development time and transition points for each life stage from eclosion to adult emergence at five constant temperatures: 15, 20, 25, 30, and 35 °C. For each transition, the 10th, 50th, and 90th percentiles were calculated with a logistic linear model. The mean transition times and % survivorship were determined directly from the raw laboratory data. Development times of C. megacephala were compared with that of two other closely related species, Chrysomya rufifacies (Macquart) and Phormia regina (Meigen). Ambient and larval mass temperatures were collected from field studies conducted from 2001–2004. Field study data indicated that adult fly activity was reduced at lower ambient temperatures, but once a larval mass was established, heat generation occurred. These development times and durations can be used for estimation of a postmortem interval (PMI).

  5. Invisible face of boron pollution in fluvial ecosystem: the level in the tissues of sentinel and nectonic organisms.

    PubMed

    Arslan, Naime

    2013-10-01

    Turkey is the largest producer of borate products in the world. Among four largest boron mines in Turkey two of them are located in basins of Orhaneli and Emet Streams. In this study, boron levels in abiotic (water-sediment) and some biotic elements (sentinel organisms; Asellus aquaticus, Gammarus pulex, Chironomus tentans, Limnodrilus hoffmeisteri and nektonic organism; Squalius cii) of Orhaneli and Emet Streams were investigated and their ranks among the food chain were demonstrated. Since Orhaneli and Emet Streams confluence to form Mustafakemalpaşa Brook which feeds Uluabat Lake which is one of the most important Ramsar fields of the world, Boron levels in those two streams have importance in terms of both continuances of aquatic systems. Present study results have shown that boron levels in water of both streams are much higher (vary between 8.64 and 16.73 mg L(-1)) than not only Turkish Standard but also limits determined by WHO, US EPA, and NAS. Boron levels determined in sediments of two streams vary between 18.05 and 36.7 mg kg(-1). The highest boron level in the biotic elements was determined in liver of Squalius cii (34.64 mg kg(-1)), it is followed by Limnodrilus hoffmeisteri (2.84 mg kg(-1)), Chironomus tentans (2.11 mg kg(-1)), and Gammarus pulex (1.98 mg kg(-1)).

  6. Spatial variation in incidence of mouthpart deformities in larval chironomids (Diptera) from western Lake Erie

    SciTech Connect

    Hudson, L.A.; Ciborowski, J.J.H.; Corkum, L.D.

    1995-12-31

    The major source of contaminants to the sediments of the western basin of Lake Erie is the Detroit River. In order to determine if contaminant levels are reflected in incidences of genotoxicity of benthic invertebrates, the authors examined larvae of chironomids for mouthpart (mentum) deformities. Sediment genotoxicity is indicated when incidence of deformities in susceptible genera exceeds 5%. Samples were collected from three locations along the contaminant gradient extending from the Detroit River along the main shipping channel of the western basin. A composite sample was taken from several central locations in the western basin. Chironomids were hand-picked from ponar grab or box core samples. The heads were mounted, identified to genus and examined for mentum deformities (extra or missing teeth). Chironomus dominated all samples. The incidence of deformities ({+-}SE) in Chironomus was greatest in the Trenton Channel of the Detroit River (7.8 {+-} 2.2%, n = 153), declined to 5.2 {+-} 1.4% (n = 233) in the center of the basin and was the lowest off East Sister Island (1.9 {+-} 0.9%, n = 210). The incidence of deformities was 4.4 {+-} 0.8% (n = 610) at a reference site on the Canadian side of the Detroit River (Crystal Bay). The spatial pattern of chironomid mentum deformities suggests that sediment genotoxicity declines from west to east in western Lake Erie.

  7. 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.

  8. Benthic macroinvertebrate associations in relation to environmental factors in Georgian Bay

    SciTech Connect

    Johnson, M.G.; McNeil, O.C.; George, S.E.

    1987-01-01

    Association analysis of data on benthic macroinvertebrates in 257 samples from Georgian Bay, followed by discriminant analysis of water and sediment characteristics, facilitated a quantitative description of trophic variability within a relatively unpolluted system. Discriminating variables were bottom water temperature, water pH and Ca, sediment organic matter, sand, silt, clay, total P, Zn, Pb, and Hg. Four discriminating functions, accounting for 86% of variance, indicated the importance of temperature, concentrations of organic matter and silt, water pH and Ca. Associations which occurred at cooler temperatures consisted of Pontoporeia hoyi with dominant oligochaetes and chironomids generally determined by sediment richness. These associations were P. hoyi - Limnodrilus hoffmeisteri - Chironomus spp, and Procladius spp. at highest sediment richness, P. hoyi - Spirosperma ferox - Micropsectra spp, at intermediate richness and P. hoyi - Stylodrilus heringianus - Heterotrissocladius sp. at lowest richness. Associations in warmer waters consisted of a Chironomus spp. - Chaoborus spp. association in richer sediments and an association of Caecidotea racovitzae and Amnicola spp. at lower sediment richness. A Hexagenia limbata - Hyalella azteca association occurred over a broad range in concentrations of organic matter and silt, but, in terms of sediment texture represented by sand content, this association was intermediate between the other two groups in warmer waters. Finally, a Zalutschia zalutschia zalutschicola - Chaoborus spp. association was related to water pH and Ca in discriminant analysis. 33 references, 4 figures, 4 tables.

  9. Sediment toxicity in the Duluth-Superior Harbor: Use of Microtox{reg_sign} and Mutatox{reg_sign} as screening assays

    SciTech Connect

    Schubauer-Berigan, M.; Hubbard, C.; Schubauer-Berigan, J.; Tesser, G.

    1995-12-31

    Sediment toxicity tests were conducted in the Duluth-Superior Harbor at 40 sites as part of an integrated sediment assessment during the fall of 1993. Two rapid assays conducted with Photobacterium phosphoreum (Microtox{reg_sign} and Mutatox{reg_sign}) were compared with three standard US EPA sediment toxicity tests: Hyalella azteca (acute tests) and Chironomus tentans (acute and sub-lethal tests). The response in the two microbial assays was also evaluated for sensitivity to various contaminants analyzed simultaneously in the Duluth-Superior Harbor sediments. Microtox{reg_sign} and Mutatox{reg_sign} were found to be sensitive to approximately one-third and one-half the sediments, respectively; Chironomus tentans was sensitive to 15% of the sediments (either acutely or sub-lethally), while Hyalella azteca was not sensitive to any of the sediments. In almost all cases, Microtox{reg_sign} and Mutatox{reg_sign} correctly identified samples that were toxic to the chironomid, making it useful as a screening tool for toxicity, to reduce the number of sites to be tested with the benthic organisms. The subsequent application of Microtox{reg_sign} as a screen for sediment toxicity in an EMAP survey in the St. Louis River (MN) estuary will be discussed. Correlation of Microtox{reg_sign} and Mutatox{reg_sign} toxicity to environmental contaminants found in the sediments will be presented.

  10. Carrion flies of forensic interest: a study of seasonal community composition and succession in Lisbon, Portugal.

    PubMed

    Prado e Castro, C; Serrano, A; Martins Da Silva, P; García, M D

    2012-12-01

    Information on Diptera community, seasonality and successional patterns in every geographical region is fundamental for the use of flies as forensic indicators of time of death. In order to obtain these data from the Lisbon area (Portugal), experiments were conducted during the four seasons of the year, using piglet carcasses as animal models. Five stages were recognized during the decomposition process. The stages, besides visually defined, could be separated taking into account the occurrence and abundance of the specific groups of Diptera collected. In general, the bloated stage recorded higher abundance and species-richness values. Seventy-one species were identified, belonging to 39 families, in a total of 20 144 adult Diptera collected. Autumn yielded the highest values of species richness, whereas winter had the lowest. In all seasons of the year, Calliphoridae was the dominant family; Muscidae and Fanniidae were very abundant as well. Calliphora vicina Robineau-Desvoidy, Calliphora vomitoria (Linnaeus), Chrysomya albiceps (Wiedemann), Lucilia ampullacea Villeneuve, Lucilia caesar (Linnaeus), Lucilia sericata (Meigen) (Calliphoridae), Hydrotaea ignava (Harris), Muscina prolapsa (Harris), Synthesiomyia nudiseta (van der Wulp) (Muscidae), Piophila megastigmata McAlpine, Stearibia nigriceps (Meigen) (Piophilidae) and Nemopoda nitidula (Fallén) (Sepsidae) were revealed to be very important members of the Diptera community collected. The necrophagous behaviour, demonstrated by their immatures, using carrion as a food source makes them useful forensic indicator species. Also of relevance is the presence of Chrysomya megacephala (Fabricius), S. nudiseta and P. megastigmata, foreign species established in the local carrion communities. This study also marks the first record of S. nudiseta in Portugal.

  11. Seasonal and Geographic Variation in Biodiversity of Forensically Important Blow Flies (Diptera: Calliphoridae) in New Jersey, USA.

    PubMed

    Weidner, L M; Jennings, D E; Tomberlin, J K; Hamilton, G C

    2015-09-01

    Determining the time of colonization of human or other animal remains by blow flies (Diptera: Calliphoridae) can play an important role in criminal investigations. However, blow fly presence in a given area is strongly influenced by abiotic and biotic variables such as temperature and habitat. We wanted to assess the biodiversity of adult blow flies in New Jersey, USA, where very little is known about these taxa. Toward that end we collected adult blow flies biweekly from traps baited with bovine liver and placed across three regions in New Jersey over a 2-yr period (2011-2013). We collected and identified 9,257 adult calliphorids, comprising six genera and 12 species. Blow fly assemblages composed of these species varied by season, but community composition did not vary among regions within a given season. Three species, Lucilia coeruleiviridis (Macquart), Lucilia sericata (Meigen), and Phormia regina (Meigen) comprised 88.5% of all adult blow flies collected (42.6, 25.9, 20.0%, respectively). Combining all regions, the dominant species for both spring and summer was L. coeruleiviridis comprising 35.1% of all adults caught in spring and 64.1% in summer. P. regina was the dominant species in fall, totaling 40.1% of all adults caught and Calliphora vicina (Robineau-Desvoidy) was the dominant species for winter, totaling 44.8% of all adults caught. Our findings provide the first assessment of blow fly communities in New Jersey, and these results can be applied to surrounding states where data are severely lacking for forensic application.

  12. Plant extracts, isolated phytochemicals, and plant-derived agents which are lethal to arthropod vectors of human tropical diseases--a review.

    PubMed

    Pohlit, Adrian Martin; Rezende, Alex Ribeiro; Lopes Baldin, Edson Luiz; Lopes, Norberto Peporine; Neto, Valter Ferreira de Andrade

    2011-04-01

    The recent scientific literature on plant-derived agents with potential or effective use in the control of the arthropod vectors of human tropical diseases is reviewed. Arthropod-borne tropical diseases include: amebiasis, Chagas disease (American trypanosomiasis), cholera, cryptosporidiosis, dengue (hemorrhagic fever), epidemic typhus (Brill-Zinsser disease), filariasis (elephantiasis), giardia (giardiasis), human African trypanosomiasis (sleeping sickness), isosporiasis, leishmaniasis, Lyme disease (lyme borreliosis), malaria, onchocerciasis, plague, recurrent fever, sarcocystosis, scabies (mites as causal agents), spotted fever, toxoplasmosis, West Nile fever, and yellow fever. Thus, coverage was given to work describing plant-derived extracts, essential oils (EOs), and isolated chemicals with toxic or noxious effects on filth bugs (mechanical vectors), such as common houseflies (Musca domestica Linnaeus), American and German cockroaches (Periplaneta americana Linnaeus, Blatella germanica Linnaeus), and oriental latrine/blowflies (Chrysomya megacephala Fabricius) as well as biting, blood-sucking arthropods such as blackflies (Simulium Latreille spp.), fleas (Xenopsylla cheopis Rothschild), kissing bugs (Rhodnius Stål spp., Triatoma infestans Klug), body and head lice (Pediculus humanus humanus Linnaeus, P. humanus capitis De Geer), mosquitoes (Aedes Meigen, Anopheles Meigen, Culex L., and Ochlerotatus Lynch Arribálzaga spp.), sandflies (Lutzomyia longipalpis Lutz & Neiva, Phlebotomus Loew spp.), scabies mites (Sarcoptes scabiei De Geer, S. scabiei var hominis, S. scabiei var canis, S. scabiei var suis), and ticks (Ixodes Latreille, Amblyomma Koch, Dermacentor Koch, and Rhipicephalus Koch spp.). Examples of plant extracts, EOs, and isolated chemicals exhibiting noxious or toxic activity comparable or superior to the synthetic control agents of choice (pyrethroids, organophosphorous compounds, etc.) are provided in the text for many arthropod vectors of tropical

  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. Nomenclatural Studies Toward a World List of Diptera Genus-Group Names. Part IV: Charles Henry Tyler Townsend.

    PubMed

    Evenhuis, Neal L; Pont, Adrian C; Whitmore, Daniel

    2015-06-25

    -Desvoidy, 1830, n. syn. [Muscidae]; Kurintjimyia Townsend, 1926 under Tachina Meigen, 1803, n. syn. [Tachinidae]; Labidigaster Macquart, 1844 under Labigastera Macquart, 1834, n. syn. [Tachinidae]; Mellanactia Guimarães, 1971 under Oxynops Townsend, 1912, n. syn. [Tachinidae]; Ochromia Townsend, 1935 under Bengalia Robineau-Desvoidy, 1830, n. syn. [Tachinidae]; Pachyrrhina Osten Sacken, 1881 under Nephrotoma Meigen, 1803, n. syn. [Tipulidae]; Procraspedothrix Townsend, 1932 under Phytomyptera Rondani, 1844, n. syn. [Tachinidae]; Pseudogymnosoma Townsend, 1918 under Neomyia Walker, 1859, n. syn. [Muscidae]; Pseudoservillia Townsend, 1916 under Tachina Meigen, 1803, n. syn. [Tachinidae]; Rhymosia Mik, 1886 under Rymosia Winnertz, 1863, n. syn. [Mycetophilidae]; Rhynchomyia Macquart, 1835 under Rhyncomya Robineau-Desvoidy, 1830, n. syn. [Rhiniidae]; Servillioides Townsend, 1926 under Tachina Meigen, 1803, n. syn. [Tachinidae]; Servilliopsis Townsend, 1916 under Tachina Meigen, 1803, n. syn. [Tachinidae]; Stephanostoma Cole, 1923 under Bercaea Robineau-Desvoidy, 1863, n. syn. [Sarcophagidae]; Stomatorhinia Townsend, 1935 under Stomorhina Rondani, 1861, n. syn. [Rhiniidae]; Toxorrhina Osten Sacken, 1869 under Toxorhina Loew, 1850, n. syn. [Limoniidae]; Trichoneura Townsend, 1935 under Stevenia Robineau-Desvoidy, 1830, n. syn. [Rhinophoridae]; Trichopticus Schnabl, 1889 under Thricops Rondani, 1856, n. syn. [Muscidae]; Tricyclopsis Townsend, 1916 under Paracalliphora Townsend, 1916, n. syn. [Calliphoridae].

  15. 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.

  16. Toxicity to freshwater organisms from oils and oil spill chemical treatments in laboratory microcosms.

    PubMed

    Bhattacharyya, S; Klerks, P L; Nyman, J A

    2003-01-01

    Toxicity and temporal changes in toxicity of freshwater-marsh-microcosms containing South Louisiana Crude (SLC) or diesel fuel and treated with a cleaner or dispersant, were investigated using Chironomus tentans, Daphnia pulex, and Oryzias latipes. Bioassays used microcosm water (for D. pulex and O. latipes) or soil slurry (for C. tentans) taken 1,7, 31, and 186 days after treatment. SLC was less toxic than diesel, chemical additives enhanced oil toxicity, the dispersant was more toxic than the cleaner, and toxicities were greatly reduced by day 186. Toxicities were higher in the bioassay with the benthic species than in those with the two water-column species. A separate experiment showed that C. tentans' sensitivity was intermediate to that of Tubifex tubifex and Hyallela azteca. Freshwater organisms, especially benthic invertebrates, thus appear seriously effected by oil under the worst-case-scenario of our microcosms. Moreover, the cleaner and dispersant tested were poor response options under those conditions.

  17. 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.

  18. 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.

  19. 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

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

    PubMed

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

    2011-10-01

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

  1. 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.

  2. Organic waste compounds in streams: Occurrence and aquatic toxicity in different stream compartments, flow regimes, and land uses in southeast Wisconsin, 2006–9

    USGS Publications Warehouse

    Baldwin, Austin K.; Corsi, Steven R.; Richards, Kevin D.; Geis, Steven W.; Magruder, Christopher

    2013-01-01

    -water-indicator compounds, among others. Urban runoff and storm-related leaks of sanitary sewers and (or) septic systems may be important sources of these and other compounds to the streams. The Kinnickinnic River, a highly urbanized site, had the highest detection rates and concentrations of compounds of all the sampled sites. The Milwaukee River near Cedarburg—one of the least urban sites—and the Outer Milwaukee Harbor site had the lowest detection rates and concentrations. Aquatic-toxicity benchmarks were exceeded for 12 of the 25 compounds with known benchmarks. The compounds with the greatest benchmark exceedances were the PAHs, both in terms of exceedance frequency (up to 93 percent for some compounds in sediment samples) and magnitude (concentrations up to 1,024 times greater than the benchmark value). Other compounds with toxicity-benchmark exceedances include Bis(2-ethylhexyl) phthalate (a plasticizer), 2-Methylnapthalene (a component of fuel and oil), phenol (an antimicrobial disinfectant with diverse uses), and 4-Nonylphenol (sum of all isomers; a detergent metabolite, among other uses). Analyzed as a mixture, the suite of PAH compounds were found to be potentially toxic for most non-base-flow samples. Bioassay tests were conducted on samples from 14 streams: Ceriodaphnia dubia in base-flow samples, Ceriodaphnia dubia and Hyallela azteca in pore-water samples, and Hyallela azteca and Chironomus tentans in sediment samples. The greatest adverse effect was observed in tests with Chironomus tentans from sediment samples. The weight of Chironomus tentans after exposure to sediments decreased with increased OWC concentrations. This was most evident in the relation between PAH results and Chironomus tentans bioassay results for the majority of samples; however, solvents and flame retardants appeared to be important for one site each. These results for PAHs were consistent with assessment of PAH potency factors for sediment, indicating that PAHs were likely to have adverse effects

  3. 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.

  4. 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

  5. Aquatic invertebrate ecology during a simulated botulism epizootic in a Sacramento Valley wetland

    USGS Publications Warehouse

    Hicks, Jane M.; Euliss, Ned H.; Harris, Stanley 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 andCorisella 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.

  6. Invasive alien species water hyacinth Eichhornia crassipes as abode for macroinvertebrates in hypertrophic Ramsar Site, Lake Xochimilco, Mexico.

    PubMed

    Rocha-Ramirez, A; Robles-Valderrama, E; Ramirez-Flores, E

    2014-11-01

    This paper presents information on the density, diversity and functional feeding groups of macroinvertebrate assemblages associated with water hyacinth in Antiguo Canal Cuemanco, part of Lake Xochimilco in Mexico City. Rare (low frequency and density) and dominant (high frequency and density) taxa prevailed in the assemblages, with the most predominant being Hyalella azteca, Chironomus plumosus and Ischnura denticollis. Nonmetric Multidimensional Scaling confirmed two climatic seasons: warm-rainy and cold-dry; the former with the highest diversity and density of taxa. Canonical Correspondence Analysis showed that conductivity, nitrates and turbidity explained the density variations of taxa. Antiguo Canal Cuemanco waters are spatially homogeneous with the characteristics of hypertrophic shallow lakes, inhabited by scrapers and gathering-collectors. The species found were tolerant to organic pollution.

  7. A comprehensive assessment of aquatic ecosystem quality: The role of sediments

    SciTech Connect

    Burton, G.A. Jr.; Rowland, C.; Monzingo, R.

    1995-12-31

    A comprehensive multi-level ecosystem was conducted on 55 miles of the upper Illinois waterway. A sub-component of this assessment included measures of sediment contamination. A species sensitivity comparison of Pimephales promelas, Hyalella azteca and Chironomus tentans whole sediment exposures showed C. tentans to be the most sensitive species. Acute to chronic level toxicity was observed throughout the waterway, and was greatest in high deposition areas and at the mouth of tributaries to the main channel. Toxicity responses were significantly correlated with several parameters, including ammonia, particle size, total volatile solids, chromium, zinc, and fluorene. Ammonia concentrations were related to several synthetic organic compounds, moisture, silt, and TVS. Follow-up Toxicity Identification Evaluations showed ammonia to dominate toxicity at one key location with some effects from photoinduced toxicity (implicating polycyclic aromatic hydrocarbons). Contaminated sediments appear to be a major stressor in this system.

  8. Evaluations of bioavailable copper in amended wetland sediments

    SciTech Connect

    Deaver, E.; Rodgers, J.H. Jr.

    1994-12-31

    Copper sulfate was added to the water column of six of twelve wetland mesocosms. In successive 10d experiments using invertebrates Hyalella azteca and Chironomus tentans, sediment toxicity and copper bioavailability were examined in sediments collected monthly from wetlands amended with copper sulfate, untreated wetlands, and control sediments. Evaluations included examinations of temporal changes in toxicity, bioavailability of aqueous and sediment associated copper, and comparison of organism responses to copper. In some cases copper remained acutely toxic over the 6 month study period, however, total copper concentrations in sediment had no relation to bioavailable copper. The relationship of copper speciation to bioavailability was discerned by measuring total copper (AA), labile copper (ASV) and copper ion activity (ISE) during these sediment toxicity experiments.

  9. Derivation and selection of freshwater sediment quality values in Washington state

    SciTech Connect

    Cubbage, J.; Breidenbach, S.; Batts, D.

    1995-12-31

    To derive chemical-based Freshwater Sediment Quality Values (FSQV), bioassay data (Hyalella azteca, Microtox, Chironomus tentans, Daphnia magna, Ceriodaphnia dubia, and Hexagenia limbata) and chemistry data (metals, PAH, pesticide/PCBs, and phenols) were merged from 33 studies and 245 sites in Washington and Oregon into a single database. Apparent Effects Thresholds (AET) and Probable AETs (PAET: 95th percentile of no effects sites) were calculated for Hyalella azteca (n = 228) and Microtox. The efficiency and sensitivity of these values in predicting biological response from chemical concentrations were compared with Ontario`s Severe Effects Level (SEL), Environment Canada`s Probable Effects Level (PEL) and Threshold Effects Level (TEL), EPA`s Equilibrium Partitioning (EQP), and Washington`s marine Sediment management Standards (SMS). For PAH, dry weight normalized values for AETs and PAETs were significantly more sensitive and efficient than organic carbon normalized values. TEL was always the most sensitive and least efficient.

  10. Sediment testing intermittent renewal system for the automated renewal of overlying water in toxicity tests with contaminated sediments

    SciTech Connect

    Benoit, D.A.; Phipps, G.L.; Ankley, G.T.

    1993-01-01

    A sediment testing intermittent renewal (STIR) system (stationary or portable) for invertebrate toxicity testing with contaminated sediments has been successfully developed and thoroughly tested at ERL-Duluth. Both the stationary and portable systems enable the maintenance of acceptable water quality (e.g. DO) through the capability of automatically renewing overlying water in sediment tests at rates ranging from 1 to 21 volume renewals/day. The STIR system not only significantly reduces the labor associated with renewal of overlying water but also affords a gentle exchange of water that results in virtually no sediment resuspension. Both systems can also be installed in a compact vented enclosure to permit safe testing of hazardous contaminated sediments. To date the STIR system has been used extensively for conducting 10-day bulk sediment tests with Chironomus tentans, Hyalella azteca and Lumbriculus variegatus.

  11. 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.

  12. 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.

  13. Passive internal dispersal of insect larvae by migratory birds

    PubMed Central

    Green, Andy J; Sánchez, Marta I

    2005-01-01

    It has long been assumed that the resistant eggs of many zooplankton are able to survive passage through the gut of migratory waterbirds, thus facilitating their dispersal between isolated aquatic habitats. We present the first evidence that such passive internal transport within birds may be relevant for insect populations. In three out of six faecal samples from black-tailed Godwits on autumn migration in southwest Spain, we found larvae of the chironomid Chironomus salinarius which had survived gut passage. Although adult chironomids can fly, they are likely to disperse greater distances when transported as larvae via birds. In insects with discrete generations, such passive transport also enables colonization of new habitats at times when flight by adults is not an option. PMID:17148325

  14. Divisispiculimermis mirus n. gen., n. sp. (Mermithidae: Nematoda) Parasitizing Midges in Córdoba, Argentina

    PubMed Central

    Agüera de Doucet, María M.

    1986-01-01

    Divisispiculimermis mirus n. gen., n. sp., a mermithid parasitizing larvae of Chironomus sp. in the Cajón o Grande Stream, Córdoba, Argentina, is described. The new genus differs from all other mermithid genera in having paired spicules which are separated and divided into proximal and distal sectors. The other diagnostic characters of the genus are medium size, nematodes with the cuticle appearing smooth (lacking cross fibers under the light microscope); head separated from the rest of the body by a slight constriction at the level of the amphids, six cephalic papillae, mouth papillae absent, mouth opening posterior to level of cephalic papillae; six hypodermal chords at midbody; weakly S-shaped vagina; postparasitic juvenile with a tail appendage. PMID:19294174

  15. 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.

  16. Is the chronic Tier-1 effect assessment approach for insecticides protective for aquatic ecosystems?

    PubMed

    Brock, Theo Cm; Bhatta, Ranjana; van Wijngaarden, René Pa; Rico, Andreu

    2016-10-01

    We investigated the appropriateness of several methods, including those recommended in the Aquatic Guidance Document of the European Food Safety Authority (EFSA), for the derivation of chronic Tier-1 regulatory acceptable concentrations (RACs) for insecticides and aquatic organisms. The insecticides represented different chemical classes (organophosphates, pyrethroids, benzoylureas, insect growth regulators, biopesticides, carbamates, neonicotinoids, and miscellaneous). Chronic Tier-1 RACs derived using toxicity data for the standard species Daphnia magna, Chironomus spp., and/or Americamysis bahia, were compared with Tier-3 RACs derived from micro- and mesocosm studies on basis of the ecological threshold option (ETO-RACs). ETO-RACs could be derived for 31 insecticides applied to micro- and mesocosms in single or multiple applications, yielding a total number of 36 cases for comparison. The chronic Tier-1 RACs calculated according to the EFSA approach resulted in a sufficient protection level, except for 1 neonicotinoid (slightly underprotective) and for several pyrethroids if toxicity data for A. bahia were not included. This latter observation can be explained by 1) the fact that A. bahia is the most sensitive standard test species for pyrethroids, 2) the hydrophobic properties of pyrethroids, and 3) the fact that long-term effects observed in (epi) benthic arthropods may be better explained by exposure via the sediment than via overlying water. Besides including toxicity data for A. bahia, the protection level for pyrethroids can be improved by selecting both D. magna and Chironomus spp. as standard test species for chronic Tier-1 derivation. Although protective in the majority of cases, the conservativeness of the recommended chronic Tier-1 RACs appears to be less than an order of magnitude for a relatively large proportion of insecticides when compared with their Tier-3 ETO-RACs. This may leave limited options for refinement of the chronic effect assessment

  17. Structurally divergent histone H1 variants in chromosomes containing highly condensed interphase chromatin.

    PubMed

    Schulze, E; Nagel, S; Gavenis, K; Grossbach, U

    1994-12-01

    Condensed and late-replicating interphase chromatin in the Dipertan insect Chironomus contains a divergent type of histone H1 with an inserted KAP-KAP repeat that is conserved in single H1 variants of Caenorhabditis elegans and Volvox carteri. H1 peptides comprising the insertion interact specifically with DNA. The Chironomid Glyptotendipes exhibits a corresponding correlation between the presence of condensed chromosome sections and the appearance of a divergent H1 subtype. The centromere regions and other sections of Glyptotendipes barbipes chromosomes are inaccessible to immunodecoration by anti-H2B and anti-H1 antibodies one of which is known to recognize nine different epitopes in all domains of the H1 molecule. Microelectrophoresis of the histones from manually isolated unfixed centromeres revealed the presence of H1 and core histones. H1 genes of G. barpipes were sequenced and found to belong to two groups. H1 II and H1 III are rather similar but differ remarkably from H1 I. About 30% of the deduced amino acid residues were found to be unique to H1 I. Most conspicuous is the insertion, SPAKSPGR, in H1 I that is lacking in H1 II and H1 III and at its position gives rise to the sequence repeat SPAKSPAKSPGR. The homologous H1 I gene in Glyptotendipes salinus encodes the very similar repeat TPAKSPAKSPGR. Both sequences are structurally related to the KAPKAP repeat in H1 I-1 specific for condensed chromosome sites in Chironomus and to the SPKKSPKK repeat in sea urchin sperm H1, lie at almost the same distance from the central globular domain, and could interact with linker DNA in packaging condensed chromatin.

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

    PubMed

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

    2010-01-01

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

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. Taxonomic review of New World Tachyina (Coleoptera, Carabidae): descriptions of new genera, subgenera, and species, with an updated key to the subtribe in the Americas

    PubMed Central

    Boyd, Olivia F.; Erwin, Terry L.

    2016-01-01

    Abstract The classification of the carabid subtribe Tachyina (Trechitae: Bembidiini) is reviewed in light of newly discovered diversity from Central and South America. Described herein are three new genera (Tachyxysta gen. n., Stigmatachys gen. n., Nothoderis gen. n.), two new subgenera of Meotachys (Scolistichus subgen. n., Hylotachys subgen. n.), and two new subgenera of Elaphropus (Ammotachys subgen. n., Idiotachys subgen. n.). Two names previously synonymized under Polyderis (Polyderidius Jeannel, 1962) and Elaphropus (Nototachys Alluaud, 1930) are elevated to generic and subgeneric status, respectively. Eight new species are recognized: Tachyxysta howdenorum (type locality: México: Chiapas: El Aguacero, 680m); Elaphropus marchantarius (type locality: Brazil, Amazonas, Rio Solimões, Ilha de Marchantaria), Elaphropus acutifrons (type locality: Brazil: Pará, Santarém) and Elaphropus occidentalis (type locality: Perú: Loreto, Pithecia, 74°45'W 05°28'S); Stigmatachys uvea (type locality: Perú: Loreto: Campamento San Jacinto, 2°18.75'S, 75°51.77'W, 175–215m); and Meotachys riparius (type locality: Colombia: Amazonas: Leticia, 700 ft), Meotachys ballorum (type locality: Brazil: Amazonas, Rio Negro Cucui), and Meotachys rubrum (type locality: Perú: Madre de Dios: Rio Manu, Pakitza, 11°56°47'S 071°17°00'W, 356m). An updated key to the genera and subgenera of Tachyina occurring in the New World is provided, with accompanying illustrations. PMID:27833435

  5. Aquatic hazard assessment of the organophosphate insecticide fonofos

    USGS Publications Warehouse

    Fairchild, James F.; Little, Edward E.; Huckins, James N.

    1992-01-01

    This study determined the acute and chronic toxicity of the organophosphate insecticide fonofos to standard freshwater aquatic organisms under laboratory conditions. Fonofos was acutely toxic to bluegill (Lepomis macrochirus), Daphnia (D. magna), and midge (Chironomous riparius) at 5.3, 2.7, and 39 μg/L, respectively. Three fonofos formulations (technical, 94.8% A.I.; 20G, field granular 20% A.I.; and 4E, field liquid 4#/gal A.I.) exhibited similar acute toxicities to bluegill. Exposure to fonofos delayed reproduction and decreased the intrinsic rate of increase of Daphnia during 21-d chronic exposure at the lowest tested concentration (0.08 μg/L). The no observable effect concentration (NOEC) for Daphnia survival was 0.42 μg/L; 0% survival occurred at the lowest observable effect concentration (LOEC) of 1.45 μg/L. The NOEC for midge emergence was 3.42 μg/L; only 34% emergence occurred at the LOEC of 8.24 μg/L. Chronic 30-d exposure of juvenile bluegills decreased growth and survival at 5.65 μg/L (LOEC), but no effects occurred at 2.33 μg/L (NOEC). The relative hazard of fonofos to aquatic life is similar to other carbamate and organophosphate corn insecticides.

  6. 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

  7. Taxonomic review of New World Tachyina (Coleoptera, Carabidae): descriptions of new genera, subgenera, and species, with an updated key to the subtribe in the Americas.

    PubMed

    Boyd, Olivia F; Erwin, Terry L

    2016-01-01

    The classification of the carabid subtribe Tachyina (Trechitae: Bembidiini) is reviewed in light of newly discovered diversity from Central and South America. Described herein are three new genera (Tachyxystagen. n., Stigmatachysgen. n., Nothoderisgen. n.), two new subgenera of Meotachys (Scolistichussubgen. n., Hylotachyssubgen. n.), and two new subgenera of Elaphropus (Ammotachyssubgen. n., Idiotachyssubgen. n.). Two names previously synonymized under Polyderis (Polyderidius Jeannel, 1962) and Elaphropus (Nototachys Alluaud, 1930) are elevated to generic and subgeneric status, respectively. Eight new species are recognized: Tachyxysta howdenorum (type locality: México: Chiapas: El Aguacero, 680m); Elaphropus marchantarius (type locality: Brazil, Amazonas, Rio Solimões, Ilha de Marchantaria), Elaphropus acutifrons (type locality: Brazil: Pará, Santarém) and Elaphropus occidentalis (type locality: Perú: Loreto, Pithecia, 74°45'W 05°28'S); Stigmatachys uvea (type locality: Perú: Loreto: Campamento San Jacinto, 2°18.75'S, 75°51.77'W, 175-215m); and Meotachys riparius (type locality: Colombia: Amazonas: Leticia, 700 ft), Meotachys ballorum (type locality: Brazil: Amazonas, Rio Negro Cucui), and Meotachys rubrum (type locality: Perú: Madre de Dios: Rio Manu, Pakitza, 11°56°47'S 071°17°00'W, 356m). An updated key to the genera and subgenera of Tachyina occurring in the New World is provided, with accompanying illustrations.

  8. Flight height preference for oviposition of mosquito (Diptera: Culicidae) vectors of sylvatic yellow fever virus near the hydroelectric reservoir of Simplício, Minas Gerais, Brazil.

    PubMed

    Alencar, Jeronimo; Morone, Fernanda; De Mello, Cecília Ferreira; Dégallier, Nicolas; Lucio, Paulo Sérgio; de Serra-Freire, Nicolau Maués; Guimarães, Anthony Erico

    2013-07-01

    In this study, the oviposition behavior of mosquito species exhibiting acrodendrophilic habits was investigated. The study was conducted near the Simplicio Hydroelectic Reservoir (SHR) located on the border of the states of Minas Gerais and Rio de Janeiro, Brazil. Samples were collected using oviposition traps installed in forest vegetation cover between 1.70 and 4.30 m above ground level during the months of April, June, August, October, and December of 2011. Haemagogus janthinomys (Dyar), Haemagogus leucocelaenus (Dyar and Shannon), Aedes albopictus (Skuse), and Aedes terrens (Walker) specimens were present among the collected samples, the first two of which being proven vectors of sylvatic yellow fever (SYF) in Brazil and the latter is a vector of dengue in mainland Asia. As the data set was zero-inflated, a specific Poisson-based model was used for the statistical analysis. When all four species were considered in the model, only heights used for egg laying and months of sampling were explaining the distribution. However, grouping the species under the genera Haemagogus Williston and Aedes Meigen showed a significant preference for higher traps of the former. Considering the local working population of SHR is very large, fluctuating, and potentially exposed to SYF, and that this virus occurs in almost all Brazilian states, monitoring of Culicidae in Brazil is essential for assessing the risk of transmission of this arbovirus.

  9. 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.

  10. 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

  11. Validation of Comet assay in Oregon-R and Wild type strains of Drosophila melanogaster exposed to a natural radioactive environment in Brazilian semiarid region.

    PubMed

    Verçosa, Cícero Jorge; Moraes Filho, Aroldo Vieira de; Castro, Ícaro Fillipe de Araújo; Santos, Robson Gomes Dos; Cunha, Kenya Silva; Silva, Daniela de Melo E; Garcia, Ana Cristina Lauer; Navoni, Julio Alejandro; Amaral, Viviane Souza do; Rohde, Claudia

    2017-03-21

    Natural radiation of geological origin is a common phenomenon in Brazil, a country where radioactive agents such as uranium may be often found. As an unstable atom, uranium undergoes radioactive decay with the generation of a series of decay by-products, including radon, which may be highly genotoxic and trigger several pathological processes, among which cancer. Because it is a gas, radon may move freely between cracks and gaps in the ground, seeping upwards into the buildings and in the environment. In this study, two Drosophila melanogaster Meigen (Diptera, Drosophilidae) strains called Oregon-R and Wild (collected in a non-radioactive environment) were exposed to atmospheric radiation in the Lajes Pintadas city, in the semiarid zone of northeastern Brazil. After six days of environmental exposure, the organisms presented genetic damage significantly higher than that of the negative control group. The genotoxic effects observed reinforce the findings of other studies carried out in the same region, which warn about the environmental risks related to natural radioactivity occurrence. The results also validate the use of the Comet assay in hemocytes of D. melanogaster as a sensitive test to detect genotoxicity caused by natural radiation, and the use of a recently collected D. melanogaster strain in the environmental of radon.

  12. 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.

  13. Comparing growth of pork- and venison-reared Phormia regina (Diptera: Calliphoridae) for the application of forensic entomology to wildlife poaching.

    PubMed

    Wilson, J M; Lafon, N W; Kreitlow, K L; Brewster, C C; Fell, R D

    2014-09-01

    Laboratory rearing of Phormia regina Meigen larvae on pork and venison was conducted as part of a study to determine whether forensic entomology approaches can be used in wildlife poaching investigations. Larvae were reared at 30 degrees C, 75% relative humidity, and a photoperiod of 14:10 (L:D) h on pork or venison diets, and samples were collected every 8 h until >90% of the maggots reached the third-instar wandering or prepupal stage. Significant differences were found in the distribution of lengths of the third instar and combined instars for maggots reared on the two different meat sources. Maggots reared on venison reached the prepupal wandering stage significantly faster (approximately 6 h) compared with maggots on the pork diet. Mean adult weight and wing length of venison-reared flies were significantly greater than for flies reared on pork. The lower crude fat content of venison appears to make this meat source a more suitable medium than pork for larvae of P. regina. The difference in growth rate could introduce error into PMImin estimations from third-instar maggots in deer poaching cases if estimates are based on data from studies in which maggots were reared on pork.

  14. 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.

  15. Impact of experimental flooding on larvae and pupae of dung-breeding Culicoides.

    PubMed

    Steinke, S; Lühken, R; Kiel, E

    2016-10-01

    Culicoides biting midges (Diptera: Ceratopogonidae) spend the greatest part of their life in the larval stage. However, knowledge on the immature stages and the impact of abiotic factors on their development is still poor. Therefore, we investigated the effect of flooding on the larvae and pupae of Culicoides chiopterus (Meigen, 1830) and C. dewulfi Goetghebuer, 1936. In water, the larvae of both species showed head-to-tail flexions and sinuous flexions, at slow rates, but were not able to swim. Flooding of larvae for 24 h did not affect the number of emerging adults; flooding of pupae significantly reduced the emergence rate of C. chiopterus, compared to the control group, while C. dewulfi was not affected. Pupae were not able to float and no pupae survived flooding for 10 days. After flooding of larvae for 10 days, 50 % of C. chiopterus and 4 % of C. dewulfi completed the pre-adult development. During this treatment, 84 % of C. chiopterus and 48 % of C. dewulfi larvae pupated in water.

  16. 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.

  17. Blackflies (Diptera: Simuliidae) in Croatia: species richness, distribution and relationship to surrounding countries.

    PubMed

    Ivković, Marija; Kúdela, Matuš; Kúdelová, Tatiana

    2016-05-05

    All records of blackflies (Simuliidae) from the territory of Croatia are summarized, including previously unpublished data. The blackfly fauna of Croatia consists of 28 species. Simulium (Nevermannia) angustitarse (Lundström), Simulium (Nevermannia) cryophilum (Rubtsov) complex, Simulium (Nevermannia) lundstromi (Enderlein), Simulium (Nevermannia) vernum Macquart complex, Simulium (Simulium) argyreatum Meigen, Simulium (Simulium) bezzii (Corti) complex, Simulium paraequinum Puri and Simulium pseudequinum Séguy are reported for the first time from Croatia. Information related to the ecoregions, in which species were found and specific species traits are given. Genus Prosimulium Roubaud is represented by one species only. Genus Simulium Latreille is represented by 27 species in six subgenera, with subgenus Simulium Latreille s. str. being most species rich (13 species) and subgenera Boophthora Enderlein and  Trichodagmia Enderlein represented each by only one species. Compared to the neighboring countries, the Croatian species assemblage is most similar to the fauna of Slovenia and least similar to that of Italy. The relatively low number of species, presence of several species complexes and unclear identity of other species show that further research of blackflies in Croatia is needed.

  18. Activity of Culicoides spp. (Diptera: Ceratopogonidae) inside and outside of livestock stables in late winter and spring.

    PubMed

    Kameke, Daniela; Kampen, Helge; Walther, Doreen

    2017-03-01

    Culicoides Latreille, 1809 midge species are the putative vectors of Bluetongue virus (BTV) and Schmallenberg virus (SBV) in Europe. To gain a better understanding of the epidemiology of the diseases, basic knowledge about the overwintering of the vectors is needed. Therefore, we investigated culicoid activity in relation to air temperature at livestock stables during late winter and spring season. Ceratopogonids were captured weekly indoors and outdoors on three cattle farms, three horse farms and one sheep farm in the federal state of Brandenburg, Germany between January and May, 2015 by BG-Sentinel UV-light suction traps. First seasonal activity was measured inside a sheep barn and cattle stables in mid-March, suggesting the existence of a preceding vector-free period. The first species at all trapping sites were members of the Obsoletus Complex followed by Culicoides punctatus (Meigen), 1804 and Culicoides pulicaris (Linnaeus), 1758 simultaneously. In total, 160 collections were made, including 3465 Culicoides specimens with 2790 (80.6%) of them being members of the Obsoletus Complex. The remaining 675 individuals belonged to six other culicoid species. 59.8% of all Culicoides were collected indoors, and almost five times as many midges were sampled on cattle farms as on horse farms. Cattle farms harboured seven species while only two species were found on the horse and the sheep farms, respectively. Temperatures, husbandry practises and the presence/quality of potential breeding sites might be responsible for the difference in species and numbers of caught specimens between livestock holdings.

  19. A review of insect parasitoids associated with Lobesia botrana (Denis & Schiffermüller, 1775) in Italy. 1. DipteraTachinidae and HymenopteraBraconidae (Lepidoptera, Tortricidae).

    PubMed

    Scaramozzino, Pier Luigi; Loni, Augusto; Lucchi, Andrea

    2017-01-01

    This paper is aimed to summarize the information available on the parasitoid complex of the European Grapevine Moth (EGVM), Lobesia botrana (Denis & Schiffermüller, 1775) (Lepidoptera Tortricidae) in Italy. The list is the result of the consultation of a vast bibliography published in Italy for almost two hundred years, from 1828 to date. This allowed the clarification and correction of misunderstandings and mistakes on the taxonomic position of each species listed. In Italy the complex of parasitoids detected on EGVM includes approximately 90 species belonging to ten families of Hymenoptera (Braconidae, Ichneumonidae, Chalcididae, Eulophidae, Eupelmidae, Eurytomidae, Pteromalidae, Torymidae, Trichogrammatidae, and Bethylidae) and one family of Diptera (Tachinidae). This paper deals with EGVM parasitoids of the families Tachinidae (Diptera) and Braconidae (Hymenoptera). Only two species of Tachinidae are associated to EGVM larvae in Italy, Actia pilipennis (Fallen) and Phytomyptera nigrina (Meigen), whereas the record of Eurysthaea scutellaris (Robineau-Desvoidy) is doubtful. Moreover, 21 species of Braconidae are reported to live on EGVM, but, unfortunately, eight of them were identified only at generic level. Bracon mellitor Say has been incorrectly listed among the parasitoids of Lobesia botrana. Records concerning Ascogaster rufidens Wesmael, Meteorus sp., Microgaster rufipes Nees, and Microplitis tuberculifer (Wesmael) are uncertain.

  20. 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.

  1. [Human myiasis in Bahía Blanca, Argentina. Period 2000 / 2005].

    PubMed

    Visciarelli, Elena; Costamagna, Sixto; Lucchi, Leandro; Basabe, Norma

    2007-01-01

    Myiasis is the infestation of live human and vertebrate animals with dipterous larvae which, at least for a short period, feed on the host's dead or living tissue, liquid body-substance, or ingested food. The objective of this study was to identify the flies producing myiasis in Bahía Blanca city, Argentina, from 01/03/2000 to 31/05/2005. Seventeen clinical cases were studied. The larvae obtained from lesions were forwarded from laboratories and from public and private hospitals. Part of the larvae were fixed in alcohol 70 masculine and processed according to the Mazza & Jörg technique (1939). The other part continued growing in flasks with meat in laboratory conditions to obtain the adults. The etiological agents of myiasis were identified by observing the diagnostic characteristics of the larvae III and of the adults, and by using taxonomic keys. Myiasis was produced by Cochlyiomia hominivorax (Coquerel) in thirteen of the cases and by Phaenicia sericata (= Lucila sericata) (Meigen) (Diptera: Calliphoridae) in the other four. The cases were traumatic and aural myiasis and happened from December to March. The ages of patients were four to eighty-six years and 76.5% of the cases occurred in male patients. Given the aggressiveness of these larvae, mainly C. hominivorax, in causing human myiasis, the importance of specific and quick diagnosis and of adequate treatment must be acknowledged.

  2. Mark-release-recapture studies with Aedes dorsalis (Diptera: Culicidae) in coastal northern California.

    PubMed

    Kramer, V L; Carper, E R; Beesley, C; Reisen, W K

    1995-05-01

    Two mark-release-recapture studies were conducted along the Sacramento-San Joaquin River Delta in northern California to describe the population ecology and dispersal pattern of Aedes dorsalis (Meigen). Immature Ae. dorsalis were collected from saline tidal marshes, reared to adults, marked, and released. Recapture grids during the July and September studies were within 8.0 and 2.4 km of the release sites, and recapture rates were 0.1 and 1.2%, respectively. The longest recorded flight was 5.8 km, and mosquitoes were recaptured up to 15 d after release. In September, 84% of the marked mosquitoes were recaptured within 2.0 km of the release site, and the mean dispersal distance was 1.9 km. Marked mosquitoes flew predominantly downwind to the east. There was no evidence that Ae. dorsalis traversed the 1.6-km-wide river from Contra Costa to Solano County. Temporal and spatial recapture patterns indicated a possible short-range migration pattern from oviposition sites to upland host-seeking areas. Changes in the recapture rate with cohort age delineated a 7-d gonotrophic cycle during September.

  3. Impacts of climate, host and landscape factors on Culicoides species in Scotland.

    PubMed

    Purse, B V; Falconer, D; Sullivan, M J; Carpenter, S; Mellor, P S; Piertney, S B; Mordue Luntz, A J; Albon, S; Gunn, G J; Blackwell, A

    2012-06-01

    Culicoides biting midges (Diptera: Ceratopogonidae) vector a wide variety of internationally important arboviral pathogens of livestock and represent a widespread biting nuisance. This study investigated the influence of landscape, host and remotely-sensed climate factors on local abundance of livestock-associated species in Scotland, within a hierarchical generalized linear model framework. The Culicoides obsoletus group and the Culicoides pulicaris group accounted for 56% and 41%, respectively, of adult females trapped. Culicoides impunctatus Goetghebuer and C. pulicaris s.s. Linnaeus were the most abundant and widespread species in the C. pulicaris group (accounting for 29% and 10%, respectively, of females trapped). Abundance models performed well for C. impunctatus, Culicoides deltus Edwards and Culicoides punctatus Meigen (adjusted R(2) : 0.59-0.70), but not for C. pulicaris s.s. (adjusted R(2) : 0.36) and the C. obsoletus group (adjusted R(2) : 0.08). Local-scale abundance patterns were best explained by models combining host, landscape and climate factors. The abundance of C. impunctatus was negatively associated with cattle density, but positively associated with pasture cover, consistent with this species' preference in the larval stage for lightly grazed, wet rush pasture. Predicted abundances of this species varied widely among farms even over short distances (less than a few km). Modelling approaches that may facilitate the more accurate prediction of local abundance patterns for a wider range of Culicoides species are discussed.

  4. Weather and land cover influences on mosquito populations in Sioux Falls, South Dakota.

    PubMed

    Chuang, Ting-Wu; Hildreth, Michael B; Vanroekel, Denise L; Wimberly, Michael C

    2011-05-01

    This study compared the spatial and temporal patterns of Culex tarsalis Coquillett and Aedes vexans Meigen populations and examined their relationships with land cover types and climatic variability in Sioux Falls, SD. Between 24 and 30 CDC CO2-baited light traps were set annually in Sioux Falls from May to September 2005-2008. Land cover data were acquired from the 2001 National Land Cover Dataset and the percentages of selected land cover types were calculated within a 600-m buffer zone around each trap. Meteorological information was summarized from local weather stations. Cx. tarsalis exhibited stronger spatial autocorrelation than Ae. vexans. Land cover analysis indicated that Cx. tarsalis was positively correlated with grass/hay, and Ae. vexans was positively correlated with wetlands. No associations were identified between irrigation and the host-seeking population of each species. Higher temperature in the current week and 2 wk prior and higher precipitation 3-4 wk before collection of host-seeking adult mosquitoes had positive influences on Cx. tarsalis abundance. Temperature in the current week and rainfall 2-3 wk before sampling had positive influences on Ae. vexans abundance. This study revealed the different influences of weather and land cover on important mosquito species in the Northern Great Plains region, which can be used to improve local vector control strategies and West Nile virus prevention efforts.

  5. A review of insect parasitoids associated with Lobesia botrana (Denis & Schiffermüller, 1775) in Italy. 1. Diptera Tachinidae and Hymenoptera Braconidae (Lepidoptera, Tortricidae)

    PubMed Central

    Scaramozzino, Pier Luigi; Loni, Augusto; Lucchi, Andrea

    2017-01-01

    Abstract This paper is aimed to summarize the information available on the parasitoid complex of the European Grapevine Moth (EGVM), Lobesia botrana (Denis & Schiffermüller, 1775) (Lepidoptera Tortricidae) in Italy. The list is the result of the consultation of a vast bibliography published in Italy for almost two hundred years, from 1828 to date. This allowed the clarification and correction of misunderstandings and mistakes on the taxonomic position of each species listed. In Italy the complex of parasitoids detected on EGVM includes approximately 90 species belonging to ten families of Hymenoptera (Braconidae, Ichneumonidae, Chalcididae, Eulophidae, Eupelmidae, Eurytomidae, Pteromalidae, Torymidae, Trichogrammatidae, and Bethylidae) and one family of Diptera (Tachinidae). This paper deals with EGVM parasitoids of the families Tachinidae (Diptera) and Braconidae (Hymenoptera). Only two species of Tachinidae are associated to EGVM larvae in Italy, Actia pilipennis (Fallen) and Phytomyptera nigrina (Meigen), whereas the record of Eurysthaea scutellaris (Robineau-Desvoidy) is doubtful. Moreover, 21 species of Braconidae are reported to live on EGVM, but, unfortunately, eight of them were identified only at generic level. Bracon mellitor Say has been incorrectly listed among the parasitoids of Lobesia botrana. Records concerning Ascogaster rufidens Wesmael, Meteorus sp., Microgaster rufipes Nees, and Microplitis tuberculifer (Wesmael) are uncertain. PMID:28325964

  6. 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.

  7. 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.

  8. 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.

  9. Differential temporal expression profiles of heat shock protein genes in Drosophila melanogaster (Diptera: Drosophilidae) under ultraviolet A radiation stress.

    PubMed

    Wang, Li-Jun; Zhou, Li-Jun; Zhu, Zhi-Hui; Ma, Wei-Hua; Lei, Chao-Liang

    2014-10-01

    Solar UV radiation is indispensable for certain behaviors of many organisms. Nevertheless, UV-A might be expected to stress insects that possess intensive positive taxis toward UV-A light. To avoid stress hazards, organisms generally exhibit the upregulation of heat shock proteins (Hsps) expression. To gain a better understanding of the roles of the different Hsps in response to UV-A stress in the diurnal phototactic fly Drosophila melanogaster Meigen, 1830 (Diptera: Drosophilidae), we tested the temporal expression patterns of 11 DmHsps following UV-A radiation. The results indicated that each DmHsp had a differential temporal expression profile under UV-A radiation stress. Potential transcription factor-binding motifs in the promoter regions of strongly inducible DmHsps were identified; results showed these transcription factor-binding motifs were highly homologous to binding sites that have been identified for transcription factors associated with UV radiation stimuli. So DmHsps might act in a coordinated and cooperative manner at the transcriptional level to counteract UV-A radiation-based stress.

  10. 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

  11. Biogeography of Drosophila (Diptera: Drosophilidae) in East and Southeast Asia.

    PubMed

    Liu, Fu-Guo Robert; 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.

  12. Stable isotope analysis of larval mosquito diets in agricultural wetlands in the coastal plain of Georgia, U.S.A.

    PubMed

    Young, Gina Botello; Golladay, Stephen; Covich, Alan; Blackmore, Mark

    2014-12-01

    Previous studies have used C and N isotope ratios to investigate the use of different food resources such as plant and animal detritus by container-breeding mosquitoes. This study is the first to report on the potential food resources assimilated by larval mosquitoes in agricultural and reference wetlands. Larval mosquitoes (Diptera: Culcidae) were sampled, along with their potential food resources, from agricultural and reference wetland habitats throughout a seasonal hydroperiod. IsoSource mixing model results indicated that food resources had greater δ(15) N isotope values in agricultural wetlands compared with cypress-gum swamps. In February, Aedes vexans (Meigen) and Culex territans Walker larvae fed primarily on lower quality food resources (coarse particulate organic matter and sediment) based on C:N. In contrast, higher quality food resources (fine particulate organic matter) were utilized by Anopheles spp. throughout the study and by Psorophora columbiae (Dyer and Knab) in May. This research contributes to a more comprehensive understanding of the food resources available and assimilated by larval mosquitoes in agricultural wetlands.

  13. Neural and non‐neural contributions to sexual dimorphism of mid‐day sleep in Drosophila melanogaster: a pilot study

    PubMed Central

    Khericha, Mobina; Kolenchery, Jaison B.

    2016-01-01

    Abstract Many of the characteristics associated with mammalian sleep are also observed in Drosophila melanogaster Meigen, making the fruit fly a powerful model organism for studying the genetics of this important process. Included among the similarities is the presence of sexual dimorphic sleep patterns, which, in flies, are manifested as increased mid‐day sleep (‘siesta’) in males compared with females. In the present study, targeted mis‐expression of the genes transformer (tra) and tra2 is used to either feminize or masculinize specific neural and non‐neural tissues in the fly. Feminization of male D. melanogaster using three different GAL4 drivers that are expressed in the mushroom bodies induces a female‐like reduced siesta, whereas the masculinization of females using these drivers triggers the male‐like increased siesta. A similar reversal of sex‐specific sleep is also observed by mis‐expressing tra in the fat body, which is a key tissue in energy metabolism and hormone secretion. In addition, the daily expression levels of takeout, an important circadian clock output gene, are sexually dimorphic. Taken together, these experiments suggest that sleep sexual dimorphism in D. melanogaster is driven by multiple neural and non‐neural circuits, within and outside the brain. PMID:27840547

  14. Late season commercial mosquito trap and host seeking activity evaluation against mosquitoes in a malarious area of the Republic of Korea

    PubMed Central

    Burkett, Douglas A.; Lee, Kwan-Woo; Kim, Heung-Chul; Lee, Hee-Il; Lee, Jong-Soo; Shin, E-Hyun; Wirtz, Robert A.; Cho, Hae-Wol; Claborn, David M.; Coleman, Russel E.; Kim, Wan Y; Klein, Terry A.

    2002-01-01

    Field trials evaluating selected commercially available mosquito traps variously baited with light, carbon dioxide, and/or octenol were conducted from 18-27 September 2000 in a malarious area near Paekyeon-ri (Tongil-Chon ) and Camp Greaves in Paju County, Kyonggi Province, Republic of Korea. The host-seeking activity for common mosquito species, including the primary vector of Japanese encephalitis, Culex tritaeniorhynchus Giles, was determined using hourly aspirator collections from a human and propane lantern-baited Shannon trap during hours when temperatures exceeded 15℃. The total number of mosquitoes and number of each species captured during the test was compared using a block design. Significant differences were observed for the total number of mosquitoes collected, such that, the Mosquito MagnetTM with octenol > Shannon trap > ABC light trap with light and dry ice > Miniature Black Light trap (manufactured by John W. Hock) ≥ New Jersey Trap > ABC light trap with light only. Significant differences in numbers collected among traps were noted for several species including: Aedes vexans (Meigen), Anopheles lesteri Baisas and Hu, An. sinensis Weidemann, An. sineroides Yamada, An. yatsushiroensis Miyazaki, Culex pipiens pallens Coquillett L., Cx. orientalis Edwards and Cx. tritaeniorhynchus. Host-seeking activity for most common species showed a similar bimodal pattern. Results from these field trap evaluations can significantly enhance current vector and disease surveillance efforts especially for the primary vector of Japanese encephalitis, Cx. tritaeniorhynchus. PMID:11949213

  15. Essential oils enhance the toxicity of permethrin against Aedes aegypti and Anopheles gambiae.

    PubMed

    Gross, A D; Norris, E J; Kimber, M J; Bartholomay, L C; Coats, J R

    2017-03-01

    Insecticide resistance and growing public concern over the safety and environmental impacts of some conventional insecticides have resulted in the need to discover alternative control tools. Naturally occurring botanically-based compounds are of increased interest to aid in the management of mosquitoes. Susceptible strains of Aedes aegypti (Linnaeus) (Diptera: Culicidae) and Anopheles gambiae (Meigen) (Diptera: Culicidae) were treated with permethrin, a common type-I synthetic pyrethroid, using a discriminate dose that resulted in less than 50% mortality. Piperonyl butoxide (PBO) and 35 essential oils were co-delivered with permethrin at two doses (2 and 10 µg) to determine if they could enhance the 1-h knockdown and the 24-h mortality of permethrin. Several of the tested essential oils enhanced the efficacy of permethrin equally and more effectively than piperonyl butoxide PBO, which is the commercial standard to synergize chemical insecticide like pyrethroids. PBO had a strikingly negative effect on the 1-h knockdown of permethrin against Ae. aegypti, which was not observed in An. gambiae. Botanical essential oils have the capability of increasing the efficacy of permethrin allowing for a natural alternative to classic chemical synergists, like PBO.

  16. New taxa of Carpomyini, with special emphasis on Goniglossum (Diptera: Tephritidae: Trypetinae).

    PubMed

    Freidberg, Amnon

    2016-07-26

    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.

  17. The Sarcophagidae (Insecta: Diptera) described by Chien-ming Chao and Xue-zhong Zhang.

    PubMed

    Zhang, Dong; Zhang, Ming; Li, Zijuan; Pape, Thomas

    2015-04-13

    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.

  18. 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.

  19. 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.

  20. Effects of temperature and photoperiod on the development of overwintering immature Culicoides chiopterus and C. dewulfi.

    PubMed

    Lühken, Renke; Steinke, Sonja; Hoppe, Nikolai; Kiel, Ellen

    2015-11-30

    In areas with harsh winters, several studies have recorded low numbers - or even zero - adult Culicoides during the winter period followed by a population peak in the subsequent spring. This experimental study determined whether temperature, photoperiod, or the combination thereof affect the development of overwintering immature dung breeding Culicoides, resulting in this peak. Temperature had a significant impact on the development period of Culicoides chiopterus (Meigen), 1830 and C. dewulfi Goetghebuer, 1936. In treatments with constant high temperature, emergence occurred shortly after the beginning of the experiment (mean=day 9). In contrast, no individuals emerged from the other two treatments, as long as the temperatures were below 10°C. In these treatments, the emergence of Culicoides started when the temperature exceeded 20°C for some days (mean=day 33). There was no significant difference between the two photoperiods (February or April day length; 9 h:15 h [light:dark] vs. 13 h:11 h). Our results highlight the importance of temperature on the spring emergence of C. chiopterus and C. dewulfi, but the response to the four temperature-photoperiod treatments did not differ between the two species.

  1. A review of Billaea Robineau-Desvoidy of the eastern Palearctic and Oriental regions (Diptera: Tachinidae).

    PubMed

    Zhang, Chun-Tian; Shima, Hiroshi; Wang, Qiang; Tschorsnig, Hans-Peter

    2015-04-23

    The species of Billaea Robineau-Desvoidy (Diptera, Tachinidae) from the eastern Palearctic and Oriental regions are revised. Ten described species are recognized, viz. B. atkinsoni (Baranov) (new records for Japan, Laos, Malaysia, Pakistan and Thailand), B. ficorum (Townsend), B. fortis (Rondani), B. impigra Kolomiets (new record for China), B. kolomyetzi Mesnil, B. malayana Malloch, B. morosa Mesnil, B. robusta Malloch, B. steini (Brauer et Bergenstamm) and B. triangulifera (Zetterstedt) and nine species are described as new to science, B. brevicauda Zhang et Shima sp. nov. (China), B. carinata Zhang et Shima sp. nov. (China), B. chinensis Zhang et Shima sp. nov. (China and Vietnam), B. flava Zhang et Wang sp. nov. (China), B. kurahashii Zhang et Shima sp. nov. (Laos and Thailand), B. micronychia Zhang et Shima sp. nov. (China and Japan; previously misidentified from China as B. irrorata (Meigen)), B. papei Zhang et Shima sp. nov. (Malaysia), B. setigera Zhang et Shima sp. nov. (China) and B. verticalis Shima et Zhang sp. nov. (China). Billaea fasciata (Townsend, 1928) is treated as a junior synonym of B. ficorum (Townsend, 1916), syn. nov. Billaea irrorata is no longer recorded from the eastern Palearctic. A key to 19 species of Billaea from the eastern Palearctic and Oriental regions and 101 figures of male terminalia, bodies, heads and abdomens are given.

  2. Fumigant Toxicity of Phenylpropanoids Identified in Asarum sieboldii Aerial Parts to Lycoriella ingenua (Diptera: Sciaridae) and Coboldia fuscipes (Diptera: Scatopsidae).

    PubMed

    Yi, Jee Hwan; Perumalsamy, Haribalan; Sankarapandian, Karuppasamy; Choi, Byeoung-Ryeol; Ahn, Young-Joon

    2015-06-01

    Lycoriella ingenua (Dufour) (Diptera: Sciaridae) and Coboldia fuscipes (Meigen) (Diptera: Scatopsidae) are two of the most economically important insect pests of cultivated mushrooms. The toxicities to the fly larvae of the three phenylpropanoids (methyleugenol, myristicin, and safrole) from aerial parts of Asarum sieboldii Miquel (Aristolochiaceae) were compared with those of the currently available carbamate insecticide benfuracarb. In a contact+fumigant mortality bioassay with L. ingenua and C. fuscipes larvae, methyleugenol (1.46 and 2.33 µg/cm2) was the most toxic compound, followed by safrole (2.03 and 2.59 µg/cm2) and myristicin (3.59 and 4.96 µg/cm2), based on 24-h LC50 values. The phenylpropanoids were less toxic than benfuracarb (LC50, 0.75 and 0.55 µg/cm2). In vapor-phase mortality tests with the larvae, the phenylpropanoids were consistently more toxic in closed versus open containers, indicating that the effect of the compounds was largely a result of vapor action. Global efforts to reduce the level of highly toxic synthetic insecticides in the agricultural environment justify further studies on A. sieboldii plant-derived products as potential fumigants for the control of mushroom fly populations in mushroom houses and mushroom compost.

  3. The Phylogeny and Evolutionary Timescale of Muscoidea (Diptera: Brachycera: Calyptratae) Inferred from Mitochondrial Genomes

    PubMed Central

    Wang, Ning; Cameron, Stephen L.; Mao, Meng; Wang, Yuyu; Xi, Yuqiang; Yang, Ding

    2015-01-01

    Muscoidea is a significant dipteran clade that includes house flies (Family Muscidae), latrine flies (F. Fannidae), dung flies (F. Scathophagidae) and root maggot flies (F. Anthomyiidae). It is comprised of approximately 7000 described species. The monophyly of the Muscoidea and the precise relationships of muscoids to the closest superfamily the Oestroidea (blow flies, flesh flies etc) are both unresolved. Until now mitochondrial (mt) genomes were available for only two of the four muscoid families precluding a thorough test of phylogenetic relationships using this data source. Here we present the first two mt genomes for the families Fanniidae (Euryomma sp.) (family Fanniidae) and Anthomyiidae (Delia platura (Meigen, 1826)). We also conducted phylogenetic analyses containing of these newly sequenced mt genomes plus 15 other species representative of dipteran diversity to address the internal relationship of Muscoidea and its systematic position. Both maximum-likelihood and Bayesian analyses suggested that Muscoidea was not a monophyletic group with the relationship: (Fanniidae + Muscidae) + ((Anthomyiidae + Scathophagidae) + (Calliphoridae + Sarcophagidae)), supported by the majority of analysed datasets. This also infers that Oestroidea was paraphyletic in the majority of analyses. Divergence time estimation suggested that the earliest split within the Calyptratae, separating (Tachinidae + Oestridae) from the remaining families, occurred in the Early Eocene. The main divergence within the paraphyletic muscoidea grade was between Fanniidae + Muscidae and the lineage ((Anthomyiidae + Scathophagidae) + (Calliphoridae + Sarcophagidae)) which occurred in the Late Eocene. PMID:26225760

  4. 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.

  5. Evaluation of Seasonal Feeding Patterns of West Nile Virus Vectors in Bernalillo County, New Mexico, United States: Implications for Disease Transmission

    PubMed Central

    LUJAN, D. A.; GREENBERG, J. A.; HUNG, A. S.; DIMENNA, M. A.; HOFKIN, B. V.

    2014-01-01

    Many mosquito species take bloodmeals predominantly from either birds or mammals. Other mosquito species are less host-specific and feed readily on both. Furthermore, some species tend to alter their feeding patterns over the course of the year; early in the mosquito season such species may feed primarily on a particular host type, and subsequently take an increasingly larger proportion of their bloodmeals from an alternative host type as the season progresses. We have examined the feeding patterns of the three mosquito species found in Bernalillo County, NM: Culex quinquefasciatus (Say), Culex tarsalis (Coquillett), and Aedes vexans (Meigen). Specifically, we seek to determine if any of these species displays a seasonal shift in terms of its host utilization pattern. Our analysis focuses on these three species because they are all considered to be competent vectors for the West Nile virus (WNV). Our current data for Cx. quinquefasciatus suggest that unlike elsewhere in its range, this species increases its proportion of avian bloodmeals as the season progresses. Alternatively, Ae. vexans feeds primarily on mammals, whereas Cx. tarsalis appears to feed on both mammals and birds throughout the mosquito season. A more complete understanding of the feeding habits of these three mosquito species may help to clarify the transmission dynamics of WNV in Bernalillo County. PMID:24605477

  6. Attraction of Culex pipiens/restuans (Diptera: Culicidae) mosquitoes to bird uropygial gland odors at two elevations in the Niagara region of Ontario.

    PubMed

    Russell, Curtis B; Hunter, Fiona F

    2005-05-01

    In an effort to determine whether female Culex pipiens L. and Culex restuans Theobald mosquitoes (Diptera: Culicidae) are attracted to crow, Corvus brachyrhynchus, uropygial gland secretions, CDC miniature light traps (baited with CO2 but with the lights removed) were placed at approximately 1.5- and 5-m elevations, in 10 trees in awoodlot near Niagara Falls, Canada. These traps were assigned either a bird odor or a blank control. Bird odors were created by attaching cotton swabs coated with crow uropygial gland secretions to the trap intake. A significantly greater number of Cx. pipiens/ restuans were found in the 5-m traps compared with 1.5-m traps, with a significant number attracted to the bird odor over the no odor traps at the 5-m elevation, but not at 1.5 m. We also found more Aedes vexans (Meigen) in the 1.5-m traps than the 5-m traps; however, presence or absence of bird odor did not influence the distribution of Ae. vexans.

  7. Vector competence of alpine, Central Valley, and coastal mosquitoes (Diptera: Culicidae) from California for Jamestown Canyon virus.

    PubMed

    Kramer, L D; Bowen, M D; Hardy, J L; Reeves, W C; Presser, S B; Eldridge, B F

    1993-03-01

    Mosquitoes collected from alpine, Central Valley, and coastal habitats in California were evaluated for their vector competence for four strains of Jamestown Canyon (JC) virus. Three of the viral strains examined were isolated from alpine Aedes species collected in California, and one, the prototype JC virus, was isolated from Culiseta inornata (Williston) collected in Colorado. Alpine Aedes tahoensis Dyar, Ae. cataphylla Dyar, Ae. hexodontus Dyar, Ae. increpitus Dyar, Ae. clivis Lanzaro and Eldridge, and coastal Aedes washinoi Lanzaro and Eldridge were variably susceptible to alpine strains of JC virus. Infection rates ranged from 22 to 77%, and peroral transmission rates of the infected females ranged from 0 to 26%. The differences were related to both mosquito species and viral strain. Coastal populations of Cs. inornata, Ae. washinoi, and Ae. sierrensis (Ludlow) were incompetent vectors when fed an alpine strain of JC virus, whereas Ae. squamiger (Coquillet) and Ae. dorsalis (Meigen) were competent vectors. Peroral transmission rates following parenteral infection of females of most species were about twofold higher than those for perorally infected females. A population of Cs. inornata from the Central Valley was highly susceptible when fed an alpine strain of JCV and transmitted virus both horizontally and vertically. Alpine strains of JC virus also were transmitted vertically by Ae. tahoensis, Ae. washinoi, and Ae. squamiger following parenteral infection of females.

  8. Larval exposure to azadirachtin affects fitness and oviposition site preference of Drosophila melanogaster.

    PubMed

    Bezzar-Bendjazia, Radia; Kilani-Morakchi, Samira; Aribi, Nadia

    2016-10-01

    Azadirachtin, a biorational insecticide, is one of the prominent biopesticide commercialized today and represent an alternative to conventional insecticides. The current study examined the lethal and sublethal effects of azadirachtin on Drosophila melanogaster Meigen, 1830 (Diptera: Drosophilidae) as biological model. Various doses ranging from 0.1 to 2μg were applied topically on early third instar larvae and the cumulative mortality of immature stage was determined. In second series of experiments, azadirachtin was applied at its LD25 (0.28μg) and LD50 (0.67μg) and evaluated on fitness (development duration, fecundity, adult survival) and oviposition site preference with and without choice. Results showed that azadirachtin increased significantly at the two tested doses the duration of larval and pupal development. Moreover, azadirachtin treatment reduced significantly adult's survival of both sex as compared to control. In addition, azadirachtin affected fecundity of flies by a significant reduction of the number of eggs laid. Finally results showed that females present clear preference for oviposition in control medium. Pre-imaginal exposure (L3) to azadirachtin increased aversion to this substance suggesting a memorability of the learned avoidance. The results provide some evidence that larval exposure to azadirachtin altered adult oviposition preference as well as major fitness traits of D. melanogaster. Theses finding may reinforce behavioural avoidance of azadirachtin and contribute as repellent strategies in integrated pest management programmes.

  9. Larval Performance and Adult Attraction of Delia platura (Diptera: Anthomyiidae) in a Native and an Introduced Crop.

    PubMed

    Guerra, Patricia C; Keil, Clifford B; Stevenson, Philip C; Mina, Diego; Samaniego, Servio; Peralta, Eduardo; Mazon, Nelson; Chancellor, Timothy C B

    2017-02-01

    Delia platura Meigen is an important pest in crops around the world. Its host range includes almost 50 species, and it can develop in soil organic matter. In Ecuador, D. platura is a serious problem for the crop, Lupinus mutabilis Sweet (Chocho), and it also attacks broccoli (Brassica oleracea L.). After broccoli is harvested, crop residue is mixed with soil or collected and stored close to Chocho fields. The objectives of this study were to determine the adaptive responses of larvae reared on different hosts and whether D. platura females are preferentially attracted to germinating L. mutabilis seeds or broccoli residue. Accordingly, larval performance and attraction of female D. platura reared on broccoli residue and L. mutabilis seeds were evaluated. The number of larvae, pupae, and adults were higher when reared on broccoli. Conversely, pupal weight was higher and time from larva to pupa, pupa to adult, and total life cycle were longer in flies reared on L. mutabilis. Although D. platura developed more quickly on broccoli, L. mutabilis was also a good host since pupae were heavier compared with flies reared on broccoli. Delia platura females reared on broccoli preferred broccoli residue to L. mutabilis in an olfactometer. Volatiles from broccoli residue in soil may attract D. platura females and stimulate oviposition on L. mutabilis seeds. Environmentally benign production of L. mutabilis crops with minimal insecticide applications may require the elimination of fresh broccoli residue as fertilizer in soils where L. mutabilis is cultivated.

  10. 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.

  11. 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

  12. 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

  13. Phylogenetic analysis of Culicoides species from France based on nuclear ITS1-rDNA sequences.

    PubMed

    Perrin, A; Cetre-Sossah, C; Mathieu, B; Baldet, T; Delecolle, J-C; Albina, E

    2006-06-01

    Biting midges of the genus Culicoides (Diptera: Ceratopogonidae) play important roles in the transmission of viral diseases affecting wild and domestic ruminants and horses, including Bluetongue (BT) and African horse sickness (AHS) respectively. In southern Europe, BT has been largely transmitted by the classical Afro-Asian vector Culicoides imicola Kieffer. However, other species such as C. obsoletus Meigen, C. scoticus Downs & Kettle and C. pulicaris Linné may also be involved in BTV transmission. As a consequence of the discovery of C. imicola followed by BTV-2 outbreaks on the island of Corsica in October 2000, further studies on these biting midges have been carried out. To better characterize the evolution and phylogenetic relations of Culicoides, molecular analysis in parallel with a morphology-based taxonomic approach were performed. Phylogenetic analyses of French Culicoides species were undertaken using the ribosomal DNA (rDNA) internal transcribed spacer 1 (ITS1) as a molecular target. This region was shown to be useful in understanding evolutionary and genetic relationships between species. Construction of several trees showed that molecular phylogeny within the genus Culicoides correlates not only with morphological-based taxonomy but also with ecological patterns.

  14. Larinus minutus (Coleoptera: Curculionidae) and Urophora quadrifasciata (Diptera: Tephritidae), Evidence for Interaction and Impact on Spotted Knapweed in Arkansas.

    PubMed

    Minteer, C R; Kring, T J; Wiedenmann, R N

    2016-03-25

    Interactions among seed-feeding insects are well noted in the literature, with many of these interactions being asymmetrical and causing a disadvantage for one of the species involved. While often effective, the use of the cumulative stress approach to biological control (where multiple natural enemy species are released) may increase the risk of interaction, which may lead to less effective biological control programs. Spotted knapweed (Centaurea stoebe ssp.micranthos(Gugler) Hayek) is an invasive plant that causes damage in rangelands and pastures. In Arkansas, two biological control agents for spotted knapweed,Larinus minutus Gyllenhal andUrophora quadrifasciata Meigen, are established. Both species attack the capitula of spotted and diffuse knapweeds. There is potential for interactions between these species, and this could affect the efficacy of the biological control program. To evaluate these potential interactions, we collected spotted knapweed capitula weekly from three sites in Arkansas from 2010 to 2012. Capitula were monitored for emergence ofL. minutus andU. quadrifasciata, and the effect on seed reduction was analyzed. Over all three years,L. minutusandU. quadrifasciata were present in 35.8% (492) and 22.8% (313) of the capitula, respectively. We determined that the occurrences ofL. minutus andU. quadrifasciatawere not independent of each other, and thatL. minutusis more effective at reducing spotted knapweed seed production thanU. quadrifasciatawithin individual capitula. Seed production in capitula with both natural enemies present was no different from capitula withL. minutus.

  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.

  16. A Comparison of Common Diets for the Continuous Culture of Adult Lucilia sericata (Diptera: Calliphoridae) for Forensic and Medical Entomological Applications.

    PubMed

    Blystone, Allissa M; Hansen, Karolyn M

    2014-11-01

    Blow fly members of the family Calliphoridae, specifically Lucilia sericata (Meigen), have application in the fields of behavioral ecology, forensics, and medicine as agents for assessing ecological succession or decomposition and postmortem interval estimation, and for maggot debridement therapy, respectively. The lack of standardization of laboratory adult insect feeding, breeding, and rearing protocols among researchers in behavioral, medical, and forensic fields has become problematic. With the goal of understanding physical and physiological effects of diet as a baseline for future behavioral experiments, this article focuses on determining basic culture requirements for the adult blow fly L. sericata by comparing nine diets and the effects of each on survivorship and fecundity under controlled laboratory conditions. Percent survival, fecundity, and the effect of culture density were analyzed over the course of 120 d. Results indicate that a simple broad spectrum diet of honey water and bovine liver is the optimum diet for extending the life span of the flies and increasing the number of eggs laid per female per oviposition event, with 5-20 female flies being the optimum number per culture vessel. This culture protocol is simple to follow, can be easily incorporated into current behavioral, forensic, and medical entomology research programs, and the dietary components are readily available across diverse geographic areas.

  17. 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.

    PubMed

    Rochlin, I; Harding, K; Ginsberg, H S; Campbell, S R

    2008-05-01

    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.

  18. Supercooling capacity of Urophora affinis and U. quadrifasciata (Diptera: Tephritidae) on spotted knapweed: comparisons among plants, sites, time of season, and gall densities.

    PubMed

    Nowierski, R M.; Fitzgerald, B C.; Zeng, Z

    2001-04-01

    Larval supercooling points of Urophora affinis Frauenfeld and U. quadrifasciata (Meigen) were compared among plants, six research sites in western Montana, four fall/winter time periods, and among gall densities. These two tephritid fly species are introduced biological control agents of spotted knapweed, Centaurea maculosa Lamarck, and diffuse knapweed, Centaurea diffusa Lamarck. Few differences in larval supercooling points for U. affinis and U. quadrifasciata were found among plants, and where differences were found, they were not consistent across fall/winter time periods. Significant differences in larval supercooling points were found among sites and across fall/winter time periods. No relationship was found between larval supercooling points and site elevation. Larval supercooling points of both U. affinis and U. quadrifasciata showed no relationship with the density of Urophora galls within spotted knapweed capitula. Mean larval supercooling points of U. affinis were consistently lower than those of U. quadrifasciata across sites and fall/winter time periods. In conclusion, temporal differences in temperature over the fall/winter time periods and microclimatic differences among sites appear to be the most important abiotic factors influencing the supercooling points in U. affinis and U. quadrifasciata.

  19. Weather and Land Cover Influences on Mosquito Populations in Sioux Falls, South Dakota

    PubMed Central

    CHUANG, TING-WU; HILDRETH, MICHAEL B.; VANROEKEL, DENISE L.; WIMBERLY, MICHAEL C.

    2011-01-01

    This study compared the spatial and temporal patterns of Culex tarsalis Coquillett and Aedes vexans Meigen populations and examined their relationships with land cover types and climatic variability in Sioux Falls, SD. Between 24 and 30 CDC CO2-baited light traps were set annually in Sioux Falls from May to September 2005–2008. Land cover data were acquired from the 2001 National Land Cover Dataset and the percentages of selected land cover types were calculated within a 600-m buffer zone around each trap. Meteorological information was summarized from local weather stations. Cx. tarsalis exhibited stronger spatial autocorrelation than Ae. vexans. Land cover analysis indicated that Cx. tarsalis was positively correlated with grass/hay, and Ae. vexans was positively correlated with wetlands. No associations were identified between irrigation and the host-seeking population of each species. Higher temperature in the current week and 2 wk prior and higher precipitation 3–4 wk before collection of host-seeking adult mosquitoes had positive influences on Cx. tarsalis abundance. Temperature in the current week and rainfall 2–3 wk before sampling had positive influences on Ae. vexans abundance. This study revealed the different influences of weather and land cover on important mosquito species in the Northern Great Plains region, which can be used to improve local vector control strategies and West Nile virus prevention efforts. PMID:21661329

  20. Ecological Niche Modeling of Potential West Nile Virus Vector Mosquito Species in Iowa

    PubMed Central

    Larson, Scott R.; DeGroote, John P.; Bartholomay, Lyric C.; Sugumaran, Ramanathan

    2010-01-01

    Ecological niche modeling (ENM) algorithms, Maximum Entropy Species Distribution Modeling (Maxent) and Genetic Algorithm for Rule-set Prediction (GARP), were used to develop models in Iowa for three species of mosquito — two significant, extant West Nile virus (WNV) vectors (Culex pipiens L and Culex tarsalis Coquillett (Diptera: Culicidae)), and the nuisance mosquito, Aedes vexans Meigen (Diptera: Culicidae), a potential WNV bridge vector. Occurrence data for the three mosquito species from a state-wide arbovirus surveillance program were used in combination with climatic and landscape layers. Maxent successfully created more appropriate niche models with greater accuracy than GARP. The three Maxent species' models were combined and the average values were statistically compared to human WNV incidence at the census block group level. The results showed that the Maxent-modeled species' niches averaged together were a useful indicator of WNV human incidence in the state of Iowa. This simple method for creating probability distribution maps proved useful for understanding WNV dynamics and could be applied to the study of other vector-borne diseases. PMID:20874412

  1. Habitat associations of eastern equine encephalitis transmission in Walton County Florida.

    PubMed

    Kelen, Patrick T Vander; Downs, Joni A; Burkett-Cadena, Nathan D; Ottendorfer, Christy L; Hill, Kevin; Sickerman, Stephen; Hernandez, José; Jinright, Joseph; Hunt, Brenda; Lusk, John; Hoover, Victor; Armstrong, Keith; Unnasch, Robert S; Stark, Lillian M; Unnasch, Thomas R

    2012-05-01

    Eastern Equine Encephalitis virus (EEEV; family Togaviridae, genus Alphavirus) a highly pathogenic mosquito-borne virus is endemic to eastern North America. The ecology of EEEV in Florida differs from that in other parts of the United States; EEEV in the northeastern United States is historically associated with freshwater wetlands. No formal test of habitat associations of EEEV in Florida has been reported. Geographical Information Sciences (GIS) was used in conjunction with sentinel chicken EEEV seroconversion rate data as a means to examine landscape features associated with EEEV transmission in Walton County, FL. Sentinel sites were categorized as enzootic, periodically enzootic, and negative based on the number of chicken seroconversions to EEEV from 2005 to 2009. EEEV transmission was then categorized by land cover usage using Arc GIS 9.3. The land classification data were analyzed using the Kruskal-Wallis test for each land use class to determine which habitats may be associated with virus transmission as measured by sentinel chicken seroconversion rates. The habitat class found to be most significantly associated with EEEV transmission was tree plantations. The ecological factor most commonly associated with reduced levels of EEEV transmission was vegetated nonforest wetlands. Culiseta melanura (Coquillett), the species generally considered to be the major enzootic EEEV vector, was relatively evenly distributed across all habitat classes, while Aedes vexans (Meigen) and Anopheles crucians Weidemann were most commonly associated with tree plantation habitats.

  2. FMRFamide-like immunoreactivity in the central nervous system and alimentary tract of the non-hematophagous blow fly, Phormia regina, and the hematophagous horse fly, Tabanus nigrovittatus.

    PubMed

    Haselton, Aaron T; Yin, Chih-Ming; Stoffolano, John G

    2008-01-01

    FMRFamide-related peptides (FaRPs) are a diverse and physiologically important class of neuropepeptides in the metazoa. In insects, FaRPs function as brain-gut neuropeptides and have been immunolocalized throughout the nervous system and alimentary tract where they have been shown to affect feeding behavior. The occurrence of FMRFamide-like immunoreactivity (FLI) was examined in the central nervous system and alimentary tract of non-hematophagous blow fly, Phormia regina Meigen (Diptera: Calliphoridae), and the hematophagous horse fly, Tabanus nigrovittatus Macquart (Diptera:Tabanidae). Although the central nervous system and alimentary anatomy differ between these two dipteran species, many aspects of FLI remain similar. FLI was observed throughout the central and stomatogastric nervous systems, foregut, and midgut in both flies. In the central nervous system, cells and processes with FLI occurred in the brain, subesophageal ganglion, and ventral nerve cord. FLI was associated with neurohemal areas of the brain and ventral nerve cord. A neurohemal plexus of fibers with FLI was present on the dorsal region of the thoracic central nervous system in both species. In the gut, processes with FLI innervated the crop duct, crop and anterior midgut. Endocrine cells with FLI were present in the posterior midgut. The distribution of FLI in these two flies, in spite of their different feeding habits, further supports the role of FaRPs as important components of the braingut neurochemical axis in these insects and implicates FaRPs as regulators of insect feeding physiology among divergent insect taxa.

  3. 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.

  4. A new trap and lure for Drosophila melanogaster (Diptera: Drosophilidae).

    PubMed

    Birmingham, Anna L; Kovacs, Ervin; Lafontaine, Jean Pierre; Avelino, Norman; Borden, John H; Andreller, Isak S; Gries, Gerhard

    2011-06-01

    We conducted a series of nine laboratory experiments testing the response of "vinegar flies," Drosophila melanogaster Meigen (Diptera: Drosophilidae), released in bioassay chambers to experimental traps and lures. These experiments showed that an effective trap could be constructed from a clear 225-ml screw-cap jar fitted with a hollow 8-mm-diameter cylindrical cross bridge. Flies could enter the trap from either end of the cylindrical "gate" and in turn could enter the interior chamber of the trap through a cut out portion at mid-span of the cylinder. The experiments also showed that a natural-component lure could be made using a teabag containing freeze-dried banana powder, yeast, and carrageenan gum powder as a humectant. When dipped in water for 10-15 s and then placed in the bottom of a trap, the teabag provided effective attraction for at least 7 d. Captured flies were immobilized on a sticky card placed in the trap, allowing them to be easily seen. Unlike other traps that cannot be opened and have liquid lures, the cylindrical-gate trap can be reused repeatedly if the teabag and sticky card are replaced. A final two experiments showed that the prototype operational cylindrical-gate trap with a teabag lure captured 3.3 and 2.3 times more released flies, respectively, than the next best of three commercially available traps.

  5. Aspects of bioecology of two Rift Valley Fever Virus vectors in Senegal (West Africa): Aedes vexans and Culex poicilipes (Diptera: Culicidae).

    PubMed

    Yamar, B A; Diallo, Diawo; Kebe, Cheikh Mouhamed Fadel; Dia, Ibrahima; Diallo, Mawlouth

    2005-09-01

    The dispersal, population dynamics, and age structure of two Rift Valley Fever Virus (Phlebovirus: Bunyaviridae) (RVFV) vectors, Aedes vexans Meigen and Culex poicilipes Theobald, were investigated in northern Senegal. The main objective was to investigate possible factors that mediate RVFV emergence and propagation at a site where humans and livestock live in proximity to temporary surface pools. In mark-release-recapture studies, recapture rates of 0.18% (156/85,500) and 3.46% (201/5,800) were obtained for Ae. vexans and Cx. poicilipes, respectively. The number of mosquitoes recaptured decreased with increasing distance from the release point and over time. The estimated daily survival rate for released females ranged from 91 to 96% for Ae. vexans and 70-79% for Cx. poicilipes. The maximum time after release when marked mosquitoes were collected was 23 and 12 d for Ae. vexans and Cx. poicilipes, respectively. The maximum distances from the release point that marked females were recaptured was 620 and 550 m for Ae vexans and Cx. poicilipes, respectively. Rainfall periodicity was a key factor controlling Ae. vexans population abundance. In contrast, rainfall had no discernible effect on the fluctuation of Cx. poicilipes numbers. The involvement of these two species in the transmission of RVFV is discussed with respect to their longevity and daily survival rate.

  6. 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.

  7. 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.

  8. 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

  9. Allocation of pederin during lifetime ofPaederus rove beetles (Coleoptera: Staphylinidae): Evidence for polymorphism of hemolymph toxin.

    PubMed

    Kellner, R L; Dettner, K

    1995-11-01

    Pederin, a hemolymph toxin found in the rove beetle genusPaederus, is quantified in individual specimens ofP. fuscipes andP. riparius. Whereas males always contain only small quantities of the toxin (0.1-1.5 µg), females are not so restricted (0.2-20.5 µg) and in most cases possess roughly 10-fold that in males. There are, however, females containing as little pederin as the males, and so two clearly separate groups of females can be discerned. These two groups hint at two types of females defined by the eggs they lay. About 85% of the females, i.e., those containing much of the substance, transfer pederin into every egg and thus are denoted (+)-females. The remaining 15%, the (-)-females, contain at best small amounts of the toxin, which is transferred in minute quantities into the first eggs while the subsequent ones lack pederin. With respect to the pederin content of their eggs, there is no overlap between these two types of females. If fed with pederin, (-)-females can transfer it into the eggs like (+)-females. After hatching the larvae store pederin when present. Larvae are not able to biosynthesize the toxin on their own, but storage of that received in the egg is very efficient, and the difference between larvae with and without pederin is preserved until imaginal eclosion. In (+)-females, pederin increases, probably reflecting a biosynthetic capacity, but in males and presumptive (-)-females the amount of pederin never exceeds the quantity transferred by parental (+)-females. Consequently, males and (-)-females probably are unable to biosynthesize pederin. This polymorphism of females may have a genetic basis. Individuals of all stages nevertheless sequester pederin if it is supplied with the diet.

  10. Incipient toxicity of lithium to freshwater organisms representing a salmonid habitat

    SciTech Connect

    Emery, R.; Klopfer, D.C.;