Sex- and Developmental Stage-Related Changes in Energy Reserves in Fourth-instar Larvae of the Midge<i>Chironomus riparius</i>Meigen (Diptera: Chironomidae): Implications for Ecotoxicity Testing

Servia, María J.; Heydorff, Micheline; Péry, Alexandre R.R.; Garric, Jeanne; Lagadic, Laurent

doi:10.1603/0046-225x-35.4.865

Cited by 8 publications

(7 citation statements)

References 47 publications

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“…Also, the direct comparison of absolute triglyceride levels between the terbutryn experiment and the emergence experiment would not be meaningful, due to the different life stages used (larvae vs. adults) and the accompanying differing triglyceride levels (Cargill et al 1985, Servia et al 2006, Winkelmann & Koop 2007). However, a reduction of triglycerides of about 24% is still a clear indication of a reduced energy uptake; especially considering that triglycerides are the major energy store of mayflies and, hence, the main indicator of physiological fitness (Koop et al 2011), as shown for Rhithrogena semicolorata, Ephemera danica (Winkelmann & Koop 2007) and Heptagenia flava .…”

Section: Discussionmentioning

confidence: 99%

Herbicide indirectly reduces physiological condition of a benthic grazer

Rybicki¹,

Winkelmann²,

Hellmann³

et al. 2012

Aquat. Biol.

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Freshwater ecosystems are polluted with various environmental chemicals. For example, pesticides enter the aquatic environment via spray drift or surface runoff from catchment areas used for industrialised agriculture. In the present study, we investigated the response of the grazer−aufwuchs interaction when exposed to the herbicide terbutryn in a microcosm experiment. Terbutryn induced a trophic cascade with negative effects on grazers by inhibiting growth of primary producers. We determined a no-observed-effect concentration (measured as particulate organic carbon, NOEC POC ) of 0.21 µg l −1 for aufwuchs biomass and a lowest-observed-effect concentration (LOEC POC ) of 2.01 µg l −1. Furthermore, a shift in the aufwuchs community was detected in all terbutryn treatments nearly 4 wk after exposure, and this shift persisted until the end of the experiment in the treatment with the highest terbutryn concentration. In addition, reduced energy stores (triglycerides, TG) of the grazer Rhithrogena semicolorata (Heptageniidae: Ephemeroptera) were found (NOEC TG = 0.03 µg l ), which was interpreted as an indication of moderate starvation during the experiment. While starvation did not result in reduced larval growth as might have been expected, the ob served reduction of TG content in larvae (24%) is consistent with results from a separate experiment in which starvation alone induced a 15% reduction of TG content as well as reduced emergence, reduced size at emergence, and reduced egg production.

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Section: Discussionmentioning

confidence: 99%

Herbicide indirectly reduces physiological condition of a benthic grazer

Rybicki¹,

Winkelmann²,

Hellmann³

et al. 2012

Aquat. Biol.

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“…Since certain PUFAs have been linked to somatic growth, body condition, immune responses, and breeding success in terrestrial consumers, ,, ignoring these parameters may lead to incorrect conclusions and hinder the assessment of effects to consumers and riparian food webs. Sex-specific differences in the FA profile of emergent aquatic insects, due to different life cycles of males and females, may further improve our understanding and thus prediction of micropollutant-induced effects.…”

Section: Introductionmentioning

confidence: 99%

Metal Exposure and Sex Shape the Fatty Acid Profile of Midges and Reduce the Aquatic Subsidy to Terrestrial Food Webs

Pietz

Kainz

Schroeder

et al. 2023

Environ. Sci. Technol.

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Aquatic micropollutants can be transported to terrestrial systems and their consumers by emergent aquatic insects. However, micropollutants, such as metals, may also affect the flux of physiologically important polyunsaturated fatty acids (PUFAs). As certain PUFAs have been linked to physiological fitness and breeding success of terrestrial consumers, reduced fluxes from aquatic systems could affect terrestrial populations and food webs. We chronically exposed larvae of the aquatic insect Chironomus riparius to a range of environmentally relevant sediment contents of cadmium (Cd) or copper (Cu) in a 28-day microcosm study. Since elevated water temperatures can enhance metals' toxic effects, we used two temperature regimes, control and periodically elevated temperatures (heat waves) reflecting an aspect of climate change. Cd and Cu significantly reduced adult emergence by up to 95% and 45%, respectively, while elevated temperatures had negligible effects. Both metal contents were strongly reduced (∼90%) during metamorphosis. Furthermore, the chironomid FA profile was significantly altered during metamorphosis with the factors sex and metal exposure being relevant predictors. Consequently, fluxes of physiologically important PUFAs by emergent adults were reduced by up to ∼80%. Our results suggest that considering fluxes of physiologically important compounds, such as PUFAs, by emergent aquatic insects is important to understand the implications of aquatic micropollutants on aquatic-terrestrial meta-ecosystems.

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“…Our results report for the first time developmental stage and sex-related changes in the vitellogenin gene expression throughout the 4 th larval instar in C . riparius , which correlate in time with morphological changes described decades ago in the development of the vitello during the oocyte formation [ 33 ] and also with the sex-dependent glycogen reserves variations previously described in this organism [ 67 ]. Although further studies are needed to understand the mechanisms that underlie vitellogenesis in C .…”

Section: Discussionmentioning

confidence: 55%

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

et al. 2015

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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.

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Sex- and Developmental Stage-Related Changes in Energy Reserves in Fourth-instar Larvae of the MidgeChironomus ripariusMeigen (Diptera: Chironomidae): Implications for Ecotoxicity Testing

Cited by 8 publications

References 47 publications

Herbicide indirectly reduces physiological condition of a benthic grazer

Herbicide indirectly reduces physiological condition of a benthic grazer

Metal Exposure and Sex Shape the Fatty Acid Profile of Midges and Reduce the Aquatic Subsidy to Terrestrial Food Webs

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

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