Chironomus Plumosus Research Articles

Content of Sodium, Potassium, Calcium, and Magnesium in the Body of Larvae of Sibling Species Chironomus balatonicus and Chironomus plumosus Depending on the Salinity of the Medium

Content of Sodium, Potassium, Calcium, and Magnesium in the Body of Larvae of Sibling Species Chironomus balatonicus and Chironomus plumosus Depending on the Salinity of the Medium

Round goby (Neogobius melanostomus) δ13C/δ15N discrimination values and comparisons of diets from gut content and stable isotopes in Oneida Lake.

Gut content analyses have found that round gobies (Neogobius melanostomus) are highly dependent on dreissenid mussels but stable isotope analysis has often suggested that the dreissenid contribution is lower. However, estimation of dietary contributions with stable isotopes relies on accurate discrimination factors (fractionation factors). To test if discrimination values commonly used in aquatic food web studies are suitable for round gobies, we collected round gobies from Oneida Lake, raised them for 63 days under four different diets (Chironomus plumosus, Mytilus chilensis, Dreissenia spp., Euphausia superba) and measured the change in white muscle δ13C and δ15N. Gobies were also collected throughout Oneida Lake for gut content and stable isotope analysis. Diets changed as round gobies grew, with small round gobies (17-42mm) feeding mostly on cladocera and chironomids, intermediate sized gobies (43-94mm) transitioning from chironomid to dreissenid consumption, and larger gobies (95-120mm) predominantly consuming dreissenids, similar to findings in other studies. Discrimination factors were obtained by fitting a commonly used asymptotic regression equation describing changes in fish δ13C and δ15N as a function of time and diet stable isotope ratios. The discrimination factor determined for δ13C (-0.4‰ ± 0.32, SE) was lower than the "standard" value of 0.4‰, while that of δ15N (4.0‰ ± 0.32, SE) was higher than the standard value of 3.4‰. Turnover rates for both δ13C and δ15N were estimated as 0.02 ‰*day-1. The use of experimentally determined discrimination factors rather than "standard" values resulted in model estimates that agree more closely with the observed increasing importance of dreissenids in gut content of larger gobies. Our results suggest that the importance of dreissenid mussels inferred from stable isotope studies may be underestimated when using standard isotopic discrimination values.

Role of Chironomus plumosus (Diptera, Chironomidae) Population in the Central Zone of the Shallow Lake Trasimeno (Italy)

Adult swarms of non-biting pestiferous midges (Chironomidae: Diptera), primarily Chironomus plumosus, prevail over and around Lake Trasimeno (Italy) during the summer season. The current field survey (2018–2021, 33 sampling occasions) was carried out in the central area of the lake. It revealed a macrobenthic community consisting of Chironomidae (40.72%) and Oligochaeta (59.23%). Chironomus plumosus was the dominant chironomid species (98.84%). A previous survey (2000–2002, 11 sampling occasions) had highlighted a similar community, although C. plumosus had a lower density, comprising a maximum of 295.0 ind. m−2. This density was five times lower than the maximum densities of 2018–2021. A survey (2018–2021, 58 sampling occasions) conducted in the littoral zone revealed much greater chironomid biodiversity, with C. plumosus abundance of only 24.35% among all chironomids. This species showed an average density (88.1 ind. m−2) five times lower than its density (467.9 ind. m−2) in the central zone (2018–2021). Therefore, the central area of the lake, constituting about 90% of its total surface area, is the main region for the origin of C. plumosus adults and, consequently, during the summer months, it is the primary source of the annoying swarms that affect residents and tourists of the lake vicinity.

Warming Affects Bioconcentration and Bioaccumulation of Per- and Polyfluoroalkyl Substances by Pelagic and Benthic Organisms in a Water-Sediment System.

Warming and exposure to emerging global pollutants, such as per- and polyfluoroalkyl substances (PFAS), are significant stressors in the aquatic ecosystem. However, little is known about the warming effect on the bioaccumulation of PFAS in aquatic organisms. In this study, the pelagic organisms Daphnia magna and zebrafish, and the benthic organism Chironomus plumosus were exposed to 13 PFAS in a sediment-water system with a known amount of each PFAS at different temperatures (16, 20, and 24 °C). The results showed that the steady-state body burden (Cb-ss) of PFAS in pelagic organisms increased with increasing temperatures, mainly attributed to increased water concentrations. The uptake rate constant (ku) and elimination rate constant (ke) in pelagic organisms increased with increasing temperature. In contrast, warming did not significantly change or even mitigate Cb-ss of PFAS in the benthic organism Chironomus plumosus, except for PFPeA and PFHpA, which was consistent with declined sediment concentrations. The mitigation could be explained by the decreased bioaccumulation factor due to a more significant percent increase in ke than ku, especially for long-chain PFAS. This study suggests that the warming effect on the PFAS concentration varies among different media, which should be considered for their ecological risk assessment under climate change.

Population Dynamics and Seasonal Patterns of Chironomus plumosus (Diptera, Chironomidae) in the Shallow Lake Trasimeno, Central Italy

Field sampling of littoral macrobenthos of the shallow Lake Trasimeno was conducted along 17 years (2005–2021) on 129 different occasions. This long-term field study deepens the knowledge concerning the life cycle of Chironomus plumosus (Diptera), the main responsible for summer chironomid swarms that adversely affect human littoral activities, providing useful information for its management. About 108,000 macrobenthic specimens were collected, belonging to Oligochaeta (Naididae) (62%), Diptera (Chironomidae) (37%), and only 1.5% to other invertebrate taxa. Eighteen chironomid taxa were found. The trend of chironomid density was not affected by C. plumosus, which showed a maximum increase in September. This peak is justified by the presence of large swarms of C. plumosus in late August in which the populations of the central area of Lake Trasimeno consistently participate. The larval density of this species did not increase over the 17 years. A detailed analysis of the sampled larvae and adult biomass catches from 2017 to 2020 reveals that four annual swarmings occurred: in April, July, August, and September–October. The water temperature remains higher than 20 °C during the night hours from the end of May to mid-September, strengthening the hypothesis of the three midge swarming cycles in the summer period until early autumn.

Ecological study of some dominant species Chironominae (Chironomidae :Diptera ) as bio-indicator for water pollution in Tigris river Al Kut city / Iraq.

Ecological study was conducted in Tigris River Al Kut city during the period (November 2013- April 2014) to see the volume of pollutants that arise into the river Within months study depending on the abundance and diversity of Chironomid species subfamily Chironominae(Chironomidae: Diptera). Ten species of Chironominae were identified Polypedilum aviceps was the most dominant made up 48.59%, Polypedilum tritum 33.19% , Einfeldia pagana 3.95% , Chironomus riparius 2.39% , Chironomus plumosus 2.39% , Chironomus piger 2.08%, Polypedilum brasenia 1.04% , Einfeldia natchitocheae 1.04% , Cryptochironomus sp. 0.73% and Paralauterborniella sp. 0.73% .Result of this study showed significant correlations between the species and several environmental parameters. Polypedilum tritum , E. natchitocheae, Paralauterborniella sp. this group showed significantly positive correlation ( p< 0.05) with PH, temperature and turbidity and showed significantly negative correlation( p<0.05 and 0.01) with water temperature and TDS.Also environmental parameters (DO, BOD) and the ten species of Chironomid showed significantly positive correlation (p< 0.05, 0.01) among stations study (S1,S2,S3) .

Interactions between microbial activity and bioturbation modes of benthic invertebrates determine nutrient releases from reservoir sediments

Abstract Bioturbating invertebrates play key roles in nutrient recycling from sediments to the water column in most lentic ecosystems. Nevertheless, the role of bioturbating fauna on nutrient cycling depends on complex interactions between their bioturbation modes and both the sedimentary conditions and the microbial activity occurring inside sediments. This study aims to evaluate the effect of different bioturbation modes by two invertebrate species (tubificid worm Tubifex tubifex and chironomid larvae of Chironomus plumosus), on the release of nutrients (NH4+, NO3−, and PO43−) from three different types of sediments characterised by distinct microbial activities and nutrient (N and P) contents. We expected that the influence of a bioturbation mode on nutrient fluxes was dependent on the microbial activity and organic matter processes occurring in sediments. Aquatic mesocosms were setup in the laboratory with three fauna treatments (i.e. without fauna, with tubificid worms, and with chironomid larvae) and three sediment types (collected in three reservoirs). The presence of bioturbating invertebrates increased PO43− concentrations into the water column (from 1.3‐ to 17‐fold higher concentrations) depending on the sediments tested. PO43− releases in the water column were positively linked to total P concentration and microbial activity in sediments. The influences of tubificid worms and chironomid larvae on PO43− releases into the water were not only due to their bioturbation modes but also depended on the interactions with P dynamics (e.g. adsorption of PO43− by iron oxides) at the water–sediment interface. The influence of fauna on the release of dissolved inorganic nitrogen (DIN) varied strongly among sediments due to the control of N cycling by microbial processes. In sediments characterised by the lowest microbial activity, DIN release from sediments to the water column was significantly stimulated by invertebrates (from 1.3‐ to 3.7‐fold higher). In contrast, no fauna effect was detected compared to controls in sediments characterised by the highest microbial activity. This study demonstrated that the influence of the bioturbation mode on nutrient (i.e. PO43− and DIN) dynamics at the water sediment interface was largely modulated by the intensity of microbial activity and biogeochemical processes occurring in sediments.

Antioxidant biomarker profile of chironomid larvae from carp ponds: Evaluation of the effects of different fish feeding patterns

A 102-day feeding trial was conducted to evaluate the effects of four different fish feeding patterns on carp pond water quality and antioxidant biomarkers [superoxide dismutase (SOD), Catalase (CAT), Glutathione peroxidase (GPx), Glutathione reductase (GR), Glutathione S-transferase (GST) and Thiol groups (SH)], protein content and biomass of the midge Chironomus plumosus. Farmed fish were fed two commercial diets: Soprofish 25/7 Standard (containing 25% protein and 7 % fat) and Soprofish 32/7 Profi Effect (containing 32 % protein and 7 % fat). These feeds were combined during a feeding trial in four different feeding patterns, designated as A, B, C and D. In feeding pattern A, the fish received Soprofish 25/7 Standard throughout the experiment and in feeding pattern D, Soprofish 32/7 Profi Effect. During feeding patterns B and C, a mixed feeding pattern was used, alternating between lower and higher protein diets. The study revealed no significant effects (P > 0.05) of the feeding regimens on water quality, so their effects on C. plumosus larvae can be evaluated independently. The activities of the chironomid enzymes CAT and GR showed a clear statistically significant dependence on the feeding pattern (P < 0.05), which increased with increasing protein content. On the other hand, the activity of SOD as well as larval biomass were noticeably affected by water quality, the former increasing with its deterioration and the latter with its improvement. The activities of GPx and GST were correlated with each other, but no statistically significant relationship was found with any of the measured abiotic factors (P > 0.05). Overall, our results suggest that long-term supplementation with a highly concentrated protein diet may have preventive effects against oxidative stress and support the use of C. plumosus as a model for assessing the effects of organic pollution on pond zoobenthic fauna.

Macroinvertebrates Assemblage Study: An attempt to Assess the Impact of Water Quality on Qua Iboe River Estuary, Akwa Ibom State, Nigeria

This study was conducted to access the water quality of Qua River Estuary, Akwa Ibom state, Nigeria by collecting water samples and macroinvertebrates using standard sampling procedures and analytical methods. The mean values of physicochemical parameters assessed in water samples gave the following ranges: DO (2.38 – 4.63 mg/l), water temperature (26.13 – 29.18 oC), turbidity (22.56 – 39.24 NTU),TDS (224.8 – 332.51 mg/l), pH (6.3 – 7.5 mg/l), salinity (3.13 – 4.84 ppt),BOD (1.13 – 3.64 mg/l), nitrate (2.45 – 6.72 mg/l), phosphate (2.12 – 5.93 mg/l) and Flow velocity (0.23 – 0.38 ms-1). ANOVA reveals significant variation in some parameters. A total of 308 individual species, comprising of three phyla and seven taxonomic groups of macro-invertebrate were identified. Arthropoda constituted the highest percentage composition (75.4%), followed by Mollusca (18.8%), and Annelida (5.8%). The dominant group was Decapoda (35.7%) and the least was Odonata accounted only for 1.9%. Station 5 has the highest number of individual’s species (112), station 3 had the least (43). Chironomus plumosus was the most occurring species, accounted for 19.2%. The result reveals that anthropogenic activities in the water system influence the abundance of aquatic biota; based on the macro-invertebrates identified, it shows that the water quality is moderately polluted owing to human activities.

Effect of Urban River Morphology on the Structure of Macroinvertebrate Communities in a Subtropical Urban River

Channelization is the most common hydraulic modification of urban rivers. Here, we assessed the effects of urban river morphology on benthic communities by analyzing the characteristics of benthic communities at various sites in channelized and natural rivers of the Longgang River system in southern China. We detected four Clitellata species, five Oligochaeta species, one Polychaeta species, 10 Gastropoda genera/species, two Bivalvia genera/species, two Crustacea genera/species, and 14 Insecta genera/species. Insecta and Oligochaeta were the dominant classes in the wet and dry seasons, and Chironomus plumosus was the most dominant species. The density of Clitellata was significantly lower in channelized rivers (0–0.74 ind/m2) than in natural rivers (0.61–4.85 ind/m2). The Shannon’s diversity index was significantly lower in channelized rivers (0.66–1.04) than in natural rivers (0.83–1.28) in the wet and dry season. NH3.N was positively correlated with Shannon’s diversity index, and chemical oxygen demand and river width were negatively correlated with Shannon’s diversity index. When the concentration of total phosphorus (TP) was low (&lt;3 mg/L), it was positively correlated with Shannon’s diversity index. Our findings indicate that river channel morphology affects benthic faunal structure and diversity, but the effects varied among seasons. Minimized channelization will prevent the loss of aquatic biodiversity in subtropical urban rivers, as will preservation of natural rivers.

Chironomids diversity of Manipur

Chironomids are Diptera and these are good bioindicators of aquatic habitats, and serve as food of aquatic as well as the lower terrestrial animals. The diversity of these were assessed from the Dhanamanjuri University Campus, which revealed three genera and one unidentified genus viz., Kiefferulus calligaster, Chironomus plumosus, Chironomus circumdatus and one morphotype closely resembling Yama (Yama type). The chromosome compliments of these were observed to be with 2n=8 (K. calligaster- AB, CD, EF, G; C. plumosus- AB, CD, EF, G; C. circumdatus- BF, CD, AE, G and Yama type- AE, BF, CD, G). The differences were in the translocation both in NOR and chromosomes. Kiefferulus calligaster, C. plumosus, Yama type and C. circumdatus were observed coexisting in cemented drainage, with Yama type being predominant in the pond; the latter was mainly collected from more contaminated ditches with domestic waste. The polytene chromosomes were species-specific and could be utilized to identify the species in the larval forms.

青弋江流域大型底栖动物群落结构及水质评价

PDF HTML阅读 XML下载 导出引用 引用提醒 青弋江流域大型底栖动物群落结构及水质评价 DOI: 10.5846/stxb202101240247 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金青年项目（41301029）；安徽高校协同创新项目（GXXT-2020-075） Macroinvertebrate community structure and water quality assessment in the Qingyi River Watershed Author: Affiliation: Fund Project: The National Science Fundation of China(General Program, Key Program,Major Research Plan) 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:研究河流大型底栖动物群落结构特征及水环境质量对水生态的保护与修复具有重要意义。以青弋江流域为研究对象，于2020年9月进行了大型底栖动物及水体理化因子的调查，采用相对重要性指数、生物多样性指数及Jaccard相似性系数分析了大型底栖动物群落结构特征，运用丰度/生物量比较曲线法及冗余分析法探究了底栖动物群落受到的干扰程度及其主要影响环境因子，最后利用水生态环境质量综合指数对河流水质进行评价。研究结果表明：（1）共采集鉴定大型底栖动物61种，隶属于3门6纲17目，平均丰度为265.9个/m2，平均生物量41.6 g/m2。相对重要性指数分析显示，日本沼虾（Macrobrachium nipponensis）、中国圆田螺（Cipangopaludina chinensis）、羽摇蚊（Chironomus plumosus）及扁蜉（Ecdyrus）为群落中的主要优势种。（2）由群落相似性分析知，Jaccard相似性系数较低，调查点位之间存在较强的空间异质性。（3）冗余分析表明，电导率、氨氮浓度及流速是影响底栖动物群落结构的主要环境因子。（4）生物指数分析结果显示该流域水质为轻度污染或中度污染，与水质理化因子评价存在较大差异。综合考虑生物及非生物因子的水生态环境质量综合指数模型计算结果显示，流域整体水环境质量偏好，但部分采样点已受到干扰或处于污染状态，与ABC曲线分析及优势种分析基本一致，评价结果更具科学性及可靠性。 Abstract:It is of great significance to study the community structure of macrobenthos and the water quality for protection and restoration of aquatic ecology. Taking the Qingyi River Basin as the research object, a survey of macrobenthos and physicochemical factors of the water body was carried out in September 2020. It analysed the structural characteristics of the macrobenthic community by means of the relative importance index, the biodiversity index and the Jaccard similarity coefficient. It investigated the extent of disturbance to the benthic community and the main environmental factors that affect it, by applying the comparative abundance/biomass curve method and redundancy analysis. Finally, the comprehensive index of water ecological environment quality was used to evaluate the river water quality. The results showed that (1) 61 species of macrobenthos were collected and identified in the Basin, which belonged to 3 phyla, 6 classes and 17 orders. The average density was 265.9 ind/m2 while the average biomass was 41.6 g/m2. The main dominant species which were shown in the index of relative importance in the community were Macrobrachium nipponensis, Cipangopaludina chinensis, Chironomus plumosus, and Ecdyrus. (2) The Jaccard similarity coefficient was low due to the analysis of community similarity, with a strong spatial heterogeneity between the investigation sites. (3) The main environmental factors-conductivity, ammonia nitrogen concentration and flow velocity-influenced the community structure of macrobenthos by the redundancy analysis. (4) The biological index analysis results indicated that the water quality in the basin was lightly or moderately polluted, which varied significantly from the assessment of the physical and chemical factors of water quality. The comprehensive water and ecological quality index model calculations, which integrated biotic and abiotic factors, suggested an overall water and environmental quality preference for the basin. But some sampling points have been disturbed or polluted, which was basically consistent with the abundance-biomass comparison curves analysis and the dominant species analysis, in which the result of evaluation was more scientific and reliable. 参考文献 相似文献 引证文献

Efficacy of acriflavin chloride and Melaleuca alternifolia extract against Saprolegnia parasitica infection in Pterophyllum scalare

The article describes cases of saprolegniosis in Pterophyllum scalare in private aquaristics and assesses the therapeutic efficacy of acriflafin chloride against Saprolegnia parasitica infection. To establish the diagnosis, the clinical signs present in sick fish, the results of mycological and microscopic examinations are taken into account. Some chemical and mycological indices of aquarium water have been studied, and also mycological studies of fish feed have been carried out. It is established that the disease of fish develops against the background of adverse changes in physical, chemical composition and microbiocenosis of aquarium water. Low water temperature, high levels of phosphates and pH, a significant level of organic pollution, compared to the norm, provoke the accumulation of opportunistic microbiota, resulting in imbalance in the parasite-host system and the development of clinical manifestations of saprolegniosis in fish. It was found that 44.4% of the studied feed samples fed to fish were contaminated with epiphytic micromycetes. Micromycetes are represented by the genera Aspergillus, Penicilium, Fusarium, Mucor, Rhizopus. Among the studied feeds, the most affected by fungi were larvae of Chironomus plumosus and dry Daphnia pulex. According to the results of our studies during outbreaks of saprolegniosis, the pH of aquarium water was 8.1 ± 0.7, the content of phosphates – 5.6 ± 1.1 mg/L, micromycetes – 18.0 ± 1.2 CFU/100 cm3. Aspergillus flavus, A. niger and Penicillium canescens were detected in the studied water samples. With saprolegniosis, the angelfish have a reduced appetite, spots, ulcers, white thin threads, and a cotton-like plaque appear on certain areas of the skin, fins, eyes, and gills. It is established that effective means for the treatment of sick fish are external use in the form of a long bath of acriflavine chloride and extract of Melaleuca alternifolia. It is also effective to increase the water temperature to 25–27 °С, to ensure the normative fish-holding density in aquariums and to exclude from the diet fish feed contaminated with micromycetes. After using the drugs for two weeks every other day, water was replaced by 20% of the aquarium volume and aerated. As a result of the treatment, gradual healing of skin lesions and recovery of 65% of fish with signs of lesions of the outer coverings were registered. Thus, the article analyzes the causes of saprolegniosis in angelfish common in private aquariums, describes the clinical signs of the disease and assesses the therapeutic efficacy of acriflavine chloride and Melaleuca alternifolia extract against Saprolegnia parasitica infection. Prospects for further research lie in search of more effective and environmentally friendly means for the treatment of saprolegniosis in aquarium fish.

Variability of Karyofunds of Chironomus plumosus (Diptera, Chironomidae) from the Rybinsk Reservoir during the Period of Climate Warming

Variability of Karyofunds of Chironomus plumosus (Diptera, Chironomidae) from the Rybinsk Reservoir during the Period of Climate Warming

A bioturbator, a holobiont, and a vector: The multifaceted role of Chironomus plumosus in shaping N‐cycling

Abstract Tube‐dwelling chironomid larvae are among the few taxa that can withstand and thrive in the organic‐rich sediments typical of eutrophic freshwater ecosystems. They can have multiple effects on microbial nitrogen (N) cycling in burrow environments, but such effects cease when chironomid larvae undergo metamorphosis into flying adults and leave the sediment. Here we investigated the ecological role of Chironomus plumosus by exploring the effect of its different life stages (as larva and adult midge) on microbial N transformations in a shallow freshwater lagoon by means of combined biogeochemical and molecular approaches. Results suggest that sediment bioturbation by chironomid larvae produce contrasting effects on nitrate ()‐reduction processes. Denitrification was the dominant pathway of reduction (&gt;90%), primarily fuelled by from bottom water. In addition to pumping ‐rich bottom water within the burrows, chironomid larvae host microbiota capable of reduction. However, the contribution of larval microbiota is lower than that of microbes inhabiting the burrow walls. Interestingly, dinitrogen fixation co‐occurred with reduction processes, indicating versatility of the larvae's microbial community. Assuming all larvae (averaging 1,800 ind./m2) leave the sediment following metamorphosis into flying adults, we estimated a displacement of 47,787 µmol of organic N/m2 from the sediment to the atmosphere during adult emergence. This amount of particulate organic N is similar to the entire N removal stimulated by larvae denitrification over a period of 20 days. Finally, the detection of N‐cycling marker genes in flying adults suggests that these insects retain N‐cycling microbes during metamorphosis and migration to the aerial and terrestrial ecosystems. This study provides evidence that chironomids have a multifaceted role in shaping the N cycle of aquatic ecosystems.

Performance of the tiger-fly Coenosia attenuata Stein reared on the alternative prey, Chironomus plumosus (L.) larvae in coir substrate

The performance of the tiger-fly Coenosia attenuata Stein was examined when fed on larvae of the buzzer midge, Chironomus plumosus (Linnaeus), and combination of buzzer midge and fungus gnat, Bradysia impatiens (Johannsen). Significant differences were observed in the developmental time of larvae, body length, and body weight of pupae and adults of C. attenuata in response to species and preservation status of prey but not in response to instar and prey number of C. plumosus. Most biological characteristics except for developmental time of pupae, length of female pupae, survival rate from the 5th day to pupation, and adult emergence improved for tiger-fly larvae fed on live B. impatiens larvae in the first four days and live C. plumosus larvae from the fifth day to pupation compared to those fed on live C. plumosus larvae in all larval stages. When live alternative prey were replaced with the frozen prey, the developmental time of larvae was prolonged, and adult male body length, survival rate from the fifth day to pupation, and the percentages of pupation and adult emergence decreased. The survival rate of larvae in the first 4 days and percentage of pupation improved with decreased alternative prey instar and increased alternative prey number. These results indicate live C. plumosus larvae can serve as an alternative food source for mass rearing of C. attenuata. As an alternative food source, C. plumosus larvae provide significant advancements for the application of tiger-fly in banker media system and/or open rearing.

Chromosomal Variability in Chironomus plumosus (Linnaeus, 1758) (Diptera, Chironomidae) from a Coastal Lagoon of the Baltic Sea (Curonian Lagoon)

Chromosomal variability of Chironomus plumosus (Linnaeus, 1758) population from the coastal Curonian Lagoon of the Baltic Sea was studied. The karyotype pool comprises 19 banding sequences (exceeding the mean value of 12.5 ± 0.4 sequences for the Palaearctic populations) and includes some unique sequences that are described here for the first time for the species: p'pluB15, p'pluB16, p'pluC7, p'pluD19, p'pluE3, and p'pluF7. The latter four banding sequences have resulted from pericentric inversions which are rare in Ch. plumosus. Altogether, 21 zygotic and 19 genomic combinations of banding sequences were found. The indices of chromosomal variability, i.e., the proportion of heterozygous individuals (54.43 ± 7.08%) and the number of heterozygous inversions per individual (0.71 ± 0.10), were lower than those in the center of the Palaearctic part of the species’ range; this is typical of peripheral populations. The structure of chromosomal variability has been stable throughout the entire study period (1975, 1998–2009), probably due to favorable living conditions in the Curonian Lagoon.

Effects of human-induced eutrophication on macroinvertebrate spatiotemporal dynamics in Lake Dianchi, a large shallow plateau lake in China.

The Yungui Plateau lakes, which are characterized by a highly endemic biodiversity, have been suffering severely from anthropogenic intervention in the recent decades. Studies on the response of these biodiversity to human-mediated effects are still limited. Here, we selected the typical Lake Dianchi to investigate the correlation between macroinvertebrate spatiotemporal dynamics and human-induced eutrophication across a 2-year span (2009-2010). A total of 26 taxa were recorded, and the assemblage pattern of the macroinvertebrate community was mainly controlled by the spatiotemporal (region, season, and year) density fluctuations of some pollution-tolerant species (Limnodrilus hoffmeisteri, Tubifex tubifex, Branchiura sowerbyi, and Chironomus plumosus). Taxon richness, total density, biomass, and the abundance of Oligochaeta and Chironomidae decreased from the north to the south of the lake but were much higher in 2009 than in 2010. Moreover, the high densities of total assemblages and oligochaete occurred during spring and/or autumn, whereas that of chironomids was only high during summer. The contributions of important factors varied in different seasons, but the community variations were mainly shaped by eutrophication-related factors (e.g., Chla, N, and P). Variance partitioning analyses showed that aquatic factors were able to explain more community variations than sediment (6.9-36.6 vs. 5.3-14.7%) across seasons, but their interactive effects were negligible. The results of this study will be beneficial for restoring and managing hypereutrophic lakes in the Yungui Plateau and imply the necessity of long-term monitoring in bioassessment projects involving intensively disturbed lakes.

Cadmium-induced developmental alteration and upregulation of serine-type endopeptidase transcripts in wild freshwater populations of Chironomus plumosus.

Cadmium, a toxic heavy metal, is a persistent environmental contaminant with irreversible toxicity to aquatic organisms. Chironomus plumosus, a natural species, is the largest sediment-burrowing aquatic midge in freshwater environments. In this study, we evaluated developmental defects in C. plumosus resulting from Cd exposure. In C. plumosus larvae, Cd exposure induced decreased survival and growth rates, reduction of emergence rate and sex ratio, and delayed emergence, as well as elevating the incidence of split tooth deformities. To identify potential biomarker genes to assess environmental pollutants such as Cd, we identified differentially expressed genes (DEGs) in C. plumosus exposed to various Cd concentrations. Among fourteen characterized DEGs, serine-type endopeptidase (SP) and heat shock protein 70 (HSP70) genes exhibited significant upregulation in C. plumosus larvae after Cd exposure. Therefore, we evaluated SP and HSP70 responses in natural C. plumosus populations collected from three sites of a Korean river and analyzed their correlations with eighteen environmental quality characteristics using principal component analysis. The highest expression of SP and HSP70 transcripts was observed in C. plumosus populations from Yeosu in Korea, which has high concentrations of polluting heavy metals. SP transcript expression was positively correlated with concentrations of Cd, Pb, Al, Fe, NO2, and NO3. These results suggested that environmental pollutants such as Cd can impair proteolytic activity in the digestive system of C. plumosus and may ultimately induce developmental alterations. We therefore suggest SP as a potential biomarker to assess the effects of environmental pollutants in aquatic ecosystems.

Preliminary investigations of the chironomid larvae fauna (Chironomidae, Diptera) from the Mavrovo reservoir – Republic of Macedonia

Larval stages of the Chironomidae (Diptera) can be found in almost any aquatic habitat, includ- ing artificial lakes. They form an important fraction of the macrozoobenthos of most freshwater ecosystems. The Mavrovo reservoir as an artificial lake in the Republic of Macedonia, to date, has never been an object of hydrobiological research of this type. For that reason, the purpose of this study was to conduct research on the composition and structure of the chironomid larvae fauna that inhabits the Mavrovo reservoir. The quantitative samples for this research were collected during one year (2017/18), seasonally from five different localities (T1–T5) – T1-Ulazna, T2-Hotel Radika, T3-Middle of the reservoir, T4-Bunec, and T5-Old church (village Mavrovo). According to the results, Chironomidae was represented with five subfamilies, two tribes, and 25 taxa. The subfamilies are Chironominae with the two tribes Chironomini and Tanytarsini, Tanypodinae, Orthocladiinae, Diamesinae, and Prodiamesinae. The dominant taxon is Tanytarsus sp., and besides it, the following taxa: Procladius sp., Chironomus plumosus, Harnischia sp., Polypedilum nubeculosum, and Orthocladius saxicola are characterized by greater community participation. The highest density of chironomid larvae fauna was recorded during the summer, a total of 1013.69 ind/m2, compared to the lowest registered in the spring season which is only 9.78 ind/m2.