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Here we present new insights into Chironomidae (Insecta, Diptera) preserved in Lower Cretaceous Lebanese amber. We describe a new genus and species, Electroneura pinhoi gen. et sp. nov., seemingly related to Tanypodinae and offer an amended description of Libanopelopia cretacica Veltz, Azar and Nel, 2007. Moreover, our investigation highlights the challenges of assigning fossils to modern taxonomic groups, based on previous studies of Tanypodinae, underscoring the necessity of considering the geological context and utilizing, when possible, both morphological and molecular data from extant taxa to validate taxonomic assignments in paleontological studies. [ABSTRACT FROM AUTHOR]

Simple Summary: Chironomids or non-biting midges, which are a diverse group of insects, can be found in various freshwater habitats. Plitvice Lakes National Park in Croatia, known for its rich freshwater environment, is an ideal location for studying these insects in the long term. Our study aimed to uncover the types of chironomids present, understand their seasonal patterns, and identify factors influencing their emergence in Plitvice Lakes. For 14 years, we set up traps at a tufa barrier within the National Park to collect chironomids on a monthly basis. During this time, we discovered more than 80 chironomid species. Interestingly, we found that water temperature and organic matter were the key factors affecting chironomid emergence in this area. Toward the end of our study, we noticed that the time these insects spent in flight seemed to increase. Although we have not yet found statistical significance, this could be related to the higher water temperatures in winter. In summary, our research sheds light on the fascinating world of chironomids in Plitvice Lakes, highlighting their diversity, seasonal patterns and the environmental factors influencing their behavior. Chironomids are found in all types of freshwater habitats; they are a ubiquitous and highly diverse group of aquatic insects. Plitvice Lakes National Park is the oldest and largest national park in Croatia and consists of numerous and diverse freshwater habitats, making the area an ideal location for long-term research into the chironomid emergence patterns and phenology. The main objectives of this study were to identify the composition of the chironomid community, determine the phenology of the identified species, and assess the main factors influencing their emergence in Plitvice Lakes. During 14 years of research, more than 13,000 chironomids belonging to more than 80 species were recorded. The most abundant species was found to be Parametriocnemus stylatus. The highest abundance of chironomids was recorded in lotic habitats with faster water current over substrates of moss and algae and pebbles. Water temperature and the availability of organic matter were found to be the main factors that drive chironomid emergence at the tufa barrier studied. In the last years of this study, a prolonged flight period was observed. Although this is not statistically significant (at this stage of the study), it could be due to a higher water temperature in winter. [ABSTRACT FROM AUTHOR]

The positive phototaxis showed by adults of some pestiferous chironomid species, annoying to waterfront residents and businesses, was investigated at Lake Trasimeno (Italy) to develop a strategy against their massive swarms. Two experimental devices (ChiroTraps), located at Passignano sul Trasimeno (PA) and at Sant'Arcangelo (SA), were employed in 2019 and 2020. The total biomass attracted by the traps amounted to 6498.78 g at PA and to 8597.05 g at SA. Chironomids biomass constituted 99.66% and 96.59% of the biomass in these sites, respectively. Only a few specimens of other fauna except chironomids were found at PA. In contrast, the values at SA were considerable, being 91- and 35-fold (number of taxa and weight, respectively) higher than in PA. These results demonstrated that exploiting the light attraction behaviour of adult chironomids is an efficient method for managing their pestiferous populations, thereby reducing the necessity of using insecticides. By comparing the biodiversity in the two sites, it was evident that the differences were linked primarily to the environmental conditions. Finally, it is suggested that light trapping systems should be located in urban centres or floated on the lake surface to maximise the efficiency of trapping chironomids and minimising the impact on biodiversity. [ABSTRACT FROM AUTHOR]

For the first time, the size spectra of 28 chironomid genera/species are reported for the most common chironomid taxa in the deep subalpine Lake Maggiore (northwestern Italy). Species-specific length–mass regression models were developed to predict the dry masses of the larval stages of Cladotanytarsus sp., Cryptochironomus sp., Polypedilum bicrenatum, P. nubeculosum, and Stictochironomus pictulus. The predicted dry-mass values differed by less than 20% from the measured values, suggesting that these original equations will be important in chironomid production studies. Regressions at the subfamily level were also developed for case identification at the genus or species level, which is difficult to obtain. The chironomid weights were determined directly and a dry/wet-weight-conversion ratio was estimated. The results were consistent with previously reported results. The relationships between the dry masses and the body lengths were compared with published data for different types of lake all over the world. We found that regression models for other freshwater environments somehow differed from those in Lake Maggiore, albeit slightly. The combination of diversity-based and trait-based approaches improves our knowledge about chironomids and our understanding of the effects of global environmental changes on freshwater biota. This first collection of trait data on summer–autumn chironomid assemblages in a temperate subalpine lake is a valuable contribution to the European trait database. The taxonomic diversity and abundance of chironomids were uploaded for open access on the GBIF platform. [ABSTRACT FROM AUTHOR]

Chironomids are found in all types of freshwater habitats; they are a ubiquitous and highly diverse group of aquatic insects. Plitvice Lakes National Park is the oldest and largest national park in Croatia and consists of numerous and diverse freshwater habitats, making the area an ideal location for long-term research into the chironomid emergence patterns and phenology. The main objectives of this study were to identify the composition of the chironomid community, determine the phenology of the identified species, and assess the main factors influencing their emergence in Plitvice Lakes. During 14 years of research, more than 13,000 chironomids belonging to more than 80 species were recorded. The most abundant species was found to be Parametriocnemus stylatus. The highest abundance of chironomids was recorded in lotic habitats with faster water current over substrates of moss and algae and pebbles. Water temperature and the availability of organic matter were found to be the main factors that drive chironomid emergence at the tufa barrier studied. In the last years of this study, a prolonged flight period was observed. Although this is not statistically significant (at this stage of the study), it could be due to a higher water temperature in winter.

The positive phototaxis showed by adults of some pestiferous chironomid species, annoying to waterfront residents and businesses, was investigated at Lake Trasimeno (Italy) to develop a strategy against their massive swarms. Two experimental devices (ChiroTraps), located at Passignano sul Trasimeno (PA) and at Sant’Arcangelo (SA), were employed in 2019 and 2020. The total biomass attracted by the traps amounted to 6498.78 g at PA and to 8597.05 g at SA. Chironomids biomass constituted 99.66% and 96.59% of the biomass in these sites, respectively. Only a few specimens of other fauna except chironomids were found at PA. In contrast, the values at SA were considerable, being 91- and 35-fold (number of taxa and weight, respectively) higher than in PA. These results demonstrated that exploiting the light attraction behaviour of adult chironomids is an efficient method for managing their pestiferous populations, thereby reducing the necessity of using insecticides. By comparing the biodiversity in the two sites, it was evident that the differences were linked primarily to the environmental conditions. Finally, it is suggested that light trapping systems should be located in urban centres or floated on the lake surface to maximise the efficiency of trapping chironomids and minimising the impact on biodiversity.

Multiscale determinants of riverine chironomid species richness were assessed in seven rivers in Central Poland, an area representative of the European temperate climatic zone. The impact of environmental factors, seasonality, as well as the concepts of gamma diversity, i.e. habitat species richness (HSR), alpha diversity, i.e. local species richness (LSR), and the relationships between these, i.e. beta diversity, were studied.One site in each river was defined as a habitat and monthly LSR time series data were obtained at each site over a full annual cycle for analysis. No strong trend in the time series was detected. The autocorrelation function (ACF) indicated that the time series were uncorrelated white noise.A stepwise forward regression model with no HSR indicated that depth, Substrate Index (SI), velocity and dissolved oxygen were significant factors of LSR values in the studied area, explaining together with summer (as a dummy variable) 67.01% of LSR variance (R2adj = 0.66). Seasonality was noticeable in the impact of summer on increase in species richness. When HSR was included in a similar model then it explained, together with benthic particulate organic matter (BPOM), SI, depth, and velocity, 70.90% of variability in LSR variance (R2adj = 0.69), HSR alone accounting for 58.95% in LSR variance (R2adj = 0.59).In both the annual cycle and in given seasons, HSR strongly positively correlated with the minimum, maximum, and mean LSR values, and there was no saturation of the rivers by chironomid species, i.e. other chironomid species were still able to inhabit the rivers beside the present ones. HSR did not correlate with beta diversity when measured by two widely used setwise beta diversity indices, or by three pairwise beta diversity indices. The exception was in autumn, where one setwise and two pairwise beta diversity measures correlated with both alpha and gamma diversity measures, which suggests a greater stability of larval chironomid assemblages in that season. This larval stability was not associated with greater stability of environmental factors in autumn, hence the stability seems to be related to undisclosed biotic mechanisms.Seasonality was also a strong factor in predicting the exchange of species. Turnover index between seasons ranged from 0.133 (spring vs summer) to 0.261 (autumn vs winter) and UPGMA clustering determined least chironomid similarity between winter and other seasons.

In the end of Saalian Glaciation (Wartanian Stadial, MIS 6a) there formed many glacial depressions, melt-out kettle holes and subglacial channels in central Poland's ice-marginal zone. In these landforms, there developed a lakeland that existed to the Early Weichselian (5d-a). Following excavation in 2016 on the eastern wall of the Szczerców field, lacustrine deposits were recognised in the Parchliny 2016 profile. A previous multi-proxy study of the Parchliny 2016 profile concerning a reconstruction of the palaeolake included analyses of pollen, plant macrofossils, wood macrofossils, diatoms, cladocerans, ostracods and molluscs. The present work presents the Chironomidae analysis for the above-mentioned section. The collected subfossils could be identified from the keys presenting modern Palaearctic fauna. The Chironomidae indicate a temperate climate in the region and favourable, meso/eutrophic conditions in the palaeolake during the Late Saalian (MIS 6a). The changes in subfossil numbers reveal that the Zeifen interstadial fells at 24.38-24.23 m core depth and the subsequent Kattegat stadial at 24.18-23.83 m, but head capsule count is too low for quantitative temperature estimations. From the Eemian (MIS 5e) transition, they decline in the sediment and are represented only by two head capsules at the 23.33 m core depth below the ground surface. The increase in summer temperature, trophic status and stratification of the lake may have caused an oxygen depletion that eliminated sensitive taxa. However, no species are observed that are resistant to eutrophication and anoxia replacing sensitive ones in the assemblages. Sediment desiccation and compaction may have caused the decomposition of Chironomidae subfossils in the deposits from the Eemian interglacial, so their apparent decline in the ecosystem may be misleading. [ABSTRACT FROM AUTHOR]

Introduction: Chironomidae (Diptera) is the most widespread and abundant aquatic insect family in freshwater ecosystems. Chironomids are considered good indicators of water quality but are seldom identified at the genus level in broad spatial scale studies. Objective: To identify environmental conditions associated with chironomids in an altitudinal gradient. Methods: We compared ecoregions, river types, and seasons, for chironomids in neotropical streams and rivers (18 river sites; 2014-2018; Yungas rainforest and Western Chaco dry forest, Argentina). We used non-metric multidimensional scaling, dissimilarity, envfit analysis and rank-abundance curves. Results: Chironomid "assemblages" matched both ecoregions and river types. However, ecoregions presented a better fit with species composition. The stenothermal taxa of Orthocladiinae were dominant at high elevations and the eurythermal Chironominae in lowland rivers. Altitude, water temperature and conductivity were important. Seasonal differences were smaller than ecoregional differences. Conclusions: Ecoregions, altitude, water temperature and conductivity correlated with chironomid communities. Orthocladiinae were dominant at high elevations and Chironominae in lowland rivers. [ABSTRACT FROM AUTHOR]

The Salar de Olaroz, located in the Argentine Puna, is one of the largest lithium deposits of the world. Lithium extraction requires large amounts of fresh and brackish water, creating pressure on wetlands of these desert environments. The knowledge of the aquatic fauna of the area is of interest to monitor impacts of these extractive activities. In this work, a study of the Chironomidae (Diptera) prior to mining is carried out in order to understand the structure of the Chironomidae assemblage at morphospecies level, with the aim of evaluating its spatial and seasonal variation, relating changes in the assemblage to some environmental variables. Quantitative biological samples and environmental variables of interest were taken and registered in three streams during four season in three consecutive years (2013-2015). Our results show that the Chironomidae assemblage could respond to variables related with discharge by decreasing its richness. Some morphotypes (e.g., Podonomus, Parametriocnemus, Limnophyes and Polypedilum) associated with changes in pH, decreases in dissolved oxygen and water velocity, and increases of finer sediments could disappear from the area. [ABSTRACT FROM AUTHOR]

Aims: The main aim of this study was to fill a gap in barcoding data of the European Chironomidae of the Balkan region, developing and testing the efficiency of a reference DNA barcode library for ancient Lake Skadar basin species (Montenegro/Albania), a region of Europe never before subjected to barcoding studies on Chironomidae. Another aim was to test the efficiency of DNA barcoding for the identification of European Chironomidae, including the estimation of optimal identification thresholds, using >12,000 barcodes. Location: Lake Skadar basin and adjacent area (Montenegro/Albania). Methods: Through this study, 770 individuals of Chironomidae from the Lake Skadar region were barcoded, both at adult and pre‐imaginal stages. Adults were morphologically identified, while larvae were assigned to species by molecular identification, using different methods, of which the efficiency was tested, for a total of 97 different barcoded species. Results: The identification efficiency of the reference dataset developed for the Lake Skadar region was 98.6%, a value in line with that obtained when the identification efficiency for European Chironomidae was evaluated (95.8%), which confirms the accuracy of DNA barcoding for the identification of these insects. Moreover, we found that the optimal threshold for the molecular identification of the family is 1.6% nucleotide distance, though more specific thresholds are suggested for the identification of species belonging to Chironomidae subfamilies, since they are related to lower identification errors than to the use of a general threshold. The analysis of inconsistency between molecular and morphological identification shed light on taxonomic issues within European Chironomidae. Previously postulated species synonyms were confirmed, and also further cases requiring deeper investigation were detected. Main conclusions: Our de novo DNA barcode library was shown to have a high identification efficiency. Taxon‐specific thresholds increase the efficacy of molecular identification. Hypothesized species synonyms could be validated through molecular techniques. [ABSTRACT FROM AUTHOR]

Chironomids are the most abundant aquatic insects in freshwater habitats that can survive in extreme conditions. In this study, as the microbiome provides extended genotype to the host to perform various functions, we explored the microbiota of the Chironomus circumdatus larvae to find out the putative role played by the symbiotic bacteria for the host. The metabarcoding analyses of the larvae revealed that the insect harbors 1771 phylotypes. Out of the various microbial communities found, the majority corresponded to the phyla Proteobacteria (52.59%) and Actinobacteria (20.56%), respectively. The midges also harbored Klebsiella (2.57%), Enterobacter (1.32%), Bacillus (2.29%), and Acinetobacter (2.13%) genera that are involved in detoxification of xenobiotics present in the water. The presence of radiation-resistant genera like Deinococcus, including bacterial species like radiodurans, a highly radiation-resistant bacterium, indicates its potential to support the host's ability to sustain in adverse environments. The functional profiling of the bacteria showed the relative abundance of many enzyme groups, such as transferases (40.62%), oxidoreductases (23.49%), and hydrolases (3.77%). The results indicate that the larvae harbor a considerable variety of bacteria that help the host adapt and survive in the polluted waters. The present study provides thorough insights into the microbiome of the C. circumdatus larvae that can be exploited for the bioremediation of certain pollutants through biomimetic strategies. It also gives us a wake-up call to take a good look at the guts of these disease-carrying insects' inabilities to spread deadly human diseases. [ABSTRACT FROM AUTHOR]

The Salar de Olaroz, located in the Argentine Puna, is one of the largest lithium deposits of the world. Lithium extraction requires large amounts of fresh and brackish water, creating pressure on wetlands of these desert environments. The knowledge of the aquatic fauna of the area is of interest to monitor impacts of these extractive activities. In this work, a study of the Chironomidae (Diptera) prior to mining is carried out in order to understand the structure of the Chironomidae assemblage at morphospecies level, with the aim of evaluating its spatial and seasonal variation, relating changes in the assemblage to some environmental variables. Quantitative biological samples and environmental variables of interest were taken and registered in three streams during four season in three consecutive years (2013-2015). Our results show that the Chironomidae assemblage could respond to variables related with discharge by decreasing its richness. Some morphotypes (e.g., Podonomus, Parametriocnemus, Limnophyes and Polypedilum) associated with changes in pH, decreases in dissolved oxygen and water velocity, and increases of finer sediments could disappear from the area.

For the first time, the size spectra of 28 chironomid genera/species are reported for the most common chironomid taxa in the deep subalpine Lake Maggiore (northwestern Italy). Species-specific length–mass regression models were developed to predict the dry masses of the larval stages of Cladotanytarsus sp., Cryptochironomus sp., Polypedilum bicrenatum, P. nubeculosum, and Stictochironomus pictulus. The predicted dry-mass values differed by less than 20% from the measured values, suggesting that these original equations will be important in chironomid production studies. Regressions at the subfamily level were also developed for case identification at the genus or species level, which is difficult to obtain. The chironomid weights were determined directly and a dry/wet-weight-conversion ratio was estimated. The results were consistent with previously reported results. The relationships between the dry masses and the body lengths were compared with published data for different types of lake all over the world. We found that regression models for other freshwater environments somehow differed from those in Lake Maggiore, albeit slightly. The combination of diversity-based and trait-based approaches improves our knowledge about chironomids and our understanding of the effects of global environmental changes on freshwater biota. This first collection of trait data on summer–autumn chironomid assemblages in a temperate subalpine lake is a valuable contribution to the European trait database. The taxonomic diversity and abundance of chironomids were uploaded for open access on the GBIF platform.

Weaving and dyeing, as both a household industry and in small factories, are very popular in Chonnabot District, Khon Kaen Province, Thailand. The dyes used are inorganic and organic substances that can cause high electrical conductivity (EC) and increase biochemical oxygen demand (BOD), affecting the aquatic food chain as well as human health. The mouthpart deformities of chironomid larvae, a member of benthic macroinvertebrates, occur when the developmental homeostasis is insufficient to compensate for environmental stress and has been proposed as a bioindicator of stress in aquatic environment. Studies on the effects of waste from the dyeing processes contaminating freshwater environments were conducted in August 2018. Water quality variables were measured, and benthic macroinvertebrates were investigated in five sampling sites in Kong Kaew Pond. The chironomid larvae were analyzed. The results demonstrate that sites which received dyeing process waste (K02, K03 and K05 sites) directly had higher EC and BOD, lower diversity index, lower evenness index, higher relative abundance of tolerate taxa (Chironomidae and air-breathing freshwater snails) and a higher percentage of chironomid mouthpart deformity than those of less polluted sites (K01 and K04 sites). Dissolved oxygen (DO) concentations were high in all sampling sites. A complete wastewater treatment system is recommended to treat dyeing process wastes before they are discharged and contaminate natural freshwater and to avoid hazards to human health. The combination of benthic macroinvertebrate diversity measurement and the incidence of mouthpart deformity in chironomid larvae may be useful as an early warning to indicate the ecological state of freshwater habitats. [ABSTRACT FROM AUTHOR]

Larvae of non-biting midges in the family Chironomidae can be found in association with several species of fish in the family Loricariidae. In this study, we describe the first record of phoretic interaction between larvae of Ichthyocladius sp. and the fish Hisonotus chromodontus in streams in the Amazon basin. Between July 2010 and March 2019, fish were collected from three streams of the Teles Pires River basin in the state of Mato Grosso, Brazil. We investigated the attachment site of chironomid larvae on the body of fish and the frequency of attachment. A total of 1.241 specimens of H. chromodontus were collected, among which nine hosts were found carrying in the ventral region a single Ichthyocladius sp. specimen. All Ichthyocladius sp. were attached to a spicule of fish between the pectoral and pelvic fins, in which they were observed at the fourth developmental stage at the beginning of the cocoon construction (1.50 mm). In addition, a pre-pupa larva (2.60 mm) and an empty cocoon (2.50 mm) were reported. The Loanda stream had the highest occurrence of this type of association (of 12 fish examined, three had larvae). The other two streams reported a lower occurrence: the Baixada Morena stream had three fish associated with larvae amongst 1105 fish examined, whereas the Selma stream had three out of 124 fish infested by larvae. The occurrence of only one larva per host can be related to the small body area of the host fish (average standard length = 26.60 mm and average weight = 0.31 g). We observed that the larvae prefer fixation sites in the vicinity of the pectoral and pelvic fin of the fish, which is presumably associated with the fact that chironomids feed on algae and debris suspended by the movement of loricariids. These streams differ with respect to the presence of riparian forests, which may affect resource availability and thereby influence ecological interactions between the species. [ABSTRACT FROM AUTHOR]

The male adult of Boreoheptagyia zhengi Lin & Liu, sp. nov. is described and illustrated based on material collected in China. Associated morphological characteristics and reference to its DNA barcode are provided. Boreoheptagyia kurobebrevis (Sasa & Okazawa, 1992) is newly recorded from China based on both a male and female, with additional associated data on the DNA barcode of the male adult. A neighbor-joining tree based on available Boreoheptagyia DNA barcodes and a key to the adults of Boreoheptagyia from China are given. [ABSTRACT FROM AUTHOR]

ABSTRACT Abalesmyia cordeiroi Neubern was originally described based on adult males collected in the Amazon region; therefore, females and immatures of this species are unknown. In the present study, the pupal and larval stages of A. cordeiroi are described and illustrated. In addition, an amendment to the larval diagnosis of Ablabesmyia is provided.

In-vitro effects of sub-lethal concentrations of malathion, phenanthrene (Phe) and cadmium (Cd) were tested on Chironomus sancticaroli larvae in acute bioassays by measuring biochemical and molecular parameters. Malathion was evaluated at 0.001, 0.0564 and 0.1006 mg L-1; Phe at 0.0025, 1.25 and 2.44 mg L-1; and Cd at 0.001, 3.2 and 7.4 mg L-1. The recovery test carried out at the highest concentration of each compound showed that survival of larvae exposed to Phe ranged from 4% to 5%, while the effects of malathion and Cd were irreversible, not allowing the emergence of adults. Results showed that malathion and Cd inhibited AChE, EST-α and ES-β activities at the two highest concentrations. Phe at 0.0025, 1.25 and 2.44 mg L-1; and Cd at 3.2 and 7.4 mg L-1 inhibited glutathione S-transferase activity. Oxidative stress was exclusively induced by the lowest concentration of malathion considering SOD activity once CAT was unaffected by the stressors. Lipid peroxidation was registered exclusively by malathion at the two highest concentrations, and total hemoglobin content was only reduced by Cd at the two highest concentrations. The relationship among biochemical results, examined using the PCA, evidenced that malathion and Cd concentrations were clustered into two groups, while Phe only formed one group. Four hemoglobin genes of C. sancticaroli were tested for the first time in this species, with Hemoglobin-C being upregulated by malathion. The toxicity ranking was malathion > Phe > Cd, while biochemical and molecular results showed the order malathion > Cd > Phe. Our results highlight the importance of combining different markers to understand the effects of the diverse compounds in aquatic organisms.

Aim: While we understand broad climate drivers of insect distributions throughout the Arctic, less is known about the role of spatial processes in determining these relationships. As such, there is a need to understand how spatial controls may influence our interpretations of chironomid environment relationships. Here, we evaluated whether the distribution of chironomids followed spatial gradients, or were primarily controlled by environmental factors. Location: Eastern Canadian Arctic, Greenland, Iceland. Taxon: Non‐biting midges (Chironomidae). Methods: We examined chironomid assemblages from 239 lakes in the western North Atlantic Arctic region (specifically from the Arctic Archipelago of Canada, two parts of west Greenland (the southwest and central west) and northwest Iceland). We used a combination of unconstrained ordination (Self Organizing Maps); a simple method with only one data matrix (community data), and constrained ordination (Redundancy Analysis); a canonical ordination with two datasets where we extracted structure of community related to environmental data. These methods allowed us to model chironomid assemblages across a large bioregional dimension and identify specific differences between regions that were defined by common taxa represented across all regions in high frequencies, as well as rare taxa distinctive to each region found in low frequencies. We then evaluated the relative importance of spatial processes versus local environmental factors. Results: We find that environmental controls explained the largest amount of variation in chironomid assemblages within each region, and that spatial controls are only significant when crossing between regions. Broad‐scale biogeographic effects on chironomid distributions are reflected by the distinct differences among chironomid assemblages of Iceland, central‐west Greenland, and eastern Canada, defined by the presence of certain common and low‐frequency, rare taxa for each region. Environmental gradients, especially temperature, defined species distributions within each region, whereas spatial processes combine with environmental gradients in determining what mix of species characterizes each broad and geographically distinct island region in our study. Main conclusions: While biogeographic context is important for defining interpretations of environmental controls on species distributions, the primary control on distributions within regions is environmental. These influences are fundamentally important for reconstructing past environmental change and better understanding historical distributions of these insect indicators. [ABSTRACT FROM AUTHOR]

We here present a pioneering systematic review of fossil dipterans of the tribe Tanytarsini (family Chironomidae) discovered in Indian amber from Cambay. The specimens examined belong to five species: Gujaratomyia miripes , Stempellina stebneri sp. nov. , Stempellinella pollex sp. nov. , Tanytarsus forfex sp. nov. and Tanytarsus ramus sp. nov. , which are described. All species belong to the oldest known Tanytarsini and come from the Cambay shale formation in Tadkeshwar, dated to the early Eocene (~54 Mya). Displaying unusual characters/structures of diagnostic and phylogenetic importance, the specimens studied are discussed against the background of the evolution and systematics of the oldest fossil (Eocene) and extant representatives in the tribe. An updated checklist and key to the identification of genera and species of Tanytarsini from Eocene amber is also provided. The spectral characteristics and physical properties of Cambay amber are similar to those of glessite resins, which are discussed in detail in order to substantiate the identity of the amber and the origin of the inclusions studied. [ABSTRACT FROM AUTHOR]

is a speciose genus, with about 90 species distributed worldwide, 37 of which occurring in the Neotropical region. In Colombia, A. metica is the only species of the genus recorded so far, which was initially described with material collected in the Colombian Orinoquia and more recently recorded in the southeastern Brazil. In the present study, Ablabesmyia opita sp. n. from the Colombian Andes is described and illustrated based on adult males collected at the inter-andean valley of Magdalena river basin. In addition, an updated taxonomic key for Neotropical species and a map of Ablabesmyia records in Colombia are provided. The male of the new species is similar to that of A. laurindoi but can be easily distinguished by the coloration patterns of the legs, the shape of the sternapodeme and by the number of antepronotals. [ABSTRACT FROM AUTHOR]

The first summarising checklist of Ukrainian Chironomidae (Insecta, Diptera) consisted of 302 species. Compared to other European countries, it is obvious that the real chironomid diversity of Ukraine has not been fully documented and greater effort is needed to discover the actual richness of this family. Thus, our survey focused on the chironomid fauna of some alpine lakes situated above the treeline in the Ukrainian Carpathians (a part of the Eastern Carpathians) aiming to contribute to the knowledge of the Ukrainian chironomid fauna and create the basis for more comprehensive neo- and palaeolimnological studies of these, regionally, little-known ecosystems. [ABSTRACT FROM AUTHOR]

Subfossil chironomid (Diptera, Chironomidae) remains are often used as indicators of lake level changes in palaeolimnological studies. However, their usefulness as a water depth proxy can vary between the sites, depending on the lake morphology, mode of taphonomic processes or amplitude of past water level fluctuations, among other factors. In this study, we have examined the distribution of subfossil chironomids in the shallow Lake Spore (northern Poland) to assess the influence of water depth on the fauna. Our aim was to evaluate the site-specific utility of subfossil chironomids for lake level reconstruction at Lake Spore. The subfossil chironomid assemblages in Lake Spore have heterogeneous distribution, suggesting they are predominately composed of remains deposited close to the sampling location. A strong relationship between the water depth and the chironomids is marked by the 25.12% variance explained by water depth in the taxonomic data. Moreover, according to generalized linear models (GLMs) out of 44 dominant taxa, 12 have significant relationships with water depth. However, the sensitivity of our chironomid fauna to water depth changes is not continuous along the entire depth gradient. The most abrupt assemblage change occurs at 2.6–3.7 m water depth, in proximity to the depth where macrophytes become less dense and finally disappear. We conclude that, despite these strong chironomid-water depth relationships, only major water level fluctuations can be satisfactorily reconstructed due to the limited turnover rates of the fauna along a depth gradient and relatively small amplitude of the lake level variations characteristic for East-Central Europe.

This special issue provides an overview of recent advances in the study of chironomids (Diptera chironomidae), as an outcome of the 20th International Symposium on Chironomidae held in Trento (Italy), in July 2017. it includes 27 selected papers, representative of the six topics of the symposium: genetics and cytogenetics, taxonomy and systematics, autecology and physiology, toxicology and adaptive biology, ecology and biomonitoring, palaeolimnology. Most papers emphasise the value of chironomids in the monitoring programmes, mainly on Europe and case histories from South America and Africa. however, as our title indicates, the reported contemporary studies represent a range from the genetic through the autecological to the ecosystem scale. the aim of the volume is to give new insights on ecology and biology of non-biting midges, the freshwater insect family that comprises the highest number of species in the world, in both lentic and lotic habitats.

Subfossil chironomid (Diptera, Chironomidae) remains are often used as indicators of lake level changes in palaeolimnological studies. However, their usefulness as a water depth proxy can vary between the sites, depending on the lake morphology, mode of taphonomic processes or amplitude of past water level fluctuations, among other factors. In this study, we have examined the distribution of subfossil chironomids in the shallow Lake Spore (northern Poland) to assess the influence of water depth on the fauna. Our aim was to evaluate the site-specific utility of subfossil chironomids for lake level reconstruction at Lake Spore. The subfossil chironomid assemblages in Lake Spore have heterogeneous distribution, suggesting they are predominately composed of remains deposited close to the sampling location. A strong relationship between the water depth and the chironomids is marked by the 25.12% variance explained by water depth in the taxonomic data. Moreover, according to generalized linear models (GLMs) out of 44 dominant taxa, 12 have significant relationships with water depth. However, the sensitivity of our chironomid fauna to water depth changes is not continuous along the entire depth gradient. The most abrupt assemblage change occurs at 2.6-3.7 m water depth, in proximity to the depth where macrophytes become less dense and finally disappear. We conclude that, despite these strong chironomid-water depth relationships, only major water level fluctuations can be satisfactorily reconstructed due to the limited turnover rates of the fauna along a depth gradient and relatively small amplitude of the lake level variations characteristic for East-Central Europe. [ABSTRACT FROM AUTHOR]

New records and distributional notes of Chironomidae (Insecta, Diptera) are provided for four protected areas in the state of Pernambuco, northeastern Brazil. Additionally, we also present new records and update of distributional ranges from Brazil and the Neotropical Region. In total, 810 specimens belonging to 35 genera within the subfamilies Chironominae (22 taxa), Tanypodinae (11 taxa) and Orthocladiinae (2 taxa) were found. The subfamilies Chironominae and Tanypodinae predominated. Axarus Roback, 1980 and the Tanytarsus ortoni-group were recorded for the first time in the state of Pernambuco, while Nanocladius Kieffer, 1913a was recorded for the first time in the Northeast Region of Brazil. Our results make evident how much and where current knowledge of the northeastern Brazil chironomids remains fragmentary. [ABSTRACT FROM AUTHOR]

The monotypic genus Pentaneurella Fittkau & Murray was originally described based on larvae, pupal exuviae and pharate males. The latter prevented the observation of key features, such as wing dimensions, abdominal coloration pattern, and hypopygial apodemes (sternapodeme and phallapodeme), and the description of the adult male was considered incomplete by the authors. Herein, the adult female of Pentaneurella katterjokki is described for the first time, and the adult male, pupa and larva are redescribed and figured based on specimens recently collected in Germany and Norway. We also discuss the phylogenetic position of Pentaneurella. [ABSTRACT FROM AUTHOR]

Chironomidae (Diptera) are among the most diverse and widespread aquatic insects, with roughly 5,500 described species inhabiting an enormous variety of aquatic ecosystems, ranging from moist soils to lakes and rivers, and even marine ecosystems. Despite its ubiquity, the group remains underrepresented in studies addressing aquatic insect assemblages of high-altitude systems, either glacier-fed or non-glacial, particularly in South America. Glacier-fed streams possibly are one of the harshest ecosystems in nature, and present a distinct downstream pattern in species distribution and diversity away from the constraining influence of the glacier. In this context, the goal of our study was to provide data on the chironomid fauna of glacier-fed streams, together with neighboring non-glacial streams in Ecuador, in order to contribute to the overall knowledge of tropical fauna in high Andean regions. Also, we sought to provide an identification key and photography material for future studies. Collections of non-biting midges were made in Ecuador during Jan 2008. In total, 1,412 specimens belonging to 16 genera and at least 23 species within the subfamilies Chironominae (3 taxa), Diamesinae (3 taxa), Podonominae (3 taxa), Orthocladiinae (13 taxa), and Tanypodinae (1 taxon) were found. The subfamilies Podonominae and Orthocladiinae predominated in terms of abundance. Parochlus was the most widespread genus of Chironomidae, while Cricotopus was the most diverse. This study contributes to the knowledge of the chironomid fauna in the high-altitude streams in Ecuador, and hopefully will motivate further studies in the area. [ABSTRACT FROM AUTHOR]

Non-biting midges of the fly family Chironomidae are extremely abundant and diverse in Arctic regions and are essential components of Arctic ecosystems. Modern identification tools based on documented records of Arctic chironomid species are therefore important for ecological research and environmental monitoring in the region. Here, we provide an updated review of the chironomid fauna of the Svalbard archipelago and the island of Jan Mayen, Norway. Our results show that a total of 73 species distributed across 24 genera in four subfamilies are known from these areas. Our review treats 109 taxa, including nomina dubia and misidentifications. It includes morphological identification keys to all known species as well as photographs of most taxa and DNA barcodes of 66 species. Taxonomic remarks are given for selected taxa, including previous misidentifications and erroneous records. Chironomus islandicus, Tvetenia bavarica, Limnophyes schnelli, Metriocnemus brusti and Metriocnemus fuscipes as well as the genera Allocladius, Corynoneura and Bryophaenocladius are reported from Svalbard for the first time, while Procladius (Holotanypus) frigidus, Stictochironomus psilopterus, Chaetocladius incertus, Orthocladius (Orthocladius) mixtus and Smittia longicosta, previously considered as junior synonyms or nomina dubia, are revived as valid species based on examination of type material or literature. Twenty species within eleven genera are introduced with interim names. Metriocnemus similis is regarded as a junior synonym of Metriocnemus ursinus, and Smittia incerta, Smittia flexinervis and Smittia spitzbergensis are regarded as nomina dubia. Valid taxa no longer considered as part of the Svalbard fauna are Parochlus kiefferi, Arctopelopia barbitarsis, Procladius (Holotanypus) crassinervis, Diamesa lindrothi, Diamesa incallida, Diamesa lundstromi, Chironomus hyperboreus, Sergentia coracina, Camptocladius stercorarius, Chaetocladius dissipatus, Chaetocladius dentiforceps, Chaetocladius laminatus, Chaetocladius perennis, Cricotopus (Cricotopus) humeralis, Cricotopus (Cricotopus) polaris, Hydrosmittia ruttneri, Limnophyes edwardsi, Metriocnemus picipes, Metriocnemus tristellus, Orthocladius (Eudactylocladius) gelidus, Orthocladius (Euorthocladius) thienemanni, Orthocladius (Orthocladius) obumbratus, Orthocladius (Orthocladius) rhyacobius, Paralimnophyes, Paraphaenocladius impensus, Psectrocladius (Monopsectrocladius) calcaratus, Psectrocladius (Psectrocladius) psilopterus, Psectrocladius (Psectrocladius) ventricosus, Smittia lasiophthalma, Smittia lasiops and Zalutschia tatrica.

Abstract: River basins are important for both industrial and agricultural activities. Pollution of air, water and soil is increasing owing to an insufficient number of treatment facilities; thus, most industrial and domestic wastewater either is directly discharged into water or is improperly treated. Here Chironomus spp. mentum deformities were used to determine environmental stress sources. A total of 4701 chironomid larvae were collected from 31 stations located in the Büyük Menderes River Basin. The mean mentum deformity incidence was 2.82%, and the frequency of deformities varied from 0 to 14.7%, with the highest frequencies calculated for the Dokuzsele (14.7%) and Banaz (9%) streams. The feature common among both stations is that they receive wastewater from textile, tannery and agricultural facilities. Our results show that mentum deformities are at least five times more pronounced at the most highly polluted sampling stations and indicate that mentum deformities of chironomid larvae are strongly related to ammonium-N and Cl is positively associated with agricultural and household wastewater. [ABSTRACT FROM AUTHOR]

We studied the diversity and abundance of Chironomidae assemblages according to the metacommunity framework, aiming to disentangle environmental and dispersal-driven processes in Amazonian streams. Because of the high heterogeneity in Amazonian landscapes and daily flood regimes connecting stream network, we tested if dispersal limitations play a smaller role than environmental variation in explaining variation in community composition. We investigated how community structure and species richness were affected by environmental variables, and how differences in geographic distance between streams best explain metacommunity patterns. We found remarkable environmental effects (i.e., species sorting) and low spatial contribution (i.e., dispersal limitation) on the metacommunity structure. Canopy density mid-stream, percentage of wood debris, and wetted width in streams were the main environmental factors for explaining community structure. Overall, we found only effects of broad-scale patterns in metacommunity structure explained by spatial filters. Community structure was most explained by Asymmetric eigenvector maps representing directional dispersion effects along the basin-scale and less explained by Moran’s eigenvectors maps suggesting that overland dispersal limitation has a weak role in ruling the assemblages. Our results support that without dispersal limitation, the combination of species sorting and mass effects is the main pattern structuring chironomid metacommunities between Amazonian floodplain streams. [ABSTRACT FROM AUTHOR]

Several studies have indicated the presence of contaminants in Alpine aquatic ecosystems. Even if measured concentrations are far below those that cause acute effects, continuous exposure to sub-lethal concentrations may have detrimental effects on the aquatic species present in these remote environments. This may lead to a cascade of indirect effects at higher levels of the ecological hierarchy (i.e., the community). To improve the determination of ecologically relevant risk endpoints, behavioural alterations in organisms due to pollutants are increasingly studied in ecotoxicology. In fact, behaviour links physiological function with ecological processes, and can be very sensitive to environmental stimuli and chemical exposure. This is the first study on behavioural alteration in a wild population of an Alpine species. In the present study, a video tracking system was standardized and subsequently used to identify contaminant-induced behavioural alterations in Diamesa zernyi larvae (Diptera, Chironomidae). Diamesa zernyi larvae, collected in an Italian Alpine stream (Rio Presena, Trentino Region), were acclimated for 24 h and successively exposed to several aquatic contaminants (pesticides: chlorpyrifos, metolachlor, boscalid, captan; pharmaceuticals: ibuprofen, furosemide, trimethoprim) at concentrations corresponding to their Lowest Observed Effect Concentration (LOEC). After 24, 48, 72, and 96 h of exposure, changes in the distance moved, the average speed, and the frequency of body bends were taken to reflect contaminant- and time-dependent effects on larval behaviour. In general, metolachlor, captan, and trimethoprim tended to reduce all the endpoints under consideration, whereas chlorpyrifos, boscalid, ibuprofen, and furosemide seemed to increase the distances moved by the larvae. This could be related to the different mechanisms of action of the investigated chemicals. Independently of the contaminant, after 72 h a general slowing down of all the behavioural activities occurred. Finally, we propose a behavioural stress indicator to compare the overall behavioural effects induced by the various contaminants. [ABSTRACT FROM AUTHOR]

Thin layers of water running over rocky surfaces are characteristic of madicolous habitats, which harbor a peculiar Chironomidae community. However, information on the identity, distribution, and ecology of madicolous chironomids in the Neotropical region are still sparse. The main purpose of this research is to reveal and contribute to the ecology of madicolous Chironomidae species, especially regarding their altitudinal distribution in the Atlantic Forest. Sampling was performed using our own designed emergence traps deployed from 0 to 2700 m a.s.l. in 70 sites in three mountains in southeastern Brazil. Sixty taxa of chironomids were collected and identified, of which only 22 are known to science. Most of the species showed a wider distribution than previously known, both in terms of geographic and altitudinal ranges, while others showed significant association with particular altitudinal bands (as evidenced by the indicator species analysis). Atlantic Forest mountainous regions are known to harbor one of the richest fauna in the world and have been suffering from several types of environmental impacts, including climate change, which will especially affect taxa living in specialized habitats. The narrow range of tolerance to environmental conditions verified for mountain species, and the fact that many of them are rare and endemic, make the conservation efforts in these areas indispensable. [ABSTRACT FROM AUTHOR]

Tropical high mountain lakes show unique environmental conditions where chironomids play an important role in ecosystem functioning. The characteristics of these environments could favor diet overlap and therefore a high interspecific competition. This study described the dietary habits of chironomid genera, identified whether the dietary habits were specialized or generalist, and analyzed the diet overlap in the genera. Chironomidae larvae were collected from four lakes of the Chingaza paramo during the dry season, between April and May of 2 016. The feeding habits of larvae were evaluated by analyzing gut contents following standard methods. Each genus was assigned to trophic guilds (carnivore, detritivore and algivore) and the diet overlap was estimated using the Pianka's index. A total of 1 003 individuals were collected and nine genera were identified. Larvae consumed mainly fine particulate organic matter (FPOM), algae, macrophyte fragments, macroinvertebrates, and animal tissues. FPOM was the main feeding resource of detritivores. The analysis of diets showed a high affinity of each genus for a single trophic guild and most of the genera were generalist in the use of resources. For all lakes, high levels of diet overlap were observed among genera and trophic guilds, mainly among detritivores. Our results suggested that Chironomidae larvae of these lakes presented well differentiated trophic habits, and showed a moderate diet overlap within detritivores and carnivores. Rev. Biol. Trop. 66(1): 136-148. Epub 2018 March 01. [ABSTRACT FROM AUTHOR]

The decline of species richness with altitude is one of the most obvious patterns in ecology and results from the combination of ecological and evolutionary mechanisms. In harsh high-altitude environments, the effect of altitude usually overrules other environmental variables related to biodiversity. Studies using species richness along altitude gradients in high altitude are relatively numerous for lakes, but not for ponds. However, due to their special features, such as small size, high isolation and regional variability, ponds have been proved to be different systems compared to lakes. In high-altitude waterbodies, species of the family Chironomidae often dominate in benthic invertebrate communities and thus serve as an ideal model to study aquatic community changes along an altitude gradient. However, due to the time-consuming processing and expertise needed to identify the species, chironomids are often excluded from regular surveys. In the present study, we sampled 66 Tatra ponds over a 1100-m altitude gradient for benthic invertebrates, with special attention to chironomids. Out of the total 122 taxa collected, Chironomidae constituted the richest group with 58 taxa, being present in all the study ponds. The most diverse pond supported 13 chironomid taxa, and mean diversity was 6 taxa/pond. While total invertebrate richness decreased with altitude, chironomid richness showed only a weak negative response to altitude. The proportion of total chironomid diversity made up of Tanypodinae and Chironominae subfamilies decreased with altitude, while the opposite trend was recorded for the proportion of Diamesinae and Orthocladiinae. [ABSTRACT FROM AUTHOR]

• Chironomid local species richness (LSR) in European rivers is strongly impacted. • Depth, substrate index and velocity are primary environmental factors of the impact. • Habitat species richness (HSR) is stronger than each of the factors. • Correlations between α, β, and γ diversity assess seasonal assemblage stability. • Biotic mechanisms confer a greater stability in autumn than in any other season. Multiscale determinants of riverine chironomid species richness were assessed in seven rivers in Central Poland, an area representative of the European temperate climatic zone. The impact of environmental factors, seasonality, as well as the concepts of gamma diversity, i.e. habitat species richness (HSR), alpha diversity, i.e. local species richness (LSR), and the relationships between these, i.e. beta diversity, were studied. One site in each river was defined as a habitat and monthly LSR time series data were obtained at each site over a full annual cycle for analysis. No strong trend in the time series was detected. The autocorrelation function (ACF) indicated that the time series were uncorrelated white noise. A stepwise forward regression model with no HSR indicated that depth, Substrate Index (SI), velocity and dissolved oxygen were significant factors of LSR values in the studied area, explaining together with summer (as a dummy variable) 67.01% of LSR variance (R2 adj = 0.66). Seasonality was noticeable in the impact of summer on increase in species richness. When HSR was included in a similar model then it explained, together with benthic particulate organic matter (BPOM), SI, depth, and velocity, 70.90% of variability in LSR variance (R2 adj = 0.69), HSR alone accounting for 58.95% in LSR variance (R2 adj = 0.59). In both the annual cycle and in given seasons, HSR strongly positively correlated with the minimum, maximum, and mean LSR values, and there was no saturation of the rivers by chironomid species, i.e. other chironomid species were still able to inhabit the rivers beside the present ones. HSR did not correlate with beta diversity when measured by two widely used setwise beta diversity indices, or by three pairwise beta diversity indices. The exception was in autumn, where one setwise and two pairwise beta diversity measures correlated with both alpha and gamma diversity measures, which suggests a greater stability of larval chironomid assemblages in that season. This larval stability was not associated with greater stability of environmental factors in autumn, hence the stability seems to be related to undisclosed biotic mechanisms. Seasonality was also a strong factor in predicting the exchange of species. Turnover index between seasons ranged from 0.133 (spring vs summer) to 0.261 (autumn vs winter) and UPGMA clustering determined least chironomid similarity between winter and other seasons. [ABSTRACT FROM AUTHOR]

Climate change is one of the key drivers of changes in the biodiversity of the planet. There is, however, a general lack of long-term data sets showing trends in taxonomic diversity of aquatic insects in high mountain environments particularly vulnerable to climate change. Using palaeolimnological techniques, we explored the changes in subfossil chironomid assemblages from three remote water bodies in the Eastern Alps, with the main focus on taxonomic turnover over different intervals of the late Holocene., Major changes in the assemblages coincided with shifts between different climate regimes and were mainly associated with the taxonomic shifts indicating the crossing ecological thresholds related to the ice-cover duration in alpine lakes., Patterns of assemblage turnover through the past 2000 years differ between the study sites. Nevertheless, despite site-specific differences in the physical setting and taxonomic composition, the study sites reveal substantial chironomid assemblage turnover (>1.0 SD) since AD 1850. The highest chironomid turnover (0.87 SD) over the last 30 years ( AD 1980-2010), more than three times greater (0.26 SD) than in the previous 30 years, is observed in the lake situated at the highest elevation among the study lakes., Applying non-linear structural equation modelling, we found that cold-season (October-May) temperatures and therefore lake ice phenology are among the most important environment variables affecting the chironomid assemblages., The results of this study suggest that further climate warming will increase the risk of ecological alterations in remote Alpine freshwaters, including major shifts in chironomid fauna. [ABSTRACT FROM AUTHOR]

Examination of the syntypes of Metriocnemus volitans Goetghebuer, 1940 revealed that these specimens belong to the genus Chaetocladius and are not con-specific with Gymnometriocnemus volitans (Goetghebuer, 1940) sensu Brundin (1956) and Sæther (1983). A literature search showed that Gymnometriocnemus kamimegavirgus Sasa & Hirabayashi, 1993 fits well with the species figured and diagnosed by Brundin (1956) as well as with specimens of this species from Norway. We present arguments for Chaetocladius volitans (Goetghebuer) comb. n. and for the use of G. kamimegavirgus for G. volitans sensu Brundin. In addition, we provide DNA barcode data that indicate the presence of at least seven Gymnometriocnemus species in Norway of which six are collected as male adults. Two of these, Gymnometriocnemus (Gymnometriocnemus) pallidus sp. n. and Gymnometriocnemus (Raphidocladius) autumnalis sp. n. are regarded as new to science and diagnosed based on adult male morphology and DNA barcodes. The species Gymnometriocnemus (Gymnometriocnemus) marionensis Sæther, 1969 is re-established and a key to all Holarctic species is provided. [ABSTRACT FROM AUTHOR]

Abstract: Members of the families Chironomidae (chironomids or non-biting midges), Ceratopogonidae (ceratopogonids or biting midges) and Simuliidae (simulids or blackflies) are ubiquitous dipterans of the infraorder Culicomorpha. They are extremely diversified in ecological strategies. Their larvae play major roles in aquatic food webs as detritivores or predators, whereas their adults can be general predators (Chironomidae), hemolymphagous or hematophagous predators (Ceratopogonidae and Simuliidae) or pollinators. Both larval and adult stages are commonly infected by bacteria, viruses, protists, nematodes, true fungi and oomycetes. These phylogenetically diverse assemblages of microorganisms can simultaneously infect multiple species of chironomids, ceratopogonids and simulids, and each host may become trophically interrelated with other hosts by sharing their parasites. Here, we review the information on fungal and oomycete parasites of these dipteran groups with special reference to the natural regulation of host populations, the impact of parasitism in food webs, and the potential of these parasites as biocontrol agents. [Copyright &y& Elsevier]