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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: Chironomic “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. Introducción: Chironomidae (Diptera) es la familia de insectos acuáticos más extendida y abundante en los ecosistemas dulceacuícolas. Los quironómidos se consideran buenos indicadores de la calidad del agua, pero rara vez se identifican a nivel de género en estudios de amplia escala espacial. Objetivo: Identificar las condiciones ambientales asociadas a los quironómidos en un gradiente altitudinal. Métodos: Comparamos ecorregiones, tipos de ríos y estaciones para quironómidos en arroyos y ríos neotropicales (18 sitios en ríos; 2014-2018; en un bosque tropical de Yungas y un bosque seco del Chaco Occidental, Argentina). Utilizamos escalamiento no métrico multidimensional, disimilitud, análisis de envfit y curvas de rango-abundancia. Resultados: Los “ensamblajes” de quironómidos coincidieron tanto con las ecorregiones como con los tipos de ríos. Sin embargo, las ecorregiones presentaron un mejor ajuste con la composición de especies. Los taxones estenotérmicos de Orthocladiinae fueron dominantes en las elevaciones altas y los euritermales de Chironominae en los ríos de las tierras bajas. La altitud, la temperatura del agua y la conductividad fueron importantes. Las diferencias estacionales fueron menores que las diferencias ecorregionales. Conclusiones: las ecorregiones, la altitud, la temperatura del agua y la conductividad se correlacionaron con las comunidades de quironómidos. Orthocladiinae fue dominante en los sitios altos y Chironominae en los ríos de tierras bajas

Ablabesmyia cordeiroi Neubern foi descrita originalmente com base em machos coletados na região amazônica, portanto, a fêmea e os imaturos desta espécie são desconhecidos. No presente estudo, os estágios de pupa e larva de A. cordeiroi são descritos e ilustrados. Além disso, uma emenda à diagnose da larva de Ablabesmyia é fornecida. 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.

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.

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.

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.In total, 34 species/taxa, belonging to 22 genera and 4 subfamilies were collected in June 2019. Ten species were recorded for the first time in Ukraine:Zavrelimyia melanura,Acamptocladius reissi, Cricotopus speciosus, Cricotopus curtus, Heterotrissocladius marcidus,Orthocladius dentifer,Psectrocladius oligosetus, Polypedilum uncinatum, Paratanytarsus laccophilusandTanytarsus bathophilus. The occurrence of six species previously considered as “doubtfully present” in Ukraine was finally confirmed. Generally, the surveyed lakes have a unique composition of chironomids consisting of a mixture of species typical for cold alpine lakes and acidic ponds situated at lower altitudes.

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.

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. © 2018, Pleiades Publishing, Ltd.

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.

The chironomid diversity of Central America is virtually underestimated and there is almost no knowledge on the chironomid remains accumulated in surface sediments of lakes. Thus, in the present study we provide information on the larval sub-fossil chironomid fauna from surface sediments in Central American lakes for the first time. Samples from 27 lakes analysed from Guatemala, El Salvador and Honduras yielded a total of 1,109 remains of four subfamilies. Fifty genera have been identified, containing at least 85 morphospecies. With 45 taxa, Chironominae were the most specious and also most abundant subfamily. Tanypodinae with 14 taxa dominated in about one third of the sites. Orthocladiinae were presented by 24 taxa, but were recorded in 9 sites, being dominant in only one site. Podonominae were collected only in one locality. Head capsules of Heterotrissocladius found in the high elevation lake Magdalena, Guatemala, represent a first record for the Neotropical region. Both relative abundance and species richness of Chironominae and Orthocladiinae showed significant relationship to elevation, while Tanypodinae were indifferent. Hopefully, the list of taxa provided by our study will be a base line for future limnological and paleolimnological investigations using chironomid remains in the region.

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.

Propsilocerus akamusi (Diptera: Chironomidae) is a dominant macroinvertebrate species in many eutrophic lakes in subtropical and temperate zones. P. akamusi larvae can migrate deep into the sediment (>30 cm) during summer where is no oxygen. However, to our knowledge, the specific adaptive tactics of its tube-dwelling life (>30 cm) and underlying mechanisms why this species is favored by nutrient-rich lakes remain limited. With the understanding above-mentioned issues, we can provide important information for the development of sensitive biomonitoring. We examined monthly morphological dynamics and physiological adaptations of P. akamusi to anoxic conditions, and environmental relationships of the species abundance in a subtropical eutrophic lake. Results of our experiments indicated that this species presented extremely low fuel consumption at a state of estivation when the larvae dwelt in deep sediment, and conducted anaerobic respiration, with ethanol as a major metabolite, to withstand long term anoxic conditions. Additionally, in our field study, the abundance of P. akamusi correlated positively with most nutrient-related variables, indicating that this species can serve as sentinel organisms of nutrient enrichment. We suggest that the high tolerance to anoxia and detritivorous diet of P. akamusi larvae may allow the species to benefit from nutrient enrichment. The vertical niche differentiation and the avoidance of benthivorous predator by vertical sediment migration behavior may also contribute to its high dominance in eutrophic freshwaters. peerReviewed