Analysis of chlordane-impacted streams using chironomid pupal exuviae (Diptera: Chironomidae)

A method of rapidly assessing streams and rivers using chironomid pupal exuviae was tested on a chlordane-impacted stream near St. Louis, Missouri. Various concentrations of chlordane were found in sediments of Grand Glaize Creek, most likely resulting from soil runoff around housing and business developments throughout the stream's course. Chironomid pupal exuviae and sediment samples were collected concurrently from Grand Glaize Creek on two separate occasions, once in 1988 and again in 1990. Cluster analysis of samples at sites, based on the percent abundances of taxa within habitats and by subfamilies, produced two distinct clusters; one grouping samples with lower chlordane concentrations and the other grouping samples with higher chlordane concentrations. Further analysis showed a trend towards lower percent abundances of taxa living in depositional and transitional/depositional zones (Chironominae and some Tanypodinae) at the higher chlordane site, while the lower chlordane sites had lower percent abundances of taxa within erosional and erosional/transitional zones (Orthocladiinae and some Tanypodinae). These findings support the hypothesis that taxa living in close association to fine organic sediments will be exposed to higher concentrations of chlordane in the stream and more negatively affected than taxa feeding and living in habitats removed from chlordane-bound sediments. Comparisons from the present study were made to related studies revealing similar patterns among the Chironomidae.     

Incidence of deformed chironomid larvae (Diptera: Chironomidae) in Swedish lakes

The occurrence of deformed mouth parts in recent and subfossil material of mostly Chironomus, Micropsectra and Tanytarsus increased from less than 1 % of the larvae at unpolluted sites or time periods to figures in the range of approx. 5–25% at strongly polluted sites. Deformities occurred in species that are widely separate in taxonomic position and way of living. Several heavy metals are suspected causative agents. Deformities in various mouth parts are illustrated by SEM photographs.     

Allergens of non-biting midges (Diptera: Chironomidae): a systematic survey of chironomid haemoglobins

Various genera of non-biting midges (Diptera: Chironomidae) possess haemoglobins in larvae and adults. For certain species, these haemoglobins have been implicated in human allergic disease in several countries. The present study confirms and extends observations that haemoglobin is present in many species of Chironomidae, establishes that it is retained from the larval to the adult stage and shows that haemoglobin persists both in live and in dead dry flies. Previous suggestions that Chironomidae should be seen as important environmental and occupational allergens are clearly substantiated.     

The larva and habitat ofParakiefferiella nigra Brundin (Diptera: Chironomidae)

Collections of adults ofParakiefferiella nigra Brundin indicate that this chironomid occurs widely in arctic and subarctic zones. In addition, it has occasionally been collected in cool temperate and boreal forest lakes of both North America and Europe. Although widely distributed, the larva and its habitat have not previously been described. Identity of the larva ofP. nigra has been established by studying associated reared specimens. The distinctive larva, with reduced second lateral mental teeth, is stenotopic, and on the basis of modern collections appears to be most abundant in cold, oligotrophic lakes. More data is required to establish the range of thermal environments inhabited by the larva. Larval head capsule remains ofP. nigra are common in late-glacial sediments of southwestern British Columbia lakes and provide important evidence for oligotrophic conditions during late-glacial time.     

The identity of Dactylocladius commensalis (Diptera: Chironomidae) revealed

A new dipteran species, Parapsectra wagneri sp. n. (Chironomidae), is described from emergence traps on Breitenbach, Schlitz, Germany. It differs in antennal ratio and characteristics of the genitalia from the three known species.     

Ecological background and importance of the change of chironomid fauna (Diptera: Chironomidae) in shallow Lake Balaton

The objectives of this research were to record the changes in composition of the open-water, bottom-dwelling chironomid fauna in Lake Balaton between 1978–1984, to examine the causes of these changes, and to discover their significance in the life of the lake.The spatio-temporal dispersion of larvae is compared with the water and sediment quality of each basin in the lake. It is established that, under present conditions, nutrient status can be regarded as the chief environmental factor.Studies of population dynamics show that chironomids play a highly important role in preserving sediment quality. Chironomids are an essential element in the organic matter circulation of the lake. They dominate a sub-system that retards water quality degradation, and thus they play a prominent role in the natural prevention of eutrophication.     

Trophic level assessment of profundal sediments of the artificial Lake Campotosto (Central Italy), using midge larval community (Diptera: Chironomidae)

A study on the profundal chironomids of the artificial Lake Campotosto (Central Italy) was carried out during the summer/early autumn of 1983 and 1984, in order to analyse their composition and community structure in relation to the lake trophic level assessed by water chemical analysis.A total of about 2000 specimens belonging to 15 taxa were collected during the study.Chironomus plumosus group andTanytarsus spp. dominated in 1983 and 1984, respectively, showing a competitive relationship probably due to the larval size. The functional feeding organization was mostly composed of collectors (percentages greater than 90%), revealing the presence of abundant fine organic deposits (FPOM). Diversity and evenness appeared to be negatively affected by the monotony of food, which seems to constitute the key factor in governing both the taxonomic and the trophic structure of chironomid fauna.A clear discrepancy between water chemical data and profundal chironomid analyses was observed in the assessment of the lake trophic level. Sediments exhibited eutrophicated conditions, whereas overlying waters indicated an oligotrophic status. The relevance of profundal macrobenthic investigations in detecting eutrophication is stressed.     

Species composition and assemblage structure of chironomid larvae (Diptera: Chironomidae) attaching to the artificial substrates in a Japanese temperate basin,in relation to the longitudinal gradient

The relative importance of natural and anthropogenic factors, especially topographic type, riparian canopy, altitude, temperature and bank protection, on larval chironomid assemblage was investigated in a Japanese basin. To focus on the macro-scale factors, a concrete block, as an artificial substrate, was used for chironomid collection so that sampling regime may be identical among the sites. Partial CCA using sampling month as a covariable revealed that topographic type, riparian canopy coverage, water temperature and altitude were the main factors influencing species distribution. Stempellinella tamaseptima, Polypedilum tamanigrum and five Rheotanytarsus species showed positive, whereas five Cricotopus species showed negative associations with canopy coverage. Some traditional longitudinal zonations of species were still shown. Chironomus flaviplumus and Chironomus yoshimatsui were merely associated with lower reaches. Stepwise multiple regressions of the assemblage indices on the environmental variables were applied. Bank protection and depth showed negative correlations with Shannon diversity H′. Both topographic type and depth showed negative correlations with Pielou equitability J. Topographic type (lower reach) and specific conductance showed positive, while bank protection showed a negative correlation with abundance. Species richness was not explained by any variables. As a whole, topographic type was the most directly related factor to chironomid assemblages.     

Incidence of Mentum Deformities in Midge Larvae (Diptera:Chironomidae) from Northern Nova Scotia, Canada

Deformities in the mouthparts of larval Chironomidae, particularly of the teeth on the mentum, have been proposed as a bioindicator of sediment quality and environmental stress. Most work to date has concentrated on relatively few abundant, responsive genera common in soft-bottom lakes. We examined mentum deformities in 25 genera of Chironominae, Orthocladiinae and Diamesinae (one genus) from streams and a lake in rural Nova Scotia where farming and forestry are the principal land uses. Incidence of deformity at similar stream sites varied across genera from zero to >10%. Average frequencies of deformity across all three subfamilies at sites with no known sources of contamination ranged from <4% to 8%, and increased to nearly 15% at a site receiving treated municipal sewage effluent. Differences in chironomid community structure and rates of leaf litter decomposition above and below the sewage effluent outfall were congruent with the difference in mentum deformities. Frequencies of deformity observed here are an order of magnitude greater than in similar studies of rural areas. Low-level stress from agriculture or forest harvesting may be widespread in rural regions even in aquatic ecosystems that are seemingly free of industrial discharges or sediment contamination.     

Colonization and emergence of midges (Chironomidae: Diptera) in slow sand filter beds

Colonization by midges, and temporal changes in their community structure, were examined in slow sand filter beds. The replicated beds allow the development of communities to be traced from a known starting point.The filter beds (rectangular concrete containers filled with water) have a substratum of sand on which a rich coating of organic particles develops during passage of the water through the bed. The containers (ponds) are drained from time to time and the organic layer is then scraped off the sand surface. This occurs on average, once a month. The length of time the ponds were filled with water (bed run) during the present study ranged from 16 to 77 days.In long bed runs small midges with a short aquatic phase (Cricotopus sylvestris, Psectrocladius limbatellus, Tanytarsus fimbriatus) produced adults after 16–20 days; other, larger midges,e.g. Psectrocladius barbimanus and the Tanypodinae required a longer aquatic phase. Of the Tanypodinae, the smallAblabesmyia phatta, had the shortest duration of the four species found, and was much the most numerous member of this subfamily. Some Chironomini only appeared when the organic coating had developed over the sand surface. Midges of this tribe frequently failed to complete their larval development within the duration of bed runs and were thus trapped on the substratum at the time of cleaning. When ponds were drained after short bed runs the succession in community structure observed in long runs was arrested.Three small midgesC. sylvestris, P. limbatellus andT. fimbriatus, were collected in high numbers throughout the life of all beds, except towards the end of the longest runs in the study. This suggests that small size, short life cycles, and the ability to colonize clean substrata, are important characteristics for the development of primary chironomid communities in short-lived temporary habitats.     

A new genus and species of Chironominae (Diptera: Chironomidae) with wood-mining larvae

Abstract  Xylochironomus kakadu , a new genus and species of wood-mining chironomid, is described from northern Australia. Formerly known by a code 'unknown genus K1', the larvae mine soft immersed timber in tropical Australia. The basal striae on the larval mandible are observed otherwise only in Chironomus Meigen and likely close relatives currently placed in Einfeldia Kieffer. The adult male could key as a tanytarsine, and all stages superficially resemble Polypedilum Kieffer, except for the bare squama and the non-tapered male tergite VIII, and the dorsal larval head sclerites. However, analyses of a morphological data matrix derived from all life history stages support no such relationships. Instead, a relationship to Paralauterborniella Lenz and Apedilum Townes, and at one remove, to Fissimentum Cranston & Nolte and Imparipecten Kieffer is postulated. Larval wood-mining among the early branching Chironomini is evidently frequent, but taxa appear not to form a monophyletic clade.     

Six new and two newly recorded species of Chironomidae (Insecta: Diptera) in Korea

Adult chironomids were collected by light trap operations, sweeping grasses with insect nets, and aspiration of light‐attracted adults at various localities. All collected specimens were slide‐mounted and identified. Six species new to science were found and named: Rheotanytarsus pseudopentapoda n. sp., Cricotopus byeonsanensis n. sp., Cricotopus parajogantertius n. sp., Limnophyes bukhandecimus n. sp., Limnophyes simensis n. sp. and Orthocladius jeongnungensis. Two species, Ainuyusuroka tuberculatum (Tokunaga) and Pseudosmittia nishiharaensis Sasa and Hasegawa, are found for the first time in Korea. All species are fully described with illustrations. This is the first report of the genus Ainugusurika in Korea.     

不同营养类型水库大型底栖动物的群落结构特征及其水质评价

2006～2007年对湖北省4座不同营养类型水库的大型底栖动物群落结构和多样性进行周年研究,并进行了水质评价.共采集到底栖动物39种,其中寡毛类14种、水生昆虫19种、软体动物6种.以金沙河的底栖动物种类最多,达24种,其次为徐家河19种,道观河和桃园河各10种.4座水库优势种类各异,金沙河为多毛管水蚓(Aulodrilus pluriseta)、隐摇蚊(Cryptochironomus sp.)、多足摇蚊(Polypedilum sp.);徐家河为瑞士水丝蚓(Limnodrilus helveticus)、前突摇蚊(Procladius sp.);桃园河为多毛管水蚓(Aulodrilus pluriseta)、长跗摇蚊(Tanytarsus sp.);水质污染比较严重的道观河水库优势种类为霍甫水丝蚓(Limnodrilus hoffmeisteri)、大红德永摇蚊(Tokunagayusurika akamusi).各库底栖动物年平均密度和生物量分别为:金沙河316 8ind · m-2,1294.3mg · m-2 ;道观河318.2ind · m-2,430.7mg · m-2 ;徐家河330.3ind · m-2,517.4mg · m-2;桃园河209ind · m-2,325 3mg · m-2 .TN、TP、COD平均含量变幅分别为0.392～1.018、0.011～0.042、3.505～9.166mg · L-1;采用理化分析、Goodnight-Whitley指数、Shannon-Wiener指数、Margalef指数、Simpson指数、Pielou均匀度指数对水库的水质进行了综合评价,结果表明:金沙河水库属中营养型;徐家河和桃园河属中-富营养型;道观河水库属富营养型.对水库主要的物理化学因子与寡毛类、水生昆虫、软体动物密度,以及各类底栖动物之间进行矩阵分析,发现水生昆虫与水深呈负相关关系,随着水深的增加,其密度和种类下降,水深超过10m,下降的幅度更明显;寡毛类有从属于TN和TP含量的趋势, TP变化对底栖动物的影响更大;寡毛类、水生昆虫、软体动物三者之间无相关性.     

The distribution of Heterotrissocladius oliveri Saether (Diptera: Chironomidae) in Lake Michigan

Fifty one chironomid species were identified from 504 samples collected at depths ranging 8 to 267 m in Lake Michigan, U.S.A. Heterotrissocladius oliveri Saether occurred in 32% of these samples and had an average abundance of 22 m^–2 which was similar to other estimates from the Great Lakes. Maximum average lake-wide density was at 30 to 60 m (41 m^–2). At depths 60 m, H. oliveri was the dominant chironomid species comprising 75% of total Chironomidae. The substrate preference of H. oliveri differed within each depth regime considered: at 30–60 m, 2–3 ; at 60–120 m, 3–5 , 7–9 ; and at 120–180 m, 6–8 . Abundance was notably reduced at all depths in substrates characterized as medium silt (5–6 ). On a lake-wide basis, the distribution pattern suggested H. oliveri was most numerous from 30 to 60 m along the southwestern, eastern, and northern shorelines and at 60–120 m depths along the southern and eastern shorelines. Increased abundance in the South Basin was concurrent with evidence of increased sedimentation at 60 to 100 m. However, in several other areas of the lake, high densities were associated with medium to very fine sands relatively free of silts and clays. This observation suggested occurrence of H. oliveri was minimally affected by sediment type.Widely variable, but generally elevated water temperatures likely prevent H. oliveri from establishing a substantial population density at depths < 30 m. With increased depth, temperature fluctuation is negligible and food is more stable, though the source is variable. Factors limiting abundance of H. oliveri at depths 30 m were related to decreased food supply due to distance from shore, food sources of lower value (clays), and, most importantly, to reproductive replenishment.Although still oligotrophic in nature, high density occurrences in both high and low sedimentation areas of the lake suggest the trophic indicator status of H. oliveri might be broader than previously thought.     

New species and records of Neotropical Cardiocladius Kieffer, 1912 (Diptera: Chironomidae,Orthocladiinae)

Cardiocladius moreloensis sp. n. is described and figured based on adult males collected in Morelos State in Mexico. Males of C. brasiliensis Oliveira, 1949 and C. travassosi Oliveira, 1951 are redescribed and figured based on new material from São Paulo State in Brazil. The generic diagnosis is expanded, and a key to the males of the Neotropical Cardiocladius species is presented.

http://zoobank.org/urn:lsid:zoobank.org:act:EE8B2267-3362-4A1F-BED6-0A1E35D7D480     

Identification of instars and species in some larval Polypedilum (Polypedilum) (Diptera: Chironomidae)

Instars II and III of Polypedilum aviceps Townes, Polypedilum convictum (Walker), and Polypedilum illinoense (Malloch) can be identified to species by associating them with instar IV because key taxonomic characters remain relatively unchanged from instar to instar. Instars I cannot be identified to species or genus unless they are associated with older, identifiable larvae reared from the same egg masses. No single character evaluated on slide material can be used to clearly separate instars in all three species. Larvae of P. aviceps can be separated into instars based on any four of seven characters; P. convictum by either of two characters; and, P. illinoense by a combination of two characters. Changes in structures of instars II, III, and IV are described for all three species. Growth ratios for some structures are compared and discussed with regard to Dyar's Rule.     

The evolutionary history of two species of Orthocladiinae (Diptera: Chironomidae) from Lake Baikal (Eastern Siberia)

The evolutionary history of two species belonging to the genus Orthocladius van der Wulp, 1874 van der Wulp, F.M. (1874), ‘Dipterologische Aanteekneningen’, Tijdschrift voor Entomologie, 17, 109–148. [Google Scholar] (Diptera: Chironomidae) from Lake Baikal was investigated using the mitochondrial gene coding the first subunit of the cytochrome c oxidase (CO1 mtDNA). The phylogenetic analysis indicated that the Baikal Orthocladius species were divided into two well-defined clades where O. (Orthocladius) gregarius Linevitsh, 1970 was a sister species to Palaearctic O. (Orthocladius) nitidoscutellatus Lundstrom, 1915 and the O. (Eudactylocladius) sp. was a sister species to Nearctic O. (Eudactylocladius) subletteorum Cranston, 1998 Сranston, P.S. (1998), ‘Nearctic Orthocladius Subgenus Eudactylocladius Revised (Diptera: Chironomidae)’, Journal of the Kansas Entomological Society, 71(3), 272–295.[Web of Science ®] , [Google Scholar]. Divergence time estimates indicated that these species had been evolving independently for about 18 Ma (Neogene, Early Miocene), while emergence of the most recent common ancestors of the modern O. (Orthocladius) gregarius and O. (Eudactylocladius) sp. was dated to about 3.5 Ma (Neogene, Pliocene). The evolution of Baikal orthoclads occurred from the rheophilic fauna under conditions of global climate change during the geological history of the Baikal Depression in the Tertiary Period.