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.     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

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     

Distribution and production of chironomids (Diptera: Chironomidae) in a shallow, alkaline lake (Neusiedler See, Austria)

From July 1990 to July 1991 the benthic community of the open water zone of Neusiedler See, one of the largest shallow lakes in central Europe, was studied with special reference to the chironomids. Only 16 spp. of chironomids inhabited the sediment of the open water zone. The numerically dominant species were Tanypus punctipennis, Procladius cf. choreus, Microchironomus tener and Cladotanytarsus gr. mancus. Most invertebrates showed a distinct horizontal distribution. Species richness and abundance were highest on muddy and organically rich substrates near the reed belt. Chironomid densities in this area reached 54,000 ind m^–2 and biomass was 2.0 g dw m^–2. The two tanypod species accounted for more than 90% of the standing stock of the macrozoobenthos near the reed belt. The sediment of the open lake and of the eastern part of Neusiedler See was composed of compact clay and sand as a result of the erosion of fine material due to strong waves and currents. Individual densities in these areas were much lower. Production of the numerically dominant species T. punctipennis was estimated using the increment-summation method, whereas production of the remaining species was estimated using an empirically derived multiple regression. Mean annual production of chironomids exceeded 6 g dw m^–2 yr^–1 near the reed belt, but it reached only 0.55 g dw m^–2 yr^–1 in the open lake. These values are rather low compared with other lakes and can be explained by unfavourable sediment conditions due to wave action and by physiological stress due to the water chemistry.     

Effects of fish predation on larval chironomid (Diptera: Chironomidae) communities in an arctic ecosystem

Chironomid communities were analyzed in systems with three types of predator regimes to determine hierarchical effects of predation; ponds without fish present, lakes with slimy sculpin (Cottus cognatus) present, and lakes with slimy sculpin present along with burbot (Lota Iota) and lake trout (Salvelinus namaycush). Samples were collected by coring bare sediment habitats in 4 systems of each type near the Toolik Lake field station in northern Alaska. Lakes with burbot and lake trout present in addition to slimy sculpin displayed significantly higher (P<0.05) biomass, density, richness, and diversity. This is likely due to the increased complexity of the predator regime. Ponds without fish had a significantly greater percentage of predacious chironomids present.     

The oldest known chironomids of the tribe Tanytarsini (Diptera: Chironomidae) indicate plesiomorphic character states

Taxonomic studies on chironomids of the tribe Tanytarsini recorded in Eocene Baltic amber from the Rovno region have revealed two new species: Archistempellina perkovskyi and Stempellinella ivanovae. Both species display interesting characters supporting evolutionary trends in the tribe. A. perkovskyi nov. sp. combines plesiomorphic characters, thus consolidating the hypothesis that the genus Archistempellina is one of the basal lineages of the tribe Tanytarsini. The antennal flagellum composed of 13 discernible segments found in S. ivanovae nov. sp. is defined as a plesiomorphic character state opposite to a reduced number of flagellomeres in extant species; the nipple-like process on the apex of the gonostylus is recognised as a unique character in the Tanytarsini and a possible homologue of the horn-like tip of the gonostylus known from several extant species of the genus Stempellinella Brundin. A key to determination of all genera and species of the Tanytarsini recorded in the Eocene is presented. Notes on evolutionary trends in the tribe are also provided.     

Impact of long-term alternations of discharge and spate on the chironomid community in the lowland Widawka River (Central Poland)

Spatial and temporal distribution, abundance and production of macroinvertebrate communities were estimated over two years in a fifth-order section of the Widawka River. Discharge of this river has been increased artificially by coal mine water inputs. Additionally, during the second year, one of the highest discharges of the current 20-year period was recorded. Chironomidae were co-dominant in macrobenthos, both in a straight reach (WIA) and in a meandering site (WIB). More mosaic habitats resulted in higher densities of midges, reaching 6215 ind.m^–2 in year 1 and 1141 ind.m^–2 in year 2 at WIA, while at WIB 896 densities were ind.m^–2 and 257 ind.m^–2, respectively. Flooding affected the distribution and abundance of the chironomid assemblages. Recolonization by psammophilous Polypedilum began after the various microhabitats were buried with sand. Chironomid production was estimated on a species-specific basis for the dominant taxa. In year 1 (mean annual water temperature 10.0° C) chironomid production was 12.4 g dry wt m^–2 yr^–1 1 at WIA and 1.9 g dry wt m^–2 yr^–1 at WIB. These values sharply decreased in year 2 (mean annual water temperature 9.8° C) reaching 1.9 g dry wt m^–2 yr^–1 at WIA and 0.4 g dry wt m^–2 yr^–1 at WIB, as effects of the high spate.     

Phenology and life history of Belgica antarctica, an Antarctic midge (Diptera: Chironomidae)

ABSTRACT.

• 1 An account of the life-history with emphasis on phenology and number of instars is presented for Belgica antarctica Jacobs, the southernmost holometabolous insect.
• 2 Contrary to earlier reports, Belgica has four instars, in common with most other chironomids. Mean head capsule lengths varied between different populations but no overlap was found between discrete size classes of successive instars.
• 3 Belgica overwinters in all four instars.
• 4 Relative frequency of different instars from samples taken through the season indicates that a 2-year life-span is the commonest pattern.
• 5 Emergence of adults is relatively synchronous. Belgica exhibits protandry, which may be established at the time of pupation.

     

Spatial distribution and diversity of chironomid assemblages in a small hilly stream (Diptera: Chironomidae)

In 2006–2007, spatial variations of chironomid assemblages of a small chalky watercourse were investigated in the hilly region of Balaton Upland, Hungary. Samplings were carried out every three weeks at seven characteristically different sites along the whole length of the watercourse. Altogether 2966 specimens were collected and identified. The chironomid fauna of the stream was relatively rich with 40 taxa belonging to four subfamilies (eight Tanypodinae, one Prodiamesinae, 17 Orthocladiinae, 14 Chironominae). The lowest number of species and number of individuals was found at the spring, and the highest at the middle reach. Based on multivariate analysis the different sections of the creek were characterised by distinctive chironomid communities. Although longitudinal changes in the chironomid community of the Örvényesi creek were detectable due to changes in natural environmental factors, land-use changes also significantly influenced the chironomid community composition and diversity. The natural and anthropogenic effects were hardly distinguishable. Furthermore, we found that the response of different diversity indices to environmental variability was different. This draws attention to the difficulties in evaluating the relationships between stream communities and environmental variables using different diversity indices. The taxonomic diversity, which incorporates the taxonomical relationships between the specimens, proved to be one of the most useful diversity indices to characterise the stream chironomid assemblages.