Distribution Of Chironomid Larvae Research Articles

Surveillance spilled Chironomidae (Diptera) larvae from drinking water treatment plants in South Korea using morphogenetic species analysis and eDNA metabarcoding

Chironomid larvae (Diptera: Chironomidae) are tremendous indicator species that can tolerate a broad range of environmental conditions, from polluted to unimpaired water ecosystems. These species are ubiquitously observed in all bioregions and can even be found in drinking water treatment plants (DWTPs). Detection of chironomid larvae in DWTPs is a critical issue because their presence may be indicative of the water quality in the supply of tap water for human consumption. Therefore, the aim of the present study was to identify the chironomid communities that reflect the water quality of DWTPs and develop a biomonitoring tool to detect biological contamination of the chironomids in DWTPs. To do so, we investigated the identity and distribution of chironomid larvae in seven DWTP areas using morphological identification, DNA barcoding, and sediment environmental DNA (eDNA) analysis. A total of 7924 chironomid individuals encompassing three subfamilies and 25 species of 19 genera were identified in 33 sites within the DWTPs. The Gongchon and Bupyeong DWTPs were dominated by Chironomus spp. larvae, which were correlated with low levels of dissolved oxygen in the water. In the Samgye DWTP and Hwajeong DWTP, Chironomus spp. were almost absent, and instead, Tanytarsus spp. were abundant. Additionally, the Gangjeong DWTP was dominated by a Microtendipes sp., and two species of Orthocladiinae (a Parametriocnemus sp. and a Paratrichocladius sp.) were found only in the Jeju DWTP. We also identified the eight most abundant Chironomidae larvae found in the DWTPs. Furthermore, eDNA metabarcoding of DWTP sediment indicated the presence of different eukaryotic fauna and confirmed the presence of chironomids in DWTPs. These data provide useful morphological and genetic information regarding chironomid larvae that can be used for the water quality biomonitoring of DWTPs to support the supply of clean drinking water.

Influence of Pools and Riffles on Chironomidae Diversity in Headwater Streams of the Atlantic Forest.

Studies on mesohabitat scale have been used to shed light on the ecology and distribution of chironomid larvae in small streams. Thus, the objective of the present study was to examine the diversity and distribution of the Chironomidae assemblage on the mesohabitat scale in three streams located in different preserved areas of southeastern Brazil. In each stream, litter samples were obtained in the dry season of 2010 in ten pools and ten riffles with a Surber sampler (area 0.04m(2); mesh size 0.21mm). The abundance was similar among streams and between mesohabitats, while the estimated richness was highest in riffles. There was a difference in the composition of the Chironomidae assemblages between the mesohabitats, although the litter composition was similar between them, indicating the importance of current speed on the distribution of the taxa. The dispersion of the sample units (β-diversity) of riffles and pools was similar, although it was different among the three streams. The results of this study provide further evidence of the importance of habitat heterogeneity within streams as a generator of diversity for Chironomidae in tropical lotic systems.

Multi-scale approach to the environmental factors effects on spatio-temporal variability of Chironomus salinarius (Diptera: Chironomidae) in a French coastal lagoon

Abstract The complexity of the relationships between environmental factors and organisms can be revealed by sampling designs which consider the contribution to variability of different temporal and spatial scales, compared to total variability. From a management perspective, a multi-scale approach can lead to time-saving. Identifying environmental patterns that help maintain patchy distribution is fundamental in studying coastal lagoons, transition zones between continental and marine waters characterised by great environmental variability on spatial and temporal scales. They often present organic enrichment inducing decreased species richness and increased densities of opportunist species like Chironomus salinarius, a common species that tends to swarm and thus constitutes a nuisance for human populations. This species is dominant in the Bolmon lagoon, a French Mediterranean coastal lagoon under eutrophication. Our objective was to quantify variability due to both spatial and temporal scales and identify the contribution of different environmental factors to this variability. The population of C. salinarius was sampled from June 2007 to June 2008 every two months at 12 sites located in two areas of the Bolmon lagoon, at two different depths, with three sites per area–depth combination. Environmental factors (temperature, dissolved oxygen both in sediment and under water surface, sediment organic matter content and grain size) and microbial activities (i.e. hydrolase activities) were also considered as explanatory factors of chironomid densities and distribution. ANOVA analysis reveals significant spatial differences regarding the distribution of chironomid larvae for the area and the depth scales and their interaction. The spatial effect is also revealed for dissolved oxygen (water), salinity and fine particles (area scale), and for water column depth. All factors but water column depth show a temporal effect. Spearman's correlations highlight the seasonal effect (temperature, dissolved oxygen in sediment and water) as well as the effect of microbial activities on chironomid larvae. Our results show that a multi-scale approach identifies patchy distribution, even when there is relative environmental homogeneity.

The distribution of chironomid larvae and oligochaetes within a stony-bottomed river stretch: the role of substrate and hydraulic characteristics

Combined oligochaete and chironomid data were analyzed to search for main gradients and the separate data sets were analyzed to identify the most important variables determining the structure of the communities. Preferences for particular hydraulic conditions, expressed as Froude number, were calculated for 29 most abundant taxa. The results of Correspondence Analysis (CA) indicated that the main gradient in the data could be explained by hydraulic conditions and, inversely, by the amount of sedimented particulate organic matter (POM). The second CA axis probably reflected the quantity of the available food and space resources. Canonical Correspondence Analysis (CCA) showed the amount of sedimented POM as the most important variable explaining 21 and 24 % of the variance in the oligochaete and chironomid data respectively. Among the other variables, the occurrence of aquatic vegetation, variability of nearbottom current velocity and substrate roughness were the most important.

Diversity and Distribution of Chironomid Larvae in Wetlands in Southern Brazil

Chironomidae is a cosmopolitan family of dipteran insects occurring in all zoogeographical regions of the world. The family is quite diverse and the objective of this study was to examine diversity of chironomid larvae in 115 wetlands in an extensive area of Neotropical region (∼220,000 km2, southern Brazil) by analysis of richness and composition in different wetland subsystems, types and classes. Also examined were effects of wetland area, altitude, water conductivity and nutrients on these community descriptors. A total of 36 genera was found, with Chironominae showing the greatest richness, followed by Tanypodinae and Orthocladiinae. The richness and composition changed between wetland subsystems, types and classes. However, no single parameter strongly influenced the chironomid richness and composition in this broad spatial scale survey. The broad spatial scale and details of this study make it an important contribution to knowledge of chironomid diversity in the Neotropical region.

Distribution of Chironomid Larvae in Bottom Grounds of Rivers of the Timan Ridge Area (Komi Republic)

Distribution of Chironomid Larvae in Bottom Grounds of Rivers of the Timan Ridge Area (Komi Republic)

9 茨城県北浦におけるユスリカ幼虫の水平分布

9 茨城県北浦におけるユスリカ幼虫の水平分布

Temporal and spatial distribution of chironomid larvae and oligochaetes in two Dutch storage reservoirs

Long-term changes in distribution and taxonomic composition of chironomid larvae and oligochaetes in two water storage reservoirs in The Netherlands were studied. A succession among the chironomid species was observed. In the last 10–15 years chironomid densities varied. Compared with other lakes chironomid densities were high. Densities of chironomids were higher in the littoral zone than in the profundal zone. The opposite was found for oligochaetes. Densities and composition of the chironomid fauna in the two reservoirs were similar.Procladius, Tanytarsus andHarnischia dominated at all depths. However, pupal exuviae samples showed some differences in chironomid taxonomic composition between the two reservoirs. Orthocladiinae, rarely found in bottom samples, abounded in pupal exuviae samples.

Interacting Influences of Density and Preference on the Emigration Rates of Some Lotic Chironomid Larvae (Diptera:Chironomidae)

The effects of manipulations of density and sediment type on the emigration rates of chironomid larvae (Diptera:Chironomidae) from Hunt Creek, Montmorency County, Michigan, USA, were examined in artificial stream chambers. Both basic sediment suitability and population density were found to affect larval emigration rates. Furthermore, their interaction lead to rates of emigration not predictable from an examination of either factor alone. A simple model of habitat suitability was developed and fit to the experimental data. The fitted model provided estimates of habitat carrying capacities for two important chironomid species and for a generalized chironomid assemblage. A comparison of these estimates with observed field densities indicated that competitive displacement of individuals probably occurs regularly in sand sediments. An examination of field data from 1975—1976 revealed a suppression of species diversity and of competitor standing crops by the dominant sand species. Together these results suggest that competitive interactions have an important influence on the spatial distribution of chironomid larvae in Hunt Creek.

The distribution of Chironomid larvae in relation to Chloride concentration in a brackish water region of the Netherlands

Drainage ditches are a familiar and common habitat in the Netherlands. Until recently however they have been the focus of few ecological studies. Extensive studies on Walcheren, a brackish water region of The Netherlands, have shown that chironomid larvae form a major component of the animal communities in the mud. The spatial distribution of some of these species can be correlated with the chloride concentration of the water. Biometric data are included for the speciesChironomus salinarius, C. halophilus andC. plumosus.

Core Sampling and Flotation: Two Methods to Reduce Costs of a Chironomid Population Study

On estimating the number of Chironomid larvae of a sampling area in an oligotrophic lake (sieving mesh 0.25 mm), sorting time was reduced by 82 % and total sampling cost in an example by 88 %, using core sampling instead of Ekman sampling and sorting after benzene flotation, without loss in precision. The result also showed a dependence between the sorting techniques used (flotation and hand-sorting) and the size distribution of Chironomid larvae, indicating a greater efficiency of the flotation method for small specimens.