Chironomus Larvae Research Articles

The effect of feed larvae Chironomus sp. and high pellet protein to seedling goldfish (Carassius auratus)

Goldfish production increase in four years, specifically 66,823,000 in 2010 to 72,997,000 in 2014. The increment of goldfish production growth altogether with problems which is a discontinuity of fry stock. The solution for this problem is the purpose of this study, which is understood techniques in Goldfish (Carassius auratus) hatchery. The feed given to goldfish brood is blood worms (Chironomus sp. larvae) and pellets with a ratio of 50:50 as much as 3% of the biomass. Goldfish hatchery techniques involve broodstock cultivation, spawning techniques, larval development observation, and larval cultivation. Two kinds of Goldfish used, namely Oranda and Mutiara Goldfish. The results of Oranda goldfish spawning and Mutiara goldfish spawning consecutively are Fecundity 875 eggs, FR 94%, HR 91.83%, SR 93.04% and Fecundity 3850 eggs, FR 93.66%, HR 92.48%, and SR 91.10%. Larval development observation includes embryogenesis until post-hatched larval. Larval cultivation consists of giving various types of feeds, which are artemia nauplii (for 3-7 days old larval), Moina (for 7-14 days old larval), and blood worm or tubifex (> 14 days old larval). Fertilized goldfish eggs will develop through several phases, including zygotes, initial cleavage, blastula, gastrula, segmentation, pharyngula, egg hatching, and development of larvae after hatching.

Macroinvertebrate structure and diversity in nutrient-rich ephemeral pools in Delta State University, Abraka, Nigeria

This study used the Macroinvertebrate fauna to assess the ecological status and uniqueness of temporary, ephemeral pools in Delta state university, Abraka from 26th to 28th of October 2018, using standard methods. Among the studied environmental parameters, nitrate alone was significantly different among the pools (p<0.05). The pools macroinvertebrates handicapped supported seventeen taxa only from sixteen (16) families with a total of 460 individuals belonging to Odonata (28.91%) Oligochaeta (26.09%), Diptera (24.57%) Hemiptera(12.39),Gastropoda (4.35%), Coleoptera(3.48%), and Arachnida (0.22%) in order of dominance. The pools macroinvertebrates dominated by the group odonatan of the class Insecta. (Lumbricus terrestis Linnaeus 1758) (pollution-sensitive) found dead in the pools, low diversity indices(total taxa, Margalef index, dominance, and the Shannon diversity index), the occurrence and predominant of chironomus larvae (pollution-resistant worms) at the species level (24.57%) sign deteriorated water quality. The high number of resistant blood worms, low numbers of Gyrinus and Coleoptera is suggestive that they are suitable biological indicators of high concentration of the studied parameters in the pools and thus can be bioindicators of impaired water bodies.

Prey selectivity and the effect of diet on growth and development of a dragonfly, Sympetrum sanguineum.

Despite a long tradition of research, our understanding of mechanisms driving prey selectivity in predatory insects is limited. According to optimal foraging theory, predators should prefer prey which provides the highest amount of energy per unit time. However, prey selectivity may also depend on previous diet and specific nutritional demands of the predator. From the long-term perspective, diet composition affects predator fitness. An open question is whether short-term selectivity of predators provides a diet which is optimal in the long-term. To shed more light on these issues, we conducted laboratory experiments on prey selectivity and its long-term consequences in larvae of the dragonfly Sympetrum sanguineum. We conditioned the larvae to one of two prey types, the cladoceran Daphnia magna and larvae of a non-biting midge Chironomus sp., and then exposed them to various combinations of the two prey types. We found that dragonfly larvae conditioned to Chironomus larvae consumed the same amount of D. magna, but significantly less Chironomus larvae compared to dragonfly larvae conditioned to D. magna. However, there was no effect of previous diet on their success of capture and handling time, suggesting a limited role of learning in their ability to process prey. We then tested the long-term effects of diets with different proportions of both prey for survival and growth of the dragonfly larvae. Individuals fed Chironomus-only diet had higher mortality and slower growth than dragonflies fed D. magna, while larvae fed a mixed diet had the highest survival and growth rate. In conclusion, we show that dragonfly larvae fed by Chironomus larvae performed poorly and compensated by preferring D. magna when both prey types were available. The superiority of the mixed diet suggests that a diverse diet may be needed to satisfy nutritional demands in S. sanguineum larvae. We demonstrate that merging short-term predation experiments with relevant data on predator fitness may provide better understanding of predator-prey interactions and conclude that detailed information on the (mis)matches between prey composition and predator nutritional demands is needed for further progress.

Chronic Toxicities of Neonicotinoids to Nymphs of the Common New Zealand Mayfly Deleatidium spp.

Neonicotinoid insecticides have been shown to have high chronic toxicity relative to acute toxicity, and therefore short-term toxicity tests ≤96 h in duration may underestimate their environmental risks. Among nontarget aquatic invertebrates, insects of the orders Diptera and Ephemeroptera have been found to be the most sensitive to neonicotinoids. To undertake a more accurate assessment of the risks posed by neonicotinoids to freshwater ecosystems, more data are needed from long-term tests employing the most sensitive taxa. Using nymphs of the common New Zealand mayfly genus Deleatidium spp., we performed 28-d static-renewal exposures with the widely used neonicotinoids imidacloprid, clothianidin, and thiamethoxam. We monitored survival, immobility, impairment, and mayfly moulting propensity at varying time points throughout the experiment. Imidacloprid and clothianidin exerted strong chronic toxicity effects on Deleatidium nymphs, with 28-d median lethal concentrations (LC50s) of 0.28 and 1.36 µg/L, respectively, whereas thiamethoxam was the least toxic, with a 28-d LC50 > 4 µg/L (highest concentration tested). Mayfly moulting propensity was also negatively affected by clothianidin (during 3 of 4 wk), imidacloprid (2 of 4 wk), and thiamethoxam (1 of 4 wk). Comparisons with published neonicotinoid chronic toxicity data for other mayfly taxa and larvae of the midge genus Chironomus showed similar sensitivities for mayflies and midges, suggesting that experiments using these taxa provide reliable assessments of the threats of neonicotinoids to the most vulnerable freshwater species. Environ Toxicol Chem 2019;38:2459-2471. © 2019 SETAC.

Morphological characterization of Chironomidae (Diptera) larvae in Anzali Wetland, Southwest Caspian Sea: First record of Chironomus plumosus

Chironomids (Diptera) include the most abundant group of macroinvertebrates. They are usually collected from aquatic environments for quality evaluation. Tolerant aquatic organisms such as Chironomids are more abundant in polluted sites. This note makes the Chironomids as an excellent bioindicators. This group is not characterized in Anzali Wetland as well. So that, the aim of this study was to recover and characterize chironomidlarvae in this wetland. Hence, Chironomidlarvae were collected on the seasonal basis from 13 stations in the wetland. The main characteristics for their identification were eye spot, mentum, ventromental plate, antenna, and ventral tubules. The mitochondrial cytochrome oxidase I (COI) gene was applied to simplify the identification of Chironomus species by polymerase chain reaction (PCR) and sequencing method. The nucleotide sequence alignments were used for construction of the phylogenetic trees based on maximum likelihood method. Six genera were identified in three subfamilies, including: Chironominae (1 genus), Orthocladinae (1 genus), and Tanypodinae (4 genera). Based on ventral tubules, the dominant population of Chironomus larvae found in this study, lie in thummi and plumosus types. Five genera were reported for the first time from Anzali Wetland. The dominant genus was Chironomus. These groups of larvae were ultimately identified as Chironomus plumosus reporting for the first time from the wetland. It was also found that the Chironomids diversity is higher than those described in few studies before, however, further studies are still needed.

An Approach to Measure the Biomass of Bloodworms (Diptera: Chironomidae) in Different Nutrients

Due to their rich nutrient content, late stage Chironomus larvae or bloodworms are considered as the most preferred natural food source of cultured fish. However, it is not popular due to its high cost and low availability. Bloodworm culture is still in its infant stage and mainly therefore harvested from nature. The objective of the study was to achieve a cost-effective culture practice of this insect under laboratory conditions. For this experiment four types of diets were selected, namely, dried potato peel powder (F1), commercial baker’s yeast powder (F2), a mixed culture medium (F3) and commercial fish food powder (F4) along with a control culture medium. The result showed a significant effect of diet on both wet mass [F = 40937.78 > F0.01 (3, 8)] and biomass [F = 13882.84 > F0.01 (3, 8)] of bloodworms. The biomass was almost similar when larvae were fed commercial fish food and mixed diet respectively, but the mixed diet was more cost effective and a rich source of both carbohydrates and protein.

Induction of Deformities of the Hard-Chitinized Mouthpart Structures of Larvae Chironomus riparius Meigen under Various Contents of Persistent Organic Substances in Bottom Sediments

It is shown that the number of deformations of mouthpart structures of larvae Chironomus riparius reflects the potential danger of contaminated bottom sediments and can serve as a good biomarker when monitoring the ecological status of freshwater ecosystems. The method of quantification of the deformation rate of hard-chitinized structures (mentum and mandibles) has been approbated. It has been revealed that the total amount of polychlorinated biphenyls in bottom sediments affects the portion of larvae with multiple deformations and the relative number of larvae with deformations of mentum and mandibles. Examples of calculating the index of the morphological response of hard-chitinized mouthpart structures of chironomid larvae exposed to bottom sediments with various contents of persistent organic substances are given.

Comparative susceptibility of Chironomus and Drosophila to exposure to each and combinations of the following stressors: desiccation, heat stress and starvation

In natural ecosystems, organisms are usually subject to environmental stress. In order to understand the response to a combination ofthree stressors (desiccation, heat stress and starvation), two dipteran insects, Chironomus ramosus (aquatic) and Drosophila melanogaster(terrestrial) were chosen, the former being more primitive than the latter. The mortality level as a function of the duration of the exposureto stress revealed that these two evolutionarily distinct and ecologically diverse insects differ in their response. Interestingly, when thetolerance thresholds of C. ramosus and D. melanogaster to single and multiple stressors was compared, a synergistic effect was recordedwith much higher levels mortality occurring when subjected simultaneously to several stressors. Chironomus larvae were more vulnerablethan Drosophila larvae when subjected to all three stressors simultaneously. The findings of this pilot study indicate the ecological risk formacro-invertebrate biota posed by adverse environmental conditions.

Determination of favourable biotechnological conditions for Chironomus larva cultivation and development

The cultivation of Chironomus larva under artificial conditions needs necessary conditions in the vivarium to provide the biological characteristics of its reproduction, growth and development. Chironomus larva is biologically valuable feed and source of protein for many young species of fish. Being the natural feed it is of great demand now days. The article presents the research results connected with the optimal water mass ratio and the nutrient medium for Chironomus larva. It has been prouved that the auxiliary agents have positive influence on Chironomus mosquitoes egg laying. The study has been conducted in the vivarium of Bila Tserkva NAU Research Institute of Food and Animal Products Processing Technologies. The observation methods and statistical techniques have been used to establish the optimal technological parameters. It has been scoped that Chironomus larva survives better in the nutrient medium, where the water mass ratio of silt is 1:5 and 1:6. There is a bigger amount of larva survival in these examples (in 5.6% times) in comparison with the control group (the ratio of water to silt is 1:2). There is the biggest amount of Chironomus larva deathratein the medium with the water mass ratio of silt 1:1. The use of auxiliary agents in the nutrient medium has a positive effect on Chironomus egg laying. After washing the nutrient medium, it was found that the optimal amount of auxiliary agents was 40 items bigger (20 floating and 20 immersed in sludge), but their use allows to increase the number of eggs laid in 1.2 times. Key words: silt, cultivation biotechnology, Chironomus, larvae, auxiliary agents, water to silt ratio, the survival of Chironomus larvae, water.

Comparison of the propensity to drift for three invertebrate taxa: a laboratory study

Invertebrate drift is an important ecological process but factors affecting the downstream transport of invertebrates are difficult to assess. The influence of water velocity on drift entry rates is still unclear and has rarely been quantified. In this study, conducted in spring and autumn, we investigated the drift propensity for different sizes of Baetis, Simulium and Chironomus larvae which, over a 24-h period, were subjected to low, moderate or high water velocities (14, 30 and 40 cm s−1, respectively) in either fine or coarse gravel beds. Interspecific differences were detected: Baetis drifted the most, Chironomus showed intermediate values and Simulium drifted the least. Chironomus was the only taxon that responded to water velocity. Baetis and Simulium were only slightly constrained to drift by the experimental conditions, while, in contrast, Chironomus larvae were very sensitive to flow increase. Substrate size (fine/coarse gravel bed) had no effect on any taxa. Small Simulium and Chironomus drifted more than larger ones. A seasonal effect was also detected, with Baetis drifting more in fall and Simulium drifting more in spring. Results suggest that community structure may be as or more important than hydraulics as a determinant of drift rates.

Is it justifiable to pool Chironomus species in trace element contamination studies?

Larvae of the insect Chironomus (Chironomidae: Diptera) have great potential for estimating the bioavailability of sedimentary trace elements because they are common in fine sediments and tolerate high concentrations of these contaminants. Their use as biomonitors is limited by the fact that they are difficult to identify as to species, and the species can differ in their trace element concentrations. To determine whether pooling species would compromise their use as trace element biomonitors, we identified species of Chironomus larvae collected from 22 lakes and measured their concentrations of 9 trace elements. We found that the concentrations of arsenic, barium, cobalt, copper, manganese, and nickel did not generally differ between sympatric Chironomus species, which indicates that they could be pooled for analyses of these trace elements. In contrast, we found that cadmium (Cd), selenium (Se), and zinc (Zn) concentrations differed between species living at the same site according to their feeding behavior, that is, Chironomus species feeding on oxic sediments tended to have higher Cd and Zn concentrations, whereas those feeding on deeper anoxic sediments had higher Se concentrations. Because Se and Zn concentrations in sympatric Chironomus species usually differed by only a factor of 2, separating species based on their feeding behavior might not be as crucial as for Cd if larval Se and Zn concentrations vary greatly from site to site. Environ Toxicol Chem 2019;38:145-159. © 2018 SETAC.

Rhabdostylid Ciliates (Ciliophora, Peritrichia, Epistylididae) as Epibionts on Chironomid Larvae: Evidence of High Specificity and Association with Organic Pollution.

Although epibiont ciliates make up a significant part of the biomass in aquatic ecosystems and may cause perceptible alterations in the population dynamics of their hosts, studies on the extrinsic and intrinsic factors that control the abundance of these microorganisms are scarce in literature. In the present study, we investigated the colonization site and intensity of rhabdostylid epibiont upon chironomid larvae and assessed the influence of organic pollution and chironomid communities on the prevalence and abundance of epibiont ciliates at five sampling stations (two in rural areas and three in urban areas) along a neotropical urban stream over a period of 12 months. Among the 24 genera of chironomids found and the 31,976 larvae analyzed, 96.12% belonged to the Chironomus genus, of which 16.95% (5212) were colonized by Rhabdostyla aff. chironomi. The infestation intensity varied from one to 67 individuals per host with an average intensity of 4.86 (± 33.45). Ciliates were only found colonizing the chironomids' ventral tubules. The high number of chironomid larvae, high host- and site-specificity, low infestation intensity, and absence of apparent structural damage to hosts evidence an intimate relationship between epibiont and basibiont as well as a possibly long coevolutionary history. Both prevalence and abundance of epibiont ciliates were correlated to the pollution rate of the studied stream. There was an alteration in the composition and structure of the chironomid community along the sampling stations. Numeric dominance of Chironomus-tolerant chironomids and its direct correlation to infestation prevalence and to ciliates abundance highlights the predilection of both peritrich ciliates and Chironomus larvae for organically-enriched environments.

Extracellular hemoglobin and environmental stress tolerance in Chironomus larvae

Hemoglobin (Hb) is one of the most common conserved molecules found in organisms belonging to all major kingdoms of life. Chironomid midge larvae are unique among the invertebrates being the only free-living group of organisms possessing extracellular hemoglobins (Hbs) in monomeric and dimeric forms floating in their hemolymph. Remarkable ability of individual species of chironomid midges to tolerate wide range of environmental stressors prevailing in their respective ecosystems has enabled chironomids to sustain as one of the most widely distributed insects in the world. Ability of different Chironomus spp to thrive under extreme hypoxic conditions as well as in the presence of chemical pollution made chironomid midges an efficient model system to assess the effect of environmental stress in different freshwater ecosystems. The modulation of Hb concentration has been found to be a function of different type of abiotic stressors and thus Hb of chironomid midges (Ch-Hb) has attracted the attention as a potential biomarker for environmental biomonitoring. Large body of literature on Ch-Hb accumulated mainly during sixties to eighties of twentieth century has enriched our understanding of its physiological, developmental and biochemical features. Empirical as well as in-silico studies carried out in recent years provided insights into many structure-function relationships of Ch-Hb. However, for the last few decades, majority of the studies were carried out to project and validate Ch-Hb as potential bioindicator for evaluating toxicants, chemical pollutants and environmental gradients of dissolved oxygen concentration. In this review, historical development of the subject has been compiled with notes on future implications of contemporary studies on Ch-Hb.

Chironomus rishii sp. n., an enigmatic non-biting midge (Diptera: Chironomidae: Chironominae) from Neotropical region.

A new species of Chironomus Meigen, C. rishii (Diptera: Chironomidae: Chironominae) from Brazil, is described and figured as adults male and female, pupa and larva. Adults of C. rishii sp. n. can be recognized by the prominent scutal tubercle and the hypopygium with narrow, elongated and strongly hooked superior volsella. Pupae of this new species are indistinguishable from most of the described Neotropical species, while larvae may be separated by the mentum with deeply incised trifid median tooth and 7 pairs of lateral teeth and the absence of lateral and ventral tubules. This last feature would place C. rishii sp. n. within the 'salinarius group'. However, this is not a group in the systematic sense, but an artificial grouping equivalent to a morphotype that reflects only the tubule character state. It is suggested that the absence of tubules is an adaptation for tolerating a wide range of salinity levels, however the 'salinarius group' had been also recorded in freshwater environments. Here, larvae without abdominal tubules were found in an environment with low levels of salinity, which indicates that the tubule condition may be result of further abiotic pressures, and configures a rather enigmatic scenario to this feature, particularly when considered the fact that larvae of Chironomus having tubules had also been recorded at the same habitat, living under similar conditions of C. rishi sp. n.

Comparison of selected parts of larval morphology in some species of the genus Chironomus (Diptera: Chironomidae) using Scanning Electron Microscope

Comparison of small sized and weakly chitinized structures such as the labrum (labral setae SI-SIII, labral lamella, tormal bar, pecten epipharings) and the maxilla (maxillary palp, lacinial chaeta) is provided in larvae of Chironomus plumosus, C. balatonicus, C. usenicus C. melanotus, C. acerbiphilus, and C. riparius using Scanning Electron Microscope (SEM). The general morphological structures of the labrum and the maxilla were similar in all of the Chironomus larvae. They differed only in fine details such as labral seta, mainly S I. Seta S I is always plumose on each side and differently figured: elongated in C. balatonicus, C. plumosus, C. melanotus and C. usenicus; rounded in C. acerbiphilus and C. riparius. Some differences were also observed in the shape, length or ratio of lacinial chaetae (LCh I, LCh II). Based on morphological variation in the larvae of some Chironomus species, results indicated that the SEM method is apparently beneficial and useful in the analysis of smaller and weakly chitinized morphological structures such as the labrum and the maxilla.

The effects of heavy metals on the incidence of morphological deformities in Chironomidae (Diptera)

Streams in urban areas are strongly impacted by the input of organic matter and metals, for instance copper (Cu) and zinc (Zn). These metals are essential for the aquatic biota, but when absorbed in excess they are toxic. In Chironomidae larvae, the deleterious effects of heavy metals can be ascertained by analyzing the morphological deformities of the larval mentum, a structure of the oral cavity. In this study, we evaluated I) the bioavailability of Cu and Zn in urban stream sediments and II) the relationship between Cu and Zn concentrations and the incidence of deformities in the mentum of Chironomus larvae. Chironomid flies were collected from four locations in two streams at an urban area in southern Brazil. They were identified and the incidence of deformities in the mentum was quantified. Sediment samples were collected at the same locations where larvae were collected, to quantify the bioavailable fractions of Cu and Zn. The concentrations of Cu in the sediment were similar between the collection sites. However, Zn concentrations varied among sites, being greater in the stretch directly influenced by the input of the organic waste. In total, 2,895 Chironomid larvae were collected. The incidence of deformities in the mentum was above 30% and was correlated with the concentrations of Cu (r = 0.68) and Zn (r = 0.87). This correlation indicates that the municipal waste that is thrown into the city’s streams has influenced the occurrence of deformities.

Influence of Acid Mine Drainage, and Its Remediation, on Lakewater Quality and Benthic Invertebrate Communities

The abandoned Aldermac Mine in Quebec, Canada, has been a source of acid mine drainage to Lake Arnoux since 1946. Restoration of the site was undertaken in 2008 and completed in 2010. We compared lakewater chemistry and benthic invertebrate communities in the spring of 2010, prior to complete restoration, and in spring 2011, when acid mine drainage was no longer entering the lake. Between these years, lakewater pH increased by about one unit and the concentrations of many trace metals declined substantially. In 2010, benthic taxonomic richness increased significantly with distance from the source of contamination, whereas after restoration, there was no longer a clear trend. Communities in highly contaminated stations tended to be dominated by burrowing taxa such as larvae of Chironomus (Chironomidae) and Oligochaeta, whereas less contaminated stations had taxonomic and functional communities that were more diverse. In the year following recovery, some new taxa appeared (Trichoptera, Odonata, and the Ceratopogonidae Bezzia), whereas the populations of an acid-tolerant Chironomus species declined. However, only larger individuals exhibited a significant response to pH and metal contamination.

Мінеральний склад сухої біомаси личинок Chironomus, вирощених на поживному середовищі із вмістом дріжованої маси шроту насіння соняшнику

Мінеральний склад сухої біомаси личинок Chironomus, вирощених на поживному середовищі із вмістом дріжованої маси шроту насіння соняшнику

The differential expression of Chironomus spp genes as useful tools in the search for pollution biomarkers in freshwater ecosystems.

Insects of the Chironomidae family are characterized by a wide ecological diversity in freshwater ecosystems. The larvae have the physiological potential to tolerate environmental stress even when there is a low concentration of oxygen, the presence of toxic substances or when there are changes in temperature and salinity. On the other hand, it is important to consider that at a cellular level, when individual insects are exposed to environmental changes, it induces responses of groups of genes that govern the molecular mechanisms related to such tolerance. In this review, using fourth instar larvae of Chironomus spp. in natural conditions and of Chironomus columbiensis under controlled conditions, we will discuss the genetic expression of a group of genes that respond to detoxification and also the biological functions involved and impacted on by mining stressors. The study of macroinvertebrate bioindicator species and their gene expression as a result of mining activity opens a window on the search for genetic biomarkers that could be used in environmental pollution assessments in freshwater ecosystems.

Ameliorative efficacy of bioencapsulated Chironomous larvae with Shilajit on Zebrafish (Danio rerio) exposed to Ionizing radiation

Using Zebrafish (Danio rerio) as a model organism, we evaluated the radioprotective and antioxidant effects of the Indian traditional medicine Shilajit exposed to X-Ray. The Zebrafish were divided into three experimental groups and control group, each group containing ten fish. The three experimental fish groups, group I, group II and group III were fed with 3, 5 and 7ppm shilajit encapsulated Chironomous larvae and group IV served as a control fed with non- encapsulated larvae. After 60 days of feeding trial, fish were irradiated with X-Ray at a single acute dose of 1Gy. 72h of post-irradiation, each experimental fish were observed for its morphological, behavioral, clinical symptoms, antioxidant levels and DNA damage were evaluated. Among the experimental groups 5ppm shilajit encapsulated Chironomous larvae fed fish group shows the most significant radioprotective effects compared with control and other experimental fish groups. The present study indicates that shilajit have significant radioprotective and antioxidant enhancing capability. The humus substance of shilajit may be the factor responsible to react with radiation-derived or radiation related reactive species on zebrafish.