On the chironomid (Diptera,Chironomidae) fauna in Lake Sevan

An annotated list of the chironomid species collected in Lake Sevan in the first 10 days of October 2006 and 2007 is presented. Chironomid species were identified by the aquatic stages of their development (larvae and pupae) and imagoes. The list includes 26 species, among which nine species were recorded in the lake for the first time. Altogether, 53 species of chironomids have been recorded in Lake Sevan.     

Two new chironomid species (Diptera,Chironomidae) from Wrangel Island

Two new species from Wrangel Island, Orthocladius (Eudactylocladius) tschernovi sp. n. and O. (E.) ushakovskiensis sp. n. (Orthocladiinae), are described and illustrated from on the male adults. Orthocladius (E.) tschernovi sp. n. is closely related to O. (E.) fuscimanus (Kieffer) and O. (E.) musester Sæther, but can be distinguished from both by an almost straight transverse sternapodema, a rounded triangular superior volsella, and a long phallapodema, as well as by the presence of a subapical crista dorsalis of the gonostylus and by the shape of the anal point. Orthocladius (E.) ushakovskiensis sp. n. differs from all the known species of the subgenus in the absence of superior and inferior volsellae and in the shape of both short gonostylus and the short and wide anal point.     

Organic matter processing by chironomid larvae (Diptera: Chironomidae)

In laboratory experiments, we used fluorescent dye markers to investigate processing of organic matter by larvae of Psectrocladius limbatellus (Holm.) (Diptera: Chironomidae). 59% of the organic matter used was incorporated into tubes, 39% was present in faecal pellets (both after 24 h), and 2% was found in the larval gut at the end of experiments. Ingested matter passed through the gut rapidly, resulting in the gut being emptied more than 20 times each day. Further 24-h experiments using dye-marked faecal pellets showed that 6% of pellets produced were re-ingested and 12% were incorporated into tubes. There was no preference for conditioned faecal pellets as food over those that had recently been egested and tubes also provided a food reserve on which larvae feed. Chironomid larvae recycle organic matter resulting in its mineralization and their ‘engineering’ has a dramatic effect on the substratum. This revised version was published online in July 2006 with corrections to the Cover Date.     

The drift of some chironomid egg masses (Diptera: Chironomidae)

SUMMARY. The drift of chironomid egg masses was investigated in the River Mole (Devon) and the River Wye (Powys) in 1981. Large numbers of egg masses were found in the drift just after dusk; on one occasion an estimated 50,000 egg masses passed a sampling point in 5 h. Oviposition of free-floating egg masses appeared to be initiated and synchronized by the onset of darkness. Egg masses of some Pentaneurini (Tanypodinae), Tanytarsini and Chironomini (Chironominae) were found in the drift and adhering to submerged stones.
Flotation by means of a gas vacuole within the egg mass was observed in the Polypedilum 'convictum' group. The gas vacuole decreased in size over 8–11 h and the egg masses sank after 2–3h.
Some chironomid egg masses are capable of drifting large distances after oviposition. The implications of sueh drift are briefly discussed in relation to the distribution of chironomid larvae.     

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.     

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.     

The saline nuisance chironomid Carteronica longilobus (Diptera: Chironomidae): a systematic reappraisal

Abstract. Carteronica Kieffer and Nilodorum Kieffer sensu auctt. are synonymized with Kiefferulus Goetghebuer on the basis of cladistic analysis. An expanded diagnosis for all stages of Kiefferulus and a checklist of included species is given. K.longilobus comb.n. from Carteronica , a saline tolerant nuisance pest, is redescribed in all its life history stages. The following additional new combinations are proposed: K.brevibucca (Kieffer), K.brevipalpis (Kieffer), K.rugosum (Freeman), K.tainanus (Kieffer), K.umbraticola (Yamamoto). Many new characters from larval ventromental plates are illustrated and their use in phylo-genetic analysis is discussed.     

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.     

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.     

Septicaemia of chironomid larvae (Diptera: Chironomidae) promoted by Bacillus cereus and Bacillus thuringiensis

Natural factors regulating the population of chironomids were studied. The bacteria Bacillus cereus were isolated from chironomids sampled from Kuyalnitskii Firth after epizooty of Chironomus sp., and bacteria Bacillus thuringiensis spp. israelensis (Bti) were isolated from dead larva of Chironomus plumosus sampled in the Sea of Azov (3-m depth). Bti were characterized by high insecticide activity on midges Anopheles messeae Fall, Aedes cireneus Mg., and Culex pipiens pipiens f. pipiens L.     

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.     

The chironomid midge Dicrotendipes sp. afr. (Diptera, Chironomidae) from the Republic of South Africa

The taxonomic position of the chironomid midge Dicrotendipes sp. afr. from the Republic of South Africa, earlier considered within the genus Glyptotendipes Kieffer (Petrova and Zhirov, 2010), is specified. The morphological characteristics of its larvae and features of its polytene chromosomes are analyzed in comparison with those of the known Dicrotendipes species. Data on inversion polymorphism are presented. In morphological characteristics, the species studied was found to be the closest to Dicrotendipes septemmaculatus Becker, 1908.     

Directional and frequency characteristics of auditory receptors in midges (Diptera,Chironomidae)

Individual characteristic frequencies and directional sensitivity of the Johnston’s organ auditory receptors were measured in the midges Chironomus plumosus L. using the method of positive feedback stimulation: responses of receptors recorded with a glass microelectrode from their axons in the antennal nerve were amplified and fed to the stimulating speaker. With the amplitude and the stimulating signal phase properly adjusted, the whole feedback loop fell into auto-excitation with the frequency of oscillations close to the characteristic frequency of the receptor. Three separate groups of receptors were found with mean frequencies of 180, 221, and 264 Hz. These groups differ in their directional properties: the low-frequency receptors are mostly sensitive dorsoventrally, while the directional maxima of mid- and high-frequency ones are combined to provide equal sensitivity in the plane perpendicular to the flagellum. Our data suggest that in Chironomidae a single Johnston’s organ together with the antenna can provide spatial localization of conspecific sounds and also perform the initial stages of frequency analysis.     

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.     

Larvicidal activity of Bacillus thuringiensis serovar israelensis against nuisance chironomid midges (Diptera: Chironomidae) of Japan

Chironomid larvae of the three species causing a nuisance problem in Japan were examined for their susceptibility to Bacillus thuringiensis serovar israelensis. Sporeparasporal inclusion complex gave a rapid and high mortality to larvae of Chironomus yoshimatsui (Chironominae) and Hydrobaenus kondoi (Orthocladiinae) within 24 h. However, susceptibility of Tokunagayusurika akamusi (Orthocladiinae) to this serovar was low.     

The effect of trophic/contaminant interactions on chironomid community structure and succession (Diptera: Chironomidae)

The effects of contaminants and organic pollution on the chironomid communities of two basins in Lac St. Louis, a river-lake on the St. Lawrence River above Montreal, Quebec, were assessed and compared using lake classification theory techniques and morphological deformity indices based on the ligulae and antennae ofProcladius, the dominant surviving component of the south-shore communities. Contaminants from the industrial complex around Beauharnois, Quebec, have seriously degraded communities along the south-shore gradient while the introduction of untreated domestic wastes from Laprairie, Quebec, has seriously affected the communities of the Laprairie basin. The interaction between trophic and contaminant effects constitutes a classic example of the setback or deflection in the trajectory of ecological succession in biological communities hypothesized by ODUM (1981, 1985).     

Xenochironomus ceciliae (Diptera: Chironomidae), a new chironomid species inhabiting freshwater sponges in Brazil

Chironomids living inside freshwater sponges are scarcely known, particularly in the Neotropical region where most of them are to be described. Here, male and female adults, pupa and 4th instar larva of Xenochironomus ceciliae sp. n., living in freshwater sponges of the Paraná River (Brazil) are described. The larval labrum with its several densely setose or combed structures somewhat resembling the filtering structures of simuliid larvae and the predominance of fine detritus in the larval gut contents, may indicate that the larvae of Xenochironomus ceciliae sp. n. are collector-filterers and they might be favored by the aquifer systems of the sponges.