Cytotaxonomy of Chironomidae (Diptera) from Lake Shabla (Bulgaria): cytogenetic evidence for introgressive hydribization

Twenty-two chironomid species were found in Lake Shabla. Five species (Chironomus bonus, Dicrotendipes lobiger, Kiefferulus tendipediformis, Cricotopus suspiciosus and Cricotopus sp.) are new for Bulgaria. Their karytopes are described for the first time.Cytogenetic studies of two closely related chironomid species, Glyptotendipes glaucus and G. pallens, show that in one area of sympatry (Lake Shabla, Bulgaria) about 2.5% of the naturally occuring individuals are hybrids. In most cases, in this hybrid, 1st, IInd and IIIrd chromosomes correspond fully to the chromosomes of G. glaucus. The IVth chromosome is a hybrid, with one homologue of the species G. glaucus; the other homologue is derived from G. pallens. Introgressive hybridization is of particular importance to the production of these combinations. Despite hybridization, natural selection appears to maintain the essential integrity of each separate gene pool.     

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.     

中国拟枝角摇蚊属一新种记述（双翅目：摇蚊科）

记述拟枝角摇蚊属Paracladopelma 1新种:短鞭拟枝角摇蚊P.demissum sp.nov.。该新种触角比AR低,为0.60;肛尖具中肋;第9背板后缘肩形;第9背板带V型;上附器远端膨大,向外侧成三角形突起状,亚顶端具2根大刚毛,且内侧密被小刚毛;抱器端节两侧平行,中部内弯。模式标本存放于南开大学生命科学学院摇蚊学研究室。     

Heterotrissocladius boltoni sp.n., a new orthoclad from vernal pools and streams in Ohio,U.S.A. (Diptera: Chironomidae)

Heterotrissocladius boltoni sp.n. from Ohio, U.S.A., is described in both sexes and all stages. The species belongs in themarcidus group and is found in temporary streams and pools     

A review of selected South- and East Asian Tanytarsus v.d. Wulp (Diptera: Chironomidae)

Male and pupa of Tanytarsus calorifontis sp. n. are described. Diagnoses, hypopygium drawings for the examined species and distribution are given for: Tanytarsus akantertiusSasa & Kamimura, T. angulatus Kawai, T. atagoensis Tokunaga,T. bathophilusKieffer, T. boninensis Tokunaga, T. formosae (Kieffer), T. formosanusKieffer, T. infundibulusChaudhuri & Datta, T. kikuchiiSasa, Kawai & Ueno, T. konishii Sasa & Kawai, T. mcmillani Freeman, T. mendax Kieffer, T. miyakobrevis Sasa & Hasegawa, T. monstrosus Chaudhuri et al., T. ogasaquartus Sasa & Suzuki, T. ogasatertius Sasa & Suzuki, T. okuboi Sasa & Kikuchi, T. oscillans Johannsen, T. ovatus Johannsen, T. oyamai Sasa, T. pollexus Chaudhuri & Datta, T. shouautumnalis Sasa, T. shoudigitatus Sasa, T. takahashii Kawai & Sasa, T. tamaundecimus Sasa, T. tonebeceus Sasa & Tanaka, T. tusimatneousSasa & Suzuki, T. unagiseptimus Sasa, T. uraiensis Tokunaga, T. yakuheiusSasa & Suzuki and T. yunosecundus Sasa. Tanytarsus ikiefeus Sasa & Suzuki is a new junior synonym of T. konishii. Tanytarsus ikifegeus Sasa & Suzuki, T. miyakoflavus Sasa & Hasegawa,T. oyabepallidus Sasa, Kawai & Ueno, T. simantoopeus Sasa et al. and T. tusimatheius Sasa & Suzuki are new junior synonyms of T. okuboi. Tanytarsus nippogregarius Sasa & Kamimura is a new junior synonym of T. bathophilus. Tanytarsus cultellus Chaudhuri & Datta and T. sibafegeus Sasa et al. are new junior synonyms of T. oscillans.Tanytarsus insulus (Guha et al., 1985) is a new junior synonym of T. ovatus. Tanytarsus sakishimanus Sasa & Hasegawa, T. vinculus Chaudhuri et al., T. parvistylus Chaudhuri & Datta, T. fusciabdominalis Guha et al. and T. euformosanus Kikuchi & Sasa are new junior synonyms of T. formosanus. Tanytarsus tsutaprimus Sasa, T. tokarajekeus Sasa & Suzuki, T. tusimatlemeus Sasa & Suzuki, T. tusimatopeus Sasa & Suzuki and T. yakugeheuus Sasa & Suzuki are new junior synonyms of T. shouautumnalis. Tanytarsus togasiroidus Sasa & Okazawa is a new junior synonym of T. shoudigitatus. Tanytarsus tusimatjekeus Sasa & Suzuki and T. tusimatkeleus Sasa & Suzuki are new junior synonyms of T. akantertius, and Tanytarsus tusimatpequeus Sasa & Suzuki is a new junior synonym of T. tusimatneous. Virgatanytarsus toganiveus (Sasa & Okazawa), Cladotanytarsus utonaiquartus (Sasa) and Zavrelia tusimatijeus (Sasa & Suzuki), all previously placed in Tanytarsus, are new combinations.     

Chironomidae (Diptera) of Baldwin Lake,Illinois, a cooling reservoir

The chironomid fauna of Baldwin Lake, a closed-cycle cooling reservoir for a power plant, was sampled monthly to semi-monthly for one year at four stations, two in the discharge channel and two in the main basin. Qualitative samples were also taken elsewhere and with multiple-plate samplers. Twenty-four species were collected. Annual mean population density was less than 100 larvae m^–2 in the channel, 1037 M^–2 in the main basin. Three species of Tanypodinae formed over 96 percent of the larval population in the main basin: Tanypus stellatus Coquillett, Procladius bellus (Loew), and Coelotanypus concinnus (Coquillett). The principal species on the multiple-plate samplers were Dicrotendipes nervosus (Staeger), Glyptotendipes lobiferus (Say), and Parachironomus monochromus (Wulp). Temperatures of 35°C or more in the channel virtually eliminated the chironomids, whereas temperatures up to 32°C in the main basin increased the number of generations of T. stellatus from the usual two to four at Station 3 and three at Station 4. Station 3 had almost 1,000 degree-days more heat than Station 4.     

The colonisation of experimental ponds by Chironomidae (Diptera)

The colonisation and succession of chironomids in a newly‐dug gravel pit habitat was investigated using replicate experimental ponds sampled during the summers of 1977 and 1978. In 1977 larvaeand emerging adults were collected, whilst in 1978 only adults were sampled. Benthic sampling showed the larval communities to be predominated by Chironomus spp. whilst trapping of adults showed that this group accounted for only 4% of the emergence. This difference is attributed to the selective retention of the larger Chironomus larvae by the sieve used to screen benthos samples. The pioneer chironomid communities in the ponds are compared using similarity and diversity indices on adult emergence data. These showed that the pond communities were remarkably uniform in 1977, the first year of their existence, due to the predominance of Tanytarsus gracilentus. In 1978 the communities were much more variable. The community structure changed within the two years, with equitability increasing rapidly to that characteristic of a much more mature habitat. These successional changes are attributed to a reduction in uniformity of the habitat resulting from the growth of aquatic macrophytes.     

The production of five genera of Chironomidae (Diptera) in Lake Norman,a North Carolina reservoir

The production of five genera of chironomids collected at 4- and 8-m depths at four stations in Lake Norman, North Carolina, was estimated using the size-frequency method. To correct for multivoltinism, the estimates were adjusted by multiplying by 365/Cohort Production Interval. Ranges of production estimates (P) in milligrams dry mass m^-2 yr^-1 and production/mean annual biomass ratios (P/B ratios) for each genus over both depths were: Tanytarsus, P = 744 to 8788, P/BB = 66 to 176; Cladotanytarsus, P = 74 to 2387, P/B = 69 to 100; Stempellina, P = 19 to 412, P/ B = 74 to 132; Chironomus, P = 166 to 7293, P/ B = 50 to 70; Cryptochironomus, P = 92 to 398, P/ B = 71 to 221. These estimates are among the highest reported for chironomids, due primarily to the rapid larval development times estimated for these genera.     

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.     

Dispersal of adult aquatic Chironomidae (Diptera) in agricultural landscapes

• 1 This study investigates the possible influence of terrestrial landscape structure on the spatial distribution of adult Chironomidae emerging from water bodies in three agricultural areas, each with hedgerow networks, in Brittany (France).
• 2 Using spatially explicit data from 128 yellow pan traps set in pairs at the bottom of hedges throughout the three study areas, we show that landscape structure and heterogeneity must be considered at two different spatial scales.
• 3 At a global scale, distance to water bodies was the main factor explaining the spatial distribution of adult chironomids: both species richness and abundance changed beyond a critical distance to the stream, resulting in different species assemblages of flying insects.
• 4 At a local scale, the abundance of species and individuals at rest in hedges changed with the quality of the hedge (mainly determined by canopy width and cover of the different vegetation layers).
• 5 The density of the hedgerow network, and landscape openness, both influenced the dispersal of chironomid species from water bodies.
• 6 This study, which provides the first estimate of the dispersal capabilities of chironomids in particular landscapes, suggests that the terrestrial environment is an essential component of population dynamics and community structure in aquatic Chironomidae.

     

Bathymetric distribution of some Chironomidae (Diptera) in Rutland Water

The bathymetric distribution of the eight most abundant taxa of chironomid larvae is described from benthic grab samples collected in Rutland Water from May 1977 to April 1979. Cricotopus, Psectrocladius and Endochironomus larvae were generally restricted to water less than 9 m deep. Procladius, Chironomus, Microtendipes, Polypedilum and Tanytarsini larvae were all recorded at depths down to 25 m. However, the highest population densities of the latter five taxa were recorded in shallow water. The results are discussed in relation to the diet of trout and certain management practices at the reservoir. Also described is the application of SPSS (Statistical Package for the Social Sciences) to the analysis of these data.     

辽宁省摇蚊科二新种（双翅目：摇蚊科）

作者在整理近年来采自辽宁省摇蚊科标本过程中,发现２新种,分属于虹齿摇蚊属Ｎｅｏｚａｖｅｌｌａ Ｇｏｅｔｇｈｅｂｕｅｒ,１８１４及施密摇蚊属Ｓｍｉｔｔｉａ Ｈｏｌｍｇｒｅｎ,１８６９,描述于后。模式标本存于南开大学生物系昆虫标本室。形态术语采用Ｓａｅｔｈｅｒ（１９８０）。     

Adult female of Chaetocladius insolitus Caspers, 1987 (Diptera: Chironomidae) with notes on species distribution

The adult female of Chaetocladius insolitus Caspers, 1987 (Diptera, Chironomidae) is described and discussed in the context of the generic diagnosis of adult females of the genus Chaetocladius Kieffer, 1911. In addition, distributional notes on this rare chironomid species are included.     

The winged Antarctic midge Parochlus steinenii (Gerke) (Diptera: Chironomidae) in the South Shetland Islands

The morphological variation of adult Parochlus steinenii (Gerke) is described from measurements of two populations from the South Shetland Islands. Morphologically, the population from Ardley Island is significantly larger than the population from Livingston Island, and in both populations variation in forefemur length is generally greater than variation in either antennal or wing length. The final instar larva of P. steinenii is described in detail. A consideration of the species' distribution in three geographically isolated areas, as well as of the greater morphological variation in polar as opposed to temperate populations, indicates that a flexible life history strategy in the larval stage may be important for survival in extreme environments.     

New species of Oukuriella (Diptera: Chironomidae) from Costa Rica

The males of three new species of Oukuriella Epler are described from Costa Rica. The genus had been previously recorded only from South America. Oukuriella annamae sp. nov. has genitalia similar to O. albistyla Epler, but differs in having transverse bands on abdominal segments In, IV, VI and VII, a lower AR, no humeral setae and fewer dorsocentral setae. Oukuriella costaricense sp. nov. differs from other described species in the genus by its brown abdomen, unnotched posterior margin of tergite IX and distinctive superior volsella, with its sharply bent, thin upper arm directed medially, and digitus small and directed caudad. Oukuriella rushi sp. nov. has apices of femora tipped with brown, a brown abdomen and distinctive superior volsella, with upper arm shorter and broader, and digitus longer then O. costaricense. The female of Oukuriella costaricense is also described. This is the first female described for the genus. Based on male and female genitalia, Oukuriella is closely related to Epedilum Townes and Zavreliella Kieffer. A key is provided to separate the males of the six described species.     

Two new species of the orientalis group of Rheocricotopus (Psilocricotopus) from China (Diptera: Chironomidae)

Rheocricotopus (Psilocricotopus) calviculus sp. n. and R. (P.) villiculus sp. n. from China are described as male imagines. The species are closely related to the previously described R. (P.) orientalis Wang forming a new group, the orientalis group, which eventually may deserve the rank of subgenus or even genus. The group is distinguished by lacking a humeral pit, numerous sensilla clavata on third palpomere, cuneiform wings, no or few setae on squama, long legs, banded abdomen, very long inferior volsella, gonocoxite with apical extensions, and gonostylus with a median triangular projection.     

中国真开氏摇蚊属一新种及一新记录种记述（双翅目：摇蚊科）

记述真开氏摇蚊属Eukiefferiella Thienemann 1新种:盖真开氏摇蚊E. celata sp. nov.和1种中国新记录种: 翘叶真开氏遥蚊E. brehmi Gouin, 1943;提出兵库真开氏摇蚊E. togaeuquinta Sasa & Okazawa, 1992为翘叶真开氏摇蚊 E. brehmi Gouin,1943的新异名。     

Seasonal influence on head capsule deformities in Chironomus zealandicus (Hudson) (Diptera: Chironomidae)

The natural incidence of deformities in the head capsules of Chironomus zealandicus was investigated at four lake sites in the central North Island (New Zealand) in summer (December) of 1994, 1995 and 1996, and winter (June) of 1995 and 1996. Significant differences were observed in deformities between sites and seasons. Individuals from Hamurana Stream, a relatively clean site, had the lowest incidence of deformities. However, there were still significant numbers of deformed chironomids. The incidence of deformity increased in summer in larvae from all sites except Hamurana Stream. No seasonal differences were observed in larvae from Hamurana Stream. There are indications that substrate type, season and genetic factors, as well as sediment chemistry may have collectively contributed to the incidence of head capsule abnormalities in C. zealandicus.     

Two new nearctic species of small orthocladiinae (Diptera: Chironomidae) with notes on ecology

Two new species of chironomid midges (Rheosmittia arcuata n.sp. and Mesocricotopus loticus n.sp.) are recognized. They may easily be missed in collections due to their small size, and difficulty in collecting from the larval microhabitat (sand substrates for R. arcuata n.sp., low order streams with depositional substrates including gravel, sand, and silt for M. loticus n.sp.). Some morphological features are given to distinguish the new species from similar congeneric forms. The distribution and some ecological information for each species are also briefly discussed.     

Factors influencing algal consumption and feeding rate in Heterotrissocladius changi Saether and Polypedilum nebeculosum (Meigen) (Chironomidae: Diptera)

Summary Factors influencing the consumption of algae and the rate of feeding by the larvae of Heterotrissocladius changi Saether and Polypedilum nebeculosum (Meigen) (Chironomidae: Diptera) were determined from collections made between July 1975 and May 1977 in Yellowknife Bay, situated in the Canadian subarctic. Although both species fed heavily on algae during the summer, few cells were ingested in the winter, coincident with an overall reduction in feeding intensity. H. changi fed primarily on benthic species (Achnanthes minutissima, Achnanthes pinnata, Fragilaria pinnata, Fragilaria vaucheriae, Navicula spp., Scenedesmus spp.) Whereas P. nebeculosum was restricted to planktonic forms (Dinobryon spp., Scenedesmus spp.). The consumption of algae by H. changi depended largely on the density of the microflora in the environment. This factor had little influence on P. nebeculosum and was replaced by size selection, which prevented the ingestion of many planktonic algal species. The importance of algae to both chironomids also depended on the susceptability of certain algal forms to digestion. Temperature generally regulated the intensity of feeding of both H. changi and P. nebeculosum. However, changing day-length initiated heavy feeding during April and May, despite low water temperatures. The depth of water and the organic content of the substrate had no detectable effect on the amount of material in the guts.