Annual production and life cycle of five dominant species of Chironomidae (Chironomus plumosus, Cryptochironomus sp., Tokunagayusurkia akamusi, Procladius sp.,Clinotanypus sp )were studied with samples collected month...Annual production and life cycle of five dominant species of Chironomidae (Chironomus plumosus, Cryptochironomus sp., Tokunagayusurkia akamusi, Procladius sp.,Clinotanypus sp )were studied with samples collected monthly from April, 1996 to March, 1997 in Houhu Lake at four stations. Based on instar-frequency data, C. plumosus was nnivoltine, while the other four were bivoltine.Production rates in grams wet weight m-2 a-1 calculated by the size-frequency method were C.plumosus,2.170; Cryptochironomus sp., 0. 602; T. akamusi, s. 160; Procladius sp., 0. 964; Clinotanypussp., 0.390. Their P/B ratios were 3.9, 4.9, 4.4, 5.3 and 6.6, respectively.展开更多
A new fossil chironomid, Tanytarsus serafini, found in Baltic amber is described and illustrated based on adult males. The new species and similar extant species of the genus Tanytarsus van der Wulp are compared. Due ...A new fossil chironomid, Tanytarsus serafini, found in Baltic amber is described and illustrated based on adult males. The new species and similar extant species of the genus Tanytarsus van der Wulp are compared. Due to several distinct characters of wing, legs and bypopygium, a new species group for Tanytarsus serafini is proposed, and its diagnostic features are evaluated.展开更多
The life cycle and annual production of four dominant species of Chironomids ( Chironomus plumosus, Chironomus sp., Clinotanypus sp., Tokunagayusurika akamusi) were studied with samples taken monthly in Biandantang La...The life cycle and annual production of four dominant species of Chironomids ( Chironomus plumosus, Chironomus sp., Clinotanypus sp., Tokunagayusurika akamusi) were studied with samples taken monthly in Biandantang Lake at eight stations from April, 1996 to March, 1997. Instar frequency data showed C. plumosus was univoltine, while the other three were bivoltine. Production in wet weight (g/(m 2·a)) calculated by the size frequency method for each species were: C. plumosus, 2.663 ; Chironomus sp.,1.161 ;Clinotanypus sp., 0.270; T. akamusi , 1.476. Based on the mean standing stock, their P/B ratios were 3.2, 4.0, 6.2 and 4.4, respectively.展开更多
A long-term study of adult non-biting midges （Chironomidae） active in winter on the snow in mountain areas and lowlands in Poland yielded 35 species. The lowland and mountain communities differed significantly in th...A long-term study of adult non-biting midges （Chironomidae） active in winter on the snow in mountain areas and lowlands in Poland yielded 35 species. The lowland and mountain communities differed significantly in their specific composition. The mountain assemblage was found to be more diverse and abundant, with a substantial contribution from the subfamily Diamesinae, whereas Orthocladiinae predominated in the lowlands. Orthocladius wetterensis Brundin was the most characteristic and superdominant species in the winter-active chironomid communities in both areas. Only a few specimens and species of snow-active chironomids were recorded in late autumn and early winter. The abundance ofchironomids peaked in late February in the mountain and lowland areas with an additional peak in the mountain areas in early April. However, this second peak of activity consisted mainly of Orthocladiinae, as Diamesinae emerged earliest in the season. Most snow-active species emerged in mid- and late winter, but their seasonal patterns differed between the 2 regions as a result of the different species composition and the duration of snow cover in these regions. Spearman＇s rank correlation coefficient tests yielded positive results between each season and the number of chironomid individuals recorded in the mountain area. A positive correlation between air temperature, rising to ＋3.5 ~C, and the number of specimens recorded on the snow in the mountain community was statistically significant. The winter emergence and mate-searching strategies of chironomids are discussed in the light of global warming, and a brief compilation of most important published data on the phenomena studied is provided.展开更多
Belgica antarctica(Diptera:Chironomidae),a brachypterous midge endemicto the maritime Antarctic,was first described in 1900.Over more than a century of study,a vast amount of information has been compiled on the speci...Belgica antarctica(Diptera:Chironomidae),a brachypterous midge endemicto the maritime Antarctic,was first described in 1900.Over more than a century of study,a vast amount of information has been compiled on the species(3750000 Google searchresults as of January 10,2021),encompassing its ecology and biology,life cycle and re-production,polytene chromosomes,physiology,biochemistry and,increasingly,omics.In2014,B.antarctica’s genome was sequenced,further boosting research.Certain develop-mental stages can be cultured successfully in the laboratory.Taken together,this wealthof information allows the species to be viewed as a natural model organism for studies ofadaptation and function in extreme environments.展开更多
Small water bodies are critical for maintaining freshwater biodiversity,but are among the least investigated aquatic environments.We examined physical and chemical variables at two reaches in Arroyo Tambillos,a small,...Small water bodies are critical for maintaining freshwater biodiversity,but are among the least investigated aquatic environments.We examined physical and chemical variables at two reaches in Arroyo Tambillos,a small,high-elevation Andean stream,in NW Mendoza province,Argentina,across four seasons to examine how local factors and seasonality affected the structure of the macroinvertebrate community.The Arroyo Tambillos community was numerically dominated by ephemeropterans(mainly Massartellopsis irarrazavali)while the dipteran Chironomidae were the most species rich.Total macroinvertebrate abundance was highest in summer,driven mainly by taxa that were secondary in dominance(Austrelmis sp.and Andesiops peruvianus),while richness did not differ between seasons.However,benthic composition was different in Fall 2013(March)compared to other seasons,largely because of the increased abundance of Chironomidae.Canonical correspondence analysis discriminated Chironomidae species distributions in Fall 2013 by substrate type(i.e.,big and small boulder substrate).By contrast,discharge,velocity,and depth were the variables which most affected the macroinvertebrate abundance and distributions.Contrary to our expectations,most community changes observed occurred in fall instead of summer.Nivo-kryal stream communities like the one described here have become increasingly important for conserving mountain stream biodiversity as anthropogentic impacts and climate change increasingly impact lower stream reaches.Therefore,monitoring high-altitude streams like the Arroyo Tambillos may be critical for preventing the future loss of unique and sensitive stream biota.展开更多
As a diagenetic progress, bioturbation influences solute exchange across the sediment-water interface （SWI）. Different benthic animals have various mechanical activities in sediment, thereby they may have different ...As a diagenetic progress, bioturbation influences solute exchange across the sediment-water interface （SWI）. Different benthic animals have various mechanical activities in sediment, thereby they may have different effects on solute exchange across the SWI. This laboratory study examined the impacts of different benthic animals on phosphorus dynamics across the SWI. Tubificid worms and Chironomidae larvae were introduced as model organisms which, based on their mechanical activities, belong to upward-conveyors and gallery-diffusers, respectively. The microcosm simulation study was carried out with a continuous flow culture system, and all sediment, water, and worms and larvae specimens were sampled from Taihu Lake, China. To compare their bioturbation effects, the same biomass （17.1 g wet weight （ww）/m ^2 ） was adopted for worms and larvae. Worms altered no oxygen penetration depth in sediment, while larvae increased the O 2 penetration depth, compared to the control treatment. Their emergence also enhanced sediment O 2 uptake. The oxidation of ferrous iron in pore water produced ferric iron oxyhydroxides that adsorbed soluble reactive phosphorus （SRP） from the overlying water and pore water. Larvae built obviously oxidized tubes with about 2 mm diameter and the maximum length of 6 cm in sediment, and significantly decreased ferrous iron and SRP in the pore water compared to the control and worms treatments. Worms constructed no visually-oxidized galleries in the sediment in contrast to larvae, and they did not significantly alter SRP in the pore water relative to the control treatment. The adsorption of ferric iron oxyhydroxides to SRP caused by worms and larvae inhibited SRP release from sediment. Comparatively, worms inhibited more SRP release than larvae based on the same biomass, as they successively renewed the ferric iron oxyhydroxides rich oxidation layer through their deposition.展开更多
文摘Annual production and life cycle of five dominant species of Chironomidae (Chironomus plumosus, Cryptochironomus sp., Tokunagayusurkia akamusi, Procladius sp.,Clinotanypus sp )were studied with samples collected monthly from April, 1996 to March, 1997 in Houhu Lake at four stations. Based on instar-frequency data, C. plumosus was nnivoltine, while the other four were bivoltine.Production rates in grams wet weight m-2 a-1 calculated by the size-frequency method were C.plumosus,2.170; Cryptochironomus sp., 0. 602; T. akamusi, s. 160; Procladius sp., 0. 964; Clinotanypussp., 0.390. Their P/B ratios were 3.9, 4.9, 4.4, 5.3 and 6.6, respectively.
文摘A new fossil chironomid, Tanytarsus serafini, found in Baltic amber is described and illustrated based on adult males. The new species and similar extant species of the genus Tanytarsus van der Wulp are compared. Due to several distinct characters of wing, legs and bypopygium, a new species group for Tanytarsus serafini is proposed, and its diagnostic features are evaluated.
文摘The life cycle and annual production of four dominant species of Chironomids ( Chironomus plumosus, Chironomus sp., Clinotanypus sp., Tokunagayusurika akamusi) were studied with samples taken monthly in Biandantang Lake at eight stations from April, 1996 to March, 1997. Instar frequency data showed C. plumosus was univoltine, while the other three were bivoltine. Production in wet weight (g/(m 2·a)) calculated by the size frequency method for each species were: C. plumosus, 2.663 ; Chironomus sp.,1.161 ;Clinotanypus sp., 0.270; T. akamusi , 1.476. Based on the mean standing stock, their P/B ratios were 3.2, 4.0, 6.2 and 4.4, respectively.
文摘A long-term study of adult non-biting midges （Chironomidae） active in winter on the snow in mountain areas and lowlands in Poland yielded 35 species. The lowland and mountain communities differed significantly in their specific composition. The mountain assemblage was found to be more diverse and abundant, with a substantial contribution from the subfamily Diamesinae, whereas Orthocladiinae predominated in the lowlands. Orthocladius wetterensis Brundin was the most characteristic and superdominant species in the winter-active chironomid communities in both areas. Only a few specimens and species of snow-active chironomids were recorded in late autumn and early winter. The abundance ofchironomids peaked in late February in the mountain and lowland areas with an additional peak in the mountain areas in early April. However, this second peak of activity consisted mainly of Orthocladiinae, as Diamesinae emerged earliest in the season. Most snow-active species emerged in mid- and late winter, but their seasonal patterns differed between the 2 regions as a result of the different species composition and the duration of snow cover in these regions. Spearman＇s rank correlation coefficient tests yielded positive results between each season and the number of chironomid individuals recorded in the mountain area. A positive correlation between air temperature, rising to ＋3.5 ~C, and the number of specimens recorded on the snow in the mountain community was statistically significant. The winter emergence and mate-searching strategies of chironomids are discussed in the light of global warming, and a brief compilation of most important published data on the phenomena studied is provided.
文摘Belgica antarctica(Diptera:Chironomidae),a brachypterous midge endemicto the maritime Antarctic,was first described in 1900.Over more than a century of study,a vast amount of information has been compiled on the species(3750000 Google searchresults as of January 10,2021),encompassing its ecology and biology,life cycle and re-production,polytene chromosomes,physiology,biochemistry and,increasingly,omics.In2014,B.antarctica’s genome was sequenced,further boosting research.Certain develop-mental stages can be cultured successfully in the laboratory.Taken together,this wealthof information allows the species to be viewed as a natural model organism for studies ofadaptation and function in extreme environments.
基金Funding was provided by the National Science Foundation(NSF DEB-06-42512 to T.W.)UW-Eau Claire’s Center for International Educationsupported by Consejo Nacional de Investigaciones Científicas y Técnicas(CONICET),Argentina。
文摘Small water bodies are critical for maintaining freshwater biodiversity,but are among the least investigated aquatic environments.We examined physical and chemical variables at two reaches in Arroyo Tambillos,a small,high-elevation Andean stream,in NW Mendoza province,Argentina,across four seasons to examine how local factors and seasonality affected the structure of the macroinvertebrate community.The Arroyo Tambillos community was numerically dominated by ephemeropterans(mainly Massartellopsis irarrazavali)while the dipteran Chironomidae were the most species rich.Total macroinvertebrate abundance was highest in summer,driven mainly by taxa that were secondary in dominance(Austrelmis sp.and Andesiops peruvianus),while richness did not differ between seasons.However,benthic composition was different in Fall 2013(March)compared to other seasons,largely because of the increased abundance of Chironomidae.Canonical correspondence analysis discriminated Chironomidae species distributions in Fall 2013 by substrate type(i.e.,big and small boulder substrate).By contrast,discharge,velocity,and depth were the variables which most affected the macroinvertebrate abundance and distributions.Contrary to our expectations,most community changes observed occurred in fall instead of summer.Nivo-kryal stream communities like the one described here have become increasingly important for conserving mountain stream biodiversity as anthropogentic impacts and climate change increasingly impact lower stream reaches.Therefore,monitoring high-altitude streams like the Arroyo Tambillos may be critical for preventing the future loss of unique and sensitive stream biota.
基金supported by the National Natural Science Foundation of China(No.40730528,50979102)the Society Development Project of Jiangsu Province(No.BE2009603)
文摘As a diagenetic progress, bioturbation influences solute exchange across the sediment-water interface （SWI）. Different benthic animals have various mechanical activities in sediment, thereby they may have different effects on solute exchange across the SWI. This laboratory study examined the impacts of different benthic animals on phosphorus dynamics across the SWI. Tubificid worms and Chironomidae larvae were introduced as model organisms which, based on their mechanical activities, belong to upward-conveyors and gallery-diffusers, respectively. The microcosm simulation study was carried out with a continuous flow culture system, and all sediment, water, and worms and larvae specimens were sampled from Taihu Lake, China. To compare their bioturbation effects, the same biomass （17.1 g wet weight （ww）/m ^2 ） was adopted for worms and larvae. Worms altered no oxygen penetration depth in sediment, while larvae increased the O 2 penetration depth, compared to the control treatment. Their emergence also enhanced sediment O 2 uptake. The oxidation of ferrous iron in pore water produced ferric iron oxyhydroxides that adsorbed soluble reactive phosphorus （SRP） from the overlying water and pore water. Larvae built obviously oxidized tubes with about 2 mm diameter and the maximum length of 6 cm in sediment, and significantly decreased ferrous iron and SRP in the pore water compared to the control and worms treatments. Worms constructed no visually-oxidized galleries in the sediment in contrast to larvae, and they did not significantly alter SRP in the pore water relative to the control treatment. The adsorption of ferric iron oxyhydroxides to SRP caused by worms and larvae inhibited SRP release from sediment. Comparatively, worms inhibited more SRP release than larvae based on the same biomass, as they successively renewed the ferric iron oxyhydroxides rich oxidation layer through their deposition.
