Colonization of benthic invertebrates on artificial and natural substrate in a Neotropical lotic environment in Southern Brazil

The objective of this research was to validate the colonization process on natural and artificial substrates by benthic invertebrates in a tropical stream in South Brazil. The samples were performed in July and August-2012, and 32 samplers were used, being 16 natural and 16 artificial substrates. In each sample, two replicas were taken for each substrate at the 2th, 4th, 7th, 14th, 21th28th, 35th and 42thdays of colonization. The organisms were identified to the lowest possible taxonomic level. In both substrates 3,070 benthic invertebrates were detected, of which 1,753 individuals were collected on the natural substrate, and 1,317 on the artificial substrate. From the identified taxa 8.5% were not dominant (Anacroneuria, Orthocladiinae, Tupiara, Smicridea, Baetodes, Tupiperla, Macrogynoplax, Gripopteryx, Cylloepus, Macrelmis, Microcylloepus, Hetaerina, Argia, Coryphaeschna, Atopsyche, Pomacea, Corydalus, Leptohyphes and Eccoptura), and31.5% were dominant (Tanypodinae, Chironominae, and Paragripopteryx). The genus Simulium was very common, dominant and abundant, representing 65% of the collected individuals. No significant difference was found in the abundance and species composition between artificial and natural substrates. On the natural substrate, the higher colonization index was at the 35th day with 459 individuals, and the lowest was at the 14th day, with 87. On the artificial substrate the highest index was at the 42thday with 337 individuals, and the lowest was at the 4th day, with 85. Both natural and artificial substrates are efficient in characterizing the benthic community. In the evaluation of the ecological succession, it was not possible to observe a pattern that described the process, since the composition was nearly constant throughout the study period.

Checklist de Chironomidae para o estado de Mato Grosso do Sul

ABSTRACT Family Chironomidae is widely distributed with approximately 4,147 species known to the World, but this value is already outdated; for to Brazil about 379 species are recorded. We present a current inventory of species of Chironomidae for the state of Mato Grosso do Sul. Up to now, 16 species are recorded to the state. These species belongs to the genera Aedokritus, Beardius, Chironomus, Corynoneura, Djalmabatista, Fissimentum, Goeldichironomus, Oukuriella and Xenochironomus. In addition, 83 morphospecies are known to 33 genus of Chinonominae, six of Orthocladiinae and ten of Tanypodinae, all from fauna surveys and ecological studies in the Upper Paraná River and its adjacent rivers.

RESUMO A família Chironomidae é amplamente distribuída com aproximadamente 4.147 espécies conhecidas para o mundo, entretanto esse valor já está desatualizado; para o Brasil cerca de 379 espécies são registradas. Apresentamos um inventário atualizado das espécies de Chironomidae do estado do Mato Grosso do Sul. Até o momento, 16 espécies possuem registro assinalado para o estado. Estas pertencem aos gêneros Aedokritus, Beardius, Chironomus, Corynoneura, Djalmabatista, Fissimentum, Goeldichironomus, Oukuriella e Xenochironomus. Além destas, são conhecidas 83 morfoespécies, referentes a 33 gêneros de Chironominae, seis de Orthocladiinae e dez de Tanypodinae, todas provenientes de levantamentos faunísticos e estudos ecológicos no Alto Rio Paraná e seus rios adjacentes.

Checklist de Chironomidae para o estado de Mato Grosso do Sul / Checklist of Chironomidae from Mato Grosso do Sul state

Family Chironomidae is widely distributed with approximately 4,147 species known to the World, but this value is already outdated; for to Brazil about 379 species are recorded. We present a current inventory of species of Chironomidae for the state of Mato Grosso do Sul. Up to now, 16 species are recorded to the state. These species belongs to the genera Aedokritus, Beardius, Chironomus, Corynoneura, Djalmabatista, Fissimentum, Goeldichironomus, Oukuriella and Xenochironomus. In addition, 83 morphospecies are known to 33 genus of Chinonominae, six of Orthocladiinae and ten of Tanypodinae, all from fauna surveys and ecological studies in the Upper Paraná River and its adjacent rivers.(AU)

A família Chironomidae é amplamente distribuída com aproximadamente 4.147 espécies conhecidas para o mundo, entretanto esse valor já está desatualizado; para o Brasil cerca de 379 espécies são registradas. Apresentamos um inventário atualizado das espécies de Chironomidae do estado do Mato Grosso do Sul. Até o momento, 16 espécies possuem registro assinalado para o estado. Estas pertencem aos gêneros Aedokritus, Beardius, Chironomus, Corynoneura, Djalmabatista, Fissimentum, Goeldichironomus, Oukuriella e Xenochironomus. Além destas, são conhecidas 83 morfoespécies, referentes a 33 gêneros de Chironominae, seis de Orthocladiinae e dez de Tanypodinae, todas provenientes de levantamentos faunísticos e estudos ecológicos no Alto Rio Paraná e seus rios adjacentes.(AU)

Checklist de Chironomidae para o estado de Mato Grosso do Sul / Checklist of Chironomidae from Mato Grosso do Sul state

Family Chironomidae is widely distributed with approximately 4,147 species known to the World, but this value is already outdated; for to Brazil about 379 species are recorded. We present a current inventory of species of Chironomidae for the state of Mato Grosso do Sul. Up to now, 16 species are recorded to the state. These species belongs to the genera Aedokritus, Beardius, Chironomus, Corynoneura, Djalmabatista, Fissimentum, Goeldichironomus, Oukuriella and Xenochironomus. In addition, 83 morphospecies are known to 33 genus of Chinonominae, six of Orthocladiinae and ten of Tanypodinae, all from fauna surveys and ecological studies in the Upper Paraná River and its adjacent rivers.

A família Chironomidae é amplamente distribuída com aproximadamente 4.147 espécies conhecidas para o mundo, entretanto esse valor já está desatualizado; para o Brasil cerca de 379 espécies são registradas. Apresentamos um inventário atualizado das espécies de Chironomidae do estado do Mato Grosso do Sul. Até o momento, 16 espécies possuem registro assinalado para o estado. Estas pertencem aos gêneros Aedokritus, Beardius, Chironomus, Corynoneura, Djalmabatista, Fissimentum, Goeldichironomus, Oukuriella e Xenochironomus. Além destas, são conhecidas 83 morfoespécies, referentes a 33 gêneros de Chironominae, seis de Orthocladiinae e dez de Tanypodinae, todas provenientes de levantamentos faunísticos e estudos ecológicos no Alto Rio Paraná e seus rios adjacentes.

Variación espacio-temporal de Chironomidae (Diptera) bentónicos y derivantes en un arroyo serrano en Córdoba, Argentina / Spatio-temporal variation of benthic and drifting Chironomidae (Diptera) in a mountain stream in Córdoba, Argentina

Chironomidae es una de las familias más abundantes y diversas en los ecosistemas de agua dulce, sin embargo su complejidad sistemática ha sido motivo de su escaso desarrollo en muchos estudios limnológicos. El objetivo de este estudio fue analizar los ensambles de Chironomidae bentónicos y derivantes de un arroyo serrano de la región central de Argentina evaluando abundancia, diversidad y composición de especies en diferentes hábitats fluviales y distintas estaciones del año. Se tomaron muestras cuantitativas de bentos y deriva en el arroyo Achiras (Córdoba, Argentina) en hábitats de rabión y corredera, y se registraron variables ambientales en las cuatro estaciones del año, entre 2007 y 2008. Se registró un total de 25 taxones pertenecientes a cuatro subfamilias. Los quironómidos bentónicos constituyeron el 19% de la comunidad de macroinvertebrados, mientras que en deriva representaron el 33%. En el bentos dominó Thienemannimyia sp. y en la deriva, Corynoneura sp. De acuerdo con los resultados de ANOVAs de dos vías, los mayores valores de riqueza taxonómica y densidad bentónica se registraron en el periodo de aguas bajas (otoño e invierno) y la diversidad de quirónomidos bentónicos fue mayor en rabión. Por el contrario, para el ensamble de derivantes sólo la equitatividad fue diferente entre hábitats y entre estaciones. El análisis TWINSPAN mostró una separación espacio-temporal de las muestras de bentos, mientras que las muestras de deriva se segregaron sólo temporalmente lo que sugiere que el transporte aguas abajo de los invertebrados homogeniza la variación espacial observada en el bentos. La densidad de bentos y deriva varió de manera similar a través de las estaciones del año y el coeficiente de Jaccard presentó un alto índice de similitud entre bentos y deriva (86%). Este trabajo posibilitó conocer la dinámica temporal y espacial de los quironómidos bentónicos y derivantes en un arroyo serrano[...](AU)

Chironomidae is one of the most abundant and diverse families in freshwater ecosystems, however its highly complex systematic has led to its scarce development in many limnological studies. The aim of this study was to analyze benthic and drifting Chironomidae assemblages in a mountain stream of central Argentina assessing abundance, diversity and taxa composition in different fluvial habitats and seasons. Quantitative benthic and drift samples were taken in the Achiras stream (Córdoba, Argentina) in rifles and runs, and environmental variables were measured in each season between 2007 and 2008. A total of 25 taxa were registered belonging to four subfamilies. Benthic chironomids represented 19% of the macroinvertebrate community, whereas they constituted 33% in drift. Thienemannimyia sp. dominated in benthos and Corynoneura sp. in drift. According to the two-way ANOVAs results, the highest taxonomic richness and benthic density were registered during the low flow period (autumn and winter) and the highest benthic diversity was found in riffles. On the contrary, in the drifting assemblage only evenness was different between habitats and among seasons. TWINSPAN analysis showed a spatio-temporal segregation of benthic samples, whereas drift samples were separated only temporally suggesting that the dislodgment of invertebrates downstream homogenize the spatial variation observed in benthos. Benthic and drift density varied in a similar manner through seasons and Jaccard coefficient showed a high similarity index between benthos and drift (86%). This study allowed knowing the spatio-temporal dynamic of benthic and drifting Chironomidae in a mountain stream. The increase of knowledge in relation to taxonomy, biology and ecology of Chironomidae will allow to adequate and apply management and conservation strategies of lotic ecosystems in the central region of Argentina(AU)

Variación espacio-temporal de Chironomidae (Diptera) bentónicos y derivantes en un arroyo serrano en Córdoba, Argentina / Spatio-temporal variation of benthic and drifting Chironomidae (Diptera) in a mountain stream in Córdoba, Argentina

Chironomidae es una de las familias más abundantes y diversas en los ecosistemas de agua dulce, sin embargo su complejidad sistemática ha sido motivo de su escaso desarrollo en muchos estudios limnológicos. El objetivo de este estudio fue analizar los ensambles de Chironomidae bentónicos y derivantes de un arroyo serrano de la región central de Argentina evaluando abundancia, diversidad y composición de especies en diferentes hábitats fluviales y distintas estaciones del año. Se tomaron muestras cuantitativas de bentos y deriva en el arroyo Achiras (Córdoba, Argentina) en hábitats de rabión y corredera, y se registraron variables ambientales en las cuatro estaciones del año, entre 2007 y 2008. Se registró un total de 25 taxones pertenecientes a cuatro subfamilias. Los quironómidos bentónicos constituyeron el 19% de la comunidad de macroinvertebrados, mientras que en deriva representaron el 33%. En el bentos dominó Thienemannimyia sp. y en la deriva, Corynoneura sp. De acuerdo con los resultados de ANOVAs de dos vías, los mayores valores de riqueza taxonómica y densidad bentónica se registraron en el periodo de aguas bajas (otoño e invierno) y la diversidad de quirónomidos bentónicos fue mayor en rabión. Por el contrario, para el ensamble de derivantes sólo la equitatividad fue diferente entre hábitats y entre estaciones. El análisis TWINSPAN mostró una separación espacio-temporal de las muestras de bentos, mientras que las muestras de deriva se segregaron sólo temporalmente lo que sugiere que el transporte aguas abajo de los invertebrados homogeniza la variación espacial observada en el bentos. La densidad de bentos y deriva varió de manera similar a través de las estaciones del año y el coeficiente de Jaccard presentó un alto índice de similitud entre bentos y deriva (86%). Este trabajo posibilitó conocer la dinámica temporal y espacial de los quironómidos bentónicos y derivantes en un arroyo serrano[...]

Chironomidae is one of the most abundant and diverse families in freshwater ecosystems, however its highly complex systematic has led to its scarce development in many limnological studies. The aim of this study was to analyze benthic and drifting Chironomidae assemblages in a mountain stream of central Argentina assessing abundance, diversity and taxa composition in different fluvial habitats and seasons. Quantitative benthic and drift samples were taken in the Achiras stream (Córdoba, Argentina) in rifles and runs, and environmental variables were measured in each season between 2007 and 2008. A total of 25 taxa were registered belonging to four subfamilies. Benthic chironomids represented 19% of the macroinvertebrate community, whereas they constituted 33% in drift. Thienemannimyia sp. dominated in benthos and Corynoneura sp. in drift. According to the two-way ANOVAs results, the highest taxonomic richness and benthic density were registered during the low flow period (autumn and winter) and the highest benthic diversity was found in riffles. On the contrary, in the drifting assemblage only evenness was different between habitats and among seasons. TWINSPAN analysis showed a spatio-temporal segregation of benthic samples, whereas drift samples were separated only temporally suggesting that the dislodgment of invertebrates downstream homogenize the spatial variation observed in benthos. Benthic and drift density varied in a similar manner through seasons and Jaccard coefficient showed a high similarity index between benthos and drift (86%). This study allowed knowing the spatio-temporal dynamic of benthic and drifting Chironomidae in a mountain stream. The increase of knowledge in relation to taxonomy, biology and ecology of Chironomidae will allow to adequate and apply management and conservation strategies of lotic ecosystems in the central region of Argentina

Apedilum griseistriatum comb. nov., placement of Chironomus (Polypedilum) griseistriatum (Diptera, Chironomidae) / Apedilum griseistriatum comb. nov., colocación de Chironomus (Polypedilum) griseistriatum (Diptera, Chironomidae)

El estudio del material tipo de Chironomus (Polypedilum) griseistriatum Edwards, 1931 de Patagonia nos permite transferir formalmente la especie a Apedilum Townes, 1945 como una nueva combinación, y la cría de un especimen nos permite describir su pupa. Sobre la base de varias larvas pertenecientes a Apedilum colectadas en las proximidades de las localidades en las cuales fueron encontrados los adultos y las pupas, describimos tentativamente el estadio larval. Cápsulas de larvas subfósiles de la misma especie fueron encontradas en la Laguna Stibnite a 46°S en Chile datadas en aproximadamente 2.500 años atrás y en Puerto Blest, Lago Nahuel Huapi a 41°S en Argentina datadas en aproximadamente 2.000 años atrás. Discutimos el hábitat de la especie basados en el material moderno y subfósil. Se provee además de claves de identificación del cuarto estadio larval, pupa y adulto macho(AU)

The study of the type material of Chironomus (Polypedilum) griseistriatum Edwards, 1931 described from Patagonia lead us to formally transfer the species to Apedilum Townes, 1945 as a new combination, and a reared specimen allows us to describe its pupa. Based on several larvae belonging to Apedilum collected in the proximity of the localities in which the adults and pupae were found, we tentatively describe the larval stage. Subfossil larval head capsules of the same species were found in Laguna Stibnite at 46°S in Chile dated to about 2,500 years ago and in Puerto Blest, Lago Nahuel Huapi at 41°S in Argentina dated about 2,000 years ago. We discuss the habitat of the species based on both modern and subfossil material. Identification keys to male adult, pupae and fourth instar larvae are also provided(AU)

Apedilum griseistriatum comb. nov., placement of Chironomus (Polypedilum) griseistriatum (Diptera, Chironomidae) / Apedilum griseistriatum comb. nov., colocación de Chironomus (Polypedilum) griseistriatum (Diptera, Chironomidae)

El estudio del material tipo de Chironomus (Polypedilum) griseistriatum Edwards, 1931 de Patagonia nos permite transferir formalmente la especie a Apedilum Townes, 1945 como una nueva combinación, y la cría de un especimen nos permite describir su pupa. Sobre la base de varias larvas pertenecientes a Apedilum colectadas en las proximidades de las localidades en las cuales fueron encontrados los adultos y las pupas, describimos tentativamente el estadio larval. Cápsulas de larvas subfósiles de la misma especie fueron encontradas en la Laguna Stibnite a 46°S en Chile datadas en aproximadamente 2.500 años atrás y en Puerto Blest, Lago Nahuel Huapi a 41°S en Argentina datadas en aproximadamente 2.000 años atrás. Discutimos el hábitat de la especie basados en el material moderno y subfósil. Se provee además de claves de identificación del cuarto estadio larval, pupa y adulto macho

The study of the type material of Chironomus (Polypedilum) griseistriatum Edwards, 1931 described from Patagonia lead us to formally transfer the species to Apedilum Townes, 1945 as a new combination, and a reared specimen allows us to describe its pupa. Based on several larvae belonging to Apedilum collected in the proximity of the localities in which the adults and pupae were found, we tentatively describe the larval stage. Subfossil larval head capsules of the same species were found in Laguna Stibnite at 46°S in Chile dated to about 2,500 years ago and in Puerto Blest, Lago Nahuel Huapi at 41°S in Argentina dated about 2,000 years ago. We discuss the habitat of the species based on both modern and subfossil material. Identification keys to male adult, pupae and fourth instar larvae are also provided

Diet and functional feeding groups of Chironomidae (Diptera) in the Middle Paraná River floodplain (Argentina)

Se analizó el contenido intestinal de nueve géneros de Chironominae y Tanypodinae bentónicos en ambientes de la llanura aluvial del río Paraná Medio (laguna y cauce secundario) para determinar su patrón alimentario y los grupos funcionales tróficos. En los contenidos intestinales se observaron detrito amorfo, material mineral (principalmente arena), tejidos vegetal y animal. El principal ítem alimentario encontrado en Polypedilum (Tripodura) sp., Chironomus gr. decorus sp., Endotribelos sp., Phaenopsectra sp., Cladopelma sp. y Pelomus sp. (Chironominae) fue detrito amorfo, mientras que en Ablabesmyia (Karelia) sp., Coelotanypus sp. y Procladius sp. (Tanypodinae) el ítem más importante fue tejido animal (principalmente restos de oligoquetos). Se calculó el solapamiento trófico entre todos los pares de géneros, obteniéndose el mayor solapamiento dentro de los depredadores entre Coelotanypus sp. y Ablabesmyia (Karelia) sp. y dentro de los detritívoros entre Endotribelos sp. y Phaenopsectra sp.

The gut contents of nine genera of benthic Chironominae and Tanypodinae from the Middle Paraná River floodplain habitats (a lake and a secondary channel) were analyzed to determine their feeding patterns and functional feeding groups. Amorphous detritus, animal and vegetal tissues, and mineral materials (predominantly sand) were observed in the larval guts. Amorphous detritus were the main food item found for Polypedilum (Tripodura) sp., Chironomus gr. decorus sp., Endotribelos sp., Phaenopsectra sp., Cladopelma sp., and Pelomus sp. (Chironominae), while animal tissues (mainly oligochaetes) were the most important food item found for Ablabesmyia (Karelia) sp., Coelotanypus sp., and Procladius sp. (Tanypodinae). Dietary overlap was calculated for all pairs of genera. Within predators, the highest overlap was obtained between Coelotanypus sp. and Ablabesmyia (Karelia) sp., while within detritivores the highest niche overlap was obtained between Endotribelos sp. and Phaenopsectra sp.

Diet and functional feeding groups of Chironomidae (Diptera) in the Middle Paraná River floodplain (Argentina)

Se analizó el contenido intestinal de nueve géneros de Chironominae y Tanypodinae bentónicos en ambientes de la llanura aluvial del río Paraná Medio (laguna y cauce secundario) para determinar su patrón alimentario y los grupos funcionales tróficos. En los contenidos intestinales se observaron detrito amorfo, material mineral (principalmente arena), tejidos vegetal y animal. El principal ítem alimentario encontrado en Polypedilum (Tripodura) sp., Chironomus gr. decorus sp., Endotribelos sp., Phaenopsectra sp., Cladopelma sp. y Pelomus sp. (Chironominae) fue detrito amorfo, mientras que en Ablabesmyia (Karelia) sp., Coelotanypus sp. y Procladius sp. (Tanypodinae) el ítem más importante fue tejido animal (principalmente restos de oligoquetos). Se calculó el solapamiento trófico entre todos los pares de géneros, obteniéndose el mayor solapamiento dentro de los depredadores entre Coelotanypus sp. y Ablabesmyia (Karelia) sp. y dentro de los detritívoros entre Endotribelos sp. y Phaenopsectra sp.

The gut contents of nine genera of benthic Chironominae and Tanypodinae from the Middle Paraná River floodplain habitats (a lake and a secondary channel) were analyzed to determine their feeding patterns and functional feeding groups. Amorphous detritus, animal and vegetal tissues, and mineral materials (predominantly sand) were observed in the larval guts. Amorphous detritus were the main food item found for Polypedilum (Tripodura) sp., Chironomus gr. decorus sp., Endotribelos sp., Phaenopsectra sp., Cladopelma sp., and Pelomus sp. (Chironominae), while animal tissues (mainly oligochaetes) were the most important food item found for Ablabesmyia (Karelia) sp., Coelotanypus sp., and Procladius sp. (Tanypodinae). Dietary overlap was calculated for all pairs of genera. Within predators, the highest overlap was obtained between Coelotanypus sp. and Ablabesmyia (Karelia) sp., while within detritivores the highest niche overlap was obtained between Endotribelos sp. and Phaenopsectra sp.

Ocorrência de Polypedilum (Tripodura) amataura Bidawid-Kafka, 1996 (Diptera; Chironomidae) em Aquascypha hydrophora (berk.) Reid (Fungi; Stereaceae), com descrição da pupa na Amazônia Central, Brasil

Four larvae were collected in water with the fungus Aquascyphahydrophora (Berk.) Reid (Fungi: Stereaceae), fixed in tree trunks found in the Adolpho Ducke Forest Reserve, Amazonas, Brazil. Only one specimem reached the adult phase, which was identified as Polypedilum (Tripodura) amataura Bidawid-Kafka, 1996. This is the first description of an immature form of this genus, and also the first registered in mycotelmata.

Quatro larvas foram coletadas em água retida pelo fungo Aquascypha hydrophora (Berk.) Reid (Fungi: Stereaceae) fixo em troncos de árvores eretas, na Reserva Florestal Adolpho Ducke, Amazonas, Brasil. Das larvas coletadas, apenas um exemplar desenvolveu até a fase adulta, sendo identificado como Polypedilum (Tripodura) amataura Bidawid-Kafka, 1996. Esta é a primeira descrição para uma forma imatura deste gênero, e também o primeiro registro em micotelmata.

Diversity and biomass of Chironomidae (Diptera) larvae in an impacted coastal lagoon in Rio de Janeiro, Brazil

Diversity and biomass of Chironomidae larvae were studied between January-November 1993 and March-November 1994 in an impacted lagoon in Rio de Janeiro, Southeastern Brazil, in an attempt to establish the ecological consequences of anthropogenic eutrophication processes. Nine hundred and seventy-five organisms belonging to the Tanypodinae, Orthocladiinae, and Chironominae were collected. Polypedilum (62%) and Chironomus (58%) were the most common genera found in the limnetic and littoral zones.

Foram estudadas a diversidade e a biomassa de larvas de Chironomidae entre janeiro e novembro de 1993 e março-novembro de 1994 em uma lagoa costeira no Estado do Rio de Janeiro, Sudeste do Brasil, com o objetivo de identificar as conseqüências ecológicas do processo de eutrofização artificial. Ao todo, 975 larvas de Tanypodinae, Orthocladiinae e Chironominae foram coletadas e Polypedilum (62%) e Chironomus (58%) foram os taxa mais comuns nas regiões litorânea e limnética.

Diversity and biomass of Chironomidae (Diptera) larvae in an impacted coastal lagoon in Rio de Janeiro, Brazil

Diversity and biomass of Chironomidae larvae were studied between January-November 1993 and March-November 1994 in an impacted lagoon in Rio de Janeiro, Southeastern Brazil, in an attempt to establish the ecological consequences of anthropogenic eutrophication processes. Nine hundred and seventy-five organisms belonging to the Tanypodinae, Orthocladiinae, and Chironominae were collected. Polypedilum (62%) and Chironomus (58%) were the most common genera found in the limnetic and littoral zones.

Foram estudadas a diversidade e a biomassa de larvas de Chironomidae entre janeiro e novembro de 1993 e março-novembro de 1994 em uma lagoa costeira no Estado do Rio de Janeiro, Sudeste do Brasil, com o objetivo de identificar as conseqüências ecológicas do processo de eutrofização artificial. Ao todo, 975 larvas de Tanypodinae, Orthocladiinae e Chironominae foram coletadas e Polypedilum (62%) e Chironomus (58%) foram os taxa mais comuns nas regiões litorânea e limnética.

Feeding habits of Chironomid larvae (Insecta: Diptera) from a stream in the Floresta da Tijuca, Rio de Janeiro, Brazil

Chironomids larvae are frequently one of the most abundant and diverse groups of insects in several kinds of aquatic environments. Also, they play a major role in the aquatic food webs, representing a major link among producers and secondary consumers. This work investigates the feeding behavior of the chironomid larvae present in the Rio da Fazenda, situated in the Parque Nacional da Tijuca, Rio de Janeiro, Brazil, between August 1994 and May 1995. Algae, fungi, pollen, leaf and wood fragments, animal remains, detritus and silt were the main gut contents found in the larvae studied. The main food item ingested by the larvae was detritus, except for the Stenochironomus whose main food source was leaf and wood fragments. Tanypodinae exhibited a large quantity of animal remains of several kinds in the diet. During the period studied it was observed that the diet of 16 genera (out of 24 studied) varied. Tanypodinae had mainly coarse particulate organic matter (> 1 mm) in the gut contents, while Chironominae and Orthocladiinae had fine particulate organic matter ( 1 mm).

As larvas de Chironomidae são freqüentemente o grupo de insetos mais abundante e diversificado em vários tipos de ambientes aquáticos, apresentando importante papel nas redes tróficas das comunidades aquáticas, por constituírem efetiva ligação entre produtores e consumidores. Este trabalho analisou o comportamento alimentar das larvas de Chironomidae presentes no rio da Fazenda, localizado no Parque Nacional da Tijuca, Rio de Janeiro, Brasil, entre agosto de 1994 e maio de 1995. Os principais itens alimentares encontrados foram algas, fungos, pólen, fragmentos vegetais, restos animais, detritos e silte. O principal item alimentar ingerido pelas larvas foi detrito, exceto para Stenochironomus, cujo principal componente alimentar foram fragmentos vegetais. Os Tanypodinae também exibiram grande quantidade de restos animais de diversos grupos na dieta alimentar. Foi observada variação na dieta alimentar para 16 gêneros. Os Tanypodinae apresentaram principalmente matéria orgânica particulada grossa (> 1 mm) no conteúdo digestivo, enquanto os Chironominae e os Orthocladiinae apresentaram matéria orgânica particulada fina ( 1 mm).