engleski

Functional role of chironomid larvae (Chironomidae, Diptera) within a Danube floodplain

In the Pannonian part of the Danube there is a large floodplain area, between 1383 and 1410 rkm, Kopački Rit, supporting very diverse biocoenoses. Freshwater invertebrates form different communities such as periphyton on various substrates, or benthos, and Chironomidae larvae present one of the most constant and abundant taxa groups within them. These communities can be very suitable feeding sites for fish. To test whether chironomids represent the main food in lake’s ichthyofauna, we examined the fish stomach contents. Sampling was conducted using gill net in May 2014 in Kopačko Lake. Fish were weighted, measured and their intestines were emptied, and its contents separated and inspected under a stereoscopic microscope. Out of 258 fish, we found Chironomidae larvae in 98 specimens, most of which belonged to the species Gymnocephalus baloni. Chironomids presented 70% of sorted invertebrates (larvae 64% and pupae almost 7%) and only dipterans which could be indentified among eaten Insecta. The main food source for fish was most likely periphyton, since the recorded chironomid species composition differed from that found in the sediment, and the dominant species, Glyptotendipes sp., Polypedilum nubeculosum, Cricotopus gr. sylvestris and Endochironomus albipennis, are typically found on macrophytes and have been previously recorded as dominant phytophylous species in Kopački Rit. The results confirmed the significant functional role of chironomids in hydrobiocoenoses of lentic systems.

Chironomidae ; ichthyofauna diet ; periphyton ; Glyptotendipes sp.

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