Dispersal of Midges (Chironomidae, Diptera) on Terrestrial Area after the Emergence from Saline Lake Shira

Abstract

We studied the number of midges (Chironomidae, Diptera) on the terrestrial area where flows of organic matter and essential polyunsaturated fatty acids (PUFA) provided by the emergence of the amphibiotic insects from saline steppe Lake Shira were dispersed. Records of midge specimens captured on sticky traps showed that 50 and 95 percent of the emerged adults of the Glyptotendipes and Polypedilum genera occurred within 25-m and 100-m strips surrounding the lakeshore, respectively. The areas of these strips were calculated along with quantification of flows of chironomid biomass and essential PUFA per land area unit based on data of previously measured export. For the 25-m lake-surrounding strip, where 50% of midges swarmed, the annual import of dry biomass and PUFA accounted for 1.5 g · m-2 and 15 mg · m-2, respectively. Further, the 100-m wide strip, where 95% of the midges were registered, got the annual flows of 0.7 g dry weight · m-2 and 7.2 mg PUFA · m-2. The calculated values of PUFA import were similar to measurements in relatively productive landscapes. The number of midges captured on the site located near the most productive lake part was the lowest among all the studied near-lake sites. This site of the lakeshore is part of a national preserve, where a great number of insectivorous birds live or stop. The lower abundance of swarming chironomids on this site was likely related to intensive consumption by terrestrial animals, i.e., birds, for obtaining necessary doses of essential compounds

Keywords

• Chironomidae
• emergence of amphibiotic insects
• Chironomidae
• dispersal distance
• saline lake
• South Siberia