Resistance to anoxia of Chironomus plumosus and Chironomus anthracinus (Diptera) larvae |
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Authors: | Bjö rn Nagell,Carl-Christer Landahl |
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Affiliation: | Research Lab. Environment Protection Board, P.O. Box, S-171 20 Solna, Sweden;Swedish Water and Air Pollution Research Inst., P.O. Box 21060, S-100 31 Stockholm, Sweden |
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Abstract: | Survival of the midge larvae Chironomus plumosus and C. anthracinus in anoxia at 4°C was investigated. C. plumosus survived about twice as long as C. anthracinus . The corresponding LT 50 values were ca 205 and 100 d. There was no statistically significant difference between the survival in anoxia and in aerated water, which indicates that the main reason for death in anoxia is not the absence of oxygen. This main reason is presumed to be starvation. The presence of undissociated H2S in low concentrations (ca 1.2 mg 1−1) did not influence the survival. In anoxia the larvae were usually motionless and did not feed but they increased in weight due to uptake of water. During 43 d C. plumosus and C. anthracinus increased ca. 10%. |
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