Respiratory adaptations to oxygen lack in three species of Glossiphoniidae (Hirudinea) in Lake Esrom, Denmark

AbstractThe weight-specific respiration rate (μlO2mg−1AFDWh−1) of three species of leech from Lake Esrom, Denmark, Glossiphonia concolor, G. complanata and Helobdella stagnalis was measured in a closed stirred chamber with a micro electrode. At declining oxygen concentration (mgO2l−1) all three species expressed moderate ability to regulate respiration, in G. concolor and G. complanata down to 2mgO2l−1, in H. stagnalis down to 0.75mgO2l−1. Survival in anoxia was measured in closed bottles. The time to 50% survival (LD50) was 30 days in G. concolor at 20°C and 30 and 4 days in H. stagnalis at 10 and 20°C, respectively. The results were discussed in relation to habitat and spatial distribution of the three species in the lake