| Popis: |
Tolerance to desiccation was compared among 12 Japanese species of chironomid larvae under the condition of 60% in relative humidity at 25.5 °C. Three parameters were assessed: time to 50% survival (T 50), water loss at 50% survival (WL50) and water loss rate (WLR). T 50, WL50 and WLR were determined as measures of desiccation tolerance, dehydration tolerance, and dehydration resistance, respectively. T 50 was 64.4–142 min for most species, except Propsilocerus akamusi (Tokunaga) which took 872 min. WL50 was 60.6–82.4% for all species. WLR was only 0.0664% per minute for Pr. akamusi, while it was 0.629–1.50% for the other species. These results showed that Pr. akamusi had a high desiccation tolerance due to a high preventive ability of evaporation from body surface. T 50 showed no significant relationships to WL50 or WLR among the 12 species, while there was a significant positive relationship between WL50 and WLR. These results suggest that chironomid species have a trade-off tendency that a species has a high tolerance – low resistance or a high resistance – low tolerance for dehydration. |
