Development of glyptotendipes tokunagai (Diptera: Chironomidae) under different temperature conditions

The nonbiting midge, Glyptotendipes tokunagai Sasa (Diptera: Chironomidae), is an organism that can be used as a water quality indicator. Development of this insect under different temperatures was evaluated. The highest egg hatching rate was 99.12 ± 1.47% at 30°C, and the lowest was 84.50 ± 11.09% at 10°C. No eggs hatched at temperatures of 8 and 42°C. Developmental rate (1/h) increased gradually as temperature increased from 10 to 35°C with a peak rate (0.045 ± 0.0079) at 35°C. The estimated lower thermal threshold for egg hatching was 9.3°C. Adult emergence rate was highest (80.6%) at 30°C and lowest (22.2%) at 15°C. The developmental times (egg to adult) for both males and females decreased from 2,102.6 to 457.2 h and from 2,337.1 to 619.8 h as temperatures increased from 10 to 30°C. The estimated lower thermal thresholds for males and females were 11.4 and 10.4°C, respectively. The body sizes of all G. tokunagai decreased as temperature increased from 15 to 35°C. From the results of this study, the approximate rearing temperature for G. tokunagai is suggested to be 25-30°C for egg hatching, larval development, and emergence. Our results demonstrate that G. tokunagai is a potential test insect species that can be reared in the laboratory by providing optimal temperature conditions.