Effect of thermal acclimation on preferred temperature, avoidance temperature and lethal thermal maximum of Macrobiotus harmsworthi Murray (Tardigrada, Macrobiotidae)

✍ Scribed by Xiaochen Li; Lizhi Wang

• Publisher: Elsevier Science
• Year: 2005
• Tongue: English
• Weight: 216 KB
• Volume: 30
• Category: Article
• ISSN: 0306-4565
• DOI: 10.1016/j.jtherbio.2005.05.003

✦ Synopsis

In order to understand thermal adaptation of the tardigrade Macrobiotus harmsworthi, and to test the optimality models, we measured preferred temperatures, avoidance temperatures and lethal thermal maxima of this species in an artificial thermal gradient after it was acclimated to either 2 1C or 12-22 1C for 2 weeks. The preferred temperature of the animals acclimated to 2 1C was 14 1C; the preferred temperature of the animals acclimated to 12-22 1C was 18.6 1C. There was significant difference between the preferred thermal intervals of animals acclimated to different temperatures (F ¼ 12:13, P ¼ 0:00085, df ¼ 1, N ¼ 74). There were two higher peaks in the preferred thermal interval of individuals acclimated to 12-22 1C. The avoidance temperature of the animals acclimated to 2 1C was 36 1C; the avoidance temperature of the animals acclimated to 12-22 1C was 35.1 1C. There was significant difference between the avoidance temperatures of the animals acclimated to different temperatures (F ¼ 23:562, Po0:0001, df ¼ 1, N ¼ 34). The minimum avoidance temperatures of the animals acclimated to either 2 1C or 12-22 1C were 0 1C. The lethal thermal maximum of the animals acclimated to 2 1C was 38.7 1C; the lethal thermal maximum of the animals acclimated to 12-22 was 38 1C. There was significant difference between the lethal thermal maxima of the animals acclimated to different temperatures (F ¼ 16:921, P ¼ 0:000244, df ¼ 1, N ¼ 35). Therefore, thermal acclimation imposed significant influence on the preferred temperatures, avoidance temperatures and lethal temperatures of M. harmsworthi. M. harmsworthi is an eurythermal species. The main results from our study support the optimality models.