Final Thermal Preference in Parthenogenetic Females of Daphnia magna Straus (Crustacea: Cladocera) Acclimated to Various Temperatures

摘要

The final thermal preference (FTP) range in parthenogenetic females of cladoceran Daphnia magna was assessed by "acute" and "chronic" methods. The first method included 4-month acclimation to different temperatures in the range of 14.2 ± 0.7 to 27.1 ± 0.3℃; the "chronic" method was characterized by long-term acclimation to +20℃. Two ranges of FTP were found for D. magna, 13.3- 15.4℃ and 20.2-26.2℃. The thermal preference of daphnids and the temperature of acclimation were correspondingly linearly. The range of FTP was independent of the season. The searching activity of D. magna rose in April, when the FTP range increased, and the FTP was less pronounced.