Respiration rates in Bithynia tentaculata (L.) (Gastropoda: Bithyniidae) in response to acclimation temperature and acute temperature change

Abstract

The aerobic metabolic rate of the freshwater prosobranch Bithynia tentaculata (L.) was measured as the rate of oxygen consumption by groups of snails acclimated to temperatures of 12°C, 18°C and 24°C. Responses to acute temperature alteration were also monitored. The results revealed that metabolic rate is essentially independent of ambient temperature: no differences were found among the respiration rates of the three differently acclimated groups. Metabolic effects of acutely elevated temperature were usually compensated in a highly efficient manner, resulting in low Q10 values between 1.08 and 2.24. However, the 12°C-acclimated snails remained inactive at temperatures above 18°C, which is a typical stress response in B. tentaculata. The same behaviour occurred in 24°C-acclimated snails at experimental temperatures below 24°C. In both cases no active respiration rates could be determined. When the 18°C-acclimated group was exposed to an experimental temperature of 12°C, their oxygen consumption rate declined with a Q10 of 5.53. In relation to previous findings on life-cycle strategy, as well as nutritional and reproductive physiology in B. tentaculata, the present results are discussed in the context of a seasonally controlled metabolism, reflecting the seasonally varying physiological needs of this species. © The Author 2005. Published by Oxford University Studies, all rights reserved.