Thermal Impact and the Relevance of Body Size and Activity on the Oxygen Consumption of a Terrestrial Snail, ITheba pisana/I at High Ambient Temperatures

The study focuses on the metabolism of Theba pisana, a Mediterranean land snail now also found along the Atlantic coast. We tested oxygen consumption in response to variables like shell-free mass, temperature and humidity. Results showed that 73.1% of the snail’s oxygen consumption could be explained by these factors. Notably, as temperature increases from 23 °C to 35 °C, the oxygen consumption decreases, while higher relative humidity leads to increased oxygen consumption. The rate of metabolism is proportional to an individual’s mass to the power of an exponent α, which is between 0.62 and 0.77 in the mentioned temperature range. The series of numerical values will be of great importance for future thermodynamics models of land snails. Metabolism, mainly driven by oxygen consumption, plays a key role in life, as it is one of the main ways to respond to extreme temperatures through internal processes. Theba pisana, a widespread Mediterranean land snail, is exposed to a wide range of ambient temperature. In this species the oxygen consumption was tested as a response variable by multiple regression modelling on the “explanatory” variables shell-free mass, temperature, and relative humidity. Our results show that the oxygen consumption of T. pisana can be well described (73.1%) by these three parameters. In the temperature range from 23 °C to 35 °C the oxygen consumption decreased with increasing temperature. Relative humidity, in the range of 67% to 100%, had the opposite effect: if it increases, oxygen consumption will increase as well. Metabolism is proportional to an individual’s mass to the power of the allometric scaling exponent α, which is between 0.62 and 0.77 in the mentioned temperature range. CT scans of shells and gravimetry revealed the shell-free mass to be calculated by multiplying the shell diameter to the third power by 0.2105. Data were compared to metabolic scaling exponents for other snails reported in the literature.