Ascertaining the life history and thermal preferences and tolerances of the hot spring snail Physella wrighti Te and Clarke (Gastropoda: Physidae)

Abstract

Physella wrighti Te and Clarke, 1985 is an Endangered freshwater snail endemic to the Liard Hot Springs. The thermal characteristics of its environment suggest that water temperature (WT) is essential for the snail’s survival. Initially, Physella wrighti’s preferred WT was assessed, with 23 °C preferred. To determine if WT influenced the snail, the activity level, behaviour, survivability, number of egg masses (EMs) produced, number of eggs per mass (EPM), egg volume, EM viability, and incubation period (IP) were examined in 13 °C, 23 °C (preferred WT), and 33 °C water. No differences were found in activity level, but snails in 33 °C left the water more frequently, experienced total mortality, had the shortest survival length, produced the fewest EMs, however, had the shortest IP. Snails in 13 °C survived the longest, produced the most EPM, but had the lowest viability. Snails in 23 °C produced the most EMs and had the greatest viability, EPM did not differ from 33 °C, and IP was between 13 °C and 33 °C. These data indicate that Physella wrighti benefits more from WTs in the lower range of its habitat and has implications for its ecology and conservation.