Thermal tolerance for two cohorts of a native and an invasive freshwater turtle species

Abstract

The ability to tolerate environmental stress may determine invasion success of alien species. Comparative data on physiological thermal tolerance between native and invasive vertebrates are quite limited. Here, we assessed the difference in thermal tolerance between a native (Mauremys reevesii) and an invasive (Trachemys scripta elegans) freshwater turtle species. We incubated eggs of M. reevesii and T. scripta elegans from different cohorts at 29 °C, and measured the critical thermal minimum (CTMin) and maximum (CTMax) of hatchlings. Our results preliminarily showed that the hatchlings of T. scripta elegans had a greater high-temperature tolerance and wider tolerance range than the hatchlings of M. reevesii; in the two-cohort system, individuals from the high-latitude cohort seemed to have greater low-temperature tolerance but similar high-temperature tolerance compared with those from the low-latitude cohort. Relatively greater thermal tolerance ability for T. scripta elegans might reflect its environmental adaptability to thermal stress.