Laurie presents at the 22nd European Congress of Herpetology
The 22nd European Congress of Herpetology took place in Wolverhampton UK and Laurie Araspin presented her PhD work on Xenopus acclimation:
Locomotion and physiology depending on temperature in Xenopus laevis native and invasive populations
Araspin, L., Measey, J. & Herrel, A.
Ectothermic species are dependent on temperature, which drives many aspects of their
physiology. The distribution of native and invasive populations of the frog Xenopus laevis is
characterised by an exceptional latitudinal and altitudinal range. Along these gradients, the
thermal environment changes and populations experience different temperatures. We assessed
phenotypes depending on the temperature of individuals coming from six native and one invasive
populations. We measured the thermal dependence of locomotor performance in adults given its
relevance to dispersal, predator escape, and prey capture. Results show that the thermal
performance optimum differs among populations, and the minimum critical temperature varies
among populations coming from different altitudes. Then, we compared the standard metabolic
rate (energetic cost of organismal maintenance; SMR) depending on temperature, as locomotor
performance strongly relies on metabolic activity. We tested SMR in populations from the native
range, inhabiting low (South Africa) and high altitudes (Lesotho), and from the invasive range
(France). Regarding the contrasting climatic environments of the studied populations, differences
in the SMR depending on temperature are expected. We found that populations exhibit different
energetic costs in metabolic activity and that populations show reduced metabolic activity in the
temperature range the most encountered in their environment (i.e., in cold temperatures for
populations from colder environments and in hot temperatures for populations from warmer
environments). The ability of this species to change its optimal temperature for locomotor
performance and its metabolic activity across extremely different climatic environments may help
explain its invasive potential. These findings highlight the extraordinary thermal adaptation ability
of the species. This ability to cope with a wide range of variation in environmental temperatures
suggests that the species may be particularly good at invading novel climatic areas.
