Demographic Traits Variation in a Pyrenean Newt (Calotriton asper) among Lacustrine and Stream Populations

Abstract

Demographic traits were analyzed in the Pyrenean brook newt (Calotriton asper) to evaluate whether its variability responds to the adaptation to the different habitats. In this study, life history traits of Calotriton asper were studied in nine populations living in two different kinds of habitats in the Pyrenees mountains: lakes and streams. Skeletochronology was used to determine age structure and different traits such as age at maturity and longevity. Age structure was different between populations and sexes. The two lacustrine populations, with facultative pedomorphosis, attained their maturity earlier. Age at sexual maturity ranged from 4 to 9 years and in some populations was similar between sexes while in others, females matured at younger ages than males. Maximum longevity varied from 7 to 35 years among populations and was correlated with the age at sexual maturity. Body size differed among populations, was sexually dimorphic, and this disparity was not related to the kind of habitat. The maximum size was found in the lacustrine population but exhibited high variation between populations. The results obtained show a significant variability between sexes and populations, in age and body size structure of Calotriton asper that did not depend on the habitat.

Is the Pyrenean newt (<em>Calotriton asper</em>) a thermoconformer? Cloacal and water temperature in two different thermal periods in a Pre-Pyrenean stream population

“…In general, studies on the growth of C. asper provide very different data depending on the population (Miaud and Guillaume, 2005). Looking at what has been described for other species of aquatic urodeles, these differences could be explained by the great variability of environmental conditions in which the populations inhabit (Camarasa et al, 2020;Dalibard et al, 2022), the genetic structure of the species (Lucati et al, 2020), local adaptations (Miaud Merilä, 2001), or the phenotypic plasticity in SMR (Guillaume et al, 2020). However, the lack of studies in this regard for C. asper prevents from elucidating the specific mechanisms behind the observed responses, which are probably not because of a single factor but of several causes that may be acting synergistically.…”