Temporal variation in thermal plasticity in a free-ranging subalpine lizard

• Published in: Journal of thermal biology 2020-07, Vol.91, p.102623-9, Article 102623
• Main Authors: Drummond, Emily M., Senior, Anna F., Hamilton, Katelyn, Gardner, Michael G., While, Geoffrey M., Chapple, David G.
• Format: Article
• Language: English
• Subjects: Body temperature; Critical thermal limits; Laboratories; Liopholis whitii; Locomotor performance; Plasticity; Seasons; Skink; Sprint speed; Temperature tolerance; Temporal variations; Thermal preference
• ISSN: 0306-4565; 1879-0992
• DOI: 10.1016/j.jtherbio.2020.102623

Thermally variable environments are particularly challenging for ectotherms as physiological functions are thermo-dependent. As a consequence, ectotherms in highly seasonal environments are predicted to have greater thermal plasticity. However, much of our understanding of thermal plasticity comes from controlled experiments in a laboratory setting. Relatively fewer studies investigate thermal plasticity in free-ranging animals living in their natural environment. We investigated the presence of thermal plasticity within a single activity season in adult males of a natural high elevation population of White's skink (Liopholis whitii) in south-eastern Australia. This species lives in a permanent home site (rock crevice and/or burrow), facilitating the repeated capture of the same individuals across the activity season. We monitored the thermal variation across the field site and over the activity season, and tested thermal tolerances and performance of male L. whitii on three occasions across their activity season. Maximum and average temperatures varied across the field site, and temperatures gradually increased across the study period. Evidence of temporal plasticity was identified in the critical thermal minimum and thermal tolerance breadth, but not in the critical thermal maximum. Thermal performance was also found to be plastic, but no temporal patterns were evident. Our temporal plasticity results are consistent which much of the previous literature, but this is one of the first studies to identify these patterns in a free-ranging population. In addition, our results indicate that performance may be more plastic than previous literature suggests. Overall, our study highlights the need to pair laboratory and field studies in order to understand thermal plasticity in an ecologically relevant context. •Ectotherms in highly seasonal environments are predicted to have greater thermal plasticity.•We investigated the presence of seasonal thermal plasticity in a subalpine lizard species in south-eastern Australia.•Maximum and average temperatures varied across the field site, and temperatures gradually increased across the season.•Temporal plasticity was identified in critical thermal minimum, but not in the critical thermal maximum.