Very pleased to have my PhD student, Danilo Giacometti’s paper accepted recently in Royal Open Science. This represents the culmination of over a year’s work carefully measuring temperature selection. He has a much better blog post here on the subject by Danilo Giacometti, but I’ll post the abstract and citation below.

Abstract

Temperature seasonality plays a pivotal role in shaping the thermal biology of ectotherms. However, we still have a limited understanding of how amphibians maintain thermal balance in the face of varying temperatures, especially in fossorial species. Due to thermal buffering underground, theory predicts relaxed selection pressure over thermoregulation in fossorial ectotherms. As a result, fossorial ectotherms typically show low thermoregulatory precision and low evidence of thermotactic behaviours in laboratory thermal gradients. Here, we evaluated how temperature selection (T_sel) and associated behaviours differed between seasons in the Spotted Salamander (Ambystoma maculatum). By comparing thermoregulatory parameters between the activity and overwintering seasons, we show that A. maculatum engages in active behavioural thermoregulation despite being fossorial. In both seasons, T_sel was consistently offset higher than prevailing thermal conditions. Thermoregulation differed between seasons (see table below), with salamanders having higher T_sel and showing greater evidence of thermophilic behaviours in the active compared to the overwintering season. Our study highlights that the combination of behavioural and thermal biology measurements is a necessary step to better understand the mechanisms that underlie body temperature control in amphibians. Ultimately, we provide a broader understanding of thermoregulation in the context of behavioural responses to seasonality in fossorial ectotherms.

Citation

Giacometti, D and Tattersall, GJ. 2024. Seasonal variation of behavioural thermoregulation in a fossorial salamander (Ambystoma maculatum). Royal Open Science, https://doi.org/10.1098/rsos.240537