TAYLOR, E.N*; DENARDO, D.F.; MALAWY, M.; Arizona State University; Arizona State University; Arizona State University: A comparison between point- and semi-continuous sampling for assessing body temperature in a free-ranging ectotherm

Studying the thermal biology of free-ranging ectotherms is essential to understanding the relationship between environmental variation, habitat use, and organismal function. Researchers employ several methodologies to gather data on the thermal biology of organisms, including point-sampling using temperature telemetry and semi-continuous sampling using automated systems. However, different methodologies may yield different results, and a comparison of point- and semi-continuous sampling has never been performed. We used intracoelomically-implanted temperature data loggers to obtain semi-continuous (q 2hrs) body temperature data and establish monthly thermal profiles for free-ranging Western Diamond-backed Rattlesnakes (Crotalus atrox). We mimicked both random and non-random point-sampling methods by selecting a single daily data point from all values or from restricted times of day to reflect common point-sampling constraints. We found that thermal profiles generated from point-sampling differed from those generated from semi-continuous sampling, and that the difference was more apparent when point-sampling was non-random. Point-sampling tended to overestimate maximum monthly Tb and underestimate minimum monthly Tb, yielding larger Tb ranges. We conclude that semi-continuous temperature recording provides a more complete and precise estimate of thermal profiles, and that point-sampling methods are highly sensitive to deviations from true randomness.