STEFAN CADDY-RETALIC^1,2, KIRSTEN BENKENDORFF^1* & PETER G. FAIRWEATHER¹

1School of Biological Sciences, Flinders University, GPO Box 2100, Adelaide SA 5001, Australia

Abstract

Investigating the impacts of climate change highlights a need to rapidly quantify an organism’s thermal environment. We investigated the reliability of non-contact thermal imaging for measuring temperatures in an intertidal gastropod. Thermal maxima from images of either dorsal or ventral surfaces correlated strongly with invasive temperature-probe readings, producing highly significant regression models to predict mantle temperatures from thermal images. Thermal imaging was then field-tested to non-invasively examine temperature changes of snails relative to their substrate: those exposed to sunlight had a mean temperature 4–8˚C above the substrate during the day but 2–4˚C below at night. Thermoregulation was also tested in the laboratory: when exposed to 45˚C for 24 hours, snails reached 35–44˚C, significantly higher than those (18˚C to 25˚C) held at 25˚C. Thermal imaging is reliable for rapidly measuring tissue temperatures in a shelled gastropod typical of intertidal environments, thus providing a powerful tool for testing hypotheses about thermal responses in the changing global environment.

Key words: climate change evaluation, field measurement, Nerita atramentosa, novel methodology, rocky seashore, southern Australia, temperature trends, thermal ecology, Gastropoda