Visualizing hotspots: Applying thermal imaging to monitor internal temperatures in intertidal gastropods

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 fieldtested 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.