File:Sun-Basking-in-Red-Wood-Ants-Formica-polyctena-(Hymenoptera-Formicidae)-Individual-Behaviour-and-pone.0170570.s002.ogv

English: Supplementary Material. Thermographic video showing behaviour of ants visiting a hot spot. A hot spot with a cluster of sun-basking ants is visible in the upper left corner (yellow-orange spot), which was generated with an IR lamp in a laboratory setting. In the upper and lower corners on the right, a vessel with water and a food patch are visible (both cold, depicted in dark blue). Two warm ant workers (orange) emerge from the cluster (time 00:00:01:30). They are heading down to the nest entrance (in lower part of screen) and spent some time exploring the bridge leading to the nest entrance (time 00:00:13:50). One of these workers enters the nest (time 00:00:37:05), while the other turns back and return to the hot spot after a while (time 00:01:01:23), joining the ants in the sun-basking cluster (time 00:01:07:15). On the top, a cold ant moves towards the hot spot (time 00:00:42:00), walks around and remains at the cluster, reaching a higher body temperature (00:01:01:00). Please note that ants leaving the hot spot slowly cool down over time, since the false colour is changing from bright orange to red and pink, which represents a temperature change from 23.5 to 21°C. The ants’ gaster cools down slower than other body parts. The thermographic video was taken during preliminary trials performed at ca. 15 ± 1°C ambient temperature. For the experiments presented in the manuscript, only long-term digital videos were used because the tags used to individually mark ants cannot be recognized on thermographic videos, and ambient temperatures were set at 10°C.