"The Whites, Blues and Coppers have wing surfaces
which reflect, rather than absorb solar energy. Consequently they bask with their wings half open, so that the heat produced by sunlight falling on the dark thorax is contained within the "cage" of the half-open wings, rather than being dispersed on the breeze. This behaviour is called
reflectance basking.
Hesperiine skippers such as Ochlodes Venita adopt a similar strategy, basking with their hind wings outspread, but their fore wings raised at 45 degrees. Skippers have relatively small wings and thick heavy bodies, so they need to beat their wings more rapidly than other butterflies. Using
reflectance basking enables them to
raise their body temperatures quickly to a level that allows them to fly."
Good thing we have such great light metering systems. Would be hard to take all that into account.
Wonder what an image in infrared would look like.