Why is a butterfly actively looking for cool, dark spot, long before dark?

Question

Here in Croatia, the Woodland grayling *Hipparchia fagi* flies constantly in the garden of my holiday home. \nYesterday, I observed that one of these bufferflies was **actively looking for a cool/dark spot around 6 pm**. First it hid at a wall in a shaded corner behind a bush. During the day these butterflies are very alert, but this specimen could be approached to a few cm. Finally it flew away, to take refuge inside the house, even more cool and dark. Again, it didn't move until I blew it away (couldn't lock it in, could I). \n\nNow, my question is **why this butterfly behaved like this.** \n\nI am convinced it did not seek shelter from the heat, because they keep flying during the hottest part of the day.\n\nWas it already looking for a place to spend the night? That seems rather early. At 6 pm, the sun is going down a bit, but temperature is still around 30 degrees and it won't be dark for 3 or 4 hours. Other butterflies like Iphiclides podalirius are still active. Or has H. fagi a higher heat demand than other species? That seems inconsistent with its habitat (woodland). Any thoughts?

Answer 1

Hi Asked,

Most butterflies stop foraging when their nectar suppliers stop producing for the day. Do other Woodland graylings generally keep successfully foraging around your garden until sunset?

Some possibilities: usually you observe males, staking out territory. Females may not behave thus (as in other graylings). Or perhaps he(?) was having a gender-identity crisis -- do you have neonicotinoid use in your part of the world?

They do seek to actively warm themselves, if cool -- but usually just re-orient to avoid too much rays as needed.

Any reported parasite problems on graylings around you? The evening behavior of bumblebees certainly is affected by mite infestation, around us in America. (Mited bees hang out on flowers for the night, no matter how cold. This avoids importing the mites to the nest.)

-- Cheers, - Mr. d.