I spotted this orange hairstreak butterfly sitting on a leaf on the side of Mt Joyama in Munakata. You can see that it appears to have another “head” (with antennae) at the back, at the lower edge of the wings. Several kinds of butterflies have these. The theory is that this has evolved to fool predators into attacking the wrong part of the body… In other words, if a bird tries to grab this butterfly by it’s head, it might be the fake head, and the butterfly can escape. Very cunning.
Orange Hairstreak (Japonica lutea) = aka-shijimi in Japanese