Loxura cassiopeia numana (Fruhstorfer, 1912) , commonly called the Sumatran yamfly, is a Lycaenid butterfly with a habitat distributed on the island of Sumatra.
These photos were taken near the Saweuk River in North Aceh. At that time, I noticed two yamflies mating. Insects mating? That's the best moment to take photos. Don't worry, because insects mating will ignore you.
The first one is pale yellow, and doesn't have tassels (it's probably a male), while the other one is bright saffron and has two tassels (this one may be a female).
Currently, the dry season is still ongoing. So I dare to conclude that the mating season for yamflies can occur at any time, both during the dry and rainy seasons.
All these photos are my original work, taken with a Xiaomi POCO NFC smartphone and an assembled external macro lens.