An example of Myrmecophily
The butterfly Plebejus argus larva developed in the Lasius niger anthill, secreting substances that ants really like. This is a very young butterfly, her wings are not yet fully spread, and so far she cannot fly away. But probably, she also secretes a substance pleasant to the ants, and the ants, taking this opportunity, lick it.

1 - metamorphosis seemed lengthy and slowed down. Larva in this spot for several days. Silky thread seen here. Will check again today, 11/8/19, following snow and very cold temps (low 20s).

Update, 11/8/19: appears to be dead, in pre-chrysalis stage as shown in original post