In all but the most northerly parts of Britain, Holly blue butterflies have two broods every year (and, very very occasionally, in southern Britain, depending on the weather, a late third brood), and the males of the second brood started to emerge in my area around the end of June.

As with many butterfly species, though the Holly blue butterfly feeds primarily on aphid honeydew, the males also gravitate towards damp earth, decaying vegetable matter, and the poo of other creatures, which might seem fairly disgusting to us humans, but is for them the source of essential salts and minerals.

Judging by the number of Holly blues I saw doing this at a local park recently (two males together in two separate locations), they seem to feed this way very soon after they hatch. I’ve since read that the salts they absorb from this feeding behaviour help to fuel their flight muscles and also that they then transfer the minerals to female Holly blues when they mate, which helps with egg production, so it makes sense that this mineral and salt absorption happens before they start searching for emerging females to mate with.