Wall butterfly – Lasiommata megera

So many species are on the decline because of urbanisation, intensive agriculture, and, of course, climate change. Yet some are taking advantage of the new conditions. A butterfly is redrawing the map of Britain with little fanfare. A couple of observers spot something unusual at the edge of a field, others check-in a few days later and see the same species, and suddenly a butterfly that in the post-industrial world seemed limited in its range, is now finding new territory in the margins.

The Wall, Lasiommata megera, has become one of those intriguing contradictions of British wildlife. It’s generally found on the coast but had declined inland. Yet in parts of eastern England it now appears to be probing new territory, establishing small footholds along farm tracks, sunny verges, and rough, stony field edges.

It is often assumed that the name comes from the butterfly’s habit of basking on stone walls, which it does. But, the word wall doesn’t necessarily mean an upright bricks and mortar construction, it can mean an embankment or rampart of earth and stone. That said, when it was named the Wall, we probably already used the word wall to mean those brick and stone constructions.

The male Walls are especially territorial. They pick a sunny perch, launch themselves at passing insects, then return to exactly the same spot. That kind of behaviour makes revisit a sighting site worthwhile. A butterfly seen several days earlier may not have moved on at all. If the habitat suits it,  sparse grass, shelter from the wind, warmth and open ground, it may still be there, patrolling its chosen stretch in search of a mate. The females may randomly happen up on a male’s territory and the fun can begin.

It’s nice to hear of positive wildlife stories when so many are negative. There should definitely be a pun about knocking down or building walls. But, to be honest, there are no headlines, no fanfares, just a butterfly finding its own corner of England that is no longer foreign.

Incidentally, The Wall is often called the Wall Brown. It’s one of several species of Brown, the Satyrinid butterflies, which includes Meadow Brown and even Marbled White.