Peter Martin writes:
Due to its habit of frequenting hedgerows, this butterfly was, at one time, known as the “Hedge Brown”. In even earlier years, it was called “Hedge Eye” and also “Small Meadow Brown”.
Depending upon the weather, the first butterflies usually begin to emerge from their chrysalides during mid-July, but August is the month when I have seen the greatest number. They are fairly common and the best place for seeing them at Fleet Pond Nature Reserve is probably between the Dry Heath and the Railway.
Ragwort, Fleabane, Marjoram and Buddleia are good nectar sources, as this butterfly’s proboscis is fairly short, but its favourite is probably Bramble.
The Gatekeeper is not difficult to identify. Smaller than the Meadow Brown, its uppersides are orange, with dark brown borders and dark “eye” spots on each wing. Males also have brown bands of scent scales across the orange patches on their forewings. The underside orange forewings have “eye” spots and brown borders, with hindwings being varying shades of brown.
The pale eggs, which are laid singly during August among loose grasses and in shady places under shrub canopies, gradually become mottled and then brown. Light brown caterpillars, with darker stripes, emerge after about three weeks and, after eating part of their eggshells, they nibble tender shoots of Common Couch or other grasses. They hibernate after making the first of four skin changes and resume eating in the spring. The tender grass tips are nibbled at dusk so, if you want to see them, a torch may be needed. They pupate during June.
If you see Gatekeepers well into September, completion of their life cycle may have been delayed by a wet summer!
Picture credit here.