It is believed that the word “butterfly” is a derived from “butter-coloured fly” which relates to the yellow wings of the male brimstone butterfly. Another mystery of etymology solved!
The brimstone (Gonepteryx rhamni) is also known as the “primrose”. It appears in early spring when primroses are in bloom and does look rather like an airborne primrose gently flapping past.
The wing shape is pointed like a leaf. Brimstone is another word for sulphur, but only the male has such bright colouring. The female is a much paler cream. The underside of the wings in both sexes bears a brown dot. The upper side of the wing (difficult to glimpse) has the dot in orange.
Brimstone is one of the few species that hibernates as an adult and therefore appears so early in spring. Caterpillars feed on leaves of buckthorn. I don’t believe we have any buckthorn in our bit of the woods, but there must be some in the area. Perhaps a candidate for our next round of diversification planting?