The park’s first ringlet butterfly (Aphantopus hyperantus) of the year was seen and photographed in Sleepers Field on June 10th. This newly hatched adult was a smooth, velvety dark brown fringed with white, its underwings clearly marked with the rings that give the species its common name.
The ringlet overwinters as a caterpillar, hidden inside the leaf sheath of one of several different species of grasses. This is an intermittent hibernation: the caterpillar, a night-feeder, will emerge to feed during warm winter evenings. In the spring, when the temperature rises, it begins to feed in earnest. It pupates in the late spring, forming a pupa inside a fragile cocoon of silk threads, low down in a tussock of grass.
The adult butterfly usually emerges in late June; the one that was seen in the park on June 10th was exceptionally early. The female feeds on nectar, particularly that of brambles and creeping thistles, until she is ready to mate and lay her eggs in the grass, usually in July. She doesn’t glue the eggs to grass blades, she scatters them rather haphazardly from a low perch. Most stick to the grass as they fall but many end up on the ground. The eggs will hatch in August and September to produce a new generation of caterpillars that will feed in the grass until they are ready for next winter’s hibernation.
Conservation status: not threatened; population and distribution both increasing