Ringlet is strictly a single-brooded species throughout its global distribution. Occasional records beyond mid-September are more likely to be aestivating individuals (a behaviour better known from the related Meadow Brown) than evidence of a second brood. In Yorkshire, the flight period typically extends from late May to late August, peaking around the beginning of July. However, individual colonies are often short-lived, flying for only a few weeks within the countywide flight period.
Non-adhesive eggs are dropped in flight or ejected whilst females sit on grass heads. Initially, each dome-shaped egg is a pale primrose yellow and the shell glossy and transparent. Larvae can be seen through the shell prior to hatching after about 18 days. Once hatched, they feed until about late Oct then partially hibernate after the 3rd instar. Feeding continues whenever conditions are mild, although growth is slow. Later stage larvae are easiest to find by torchlight at night. They reach about 2cm in length by June and then pupate at the base of grass tussocks, emerging after about a fortnight.
As eggs are simply ejected into grassy areas, often whilst the female is flying, it is difficult to track down the range of grass species used by the large, but this is thought to be quite restricted. Thomas & Lewington (1991) note Cock’s-foot Dactylis glomerata and Wood False Brome Brachypodium sylvaticum as favourites, whilst Emmet & Heath (1989) give Tufted Hair-grass Deschampsia cespitosa as frequently used, and Creeping Bent Agrostis stolonifera as less commonly used. A wider range of grasses has been accepted in captivity.