The month of June heralds the emergence of Skipper butterflies at St Nicks, bringing a welcome gleam of gold on flower heads, especially in the grassy areas. Of the eight British skipper species Small Skipper Thymelicus sylvestris and Large Skipper Ochlodes sylvanus can always be found on the reserve in summer, while a further two are found in smaller numbers elsewhere in Yorkshire – Dingy Skipper in chalk and limestone areas, and Essex Skipper in the south of the county.
Large Skippers are usually the first to emerge from pupation at St Nicks, in early-to-mid June. Small Skippers follow from late June onwards. Both adult species avidly feed on nectar from the flowers of thistles, knapweeds, trefoils, vetches, clover and bramble, gaining strength for courtship and mating. Their English names are not a reliable key to their identification: there is much overlap in size between the two species, though most Small Skippers do tend to look a little smaller than the Large. In Large Skippers the antennae are hooked at the ends, as shown in some of the photos.
They are fast and fluttery fliers: the Small Skipper’s genus name is taken from a dancer in ancient Greek drama – Thymelicus – who tripped and skipped across the stage. When a resting or feeding skipper is approached it is quick to take off, yet careful stalking will allow a close view of these attractive little butterflies. They have a characteristic resting position, with the upperwings held in a V shape while the underwings lie horizontally (see photos).
Small Skippers are plainer than Large, their uniform pale golden-orange wings contrasting with the Large Skipper’s more mottled orangey-brown appearance with a faint chequerboard wing pattern. In both species, but especially the Large Skipper, males can be identified by a diagonal dark stripe across each upper wing – ‘scent brands’ – which are scales containing pheromones to attract females. The genus name of the Large Skipper – Ochlodes – means ‘turbulent, unruly’ and males of this species, like robins, engage in sometimes violent aerial conflicts with each other.
A skipper’s life begins when a mated adult female deposits eggs on the larval food plants. The Large Skipper lays single eggs on the underside of a blade of Cock’s-foot grass Dactylis glomerata, while the Small Skipper lays small batches of 3-8 eggs in leaf sheaths of Yorkshire Fog Holcus lanatus. Both these grasses are found in abundance at St Nicks. On hatching, usually in August, the larvae first eat their own eggshells, then Small Skippers straightaway spin a silk cocoon (called a hibernaculum) with their siblings and hibernate for the autumn and winter ahead. The single Large Skipper caterpillars make a tube for themselves with the blade of grass, joining the edges together with threads of silk, and foray out from there to eat. A few weeks and four moults later they too spin a cocoon for over-wintering.
Perhaps this explains the earlier emergence of the Large Skipper butterflies: their caterpillars have a four-moult headstart on their Small Skipper relatives! In spring the larvae of both species wake up from their silk-sheeted hibernation, and continue feeding until they are ready for pupation, which takes place low down in the grass plant. In the pupa the body cells break down and re-form, metamorphosing into the butterfly that emerges to continue the life story. Adult butterflies live for about a week.
The little Skipper butterflies are among the most charming of the insect species found at St Nicks, and are often overlooked when the larger and more flashy butterflies are about. The many Buddleia bushes on the reserve attract most butterfly species with their abundant and nectar-filled blooms, so among the charismatic Red Admirals, Peacocks and Commas this summer look out for the pretty golden skippers, then spot them among the thistles and brambles too. Good skipping!
All photos taken at St Nicks