Essex Skipper
Essex Skipper Thymelicus lineola (Ochsenheimer 1808)
Family: Hesperidae (The Skippers)
Description
Photo above top left by Ben Rees
Photo above top right Chris Abbott (same photo used for header)
Photo above by Emma Walters
The Essex Skipper, like the Small Skipper, is a small orange-brown butterfly, with a fat and short moth-like body. Freshly emerged specimens look very golden in sunlight, but look very drab when worn.
Male and females are alike except that males have a sex brand, which is a thin, black, slightly curving line on upper forewings. Both males and females often rest in a characteristic 'skipper' fashion, with forewings held upwards in a V-shape, and hindwings horizontal. Their flight is fast and darting and the butterflies can be hard to see when nectaring or resting on flowers because of their brown-ish colour.
The Essex Skipper is of often confused with the Small Skipper and it takes some practice to tell them apart. Previously the Essex Skipper was extremely rare in Yorkshire so this was not an issue but it is now becoming more common and appears to be gradually moving north. Therefore it can no longer be assumed that all small golden skippers are Small Skippers.
The key identifying feature of an Essex Skipper are sharply defined, glossy black tips to the underside of each antenna. lt looks like the antennae tips have been dipped into black ink, leaving a stain on the undersides, but not the uppersides. The antennae are often bright orange-brown above and paler underneath, with the black tip forming a sharp contrast. They can also be darker with an orange-brown patch adjoining the black tips. Small Skipper underside antennae tips are rather variable, from orange brown to dark brown and can look as though they also have black tips, but with less sharply defined edges and the darkness extending above and below the tips.
Male Essex Skippers can also be identified by their shorter, straighter sex brands, which are parallel to the forewing edge (compared to the Small Skipper's longer brand being at an angle). Both male and female Essex Skippers also tend to have slightly thicker black edges to their wings than Small Skippers, but this can be variable.
Habitat
The Essex Skipper is a grassland species, choosing areas of wild tall grassland, but not with very lush grass. It can be seen along road and rail verges, grassy embankments, open woodland rides and is particularly found in wetlands and saltmarshes; for example, the saltmarshes on the north bank of the Humber. The larval foodplants are on Cock's-foot Dactylis glomerata, or Creeping Soft-grass Holcus mollis, as well as a whole range of other grass species.
Distribution
The Essex Skipper is a fairly recent resident species for Yorkshire because Yorkshire is on the northern edge of its range. It was rarely seen before 1996 and was only recorded in very low numbers until the last year or two.
It’s not clear why the species is spreading north so quickly but may be due to the habitats and grasses being right for it, global warming, or hay movements. It might also be due to being able to spread along road verges which are mowed less often than they were.
Life Cycle
Pale eggs are laid in small groups on the foodplants and the larvae develop inside tough eggshells in which they remain through hibernation until the following April. These eggs are well adapted to a life in fens and saltmarshes and can withstand the prolonged immersion of winter flooding. As the butterfly is also a typical species of hayfields and the eggs are not easily destroyed, they can be transported with the hay to other sites. lt is thought this is how the species has spread so successfully in North America.
After five instars larvae pupate in a silken cocoon spun inside a cluster of leaf blades at the bottom of a tussock. Essex Skippers form colonies, which vary a huge amount in size and, though they spend the daytime on their own, in the late afternoon they come together to bask and later to roost communally. Adults fly from late June to the end of August or early September. Although they overlap with the Small Skipper, they tend to peak much later, in late August. Therefore, any skippers still flying past mid-August should be checked to see which of the two species they are.
Status
The species is not under threat.
Aberrations
With thanks to the Butterflies of Yorkshire edited by Howard M Frost
C Jones 04/01/21