Cryptic Wood White Pieridae

Leptidea juvernica Williams, 1946

Description: Wingspan c 42mm. The upper side of the forewings are white apart from a dark grey to black apical spot. The underside of the hindwings are tinged green with grey markings on most Irish specimens. The tips of the antennae are brown underneath. Females are larger than males and have less pronounced markings.

Similar Species: Recent research has shown that there are two species of Wood White in Ireland. These can only be safely separated by examination of the genitalia. The adults of both wood whites are similar in size to the Green-veined White, Small White and female Orange Tip. At rest the Cryptic Wood White should be easily recognised by the less extensive dark markings, the more rounded and slender wings and the colour and patterning of the underside of the hindwing. In flight it may be more difficult to distinguish. This species is often stated to have a more floppy, delicate flight action, but this can often be hard to judge.

Key Identification Features:

Sets:  male upperside male underside female upperside female underside

Flight Period: In N. Ireland single-brooded flying from May to mid July. Occasional specimens have been reliably reported in August. These are probably second brood specimens, which is normal occurrence in Europe but which appears to be a very rare event in N. Ireland.

Status: The exact distribution of both Wood Whites needs to be determined, but it appears that only one species, the Cryptic Wood White Leptidea juvernica, is found in N. Ireland. The true L. sinapis is apparently confined to the Burren area of Co. Clare. The 'wood white' has been recorded from most of N. Ireland, most commonly in lowland parts of Armagh, Down and Fermanagh. It is much more local further north. Before 1950 the species was considered very rare and an increase was noted in the 1960's. This may have stopped or even reversed in recent years.

Ecology: More investigation is needed into to the ecology of the Cryptic Wood White in Ireland and how it differs from the true Wood White Leptidea sinapis. The wood whites are colonial species found in sheltered grassy sites at the margins of scrub and woodland. The principal larval foodplant is Meadow Vetchling Lathyrus pratensis, but there are records of it using Bush Vetch Vicia sepium and Bird's-foot trefoil Lotus corniculatus. Adults feed on any flowers available in the habitat and will also drink from puddles. The well-camouflaged larvae feed singly on the leaves of the foodplant. The overwintering stage is the pupa.

World Distribution: Wood whites are found in most of Europe apart from northernmost Scandinavia, in Asia Minor and east to western Siberia. Another species, Réal's Wood White is confirmed from many countries of western Europe but has not been found in Britain. In many areas the two species are sympatric.

Bradley & Fletcher number: 430856 Agassiz number: 58.002

Additional information:

UK Butterflies account


 Thompson, R. S. & Nelson, B., 2003 (Oct 2). [In] The Butterflies and Moths of Northern Ireland