Author: (Denis and Schiffermüller, 1775)
Species Overview:
Adult: 18-22 mm wingspan; forewing ground colour varies from white to ochreous, ochreous-brown, dark brown, purplish brown, and black; the usually prominent discocellular scale-tuft, characteristic of this species, varies in colour from white or cream to brown, orange, and black; in some forms the tuft may be obsolescent and reduced to a few scales; the typical transverse tortricoid markings are usually obsolete, but a light coloured dorsal streak or a brownish median streak is often present. A very variable species.
Egg: light grey and opalescent when first laid, later changing to reddish brown and similar in colour to the bark of a twig; the eggs are deposited singly or in batches of 3 or 4 on the twigs of the food plant.
Larva: head yellowish brown, epistomal region darker; prothorax greenish brown, anterior and posterior margins with darker shading, pinacula black; abdomen grey-green, paler ventrally, a weak narrow dark green dorsal line, pinacula distinct, lighter than integument; spiracles very inconspicuous; anal plate grey-green, with several minute black dots distributed over its surface [Acleris cristana larva].
Pupa: ca. 11 mm; pale brown, wings darker; first abdominal segment without setae; cremaster with eight long setae, four of them situated at the caudal margin of ventral surface, the rest at each side of dorsum. In a flimsy cocoon spun in a folded leaf or amongst debris on the ground [details pupa A. cristana ].
Taxonomic Description:
Male:
Acleris cristana adults 1
Acleris cristana adults 2
External characters: 18-22 mm wingspan. Labial palpus and head brown, thorax darker; abdomen brownish grey. Forewing elongate, slightly expanding terminally, costa strongly curved at base, shallowly emarginate beyond middle; apex slightly retuse; termen rather oblique, sinuate beyond apex, rounded towards tornus. Ground colour and markings variable; originally described as dark brown, usually darker basally, sometimes with weak strigulation; transverse markings obsolete, sometimes a weak indication of a large dark triangular costal blotch; a conspicuous longitudinal white streak along dorsum, the upper edge contiguous with submedian fold from near base to tornus, deeply emarginate at base; a large conspicuous erect wedge-like tuft or "button" of coarse scales near middle of wing before end of discal cell, contiguous with a diffuse black or black-brown dash reaching to end of cell; scattered, comparatively minute tufts of brown or black mixed with white scales, several in tornal area, two more or less evenly spaced between end of cell and apex, one near base above submedian fold and one pure white tuft immediately below fold in angle formed by emargination of white dorsal streak; cilia more or less concolorous with wing, with a dark grey sub-basal line finely edged basally with pale ochreous and finely irrorate outwardly with whitish. Hindwing greyish fuscous, paler basally; cilia grey, with a dark sub-basal line (after Bradley et al., 1973; Razowski, 1984).
male genitalia A. cristana
Genitalia: Tegumen rather slender, with slender terminal lobes; socii subtriangular, elongate posteriorly, bases of socii long; tuba analis very broad. Sacculus slender with ventral edge curved outwards anteriorly, concave before middle, then protruding ventrally, and slightly concave in middle of subterminal portion; spined termination slender; brachiola elongate. Aedeagus rather short, curved, broadening terminally, provided with a short, well sclerotized thorn ventrally; 4-5 short cornuti in vesica.
Female:
External characters: Forewing not expanding terminally; colour and markings similar to male.
female gen. A. cristana
Genitalia: Papillae analis rather slender; apophyses proportionally short; sterigma with elongate, pointed apically, anterior projections; antrum heavily sclerotized, fairly long; ductus bursae long, broadening posteriorly; corpus bursae with rather small, dentate signum.
Variation:
Acleris cristana is a very variable species. The forewing ground colour varies from white to ochreous, ochreous-brown, dark brown, purplish brown, and black. The usually prominent discocellular scale-tuft, characteristic of this species, varies in colour from white or cream to brown, orange, and black; in some forms the tuft may be obsolescent and reduced to a few scales.
In Acleris cristana , the typical transverse tortricoid markings are usually obsolete but when present are very weak and represented by the basal and sub-basal fasciae and the costal blotch.
Forms with longitudinal markings, which are represented by subcostal, median, and subdorsal streaks, are more frequent. The dorsal streak varies from white to cream, yellow and various shades of orange; in some forms the streak is fractured and incomplete. Less frequently a somewhat diffuse longitudinal subcostal streak is present, reaching from base to costa before apex, varying in colour from orange-brown to dark chestnut and purplish black. The costal area of the wing may be concolorous either with this streak or with the ground colour. A short median streak, reaching from the base to the end of the cell and confluent with the subcostal streak, is present in many forms, and varies from yellowish orange to reddish orange and deep chestnut. Almost unicolorous light brown forms without markings also occur (after Bradley et al., 1973).
Biology:
In the UK, moths fly from August to November, then hibernate, concealing themselves in old yew trees and similar dense cover. They are on the wing again from March until May, frequenting forests and wooded areas, and are most often to be found in dense thickets of blackthorn, hawthorn and other trees and shrubs, resting with the wings partly wrapped round the twig. The normal flight period apparently begins at dusk and the moth occasionally comes to light.
Eggs are deposited singly or in batches of 3 or 4 on the twigs of the food plant during the latter half of March and early April. Larvae occur from the end of April to early June and feed within spun leaves and occasionally on the flowers and fruit. Pupation occurs in a flimsy cocoon spun in a folded leaf or amongst debris on the ground, in July and August (after Bradley et al., 1973).
In Korea, moths fly from late April to mid October (Byun et al., 1998).
Host plants:
Prunus spinosa, Crataegus, Malus, Pyrus aria. In captivity the larva will also eat cultivated Prunus and Fagus, Quercus, Carpinus, Betula, Ulmus, Tilia and Corylus.
Damage:
Larvae feed in spun leaves and occasionally on the flowers and fruit. Acleris cristana is of no economic importance.
Distribution:
Central Europe, incl. UK, to Eastern Siberia, Korea and Japan.
Pheromone:
Pheromone unknown.
Parasitoids:
Bessa fugax Rondani (Tachinidae)
Bessa selecta Meigen (Tachinidae)