Pammene fasciana

Author: (Linnaeus, 1761)

Species Overview:

Adult: 13-17 mm wingspan; forewing ground colour white suffused with grey, diffusely strigulated with dark grey except a broad, subfalcate medio-dorsal blotch; two or three (sometimes contiguous) black spots above the pre-tornal marking; ocellus edged laterally by thick bluish metallic striae and containing a series of usually six or seven black dashes.
Egg: lenticular-ovate, ivory-white, becoming reddish purple; deposited singly or in small groups, usually along the veins, on the leaves of the food plant in the vicinity of the nuts.
Larva: 12-13 mm long; head yellowish brown, region of stemmata and postero-lateral margin sometimes darkly pigmented; prothoracic plate yellowish brown, medial sulcus very fine, each half of plate with scattered blackish markings extending more or less in a crescent transversely across the middle and a blackish patch at the postero-median angle; abdomen cream-white, spinulation of integument sparse, faintly darker; pinacula greyish brown or dark red; anal plate light brown, sometimes speckled with black; anal comb moderately well developed.
Pupa: 7-9 mm long, red-brown; in a tough silken cocoon in rotten wood or other surface litter or under moss or bark on the trunk of the tree; occasionally in old spongy oak galls.

Taxonomic Description:

Male:

Pammene fasciana adult
Pammene fasciana adults
External characters: 13-17 mm wingspan. Forewing ground colour white, suffused with grey with an admixture of ochreous and orange-ochreous and diffusely strigulated with dark grey except a broad, subfalcate medio-dorsal blotch which is diffusely marked with a blackish strigula on the dorsum, costa marked with dark fuscous strigulae, these producing bluish metallic striae; markings dark grey or brown, obsolescent; basal and sub-basal fasciae forming a strigulated patch, often weak along the submedian fold, its outer edge irregular, strongly angulated at or above middle; median fascia reduced to an oblique streak from costa, obsolete medially and dorsally, bordered distally by two or more irregular, sometimes contiguous, black spots arranged transversely from above middle to near tornus and contiguous with a subtriangular pre-tornal marking; ocellus containing a variable series of usually six or seven black dashes, often fractured or sometimes contiguous, edged laterally by thick bluish metallic striae; cilia grey, with a black basal line, sometimes weakened or interrupted below apex; hindwing fuscous, paler basally; cilia whitish, with a fuscous sub-basal line (Bradley et al., 1979).

male gen. Pammene fasciana
Genitalia: Cucullus only slightly broader than base of valva; ventral margin of valva with shallow notch; entire neck of valva covered with bristles.

Female:

External characters: Similar to male but hindwing usually darker.

female gen. Pammene fasciana
Genitalia: antrum very short; cingulum tubular, not narrowing in direction of ostium; length of postvaginal sclerites 1.5 to 2 times less than length of 7th sternite.

Variation:

Minor variation is found in the forewing colouration and markings. The normally distinct medio-dorsal blotch is sometimes obscured by a greyish suffusion. The beech feeding form is darker then the form feeding on oak and chestnut. The general colouration of the forewing is grey or slate-black, the ochreous colouration reduced, the ocellus usually weak and the curved apical part of the medio-dorsal blotch of ground colour obscured or obliterated by greyish suffusion (Bradley et al., 1979).

Biology:

Pammene fasciana is an univoltine species. Adults of the beech feeding form emerge in May and those of the form associated with oak and sweet chestnut, in June and July. The following reflects the situation of Pammene fasciana on Castanea sativa in Switzerland. Oviposition starts 5-6 days after emergence. Females live for 12 days, male adults die after 8-10 days. The eggs are glued to leaf veins or fruit covers (cupulae). They hatch in about 10 days. The neonate larva first feeds on the outside of the leaf. The feeding track is covered by silken threads, in which faecal pellets are embedded. After two days the larva penetrates the fruit cover and moults there twice. Faeces are disposed of through a hole in the fruit cover. The whitish larva first feeds on the cupula tissues, later on the growing nuts. The third instar larva leaves the emptied fruits through the hole through which excrements were ejected and penetrates an adjacent uninfested nut through a bore hole on the side. The larva attacks a new fruit after the next moult, which is left, usually in August, after termination of feeding. The larva is then in its fifth instar and 12-13 mm long. The full-grown larva spins a cocoon on the stem of the tree. Pupation occurs the following spring in the cocoon (Bogensch├╝tz, 1991).

Host plants:

Quercus, Castanea sativa, Fagus sylvatica.

Damage:

Larvae feed in the fruit of oak, chestnut and beech. They usually remain in the acorns, chestnuts and beech mast and do not bore their way out until after the nuts have fallen, the exit holes being very conspicuous. Acorns attacked by the larvae of Pammene fasciana usually fall before those infested by Cydia splendana.

Distribution:

Western Europe, from England and Scandinavia to Romania; Trans-Caucasus, Asia, Minor, Iran.

Pheromone:

Pheromone unknown.

Attractantia:

Z 8-12Ac
(Chambon and d'Aguilar, 1974)

or

Z 8-12Ac : 3
Z 8-12OH : 1
(Rotundo et al., 1991)

Parasitoids:

Pseudoperichaeta nigrolineata (Walker) (Tachinidae)

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