Author: (Linnaeus, 1758)
Species Overview:
Adult: 12-19 mm wingspan; mainly yellow, the forewings reticulate with brownish-orange, partly bordered with black and more or less suffused centrally with dark grey.
Larva: up to 10 mm long; head yellowish green, shining and unmarked, region of stemmata brownish; prothoracic plate greenish; abdomen whitish yellow, translucent; prolegs not sclerotized laterally; pinacula minute, slightly lighter in colour than ground colour of abdomen; anal plate yellowish green; anal comb present; thoracic legs light green. When full-grown the larva becomes bright yellow-green prior to pupation.
Pupa: bright yellow, changing to yellowish brown; in a white silken cocoon spun in a folded leaf of the food plant.
Taxonomic Description:
Male:
Acleris forsskaleana adult
Acleris forsskaleana adults
Acleris forsskaleana male
External characters: 12-19 mm wingspan. Antenna very shortly ciliate; labial palpus, head and anterior portion of antenna yellowish, posterior part of antenna brown scaled; thorax yellowish with rusty-brown transverse fascia anteriorly; similar fascia on tegula postbasally; abdomen yellowish to ochreous. Forewing costa curved to middle, then rather straight; apex rounded; termen straight, not oblique. Forewing ground colour primrose-yellow, conspicuously reticulate with ferruginous-ochreous or brownish-orange, the reticulation partly formed by the radial veins which are similarly lined; markings dark grey mixed with ferruginous; basal fasciae only weakly indicated by strigulae; median fascia linear from costa, strongly angulate before middle, thence broadening to form a greyish suffusion enclosing two small black scale-tufts above middle of dorsum; a thick lustrous blackish grey mixed with ferruginous terminal line from before apex to near tornus; cilia yellow along termen, grey at tornus. Hindwing light ochreous-yellow, paler at base; cilia pale yellow (after Bradley et al., 1973; Razowski, 1984).
male gen. A. forsskaleana
Genitalia: Tegumen broad, rather short, with small terminal lobes; socii large, ovate, slightly tapering anteriorly, with long hair-like scales posteriorly; tuba analis short, broad; valva elongate with well sclerotized costa; sacculus long, concave before middle ventrally, expanding beyond convexity, with small spined termination; brachiola broad. Aedeagus short, tapering posteriorly, provided with four spines, one terminally.
Female:
External characters: Forewing colour and markings similar to male
female gen. A. forsskaleana
Genitalia: Papillae analis very large with very short anterior portions; apophyses short; sterigma rather small with elongate lateral arms and short latero-anterior projections; ostium bursae large, rounded; antrum heavily sclerotized, broadest before sterigma; ductus bursae long; small signum present.
Variation:
Weakly marked specimens lacking the greyish suffusion and pronounced ferruginous-orange reticulation are common, as also are specimens with the markings and reticulation intensified.
Biology:
Larvae occur from September onwards. They hibernate in an early instar, and recommence feeding in the spring, in spun leaves or flowers. Later they feed within a longitudinally rolled leaf. Pupation occurs in June and July, in a white silken cocoon spun in a folded leaf of the food plant.
Moths fly in July and August, frequenting gardens and mixed woodland. During the day the moths rest on the leaves of maple and sycamore and are rather lethargic.
Host plants:
Acer pseudoplatanus, Acer campestre.
Records of this species on Rosa spp. probably concern Acleris bergmanniana.
Damage:
Larvae attack the unfurling leaves and flowers, and, later, inhabit a leaf rolled longitudinally. Although infestations are often common in parks and gardens, damage caused to cultivated plants is unimportant (Alford, 1995).
Distribution:
Europe; introduced to North America.
Pheromone:
Pheromone unknown.
Attractantia:
E 11-14Al
Z 11-14Al (Frérot et al., 1985)
Parasitoids:
Apanteles obscures Nees (Braconidae)
Microgaster tibialis Nees (Braconidae)
Diadromus troglodytes Gravenhorst (Ichneumonidae)