Author: (Hübner, 1799)
Illusory tortricid
Species Overview:
Adult: 15-22 mm wingspan; forewing white to greyish or pale greyish brown, with dark brown markings; basal patch indistinct or completely atrophied.
Egg: white batches [Syndemis musculana egg batch].
Larva: 18-22 mm long; head yellowish brown varying to orange-brown, region of stemmata and posterior margin dark brown; prothoracic plate greyish brown varying to yellowish brown, marked with black posteriorly; abdomen varying from olive-green or yellowish green to grey-brown or blackish brown, paler ventrally, a broad dorsal line slightly darker than ground colour; pinacula rather prominent, paler than ground colour; anal plate greenish or yellowish brown, sometimes with darker mottling [Syndemis musculana larva].
Pupa: blackish brown, in the larval habitation or in a loosely spun cocoon amongst leaf litter on the ground.
Taxonomic Description:
Male:
Syndemis musculana adult
Syndemis musculana males
Syndemis musculana male
External characters: 15-22 mm wingspan. Labial palpus, head and thorax brownish grey. Forewing weakly expanding posteriorly; costa bent throughout; apex rounded; termen oblique. Costal fold narrow, short. Forewing ground colour white suffused with grey, sparsely irrorate with blackish; markings dark brown, often with a slight ferruginous admixture; basal fasciae indistinct, outer margin almost vertical, sinuous, angulate at middle; median fascia well-developed; cilia pale, rather concolorous with ground colour. Hindwing grey (Bradley et al., 1973).
male genitalia S. musculana
Genitalia: Uncus slender, with rudimentary group of ventral hairs terminally; socius small; arm of gnathos simple. Valva ovate, with fairly small folded area of disc and small but well-defined anterior sclerite fusing with transtilla; sacculus with posterior plate; transtilla a simple transverse plate, weakly expanding laterally. Aedeagus with small coecum penis and slender caulis.
Female:
Syndemis musculana females
Syndemis musculana female
External characters: Forewing broader than in male, without costal fold; colour and markings as in male.
female gen. S. musculana
Genitalia: Sterigma moderate, concave medially with short antevaginal portion, membranously connected with antrum; antrum short, well sclerotized; inception of ductus seminalis situated just before antrum. Ductus bursae long, with short, median cestum; corpus bursae fairly small, rounded; signum rather small.
Variation:
This species shows considerable individual variation in the forewing ground colour, which ranges from white to grey-brown, and in the intensity of the markings.
Subspecies:
In Japan, the species is represented by the subspecies Syndemis musculana nipponensis Yasuda. It differs from the nominative one in having dents on the aedeagus.
In the North America the species Syndemis afflictana (Walker) occurs. This species is probably no more than a geographical race of Syndemis musculana.
Biology:
There is only one generation a year. In the UK, moths fly in May and June and sometimes early July, frequenting especially lanes, open woodland and the borders of forests, also mountain moorland. They may be readily disturbed from rest amongst vegetation during the day, flying from late afternoon until well after dusk. Larvae feed from July to September or October, living in a compact tube of spun leaves or in a folded leaf. Like no other Tortricid species, they remain concealed between the leaves of the food plant. They then hibernate in the spinning and pupate in the spring (April and May) in the larval habitation or in a loosely spun cocoon amongst leaf litter on the ground (Bradley et al., 1973).
Material from Korea, studied by Byun et al., 1998, was collected in May. According to Byun et al., 1998, the Korean species probably belongs to the nominate species.
Material of the Japanese subspecies nipponensis, studied by Yasuda, 1975b, was collected in June.
Host plants:
Larvae of this common species are polyphagous and will feed on various trees and shrubs and occasionally on herbaceous plants and grasses. It is normally associated with birch (Betula), oak (Quercus) and wild blackberry (Rubus), but it can also occur on apple (Malus), raspberry (Rubus idaeus), linden (Tilia), larch (Larix), pine (Pinus), spruce (Picea), Douglas fir (Pseudotsuga menziesii), willow (Salix), mountain ash (Fraxinus), aspen (Populus tremula) and Vaccinium.
Damage:
S. musculana damage on apple
On apple, older larvae may attack mature fruits, causing superficial but often extensive damage.
In forest nurseries larvae have been found causing damage to young conifer seedlings, especially larch, pine and Douglas fir. Larval habitations cause noticeable distortion of terminal shoots and can affect the quality of the young trees and shrubs.
Distribution:
Europe to Siberia, Korea and Japan.
Pheromone:
Z 11-14Ac : 1
E 11-14Ac : 9
(Persoons et al., 1984)
Parasitoids:
(record from the Netherlands)
Glypta varicoxa (Ichneumonidae)
Colpoclypeus florus (Eulophidae)