Author: (Linnaeus, 1758)
Pine resin-gall moth
Species Overview:
Adult: 16-22 mm wingspan; forewing ground colour white, strigulated and partially reticulate with silvery metallic and plumbeous, and with blackish brown markings forming irregular incomplete bands and strigulae; hindwing dark fuscous.
Egg: pale yellow, turning dark yellow during development; deposited singly on the young shoots, usually near the bud whorl.
Larva: about 12 mm in length; head dark chestnut-brown; prothoracic plate dark brown or dull black, medial sulcus distinct; abdomen glossy yellowish brown or pale red; pinacula small, black; anal plate small, dark brown (description Bradley et al., 1979) or: head, prothoracic shield and brownish yellow, anal shield paler than prothoracic shield, with dark spots; abdomen yellowish white to brownish yellow; pinacula yellowish brown (description Schröder, 1966).
Pupa: head, thorax and wings brown or blackish brown, abdomen reddish brown dorsally, brown ventrally; anal segment with 4 hooked bristles dorsally and 2 pairs of hooked bristles ventrally; intersegmental cuticle with spines; frons as illustrated [pupa R. resinella, head pupa R. resinella ].
Taxonomic Description:
Male:
Retinia resinella male
Retinia resinella adults
External characters: Forewing without costal fold; ground colour white, strigulated and partially reticulate with silvery metallic and plumbeous; markings blackish brown, minutely irrorate (tips of scales) with white, fractured and forming irregular incomplete bands and strigulae; cilia grey, with a dark basal line. Hindwing dark fuscous; cilia white, with a dark grey basal line (Bradley et al., 1979).
male genitalia R. resinella
Genitalia: Uncus reduced; gnathos absent; socii very long and narrow, curved outwards. Valva with clasper and deep notch on ventral margin. Length of cucullus 1.5 times greater than width.
Female:
External characters: Similar to male, but usually larger.
female genitalia R. resinella
Genitalia: Sterigma cylindrical, lamella postvaginalis slightly hairy. Ductus bursae with large cingulum near corpus bursae, ductus seminalis situated here; two signa present in corpus bursae.
Biology:
larval habitation R. resinella on Pinus
The moths are on the wing in June and deposit their eggs singly on the current year's shoots. The larva hatches from the egg in about three weeks and bores into the base of the needle under cover of a small silken web, later excavating a groove on the surface of the shoot between the needle and the bud whorl. This groove is roofed over with silk and resin and, by the time of hibernation, a small resinous gall about the size of a pea has been formed immediately beneath the bud whorl. In the following spring the larva continues to feed and grow causing the resin-gall to enlarge until it measures two to three centimeters in diameter. The second year's resin actually encloses most of the first year's gall, so that there are two distinct chambers. By the second autumn the larva is full-grown. It pupates the following spring and the pupa forces its way through the side of the gall, to release the adult. Pupation lasts 3 to 4 weeks (Scott, 1972; Schröder, 1966).
Host plants:
Pinus sylvestris.
Damage:
gall-forming by R. resinella
The two-year life cycle of Retinia resinella apparently produces peak emergences of moths in odd-numbered years in the UK. The damage caused by this moth is usually insignificant. However, on weak shoots it may terminate growth or cause some distortion of the shoots above the point of attack. On normal shoots there is little effect since the buds themselves are not directly attacked. Galls often occur on leading shoots without affecting their subsequent growth, except that a minor point of weakness is formed in the main stem, rendering them liable to wind- or snow-break (Bradley et al., 1973; Scott, 1972).
Distribution:
Europe to Eastern Russia.
Pheromone:
Pheromone unknown.
Attractantia:
Z 9-12Ac : 1
E 9-12Ac : 1
(Booij and Voerman, 1984a)
Parasitoids:
Amicroplus infirmus Nees (Braconidae)
Macrocentrus abdominalis Fabricius (Braconidae)
Macrocentrus nitidus Wesmael (Braconidae)
Orgilus obscurator Nees (Braconidae)
Actia nudibasis Stein (Tachinidae)
Graphogaster brunnescens Gir. (Tachinidae)
Ephialtes brevicornis Gravenhorst (Ichneumonidae)
Ephialtes brunneus Brischke (Ichneumonidae)
Ephialtes inquisitor Scopoli (Ichneumonidae)
Ephialtes mesocentrus Gravenhorst (Ichneumonidae)
Ephialtes ruficollis Gravenhorst (Ichneumonidae)
Ephialtes sagax Hartig (Ichneumonidae)
Ephialtes strobilorum Ratzeburg (Ichneumonidae)
Ephialtes terebrans Ratzeburg (Ichneumonidae)
Cratichneumon annulator Fabricius (Ichneumonidae)
Glypta incisa Gravenhorst (Ichneumonidae)
Glypta mensurator Fabricius (Ichneumonidae)
Glypta tennicornis Thomson (Ichneumonidae)
Glypta resinanae Hartig (Ichneumonidae)
Lissonota paralella Gravenhorst (Ichneumonidae)
Lissonota variabilis Hlmgr. (Ichneumonidae)
Campoplex ramidulus Brischke (Ichneumonidae)
Horogenes armillata Gravenhorst (Ichneumonidae)
Horogenes chrysosticta (Ichneumonidae)
Horogenes vestigialis (Ichneumonidae)
Elachertus sp. (Ichneumonidae)
Termolampa pinicola Boucek (Pteromalidae)
Retinia perangustana Snellen
Retinia perangustana Snellen occurs from Poland to Eastern Russia and China, the larvae feeding in larch cones.
Retinia spp. adults
Adults are smaller than those of Retinia resinella. Forewing with narrow whitish or light grey transverse band which is often interrupted in middle.
male gen. R. perangustana
The notch in the valva of the male genitalia is shallow compared to that in Retinia resinella.
female gen. R. perangustana
Judging by the illustration provided by Kuznetsov, 1987, the papillae analis are more slender than in R. resinella.