Author: (Hübner, 1817)
Holly tortrix moth
larva: Holly leaf tier
Blackheaded fireworm
Species Overview:
Adult: 12-16 mm wingspan: forewings notched below the apex, dark grey, marked with blackish and dark rusty brown, and with several whitish striae on the front margin; hindwings grey.
Egg: 0.7 x 0.5 mm; flat and oval; translucent-whitish, becoming yellowish to reddish; deposited singly on the twigs of the food plant, overwintering and hatching in the spring [Rhopobota naevana egg].
Larva: 10-12 mm long; head black; prothoracic plate black, edged anteriorly with grey, medial sulcus whitish; abdomen shining, varying from dark green or greyish green to yellowish brown, paler ventrally; pinacula concolorous with integument or paler; anal plate varying from green to brown, mottled with black, rounded posteriorly; anal comb black, with two to four teeth. In the larval habitation or spun up amongst ground litter [Rhopobota naevana larva].
Pupa: male 6-7 mm long, female 7-8 mm; yellowish brown; frons with 1 pair of setae; body without a distinct cremaster; anal segment with four thorn-like spines extending beyond abdomen and 3 pairs of setae dorsally, 2 pairs of setae ventrally and with a small bump behind the anal slit; spines on anal segment clearly bigger than those on the 9th abdominal segment [details pupa Rhopobota naevana ].
Taxonomic Description:
Male:
Rhopobota naevana male
Rhopobota naevana adult
Rhopobota naevana adults
under side wings R. naevana
External characters: 12-16 mm wingspan; forewing subfalcate, with a distinct notch below apex; ground colour white to ochreous-white, variably suffused or overlaid with plumbeous and sparsely strigulated with brown or fuscous; markings brown to blackish brown, sometimes with an ochreous admixture; basal and sub-basal fasciae more or less confluent and forming a moderately well-defined basal patch, its outer edge obliquely curved from costa to dorsum, sometimes obtusely angulated at or below middle; median fascia narrow, oblique and confluent with pre-tornal marking, its edges irregular and often diffuse, the outer edge usually with a blackish projection medially; subterminal fascia arising from above middle of termen, extending as a narrow band into apical area; a large, whitish ocellar patch traversed by a diffuse tornal fascia which is usually edged with thick, submetallic strigulae; cilia cream-white, suffused with grey, paler at tornus, with an indistinct dark sub-basal line. Hindwing grey or light fuscous, darker apically; upperside with a patch of violaceous-grey scales on cell area and a similar conspicuous patch of coarse grey-black scales on underside; cilia grey, with a dark sub-basal line (Bradley et al., 1979).
male genitalia R. naevana
Genitalia: "Uncus" consisting of two wide-set projections, triangular at base (whether these paired tegumentary projections are homologous with the uncus of for instance Epinotia remains uncertain); socii consisting of two laterally arranged appendages on anal tube which are apically expanded, covered with brush of bristles, and fused. Valva with clasper near mid-point of ventral margin, this margin notched before the semicircular cucullus.
Female:
External characters: Similar to male but lacking the patches of specialized scales on the hindwing.
female genitalia R. naevana
Genitalia: Sterigma funnel-shaped. Antrum with elongated sclerite, near the inception of the ductus seminalis. Sides and base of corpus bursae and distal area of ductus bursae well-sclerotized. Corpus bursae with two rather small, slender signa.
Variation:
This is a very variable species, especially in the degree of suffusion of the ground colour and the depth and clarity of the markings of the forewing. In lightly suffused specimens the ground colour is shining white, sometimes tinged with pinkish ochreous, the markings contrasting strongly. Almost unicolorous red-brown and melanistic black-brown specimens are not uncommon (Bradley et al., 1979).
Biology:
R. naevana overwintering eggs
This species overwinters as eggs laid singly on the smooth bark of trunks and branches of the trees or on the underside of holly leaves. The eggs do not hatch until the following spring, usually during the blossom period. The young larvae then feed in a webbed shelter of young leaves; they also attack unopened and opened flowers. In the UK, feeding is completed in June or July, each larva pupating in a white cocoon spun in a folded leaf or amongst dead leaves or debris on the ground (Alford, 1984; Alford, 1995; Bradley et al., 1979).
Moths occur from late June to early September.
Host plants:
Vaccinium spp., Erica carnea, Ilex spp., Malus spp., Crataegus spp., Sorbus spp., Prunus spp., Pyrus spp., Rhamnus spp.
Damage:
R. naevana damage to apple (shoot)
Larvae attack cultivated apple and pear and are also known as a pest of cultivated cranberry (Alford, 1984; Volkova, 1976).
They destroy young leaves, flowers and, occasionally, newly set fruitlets; they also kill young lateral shoots (Alford, 1984).
Distribution:
Europe incl. the British Isles, to Eastern Russia and Japan; India; Sri Lanka; North America.
Pheromone:
Z 11-14OH : 0.12 *
Z 11-14Ac : 0.6
(McDonnough et al., 1987)
or
Z 11-14Ac : <1 *
E 11-14Ac : trace
Z 11-14OH : trace *
(Slessor et al., 1987)
Components marked with * are involved in attraction.
Attractantia:
Z 11-14OH : 98
Z 9-12Ac : 2
(McDonnough et al., 1987)
or
Z 11-14Ac : 3
Z 11-14OH : 1
(Slessor et al., 1987)
or
Z 11-14Ac : 69
Z 11-14OH : 23
Z 9-12Ac : 8
(Fitzpatrick and Troubridge, 1992)
or
Z 9-12Ac
(Ando et al., 1977)
or
E 8E 10-12OH
(Arn, 1995-99)
Parasitoids:
(Records from Canada)
Hemisturmia tortricis (Tachinidae)
Sympiesis bimaculatipennis (Eulophidae)
Microplitis sp. (Braconidae)
(Fitzpatrick et al., 1994)
Similar species:
Rhopobota ustomaculana (Curtis) occurs in the Palaearctic part of Rhopobota naevana's range, feeding on Ilex and Vaccinium.
It can be distinguished from Rhopobota naevana'by the moderately conspicuous semi-ovate patch of ground colour which extends narrowly along the dorsum to the base of forewing [Rhopobota ustomaculana adults].
The male genitalia differ in the shape of the valva (ventral margin without notch in Rhopobota ustomaculana, cucullus relatively narrow) and uncoid projections (long and narrow in Rhopobota ustomaculana) [male genitalia R. ustomaculana ].
The female genitalia differ in the shape of the ostium and the size of the signa (smaller in this species) female gen. R. ustomaculana ].