Epinotia nisella Clerck 1759

Epinotia nisella Clerck (1759)

Figures 2 C–2J, 4A–4J, 5D–5G, 6D–6G, 7D–7F, 8D–8F

[Phalaena] nisella Clerck, 1759: pl. 12, fig. 6. TL: probably Sweden.

Phalaena pavonana Donovan, 1793: 59 –60, pl. 58, fig. 3, pl. 59, fig. 1. TL: Great Britain. Tortrix anana Schrank, 1802: 72. TL: Germany.

Tortrix cuspidana Haworth, 1811: 451. TL: Great Britain.

Tortrix stictana Haworth, 1811: 451. TL: Great Britain.

Tortrix rhombifasciana Haworth, 1811: 451. TL: Great Britain.

Tortrix siliceana Hübner, 1813: pl. 31, fig. 196.

Tortrix decorana Hübner, 1819: pl. 42, fig. 265.

Tortrix lepidana Frölich, 1828: 94. TL: Germany. Würtemburg.

Grapholitha nisana Guenée, 1845: 171. An unjustified emendation of [Phalaena] nisella Clerck, 1759. Epiblema nisella ab. dorsimaculana Klemensiewicz, 1902: 58. TL: Poland. Infrasubspecific. Epiblema nisella ab. albodecorana Krulikowsky, 1908: 18. TL: Russia. Infrasubspecific. Epiblema nisella ab. fulminana Krulikowsky, 1908: 18. TL: Russia. Infrasubspecific. Eucosma nisella ab. brunneana Dufrane, 1930: 161. TL: Belgium. Baudour. Infrasubspecific. Pyralis boeberana auct., nec Fabricius, 1787. Misidentification.

Tortrix rubiana Villers, 1789 sensu Haworth, 1811: 450. Misidentification.

Diagnosis. The forewing pattern of E. nisella is highly variable (Figs. 2 C–2J, 4A–4J). Generally E. nisella is more strikingly patterned than E. cinereana; there are often blotches of black or reddish colour on the wing. This is never the case in E. cinereana. There are greyish specimens with E. cinereana -like pattern. Such specimens need to be dissected for safe identification.

Some of the most distinctive forms of E. nisella were originally described as species, and are treated further below. The different forms may intergrade:

dark form: FW predominantly grey to dark grey from variously white-tipped grey scales giving the impression of fine transverse zigzag striae; basal patch distinctly darker its distal margin pointed into square or obtuse angle, usually delineated from paler distal area of wing by thin pale grey or whitish transverse line; some specimens with small, ± distinct brown spot on hind margin adjacent to lower angle of basal patch; this forms appears to be predominant in northern areas.

‘nisella’-like form: dark basal patch extended obliquely from basal third of costa to tornus, blackish grey, its outer margin incurved; area along hind margin with various extent of brown from small spot to extensive streak (as in ‘lepidana’ form), lacking altogether in some specimens; antero-distal portion of wing distinctly paler grey; overall impression of bicolored FW with dark base and pale apex.

‘cuspidana’-like form: middle area of FW extensively reddish brown, contrasting with dark grey basal patch and terminal area; overall impression of bicolored FW with dark-pale-dark areas.

‘rhombifasciana’-like form: basal patch contrastingly dark grey, median area of FW whitish grey with extensive dark grey near costa and dark grey patch near tornus; some specimens have a small amount of reddish brown adjacent to the tornal dark-grey patch; overall impression of predominantly grey to dark grey with irregular pale whitish median area.

Wingspan: North American specimens: 13.9–19.8 mm, mean = 16.5 mm (N = 50); European specimens: 12.0– 18.0 mm.

Male genitalia (Figs. 5 D–5G, 6D–6G). The valva is slightly broader than in E. cinereana. In the phallus the number of cornuti is 40–50 (against 13–20 in E. cinereana). Differences in segment VIII are described above under E. cinereana.

Female genitalia (Figs. 7 D–7F, 8D–8F). The sterigma is oval, nearly circular, posteriorly with one small triangular process on each side (in E. cinereana the sterigma is cylindrical with strongly lateral edges and large triangular processes). The signa are much smaller in E. nisella than in E. cinereana, their surface area totalling on average about 1% (0.55–1.34%, mean 0.96%, n=6) of the surface area of the flattened bursa.

No significant differences in genitalia were detected between European and North American specimens.

Life history. In Europe, E. nisella is stated to feed in the catkins or between spun leaves of Salix species, but also on Populus species, whereas E. cinereana is associated with Populus tremula (Bradley et al. 1979). However, it seems that the two species are not as restricted in their choice of host plants as indicated in the literature. A series of E. nisella specimens from Fyn, Denmark was bred from fallen catkins of Populus tremula (Larsen 1927). Also (Klemensiewicz 1902) found larvae of E. nisella numerous in catkins of Populus tremula, where they also pupated. Further study is needed to disclose differences in the early stages of the two species and details of their biology. In North America, E. nisella is recorded from catkins of Populus tremuloides, but there are also sporadic records on buds and leaves of Salix, Betula, Alnus, and reportedly Acer (Miller 1986, Gilligan et al. 2008). Acer records seem doubtful.

In North America E. nisella is recorded from catkins of Populus tremuloides and P. trichocarpa, but there are also sporadic records on buds and leaves of Salix, Betula, Alnus, and reportedly Acer (Miller 1986, Gilligan et al. 2008). Acer records seem highly dubious and possibly stem from misidentifications of Catastega aceriella Clemens whose forewing pattern can sometimes be vaguely suggestive of E. nisella: we have not seen reared specimens of E. nisella that would substantiate maple as a larval host. MacKay (1959) described and illustrated in detail the larva of North American specimens and compared it to those of a dozen other Nearctic species of Epinotia. See under E. cinereana above for differences.

Distribution. Widely distributed in Europe, apart from Mediterranean islands (Aarvik 2011); throughout most of Russia, including the Caucasus, although not recorded from parts of Siberia (Sinev & Nedoshivina 2009); Japan (Kawabe 1982); China (Liu 1981). Here recorded as new to Iceland. In North America, it ranges from Newfoundland to British Columbia, northward to the Yukon in Canada. It is stated to be widespread in the northern United States from Pennsylvania and Colorado (Heinrich 1923 and Gilligan et al. 2008), but we examined only a few specimens from Colorado (CNC).

Remarks on type material. Clerck’s (1759) figure of his [Phalaena] nisella shows a form with a broad medial black band reaching from dorsum to costa. We dissected a specimen of this form (Fig. 2 H) which confirms the identity of the name nisella. The type of E. nisella is considered lost (Robinson & Nielsen 1983).

Phalaena pavonana was described from a single specimen found in Sussex in Great Britain (Donovan 1793). It represents a form with a red dorsal spot inside a black dorsal blotch. The form figured by Kennel (1908 –1921: pl. XXII, fig. 54) and Bradley et al. (1979: pl. 29, fig. 23) under this name does not agree with Donovan’s original figures. It is a rare form. Schopfer (1912) mentioned he had two specimens in his material. A specimen of this form is shown (Fig. 2 I). The type is probably lost (K. Tuck, in litt.).

Tortrix anana was described from an unstated number of specimens collected in Neuburg an der Donau in southern Germany (Schrank 1802). Although the description does not fit in every detail (Schrank wrote about silvery lines and stated the flight time to be in May), we think it serves stability to leave T. anana in synonymy with E. nisella where it has been since the middle of the 19th century. The whereabouts of the type are unknown.

Tortrix cuspidana was described from an unstated number of specimens collected in Great Britain (Haworth 1811). We interpret it to be the same form as T. decorana Hübner (see below) (Fig. 2 E). A lectotype was designated by Bradley (1966), who concluded that T. cuspidana is a synonym of E. nisella.

Tortrix stictana was described from an unstated number of specimens collected in Great Britain (Haworth 1811). It is stated to have red forewings with scattered dark marks. A form which is close to this description is shown by Bradley et al. (1979: pl. 29, fig. 25). The type is probably lost (K. Tuck, in litt.).

Tortrix rhombifasciana was described from an unstated number of specimens collected in Great Britain (Haworth 1811). We interpret it to be the same form as T. siliceana Hübner (see below). The type is probably lost (K. Tuck, in litt.).

Tortrix siliceana is based on the figure under this name in the work of Hübner (1799–1833). The number of specimens and type locality are not stated, although the latter is probably southern Germany. It is the form with a small reddish dorsal mark, as figured by Bradley et al. (1979: pl. 29, fig. 22) (Fig. 2 J). The type is probably lost.

Tortrix decorana is based on the figure under this name in the work of Hübner (1799–1833). The number of specimens and type locality are not stated, although the latter is probably southern Germany. It is the form with the entire medial area of the forewing reddish (Fig. 2 E). The form is figured by Kennel (1908 –1921: pl. 22, fig. 55) and Bradley et al. (1979: pl. 29, fig. 24). The type is probably lost.

Tortrix lepidana Frölich, 1828 was listed as a variation of Tortrix siliceana Hübner by Herrich-Schäffer (1856 (4): 24). We interpret this to be the form with the red dorsal blotch extended along dorsum (Fig. 2 G). This form was figured by Bradley et al. (1979: pl. 29, fig. 23). The type is probably lost.

Epiblema nisella ab. dorsimaculana Klemensiewicz was described from two specimens bred from catkins of Populus tremula in Lvov, now in the Ukraine (Klemensiewicz 1902).The name depicts specimens with a large black blotch, broad at dorsum, forming a triangle which reaches the middle of the wing. It resembles the typical E. nisella form but is lighter basally.

Epiblema nisella ab. fulminana Krulikowsky was described from an unstated number of specimens (probably only one) collected in the eastern part of European Russia. It has blackish forewings almost without markings apart from a rust-red patch at dorsum (Krulikowsky 1908).

Epiblema nisella ab. albodecorana Krulikowsky was described from an unstated number of specimens (probably only one) collected in eastern part of European Russia. It has white forewings with only the base and the ocellus being grey or blackish (Krulikowsky 1908).

Eucosma nisella ab. brunneana Dufrane was described from a female holotype from France and two paratypes from Belgium. It is stated to resemble f. baeberana Haworth but with a brown rather than black spot (Dufrane 1930).

Pyralis boeberana Fabricius, 1787 is listed as a synonym of E. nisella by Brown et al. (2005). This is, however, a misidentification which apparently originates from Haworth (1811: 450) who listed P. boeberana as a synonym of E. nisella. P. boeberana Fabricius is a synonym of Anacampsis populella (Clerck, 1759) according to Karsholt & Nielsen (1976), who published a lectotype of boeberana.

Tortrix rubiana Haworth is listed as a synonym to Epinotia nisella by Brown et al. (2005). However, Haworth did not describe a new species as T. rubiana, but referred to “ Phalaena rubiana. Vill. Ent. 2. 419. 471?”, and to “ Phalaena pavonana Don. Br. Ins. 58.3 et 59.1”. Also Villers (1789) did not describe a new species as rubiana, but referred to Scopoli (1763) (“Ex Ent. D. Scop”) by virtually copying Scopoli’s text. Phalaena rubiana Scopoli, 1763 is currently considered as a synonym of Notocelia uddmanniana (1758) (Brown et al. 2005). Phalaena pavonana is, as stated above, a synonym of E. nisella, and Tortrix rubiana Haworth should accordingly be considered a misidentification of E. nisella.

Remarks. E. nisella is highly variable in forewing colouration. Schopfer (1912) treated the variation in some detail, listing 12 forms and discussing a number of intermediate forms between these.