Elachista distigmatella Frey, 1859

Kaila, Lauri, Baran, Tomasz & Mutanen, Marko, 2015, A revision of the Elachista dispilella complex (Lepidoptera: Gelechioidea: Elachistidae), Zootaxa 3963 (4), pp. 517-560 : 535-536

Elachista distigmatella Frey, 1859

Figs. 12–13 , 64–65 , 92

Elachista distigmatella Frey, 1859: 302 Elachista dispilella auct ., nec Zeller, 1839 Elachista variabilis Martini, 1902: 26

Material studied. Type material. Lectotype ♂: LECTO-TYPE [rounded with blue margin]; E. distigmatella Frey Zürich e. l.; Frey Coll. Brit. Mus. 1890-62; Lectotypus Elachista distigmatella Frey. TESTE U. Parenti 1976. B.M. Genitalia slide No. 19395 ( BMNH). Other material: Denmark: Fan, 17. VII.1949, 1 ♂, 1 ♀, 30. VI.1952, 1 ♂, N. L. Wolff leg., O. Karsholt prep. 4566, 4571 ( ZMUC); Højerup, 18. VI.1989, 2 ♂ O. Karsholt leg., O. Karsholt prep. 4618 ( ZMUC); NWJ Hansted Reservat, 11.–15. VII.1994, 1 ♂, O. Karsholt leg., O. Karsholt prep. 4839 ( ZMUC). Finland (material of MZH examined): all from the province Åland. Ecker, 1. VII.1983, 1 ♂, H. Holmberg leg., 3 ♂, H. Krogerus leg., L. Kaila prep. 3073, 4. VII.1994, 1 ♂, H. Krogerus leg., L. Kaila prep. 3071; Ecker, Degersand, 1. VII.1983, 1 ♂, H. Holmberg leg.; Ecker, Skag, 13.–18. VII.1998, 4 ♂, K. Mikkola leg.; Ecker, Käringsund, 9.– VII.1998, 3 ♂, J. Flinck leg.; Finström, 1 ♀, A. Nordman leg. [no date], L. Kaila prep. 3086, Finström, various sites, 21.VI.–12. VII. 1945, 18 ♂, 3 ♀, J. Jalava prep. 728/1979, 729/1979, L. Kaila prep. 486, 1787, 3084, 3087, 3099, Elachista dispilella E. Traugott-Olsen det., 28.–30. VI.1983, 13 ♂, 2 ♀, E. Franssila, H. Holmberg, I. Kontuniemi, K. Saloranta & K. Vaalamo leg., L. Kaila prep. 3081, 3082; 1986, 1987, 5 ♂, 1 ♀, H. Krogerus leg., L. Kaila prep. 3070, 3072; Finström, Hus, 26. VI.1976, 2 ♂, 27. VI.1977, 1 ♂, R. Teriaho leg.; Finström, Tjud, 30.VI., 3 ♂, O. Hytönen leg.; Fögl, Bän, 4. VII.1987, 1 ♂, P. Grotenfelt leg.; Geta, 1.–2. VII.1945, 5 ♂, 1 ♀, A. Nordman leg., L. Kaila prep. 488, 3088, E. dispilella E. Traugott-Olsen det., 21. VI.1951, 1 ♂, M. v. Schantz leg., 2. VII.1983, 1 ♂, I. Kontuniemi leg., 23.– VI.1985, 5 ♂, K. Vaalamo leg., L. Kaila prep. 3097, 3098; Jomala, 29. VI.1983, 1 ♂, J.-P. Kaitila leg.; Saltvik, 1. VII.1987, 1 ♂, L. Sippola leg., L. Kaila prep. 3096 ( MZH). France: Provence: Domaine de Maure Vicil, 27.–31. V.2003, 2 ♀, H. Hendriksen leg. [abdomen missing] ( ZMUC). Poland: Komarówka Podl., 14.VII.1978, J. Buszko leg., Genital praeparat 6089 ♂ E. Traugott-Olsen, Elachista dispilella det. Traugott-Olsen Coll. Traugott-Olsen ( ZMUC); Oblasy, 23. VI.1998, 3 ♂, A. Mazurkiewicz leg. (coll. Baran); Styków ad Głogów Małopolski, 10. VI.2008, 10 ♂, 8 ♀, 11. VI.2008, 5 ♂, 3 ♀, 14. VI.2008, 6 ♂, 3 ♀, 5. VII. 2008, 1 ♂, T. Baran leg. (Coll. Baran). Sweden: Gotland, Silte, Mästermyr, 24. VII.1985, 1 ♂, O. Karsholt leg., O. Karsholt prep. 4619 ( ZMUC); Scania, Sandhammaren, 22. VII.1956, 1 ♂, I. Svensson leg. Genital praeparat 6049 E. Traugott-Olsen, Coll. Traugott-Olsen ( ZMUC).

Diagnosis. Elachista distigmatella resembles E. dispilella externally. The forewing ground colour of E. distigmatella is pure white, whereas that of E. dispilella has a creamy tinge. The male genitalia of these species differ especially by the broader valva and the much larger cornutus comb of E. dispilella . For the female, see the key. These species differ also in phenology (see above). Larvae of the two can be distinguished by the different shapes of the prothoracic sclerites (TB).

Molecular characterization. The analyzed 13 specimens of E. distigmatella showed a maximum variability of 0.31 %. Average distance between the specimens was 0.07 %. The genetically closest species was E. filicornella with 5.06 % minimum distance to E. distigmatella .

Redescription of genitalia. Male genitalia. Uncus lobes 1.5 times as long as broad, tapered towards pointed and outward bent apex, sickle-shaped, mesial margin convex, lateral margin concave. Spinose knob of gnathos oval-shaped. Valva 1.5 times as long as tegumen + uncus, five times as long as broad, parallel-sided; cucullus elongate. Digitate process broad, tapered towards rather acute apex, 0.25 times as long as valva, medially and distally with stout setae. Juxta lobes devoid of setae, distinctly laterally produced, mesial margin straight, joins the concave distal margin in an acute angle. Phallus 0.8–0.9 times as long as valva, bent, parallel-sided; cornutus cluster formed of a few basally joined spines that are closely joined to each other, length of cluster a little more than twice the diameter of phallus.

Female genitalia. Apophyses posteriores slender, straight, 1.5 times as long as papillae anales. Apophyses anteriores about half the length of apophyses posteriores. Posterior margin of sternum 7 forming indistinct, shallow bowl-shaped formation almost as wide as distance between apophyses anteriores. Ostium bursae invaginated in sternum 8, very narrow; colliculum posteriorly narrow, gradually widening with elongate lateral sclerotizations; ductus seminalis granulose, distance between its inception and ostium bursae half the length of apophyses posteriores; ductus bursae 5 times as long as apophyses posteriores, tubular, membranous, granulose, anteriorly with longitudinal, slightly sclerotized foldings, incepted in corpus bursae with distinct border; corpus bursae large, pyriform, with small internal granules in median zone; signum narrow and long, dentate, boomerang-shaped.

Biology. The following account is based on observations made in Poland. Elachista distigmatella occurs in sandy, dry habitats, e.g., in sunny edges of pine or mixed forests. Larvae have been found mining the leaves of Festuca trachyphylla in May (TB). The host record of F. ovi na given by Frey (1859) and repeated by Traugott- Olsen (1990) needs to be confirmed; however, this is the most likely host plant at the Finnish localities for this species. The species has one generation annually, with adults from about the second half of June to the first half of July; it is most numerous in the second half of June. Adults of this species appear somewhat later in the season than those of E. dispilella , but occasionally both species may be present in the first half of June. Adults can be encountered sitting on leaves of the food plant during late afternoon in sunny weather.

Distribution. Czech Republic ( Šumpich 2007), Denmark, Finland, France, Lithuania ( Sruoga & Ivinskis 2005), Poland, Sweden, Switzerland.

Remarks. The species was described by Frey (1859) on the basis of material from Zürich ( Switzerland). Hering (1891), however, did not accept its validity and considered it a variation of E. dispilella . This view had been accepted until recently when Traugott-Olsen (1990) and Baran (2005) suggested otherwise. Elachista distigmatella seems to be more widespread in Western Europe than E. dispilella , which is more often encountered in Eastern Europe.

Elachista variabilis Martini was described from Thüringen, Germany to denote its distinction from E. dispilella Zeller. The author suspected it to be conspecific with E. distigmatella Frey , but decided to follow the opinion of Hering (1891) that E. distigmatella is conspecific with E. dispilella . Knowing that his species was not E. dispilella, Martini described it as new. The type series of E. variabilis was studied by Traugott-Olsen (1990) and deemed conspecific with E. distigmatella . We have not examined the lectotype but consider the genital-based identification of Traugott-Olsen to be correct. This opinion is substantiated by the original view of Martini, as well as by the type locality of E. variabilis , which falls well within the distribution range of E. distigmatella and dissimilar to other species.

Figures

FIGURES 2 – 13. Adults of Elachista spp. Scale 2 mm. 2. E. dispilella Zeller, ♂ lectotype (image in greyscale). 3. E. dispilella Zeller ♂ (Poland, Torún). 4. E. dispilella Zeller (holotype ♂ of E. steueri Traugott-Olsen). 5. E. dispilella Zeller (holotype ♂ of E. jaeckhi Traugott-Olsen). 6. E. dispilella Zeller (holotype ♂ of E. gebzeensis Traugott-Olsen). 7. E. curonensis Traugott- Olsen, ♂, holotype. 8. E. festucicolella Zeller, ♂ lectotype. 9. E. festucicolella Zeller, ♂ (Poland). 10. E. festucicolella Zeller, ♀ (Poland). 11. E. bigorrensis Traugott-Olsen, ♀, holotype. 12. E. distigmatella Zeller, ♂ lectotype. 13. E. distigmatella Zeller, ♂ (Italy).

FIGURES 64 – 65. Male genitalia of E. distigmatella Frey. Left: general image of genitalia, phallus in same scale. Right top: juxta and digitate process. Right bottom: cornutus as enlarged. 64. Lectotype, B. M. 26349. 65. France, L. Kaila prep. 4226.

FIGURES 91 – 92. Female genitalia of Elachista spp. 91. E. bigorrensis Traugott-Olsen, holotype, B. M. 24887. 92. E. distigmatella Frey, Finland, L. Kaila prep. 3089.