Stigmella ulmivora (Fologne) Beirne

Nieukerken, Erik J. van, Gilrein, Daniel Owen & Eiseman, Charles S., 2018, Stigmellamultispicata Rociene. & Stonis, an Asian leafminer on Siberian elm, now widespread in eastern North America (Lepidoptera, Nepticulidae), ZooKeys 784, pp. 95-125 : 95

Stigmella ulmivora (Fologne) Beirne Figures 3, 4, 10, 11, 13, 15, 17, 27, 30-33

Nepticula ulmivora Fologne, 1860: 199. Syntypes, Belgium, Brussels region, reared from Ulmus , 1859, emerged 1860, Fologne [probably lost].

Stigmella ulmivora ; Beirne 1945: 199 [recombination]; van Nieukerken et al. 2016: 105 [full synonymy].

Diagnosis.

Stigmella ulmivora can be separated from S. multispicata by the slightly larger size, the dark collar, and the antennae with the terminal 7-8 flagellomeres white. In Europe and North America there are no other Stigmella species with the same combination of characters. The male genitalia are very similar to those of S. multispicata , but have a deeper indentation in the uncus, and longer and more distinct sublateral processes of the transtilla. The female differs by the blunt ovipositor and the spiny ductus spermathecae.

Leafmines differ from those of S. multispicata by the egg position not being in vein axils; in Europe mines are inseparable from those of S. ulmiphaga (Preissecker, 1942). Due to the variability of mines of S. ulmivora , they sometimes are difficult to separate from those of S. lemniscella (Zeller, 1839), from which the yellow larva emerges through the leaf upper side, not the underside as in S. ulmivora .

Redescription.

Male (Figure 3). Forewing length 2.1-2.5 mm (2.3 ± 0.1, 10), wingspan 4.6-5.2 mm. Head: frontal tuft black, collar cream white. Scape cream white. Antenna fuscous, terminal 7-8 flagellomeres completely white, with 25-29 segments (26.7 ± 1.6, 10), ratio to forewing length 10-13 segments/mm (11.6 ± 0.9, 10). Thorax and forewing shining fuscous bronze, a silver fascia at 2/3, apex darker fuscous, terminal cilia concolorous, underside dark fuscous. Hindwing grey-brown. Abdomen brown, no visible anal tufts.

Female (Figure 4). Forewing length 1.9-2.6 mm (2.3 ± 0.2, 10), wingspan 4.2-5.4 mm. Antenna with 19-23 segments (21.0 ± 1.2, 8), ratio to forewing length 8-11 segments/mm (9.3 ± 1.0, 8). Otherwise as male, abdomen with conspicuous long protruding ovipositor, with small anal tufts.

Male genitalia (Figs 10, 11, 13). Capsule length 190-210 μm (203.8 ± 10.2, 4), ca 0.9 × as long as wide. Vinculum anteriorly with pointed and anteriorly protruding lateral corners. Uncus distinctly bilobed, lobes adjacent. Gnathos with widely separated posterior processes, running parallel. Valva length 180-185 μm (182.4 ± 0.7, 4), rather narrow, 2.0 –2.4× as long as wide, distally becoming narrower, slightly curved inwards, transtilla with pointed distinct sublateral processes (Figure 13). Juxta present, haltere-shaped. Phallus 275-440 μm (351.1 ± 68.4, 4), 2.0 –3.3× as long as wide; vesica with many relatively stout cornuti, varying from long and pointed to broadly triangular, with anterior cornuti smaller.

Female genitalia (Figs 15, 17). No anal papillae; T8 rounded, not elongated, anterior and posterior apophyses short, almost equal in length, anterior ones ca 170-210 μm, posterior ca 185-200 μm. Bursa length ca 770-930 μm; accessory sac strongly curved. Corpus bursae completely covered with relatively distinct pectinations; accessory sac and vestibulum without sclerotizations. Ductus spermathecae originating from accessory sac, basally wide and covered with many spines, with several narrow and indistinct convolutions.

Larva (Figs 27, 32). Head-capsule (n=2) length 300-310 μm, width 300-315 μm.

Biology.

Host plants. Ulmus minor Mill., U. glabra Huds., Ulmus spp. ( Ulmaceae ). Reared specimens labeled as coming from Acer were from cocoons found on trunks of that tree; therefore this cannot be considered a host record.

Leafmine (Figs 30-33). Egg on leaf underside, against a vein. Mine a highly variable gallery, ranging from short and filled with dense frass in thick leaves (usually in the sun) to long and narrow, often partially following a vein, with frass either linear or becoming contorted, mines sometimes much winding. Larval exit on leaf underside.

Larva (Figure 32). Bright green, feeding with venter upwards; head capsule translucent brown. Larvae descending by silken threads, spinning a brown cocoon on debris or on tree trunks.

Life history. Bivoltine, or possibly partially univoltine in northern parts of Europe. Larvae in June to early July, again in August to November. Adults recorded from May (a single April record) to early July and again in August.

Distribution.

Widespread throughout Europe, east to the Volga region in Russia ( Johansson and Nielsen 1990, van Nieukerken 2017). The species occurs both in natural habitats and on trees in cities, often in large numbers (EJvN, personal observations).

DNA barcodes.

We have 13 barcodes from across Europe, all belonging to BINBOLD:AAI0023, with some variation, a maximum distance for the Greek barcodes of 2.41% to the rest. The nearest neighbor, at 6.31%, is Stigmella multispicata (Figure 44).

Material examined.

Adults: 25♂, 50♀. Croatia: 1♂, Krk, Kampelje, 17.viii.2001; 1♀, Krk, Mt. Hlam, loc. Branusine, 15.viii.2012. Germany: 1♀, Berlin; 1♂, Thüringen, Bad Blankenburg, Muschelkalk, 1.vii.1986; 1♀, Thüringen, Bad Blankenburg, Schwarzatal, 5.vii.1986. Italy: 1♂, Cuneo, Entracque, ca 1 km SE, Il Bosco, 16.viii.2007, la on Ulmus ; 1♂, 1♀, same locality, 13.x.2008, la on Ulmus ; 1♀, Latina, Monti Aurunci, 4 km NW Castelforte, 22-23.vi.1969. Netherlands: 2♂, 2♀, Gelderland, Wageningen, Ulmus , e.l. 19.v.1977; 1♀, ibidem, larva x.1989, Ulmus ; 2♂, 3♀, Noord-Brabant, Breda, v.1877; 1♀, ibidem, e.l. 10.vi.1877, "acer pseudop."; 2♂, 1♀, ibidem, e.l. 25.vi.; 1♀, 3 damaged adults, ibidem, v.1878; 1♀, Noord-Holland, Amsterdam, 2.viii.1937; 1♂, Noord-Holland, Amsterdam, Koloniaal instituut, 7.viii.1937; 1♀, Noord-Holland, Amsterdam, Ulmus , e.p. 30.vi.1929; 1♀, ibidem, Ulmus e.l. 27.iv.1942; 5♀, ibidem, Ulmus e.l. 29. vii– 2.viii.1943; 1♀, Noord-Holland, Amsterdam N.W., Ulmus , 16.viii.1942; 1♂, 4♀, ibidem, Ulmus e.l. 2-14.viii.1947; 1♀, ibidem, Ulmus e.l. 6.vi.1948; 1♀, ibidem, Ulmus e.l. 11.vi.1948; 1♀, Noord-Holland, Bussum, 16.iv.1934; 1♂, Noord-Holland, Castricum, 15.viii.1979, Ulmus e.l. 13.vi.1980; 6♂, 9♀, Noord-Holland, Hilversum, Ulmus e.l. 4-24.vi.1943; 4♀, ibidem, Ulmus e.l. 17.v.-6.vi.1945; 1♀, Noord-Holland, Overveen, 7.vi.1929; 1♂, ibidem, 1.vii.1929; 2♀, Zuid-Holland, Den Haag, Ulmus e.l. 9. v– 10.vi.1865; 1♀, Zuid-Holland, s Gravenhage, 29.v; 1♀, Zuid-Holland, Lexmond, 3.viii.1999; 1♂, Zuid-Holland, Rottm. [Rotterdam], e.p. 22.vi.1901; 1♂, ibidem, e.l. 24.vi.1864; 1♂, ibidem, e.l. 13.vii. 1870; 1♂, ibidem, 21.vi.1877; 1♀, ibidem, pupa in iv, e.p. 21.vii.1879; 1♀, ibidem, 27.v.1877. Poland: 1♂, Silesia, Wroclaw (Breslau), e.l. iii.1882.

Leafmines and larvae. When no hostplant is given, read Ulmus sp. - Czech Republic: 1 mine, Moravia, Lednice, 3 km SW, forest near lake, 3.x.1992. France: 4 larvae, vacated mines, Alpes-Maritimes, Saorge, 0.8 km SW, vallée de Roya, 9.x.2008, U. minor ; 1 vacated mine, Alpes-Maritimes, Tende, ca 1 km S, E. slope, 10.x.2008, U. glabra ; mines, Bouches-du-Rhône, Aix-en-Provence, Parc Jourdan, 12-16.x.1983; several vacated mines, Cher, Villeneuve-sur-Cher, 30.vii.2009, U. minor ; vacated mines, Drôme, Beaurières, 4 km W: Marais des Boulignons, 21.viii.2002; 1 vacated mine, Eure, Le Marais Vernier, la Vallée, 5.x.2017; 2 vacated mines, Finistère, Presqu’île de Crozon, ca 4 km E Crozon, l’Aber, 12.vii.2006; 1 vacated mine, Haut-Rhin, Colmar, 3 km SW, Le Neuland, 26.ix.2002; 1 larva, 4 mines, Haut-Rhin, Lapoutroie, La Bohle, 21.x.2002, U. glabra ; 3 vacated mines, Indre-et-Loire, Huismes, N of Contebault, along C17, 8.x.2017; several vacated mines, Lozère, Marjoab, 2.5 km SW Meyrueis, 22.vii.2009, U. minor ; 3 vacated mines, Lozère, Barre-des-Cévennes, 26.vii.2009, U. minor ; vacated mines, Pyrénées-Orientales, Port-Vendres, near railway station, 28.vii.1982. Germany: 1 vacated mine, Brandenburg, Erkner, 9-11.ix.2007; several vacated mines, Saarland, Neunkirchen, Zoo, 30.ix.2004; 1 vacated mine, Sachsen-Anhalt, Dornburg, 2 km S, along Elbe, 19.vii.2014. Greece: 2 larvae, many mines, Akhaia, Strofilia, S Kalogria, 4.xi.2011, U. minor ; 6 larvae, several mines, Ilía, Olympia, archeological site, 5.xi.2011, U. minor . Italy: 1 vacated mine, Bolzano, Vinschgau, Prad an Stilfser Joch, Suldenbach banks, 27.vii.2005; 1 larva, many mines, Cuneo, Entracque, ca 1 km SE, Il Bosco, 16.viii.2007; several mines, Cuneo, Entracque, ca 1 km SE, Il Bosco, 13.x.2008; 3 vacated mines, Roma, Trevignano Romano, 17.ix.2005. Monaco: 3 vacated mines, Monaco Ville, E slope of Palais Principier, 9.viii.2007. Netherlands: mines, Gelderland, Winterswijk, Bekendelle, along Slinge, 1.x.1979; 1 larva, mines, Gelderland, Nijmegen, Winkelsteeg, 11.x.2008; mines, Limburg, Eys, railway near Piepert, 11.ix.1979; mines, Limburg, Thorn, klooster Bethanien, 24.ix.1979; mines, Limburg, Gulpen, NW, holle weg, 8.x.1979; 1 mine, Limburg, Thorn: Baarstraat, 3.x.1988; mines, Noord-Holland, Castricum, hedge along road, 15.viii.1979; mines, Noord-Holland, Castricum, hedge along road, 15.viii.1979; mines, Noord-Holland, Amstelveen, Beneluxbaan, median reserve, 21.ix.1979; several vacated mines, Overijssel, Weerribben, Ossenzijl, Venebosch, 27.viii.2011; several vacated mines, Zeeland, Middelburg N., Brigdamseweg, 2.viii.2009; 1 larva, 1 mine, Zuid-Holland, Den Haag, Waalsdorpervlakte, 7.x.2007; mines, Zuid-Holland, Leiden W, experimental garden University, 5.vii.1979; mines, ibidem, 5.ix.1979; mines, Zuid-Holland, Wassenaar, Meijendel, near Kijfhoek, 18.ix.1979; 1 larva, Zuid-Holland, Oegstgeest, Rhijngeest, 23.ix.1997. Portugal: 1 mine, Tras-os-Montes, PN Montesinho, Salgueiros, Vallone das Furnas, 8 km N Vinhais, 30.vii.2001. Romania: a few vacated mines, Brasov, Brașov, Mt. Tâmpa, 2.viii.2011. Sweden: several vacated mines, Bohuslan, Svenneby, Valön Nature Reserve, 7.viii.2008.

North American Ulmus leafminers

Previously only two Nepticulidae were known to feed on Ulmus in North America: Stigmella apicialbella (Chambers, 1873) and Ectoedemia ulmella (Braun, 1912). This is a much poorer fauna than the seven European species (van Nieukerken 1986, Puplesis 1994), and in Asia the number is probably still higher, but for several species that are potentially Ulmus feeders the hosts are as yet unknown.

Identification of the North American Nepticulidae mines and adults reared from Ulmus is straightforward. For convenience we provide a key that distinguishes these from other insects that form partially or entirely linear mines. Primary blotch mines on elm are formed by additional species of Lepidoptera ( Coleophoridae : Coleophora ; Gracillariidae : Cameraria , Phyllonorycter ), Coleoptera ( Buprestidae : Brachys ; possibly also Curculionidae : Tachygonus ), and Hymenoptera ( Tenthredinidae : Fenusa ). For a complete key, see Eiseman (2018).

Key to North American Ulmus (linear) leafmines