The Dutch species of Phyllonorycter with dark-sprinkled forewings, with P. populifoliella as an addition to the Dutch list (Lepidoptera: Gracillariidae) J. H. Küchlein & C. J. M. Alders KÜCHLEIN, J. H. & C. J. M. ALDERS, 2000. THE DUTCH SPECIES OF PHYLLONORYCTER WITH DARK- SPRINKLED FOREWINGS, WITH P. POPULIFOLIELLA AS AN ADDITION TO THE DUTCH LIST (LEPIDO¬ PTERA: GRACILLARIIDAE). - ENT. BER., AMST. 60 (1): 12-19. Abstract: Of the Phyllonorycter-species with dark-powdered forewings four are now known from The Netherlands. Identification keys to these species are presented, based on external characters as well as male genitalia. Moreover, bio¬ nomics, faunistics and changes in their distributional limits are discussed. One species new to The Netherlands is repor¬ ted here: P. populifoliella. J. H. Küchlein, Tinea foundation, Institute of Systematics and Population Biology, University of Amsterdam, Plantage Middenlaan 64, 1018 DH Amsterdam, The Netherlands. C. J. M. Alders, Venlosingel 32, 6845 JB Arnhem, The Netherlands. Introduction was found new to The Netherlands: P. popu¬ lifoliella (Treitschke). The species of Phyllonorycter belonging to The dynamism in their occurrence, added the populifoliella-group (see Snellen, 1882), to considerable identification problems makes have some characteristic external features in it worthwile to pay attention to the Dutch spe¬ common. The forewing is nearly always more cies of the populifoliella-group. or less dark-sprinkled, not shining as in the ot¬ her Phyllonorycter-species, and the pale stri- Dutch species of the Phyllonorycter gulae are usually diffuse. Accordingly, in the populifoliella-group keys for the identification of species of Phyl¬ lonorycter the group is almost immediately The numbering of the species of Phyllonoryc¬ keyed out (see e.g. Hering, 1932; Benander, ter, belonging to the populifoliella-group, is in 1945; Bradley et ak, 1969; Emmet et ak, accordance with the Dutch checklist (Küch¬ 1985). Moreover, the species of this group ha¬ lein, 1993). Arrangement and nomenclature of ve similar bionomics and their distributional the Phyllonorycter-species in this list are ba¬ ranges are much alike. sed on Emmet et ak, 1985. Three species of the populifoliella-group were already reported for our country in the 258 Phyllonorycter pastorella (Zeller, sixties of the last century, viz. Phyllonorycter 1846) pastorella (Zeller), P. sagitella (Bjerkander) 262 Phyllonorycter sagitella (Bjerkander, and P. comparella (Duponchel) (De Graaf & 1790) Snellen, 1866, 1869). All three were rare at the = tremulae (Zeller, 1846) time, but then P. pastorella and P. sagitella 262a Phyllonorycter populifoliella (Treitsch¬ became extreme rarities for a long period of ti¬ ke,' 1833) me. However, during the last decennium they 263 Phyllonorycter comparella (Dupon- have been recorded from quite a lot of new lo¬ chel, 1843) calities and are now often numerous where they occur. Moreover, recently one species 13 Ent. Ber., Amst. 60 (2000) Key based on external characters Identification 1 Vertex and frons white or whitish, not Identification of adults without dissection is difficult. The moths look similar and the spe¬ mixed with dark parts. P. pastorella (part) cies are variable, especially in the amount ot Wingspan 6.9 - 9.0 mm. Pale forms of P. pastorella. dark suffusion. Consequently, it is not easy to Antenna unicolorous white or pale ochreous, darkei describe the discriminating characters, and annulated. In forewing pale markings pure white; whi¬ this difficulty makes the construction of iden¬ te basal streak connected with first dorsal strigula, in tification keys for the species of this group palest specimens white markings more or less connec¬ ted. These forms cannot be considered as dark sprink¬ problematic. By using the keys mentioned in led! the introduction, determination of the moths is - Vertex from whitish to brown, always hardly possible. Accordingly, the subjoined mixed with darker parts. 2 new identification key for adult moths, based Antenna annulated, sometimes less distinct. on their external appearance, is presented heie 2 In forewing apex with blackish streak; se¬ with great reserve. cond pale costal strigula at an angle of circa Also dissection does not solve all pioblems, because the female genitalia of the Phyllono- 30° to 45° on costa ... 3 — In fore wing apex with blackish dot (someti¬ rycter-species are weakly sclerotized, which mes elliptical) or with dispersed blackish makes it difficult to prepare good slides. scales; second pale costal strigula at an an¬ Hence it is recommendable to leave female gle of circa 45° to nearly 90° on costa ... 4 genitalia in the abdomen. As a result of these fn forewing dark markings giving the impression ot problems we give neither key nor figures for blocks and triangles. female genitalia. The structure of the male ge¬ 3 Antenna annulated, except the distal part, nitalia of the species belonging to the genus which is whitish (exceptionally indistinctly Phyllonorycter, differs greatly. In the greater annulated). In forewing dark markings part of the Dutch species the genitalia are hardly or not dark-edged distally (fig. 1) asymmetrical, but the dark-sprinkled species . P. comparella belong to a group with symmetrical genitalia. Identification of the dark-sprinkled species by Wingspan 7.0 - 8.0 mm. In forewing pale colour whi¬ means of male genitalia is relatively easy as tish; four white costal strigulae (light scaling near ba- 1 2 Fig. 1-4. Fore wings of Phyl- lonorycter-species. 1, P. com¬ parella-, 2, P. sagitella-, 3, P. pastorella-, 4, P. populifoliel- 3 4 la. 14 Ent. Ber., Amst. 60 (2000) - Antenna annulated entirely. In forewing dark markings edged blackish brown distal- ly (fig. 2) . P. sagitella Wingspan 7.0 - 8.0 mm. In forewing pale colour yello¬ Fig. 6-8. Valvae of Phyllonorycter-species. 6, P. pastorel¬ wish white; five pale costal strigulae. la., 7, P. sagitella; 8, P. comparella. 4 In forewing second costal strigula at an angle of circa 45° to 60° on costa (less ob¬ - Valva with apex distinctly tapered, albeit vious in heavily suffused specimens) (fig. often slightly rounded. Sternite of abdomi¬ 3) . P. pastorella (part) nal segment viii with caudal margin Wingspan 6.9 - 9.0 mm. smooth. Aedeagus less than one and a half - In forewing second costal strigula at an times longer than valva . 3 angle of circa 60° to nearly 90° on costa 3 Valva with a thick, short tooth in the middle (fig- 4). P. populifoliella near dorsal margin; distal half of valva pro¬ Wingspan 7.0 - 8.4 mm. vided with setae (fig. 7) . P. sagitella - Valva without such a tooth, distal half of Key based on male genitalia valva only with setae at apex (fig. 8) . P. comparella 1 Valva ending distally in a large lobe, api- cally provided with a stout, curved spine (fig- 6) . P. pastorella Bionomics Aedeagus approximately two times longer than valva. - Valva not ending in a lobe, apically not pro¬ The bionomics of the species of the populifo¬ vided with a stout, curved spine. 2 liella- group show some resemblance. First 2 Valva with apex flat, not tapered. Sternite their foodplants belong to the Salicaceae, and of abdominal segment viii with caudal mar¬ second, their phenology is different from that gin slightly dentated. Aedeagus nearly two of the other Dutch Phyllonorycter-species. times longer than valva (fig. 5). In our judgement all four species are mo- . P. populifoliella nophagous or feed on closely related plant- Valva with a small tooth on ventral corner of distal species. The larvae of P. pastorella live on margin. smooth leaved Salix-species (e.g. S. alba L.) 15 Ent. Ber., Amst. 60 (2000) (preferably on shrubs), those of P. populifo- vered (also in the fluviatile phytogeographical liella live on black poplar (.Populus nigra L.) district) in 1994 and subsequent years. These (also preferably on smaller trees) and those of localities are De Laar (Arnhem, 1994), Mal¬ P. comparella on white poplar (Populus alba burgen (Arnhem, 1994, 1995), Meinerswijk L.) or grey poplar (Populus canescens L.). In (Arnhem, 1995), Rijkerswoerd (near Elst, literature additional foodplants for these spe¬ 1994, 1995, 1997), and Tiel (1995) (all situ¬ cies have been reported (e.g. Bradley et ah, ated in the province of Gelderland), and also 1969; Kuznetsov, 1990). However, other Blauwe Kamer (near Rhenen, province of foodplants than the ones mentioned above Utrecht, 1995). The second author found the need confirmation, because of possible errors mines numerous at all these localities, except due to the great similarity of the species. near Tiel, where only one mine was found. The phenology of the four species is unique Moreover, J. B. Wolschrijn collected six mi¬ among the Dutch Phyllonorycter-species. nes near Deventer (province of Overijssel) in They are bivoltine; the second generation of 1996. Furthermore, the first author collected moths emerges in autumn, then overwinters, three mines near Bunnik (province of Utrecht) and survives until following May. All other in 1995, and, together with J.A.W. Lucas, six species of Phyllonorycter hibernate as a pupa mines near Wieldrecht (province of Zuid-Hol- or, less frequent, as a larva. For breeding the land) in 1996. Finally, two adults were caught second generation of moths of the species be¬ at Klein Profijt (near Rhoon, province of Zuid- longing to the populifoliella group, the mines Holland) (J. A. W. Lucas). Phyllonorycter sagitella (fig. 11). In the se¬ can best be collected late August or early cond half of the 19th century found in five lo¬ September. In The Netherlands adults are rarely obser¬ calities (Küchlein, 1993). After a century of silence round this species Koster collected mi¬ ved in the field. Thus far no adults of P. sagi- nes at Losser (province of Overijssel) in 1985 tella and P. populifoliella have been found. Of (Huisman & Koster, 1998), and the first P. comparella and P. pastorella some adults author collected two mines in the Mariapeel were collected.