Analele Ştiinţifice ale Universităţii Al. I. Cuza Iaşi, s. Biologie animală, Tom LIII, 2007 DATA REGARDING THE PRESENCE OF THE PHYLLONORYCTER ISSIKII (KUMATA) (LEPIDOPTERA: GRACILLARIIDAE) IN ROMANIAN FAUNA Alina-Maria STOLNICU 1 and Camelia URECHE 2 1 Alexandru Ioan Cuza University, Iaşi, The Faculty of Biology, Carol I Blvd., no. 22, 700505, Iaşi, Romania e-mail: cralmap2004@yahoo.com 2 University of Bacău, The Faculty of Biology, Mărăşeşti Street, no. 157, 600115, Bacău, Romania e-mail: urechec@ub.ro Abstract. The paper we deals with the presentation of the Phyllonorycter issikii (Kumata, 1963) species in Romania. Phyllonorycter issikii (Kumata) is a leaf-minig species that attacks different species belonging to the Tilia genus. The Phyllonorycter issikii species was first identified in Romania in 2002 in the Gheorghitoaia and Frumuşica forests in Iaşi County area. There was also signalled an attack of the species in the Bacău County area, in 2005 in the Hârboanca Forest Reserve. In the present paper we present the biological chracteristics of the species as well as their larvae attack method. Keywords: leaf-minig insect, morphology, mining amplitude. Rezumat. Date asupra prezenţei speciei Phyllonorycter issikii (Kumata) (Lepidoptera: Gracillariidae) în fauna României. În lucrarea de faţă semnalăm prezenţa în România a speciei Phyllonorycter issikii (Kumata). Este o specie minieră care atacă diferite specii ale genului Tilia. Specia a fost identificată pentru prima dată în România în anul 2002 în pădurile Gheorghitoaia şi Frumuşica din judetul Iaşi. A fost semnalat un atac şi în judetul Bacău, iar în anul 2005 în Rezervaţia Forestieră Hârboanca din judeţul Vaslui. Se descrie specia şi se prezintă unele date biologice şi modul de atac al larvelor. Cuvinte cheie: insectă minieră, morfologie, amplitudinea minării. Introduction Phyllonorycer issikii (Kumata, 1963) belongs to the Gracillariidae family of the Lepidoptera order. The larvae excavate mines into the leaf limbs of some species of Tilia. The species was first identified in Japan by Kumata in 1963. It has widened its area of distribution progressively ariving to Europe: it was signalled in Russia (South of the Far East ) in 1977, and later in Ukrain, Belarus, Lithuania (Noreika, 1998), Poland, Hungary, Czheck Republic (Šefrová, 2002), Germany. In Romania, the presence of Phyllonorycer issikii (Kumata) larvae was first signaled in 2002 in the forests of Gheorghitoaia and Frumuşica in the Iaşi County area on the leaves of the Tilia cordata Miller species (coll. Ureche C., 2002). Further studies revealed its presence in the Bacău County area, in Hemeiuş and Dărmăneşti in 2002, and in 2005 in the Copou area in the town of Iaşi, also on Tilia cordata leaves. Between 2005 and 2006, intense attacks of this species were signalled on Tilia cordata Miller, T. plathyphyllos Scopoli and T. tomentosa Moench. It seems that it prefers species belonging to the Tilia genus, as it was also signalled on other species liske: T. amurensis Ruprecht, T. mandshurica Ruprecht et Maximowicz, T. maximowicziana Shirawa and other Tilia. Kumata also signalled an attack of this species on leaves of Betula plathyphylla Sukaczev in 1963 (Szabόky, 2004). The attack of the Phyllonorycter issikii (Kumata) does not cause important economic damage, but rather aesthetic damage, especially when it attacks trees with ornamental function in parks and gardens. -103-
Alina-Maria Stolnicu & Camelia Ureche Materials and Methods Our research was based in the Hârboanca Forest Reserve and it was made in 2006. The attack of the Phyllonorycter issikii (Kumata) larvae was observed on species of Tilia cordata Miller, T. plathyphyllos Scopoli and T. tomentosa Moench. There were collected leaves attacked by Phyllonorycter issikii (Kumata) that were studied in the laboratory in cultures aiming to obtain adult insects and parasitoid forms that limit this species populations. The genitalia were prepared for study by maceration and boiling in 10% KOH solution for 1-3 minutes, then they were put in glycerine. In order to reveal the frequency and the intensity of the attacks, we have observed 100 leaves per each generation. Results and Discussion As Phyllonorycter issikii (Kumata) is a new species for the Romanian fauna, we will first present some of its morphological and biological data. Description. The egg is ovoidal-globulary in shape and it has a little pedunculus that gives it a fixed position (Fig. 1). The outer skin is hard and coloured in a yellowish-creamy tone. Its diameter is of 100 µ. There are two development stages at this point, very well defined. In the first larva stage, the larvae have no setae and their body is dorso-ventrally flattened. Ciliae are well defined and placed towards the front of the head. The oculi are disposed in staight longitudinal rows on the sides of the cefalic capsule. In the second stage, the larvae have setae on the thorax as well as on the abdomen (pedespurs), the head takes on an almost cilinder shape, with the ciliae and the oculi oriented ventrally (Fig. 2). The pupa generally has the same characteristics of the larvae, but the head presents a rostrum, which serves the purpose of perforating the exuvia (the larvae shell). The head, the thorax and the thoracic appendixes are chestnut brown, while the abdomen is more lightly coloured (Fig. 5). The adults of the two generations come in different colourings. The aestive form (Fig. 6) presents a basic brownish ochre colouring of the wings, with a basal fine streak going down to the middle of the wing. The forewing has no black scales contour. The posteriour wings are copper-red and are clearly fringed. The autumnal form (Fig. 7) has brown-grey forewings with many dark, almost black scales on the margins. It has two lighter-coloured streaks: a very narrow one, situated medio-basally and covering up to 1/3 of the wing in an arched span going towards the dorsal edge and accompanied by black scales, and an even narrower one that has a dorso-basal position. The posterior wings are coloured in a lighter tone of brown-grey. The abdominal area has a creamy yellowish colour on the dorsal side, while the ventral side is brown-grey. The male genitalia is characterized by asymmetry (Fig. 8). The tegument is about as long as the left valve. The left valve is relatively narrow, obliquely parallel almost on the whole length. The right valve is ovoid, broad, and it goes until the basal third. The transtilla is rather narrow, asymmetrical; the vinculum is triangular, without a saccus. The aedeagus is longer than the right valve, and it is narrow, tubular, with an apical hook at the end. The female genitalia are symmetrical (Fig. 9). The papilla analis is of medium length, covered with just few long setae, but with many microspines on the whole surface. The ductus bursae is long and membraneous; the corpus bursae is pyriform, weakly sclerotized, with a pair of central sclerotized signa (Fig. 10). -104-
Analele Ştiinţifice ale Universităţii Al. I. Cuza Iaşi, s. Biologie animală, Tom LIII, 2007 B 1 A 2 3 4 5 6 7 Figures 1-7. Phyllonorycter issikii (Kumata, 1963). 1 - egg (A general view; B detail); 2 mature larva; 3 mine on Tilia cordata; 4 attack of the mining moth on the Tilia plathyphyllos; 5 pupa; 6 adult, aestive form; 7 adult, autumnal form. -105-
Alina-Maria Stolnicu & Camelia Ureche Figure 8. Phyllonorycter issikii male genitalia. Figure 9. Phyllonorycter issikii female genitalia. Figure 10. Phyllonorycter issikii - corpus bursae. -106-
Figure 11. Graphic representation of the intensity of mining of the Phyllonorycter issikii (Kumata) species on Tilia platyphyllos leaves. Minig species Hosting plant species The amplitude of mining 1-5 1-11 Collecting date Table 1. The intensity of mining in the Phyllonorycter issikii (Kumata) species on Tilia plahtyphyllos. No. of studied leaves No. of mined leaves No. of mines Mines Larvae The intensity of mining Leaves with: empty occupied alive parasited 1 mine 2 mines 3 mines More than 3 mines No. % No. % No. % No. % No. % No. % No. % No. % Phyll.. issikii Tilia plathyphyll os 20.07.2006 100 68 143 11 769 132 92.31 129 97.72 - - 23 33.82 29 42.64 7 10.30 9 13.23 17.09.2006 100 74 162 36 22.22 126 77.77 98 77.77 28 22.22 25 33.78 21 28.37 9 12.6 19 25.68-107-
Alina-Maria Stolnicu & Camelia Ureche The attack method is characteristic of mining insects. The egg is layed on the back of the leaf, being fixed with the pedunculus. Neonate larvae perforate the leaf epidermis and they go into the mesophyll where they begin to excavate a mine, which is elliptical in the beginning, but then it becomes a typical ptychonom, green or even in light brown tones. Generally, the mine will be placed between and on the main nervure and one of the secondary ones, but when a leaf host more than one mine, the positions will differ (Figs. 3, 4). The frass are dark coloured, granulated, and they are deposited in the form of a little pile inside the mine, on the opposite side to the direction of motion followed in the feeding process. The Phyllonorycter issikii (Kumata) larvae have oriented their attacks on the species Tilia cordata Miller, T. plathyphyllos Scopoli and T. tomentosa Moench. By carefully studying the attacks of the larvae and the dynamics of the emergence of adult insects, we were able to identify two different generations: an aestive one and an autumnal one. In order to study the frequency and the intensity of the attacks, we have collected for study 100 leaves submitted to the attack of each of the two generations. Of the 100 leaves collected on the 20.07.2006, 68 presented signs of mining attacks. The number of mines on one leaf varied between 1 and 5, and the total number of mines found on the 68 leaves was 143, of which 11 were empty and 132 populated by Phyllonorycter issikii (Kumata) larvae representing a percentage of 92.31%. By studying the mines in the laboratory, we have found out that only 129 mines contained live larvae, that is 91.72% (Table 1). Of the 100 leaves collected on the 17.09.2006, 74 were attacked by Ph. issikii larvae. We have counted 162 mines, the number of mines on one leaf varying from 1 to 11 mines (Table 1). Leaves with only one or two mines in both generations are predominant (Fig. 11). Conclusions In the paper we signal the presence of the Phyllonorycter issikii (Kumata) species in Romania. First signaled in the forests from the county areas of Iasi and Bacău, it was then found in the Hârboanca Forest Reserve in the Vaslui County area. We provide data regarding some structural data of the egg, the larva, and of the adult insect, the way of attack, as well as the preferred hosting plants. Being an invasive species, it can easily spread and cause damage to the trees of the Tilia genus. We have observed attacks of this species on Tilia cordata Miller, T. plathyphyllos Scopoli and T. tomentosa Moench. Acknowledgements Most grateful and respectful thanks to Prof. Dr. Gheorghe Mustaţă for the precious advice and guidance given throughout the elaboration of this paper. References Noreica, R., 2005. Phyllonorycter issikii (Kumata) (Lepidoptera, Gracillariidae) in Lithuania. Acta Zoologica Lithuanica, Entomologia, VIII (3): 34-37. Šefrová, H., 2002. Phyllonorycter issikii the latest information on a new member of our fauna. Abstract of a paper presented at a Conference on Zoology, Brno, CZ, 2002-01-14/15. Szabóky, C., 2004. The spread of the leaf miner Phyllonorycter issikii Kumata 1963 (Lep. Gracillariidae) in Hungary. Növényvédelem, XL (6): 301-302. -108-