©Slovenian Entomological Society, download unter www.biologiezentrum.at LJUBLJANA, MAY 2002 Vol. 10, No. 1:43-53 THE INTERSPECIFIC RELATIONSHIPS BETWEEN PLANTS, CICADEL-LIDS, AND DRYINIDS (HEMIPTERA: CICADELLIDAE -HYMENOPTERA: DRYINIDAE) Valeria GIORDANO, Alberto ALMA & Alessandra ARZONE Di.Va.P.R.A.-Entomologia e Zoologia applicate aH'Ambiente "C.Vidano", Universita di Torino - Via L. da Vinci 44 - 10095 Grugliasco (TO) Abstract - The relationships between 14 species of broadleaved trees, 29 species of cicadellids, 9 species of dryinids, and 1 species of a diapriid hyperparasitoid were examined in several areas of the western Piedmont (Northern Italy). Key words: Broadleaved trees, Auchenorrhyncha, plant sucking insects, parasitoids, hyperparasitoids Izvleček -MEDVRSTNI ODNOSI MED RASTLINAMI, ŠKRŽATKI DRUŽINE CICADELLIDAE IN OSICAMI DRUŽINE DRYINIDAE (HEMIPTERA: CICADELLIDAE - HYMENOPTERA: DRYINIDAE) Na več območjih zahodnega Piemonta (severna Italija) so bili proučeni odnosi med 14 vrstami listnatega drevja, 29 vrstami škržatkov iz družine Cicadellidae, 9 vrstami osic ščipalkark (Dryinidae) in eno hiperparazitsko vrsto iz družine Diapriidae. Ključne besede: listnato drevje, Auchenorrhyncha, rastline sesajoče žuželke, parazitoidi, hiperparazitoidi Introduction The Hymenoptera Dryinidae are poorly known parasitoids that play an important role in the control and maintenance of the delicate balances in natural environments (Arzone et al., 1988; Tavella et al., 1994; Alma & Tavella, 1997). Nevertheless, until 43 ©Slovenian Entomological Society, download unter www.biologieAaftliii«Sit>mologica sloveilica, 10 (1). 2002 now their use in biological control has not reached the desired results due to unknown elements that did not permit a positive result (Olmi, 2000). On the other hand, so far investigations concerning the dryinid-host association are few and the hypothesis of a close interrelationship between trees and parasitoids has not yet been confirmed. Therefore, for the correct use of the control activity of these parasitoids, it seems necessary to know better their biological, ecological, and ethological peculiarities. Keeping in mind the results of research on the relationship between cicadellids and plants (Arzone & Vidano, 1987; Vidano & Arzone, 1987a, 1987b), an attempt to increase knowledge about tree-cicadellid-dryinid associations seemed interesting, particularly in considering the necessity of using dryinids in controlling the flatid Metcalfa pruinosa (Say). It is now widely diffused in Italy, where it arrived from the U.S.A. without its natural enemies (Girolami & Camporese, 1994). This research has only a qualitative character, but the checked numerical data aim at least partially to light the parasitization incidence carried out by dryinids on cicadellids. Materials and methods The parasitized cicadellids were sampled on the most common trees in urban, extraurban, woody, and mountainous environments of the western Piedmont, namely, Salix spp., Populus nigra L., P tremula L., P alba L., Betula pendula Roth, Alnus glutinosa Gaertner, Carpimis betulus L., Cory his avellana L., Quercus robur L., Castanea sativa Miller, and Fagus sylvatica L. Captures and surveys were made weekly in the parks of Turin (230 m a.s.l.) and Cuneo (534 m a.s.l.), besides rarely inhabited environments in the neighbourhood of Boves (CN, 600 m a.s.l.), and sporadically also in mountain environments of the provinces of Cuneo (Valle Stura di Demonte, from 570 to 1,249 m a.s.l.; Valle Gesso, 730 m a.s.l.; Valle Maira, 1,010 m a.s.l.), Torino (Valle di Susa, 364 m a.s.l.; Val Chisone, 1,830 m a.s.l.), Aosta (Natural park "Monte Avic", 860 m a.s.l.), and Trento (Monte Bondone, 1,832 m a.s.l.). Extemporaneous and occasional collections were also made on different plants in other localities. The captures and surveys were carried out during 1993-1995 in two distinct periods: during the plant winter quiescence and the vegetative activity. During the winter quiescence of deciduous plants, the cicadellids were collected on conifers and brambles and reared in cages on host plants to check the probable presence of dryinid larval sacs. In spring, daily surveys were made on budding broadleaved trees to precisely detect the presence of cicadellid nymphs. Afterwards nymphs of different instars were collected and reared. When possible, the cicadellid instars in which the parasitization occurred were stated. Two yellow sticky traps wpre placed on the canopy of 5 plants of B. pendula and C. betulus in Turin in the 3 decade of March 1995, on 5 plants^f P alba and P nigra in Turin, and of P nigra and P tremula at Boves in the 2 decade of April 44 V Giordano. A. Alma & A. Arzone: The interspecific relationships between plants, cicatiellids, and dryinids 1994 and 1995. Similar traps were placed on all the other investigated poplars to check the emergence period of the dryinids in the open air linked to different ecological niches. The exposure date was fixed according to the appearance of the first cicadellids on broadleaved trees. Trap replacements were done weekly. The parasitized specimens were reared, one by one, in glass tubes with a layer of wet soil mixed with sand on the bottom to permit the cocooning of dryinid larvae. Inside the tubes a leaf or a bud of the cicadellid host plant was also placed, its base dipped in a nutritive solution in order to maintain turgidity for a longer time. These tubes with the parasitoid cocoons were kept in natural climatic conditions to check the nymphosis period. In 1995, where no emergence was obtained, we carefully examined the tubes to ascertain the mortality of cocooned or not cocooned larvae, and also larvae, pupae, and adults within the cocoon. The dryinids were classified according to Olmi's keys (1984). Results 468 cicadellids were collected on conifers and brambles (Table 1). No specimen showed a dryinid larval sac. The chromotactic traps captured 1 Anteon jurineanum Latreille male at the end of May on B. pendula, 34 males and 3 females of A. jurineanum at the beginning of April on C. betulus, 84 males and 50 females of A. flavicorne (Dalman) from the end of April to the end of May on P nigra, 32 males and 3 females of A. flavicorne on P alba, 19 males and 2 females of A. flavicorne on P tremula. The parasitized cicadellids collected on 14 tree species are reported in Table 2, in which we indicate the dryinids emerged in the year of cocooning as well as in the following year. About half of the dryinid larvae reared in the laboratory burrowed in the soil, but several died without spinning a cocoon. Inside the cocoons we also found dead larvae, pupae and adults. A total of 44 Aphelopus spp. (33 in the year of the hatching) and 95 Anteon spp. (84 in the year of the hatching) emerged. Namely: 33 Aphelopus melaleucus (Dalman), 1 from Edwarclsiana rosae (L.) on Pirns mains L., 1 from E. candidula Kirschbaum on P alba, 3 from E. avellanae (Edwards), 1 from E. staminata (Ribaut), and 1 from Alebra coryli Le Quesne on C. avellana, 1 from E. flavescens (F.), 3 from Typhlocyba quercus (F.), and 1 from Arboriclia ver-sutci (Melichar) on Q. robur, 21 from Fagocyba cruenta (Herrich-Schaeffer) on F sylvatica; 3 A. atratus (Dalman), 2 from E. avellanae and 1 from E. staminata on C. avellana; 5 A. serratus Richards, 2 from Arboridia ribauti (Ossiannilsson) on C. betulus and 3 from E. avellanae on C. avellana; 1 A. nigriceps Kieffer and 2 A. querceus Olmi from A. versuta on Q. robur, 23 Anteon arcuatum Kieffer, 1 from Tremulicerus vitreus (F.) and 22 from Rhytidodus decimiisquartus (Schrank) on P nigra; 71 A. flavicorne (Dalman), 18 from T vitreus and 52 from Rh. decimiisquartus on P nigra, and 1 from Metidiocerus elegans (Flor) on Salix sp.; 1 A. infectum (Haliday) from Iassus scutellciris (Fieber) on Ulmus campestris L. 45 ©Slovenian Entomological Society, download unter www.biologieAstoiffirttpmologica slovenica, 10 (1), 2002 The nymphosis mean time of the adults which emerged in the year of hatching was 28 days (from 15 to 47), that of the others was 250 days (from 176 to 336). The sex ratio ranged from 1:1 to 3:2 in favour of females, except that of A. arcuatum (3:20 in the favour of males). In Table 3 the fate of the burrowed but not emerged dryinids is illustrated. The adults of A. jurineanum died inside the cocoons of O.flavicollis on B. pendida and of O. carpini on C. betulus, but they were classified as the same. Sampling dates of dryinizided T vitreus, Rh. decimusquartus, Populicerus spp., Oncopsis flavicollis (L.), O. carpini (J. Sahlberg) and F cruenta are given in Fig. 1. The maximum parasitization ratio was 60 for Rh. decimusquartus on P nigra, 35 for F cruenta on F sylvatica, 28 for T vitreus on P nigra, 15 for Populicerus spp. on P trémula, 13 for O. carpini on C. betulus, 7 for O. flavicollis on B. péndula. In Table 4 the plant-cicadellid-dryinid associations are illustrated. Six specimens of the Diapriid hyperparasitoid Ismarus flavicornis (Thomson) were obtained: 4 from A. flavicome on Populicerus spp. on P trémula, 1 from A. jurineanum on O. flavicollis on B. péndula, 1 probably from A. flavicome on Rh. decimusquartus on P nigra. Discussion Under natural conditions, Anteon spp. were very abundant on Idiocerinae of P nigra, quite diffused on cicadellids of P trémula, P alba, and Salix spp., and less abundant on Oncopsis spp. dwelling on B. péndula and C. betulus. It must be remembered that the two Anteon species acting on P nigra showed a different distribution in the considered areas. In fact, only 3 A. arcuatum specimens emerged from the cocoons coming from the Turin area (230 m a.s.l.), the others came from cicadellids collected in the Cuneo area (534 and 600 m a.s.l.). Instead, A. flavicome was found without distinction in the two areas. Aphelopus spp. showed a minor specificity of action and a particular adaptation to some habitats. Actually, the correspondence between parasitoids and plants seemed to be a frequent phenomenon. Some research enlarged the knowledge of the biology of several Aphelopus spp. A. melaleucus and A. nigriceps are prevalently bivoltine, showing emergence peaks in May and September and passing the diapause period inside the cocoon. A. serra-tus is prevalently monovoltine and diapauses as a first instar larva inside the overwintering adults of Zygina spp. as well as in a larval instar inside the cocoon (Jervis, 1980). In this research and in a previous one on Zygina rhamni Ferrari (Alma & Tavella, 1997), we never obtained dryinids from cicadellids overwintering on conifers or brambles. In the natural environment the parasitoids act only on a part of the potential hosts as a limiting factor. In fact, some factors provoke both a discrimination and a selection of the host and favour or prevent the parasitization. The presence of dryinids and cicadellids in the same habitat is a meeting point for the two. At first the parasitoids are attracted both by a particular environment and sugar substances available on the 46 V Giordano. A. Alma & A. Arzone: The interspecific relationships between plants, cicatiellids, and dryinids same plants, afterwards they stay on the vegetable parts where the plant sucking insects are concentrated. Host searching is made in a casual way and is often determined by the meeting opportunity in the sites in which such parasitoids find the best developmental conditions. According to Picard's and Rabaud's observations, many parasitoids are more sensitive to the attraction of the phytophage's host-plants than that of the phytophage itself (Flanders, 1940). In contrast, other authors argue that there is really no strict relation between host-plant and parasitoid. They had not found a direct relation between A. atratus, A. camus, A. nigriceps, and A. servants and their habitat (Waloff & Jervis, 1987). In our research the dryinids were shown to be attracted by their cicadellid hosts rather than by the plants. Emblematic is the aphelopine A. melaleucus, which attacked several typhlocybines on different host-plants. Moreover, the aphelopine A. melaleucus and the anteonine A. flavicovne, on the same host-plant P alba, parasitized the typhlocybine E. cancliclula and the idiocerine P albicans, respectively. In any case the control activity exerted by dryinids on cicadellids is interesting and opens important perspectives in the applied field. The dryinid activity, if poorly evident, is particularly effective and helps to maintain the cicadellid populations under the damage threshold. During this research, both Aphelopus and Anteon species were checked on Salicaceae, Betulaceae, Corylaceae, and Fagaceae trees. In particular, Aphelopinae showed a different distribution on the trees independently from the species of typhlocybines present there. Some trees had a consistent number of such hymenopterans, while others were without, though frequented by cicadellids. Anteoninae were parasitoids of prevalently oligophagous cicadellids. There is no evidence of a consistent variability of their population distribution on different host-plants. Phytophage communities discussed here showed a large proportion of host specialists. Their associated parasitoids, however, had a wider host range. Such a phenomenon enabled them to adapt easily to adverse conditions when the usual victims were lacking. The reduced potential of dispersal of the parasitoid populations in comparison with those of the phytophagous ones was partially compensated both by the major capacity of adaptation and the marked polyphagy. Only one hyperparasitoid species was found in the different biocenoses. Therefore the specialization gradually decreased from the trophic level of phytophages to the parasitoids, and from the parasitoids to the hyperparasitoids. Summary Research was carried out to ascertain the relationships between plants, cicadellids, and.dryinids. The investigations were made in northern Italy, in urban, extraurban, woody, and mountainous environments of the western Piedmont on the most common broadleaved trees, from 230 to 1,832 m a.s.l. Parasitized cicadellids were collected on 14 tree species, particularly Idiocerinae, Macropsinae, and Typhlocybinae. The maximum percentage of parasitization was 60 for Rhytidodus 47 ©Slovenian Entomological Society, download unter www.biologiezkBMiffltipmologica sloveilica, 10 (1), 2002 decimusquartus on Populus nigra, 35 for Fagocyba cruenta on Fagus sylvatica, 28 for Tremulicerus vitreus on P nigra, 15 for Populicerus spp. on P tremula, 13 for Oncopsis carpini on Carpinus betulus, 1 for O.flavicollis on Betula pendula. A total of 44 Aphelopinae and 95 Anteoninae emerged from the Cicadellidae. Namely: Aphelopus melaleucus from Edwarclsiana rosae on Pints mains, from E. candidula on P alba, from Alebra coryli, E. avellanae, and E. staminata on Corylus avellana, from E. flavescens, Typhlocyba quercus, Arboridia versuta on Quercus robur, and from F cruenta on F sylvatica, A. atratus from E. avellanae and E. staminata on C. avellana, A serratus from Arboridia ribauti on C. betulus and from E. avellanae on C. avellana, A. nigriceps and A. querceus from A. versuta on Q. robur, Anteon arcuatum from Rh. decimusquartus and T vitreus on P nigra, A. flavicorne from Metidiocerus elegans on Salix sp., from Rh. decimusquartus and T vitreus on P nigra, from Populicerus spp. on P tremula, and from P albicans on P alba, A. infectum from Iassus scutellaris on Ulmus campestris. The adults of A. jurineanum died inside the cocoons of O.flavicollis on B. pendula and of O. carpini on C. betulus, but they were classified as the same. Chromotactic traps captured 1 A. jurineanum male at the end of May on B. pendula, 34 males and 3 females of A. jurineanum at the beginning of April on C. betulus, 84 males and 50 females of A. flavicorne from the end of April to the end of May on P nigra, 32 males and 3 females of A. flavicorne on P alba, 19 males and 2 females of A. flavicorne on P tremula. Six specimens of the Diapriid hyperparasitoid Ismarus flavicornis emerged: 4 from A. flavicorne on Populicerus spp. on P tremula, 1 from A. jurineanum on O. flavicollis on B. pendula, 1 probably from A. flavicorne on Rh. decimusquartus on P nigra. The Dryinids were attracted by their cicadellid hosts rather than by the plants. Emblematic is the aphelopine A. melaleucus, which parasitized several typhlocy-bines on different host-plants. The same aphelopine, A. melaleucus, and the anteo-nine A. flavicorne, on the same host-plant P alba, parasitized the typhlocybine E. candidula, and the idiocerine P albicans respectively. References Alma A., Tavella L., 1997: Parasitization activity of two Aphelopus species (Hymenoptera Dryinidae) on Zygina rhamni Ferrari (Homoptera Cicadellidae). Redia, 80: 7-13. Arzone A., Vidano C., 1987: Typhlocybinae of broadleaved trees and shrubs in Italy. 3. Corylaceae. Boll. 1st. Ent. G. Grandi Univ. Bologna, 41, 1987: 269-276. Arzone A., Vidano C., Arno' C., 1988: Predators and parasitoids of Empoasca vitis and Zygina rhamni (Rhynchota Auchenorrhyncha). Proc. 6th Auchen. Meeting, Turin, 7-11 September 1987, 623-629. Flanders S.E., 1940: Environmental resistance to the establishment of parasitic Hymenoptera. Annals ent.Soc.America, 33: 245-253. 48 V Giordano. A. Alma & A. Arzone: The interspecific relationships between plants, cicatiellids, and dryinids Girolami V., Camporese P., 1994: Prima moltiplicazione in Europa di Neodryinus typhlocybae (Ashmead) (Hymenoptera Dryinidae) su Metcalfa pruinosa (Say) (Homoptera Flatidae). Atti XVII Congr.Naz.Entomologia. Udine, 13-18 giugno, 655-658. Jervis M.A., 1980: Life history studies on Aphelopus species (Hymenoptera, Dryinidae) and Chalarus species (Diptera, Pipunculidae), primary parasites of typhlocybinae leafhoppers (Homoptera, Cicadellidae). J.nat.Hist., 14: 769-780. Olmi, M., 1984: A revision of the Dryinidae (Hymenoptera). Mem.Amer.Entomol.Inst., 37, 1. The Ent.Amer. Inst., Ann Arbor, Michigan, U.S.A. Olmi M., 2000: Bio-ecologia degli imenotteri driinidi e loro impiego in programmi di lotta biologica. In A. Lucchi. La Metcalfa negli ecosistemi italiani, Arsia Regione Toscana, 93-117. Tavella L., Alma A., Arzone A., 1994: Ricerche ecologiche su Aphelopus atratus (Dalman) e A. serratus Richards (Dryinidae Aphelopinae) parassitoidi di Zygina rhamni Ferrari. Mem. Soc. ent. ital., 72, 1993 (1994): 189-194. Vidano C., Arzone A., 1987a: Typhlocybinae of broadleaved trees and shrubs in Italy. 2. Betulaceae. Boll. 1st. Ent. G. Grandi Univ. Bologna 41, 1987, 257-267. Vidano C., Arzone A., 1987b: Typhlocybinae of broadleaved trees and shrubs in Italy. 4. Fagaceae. Redia, 70, 1987: 171-189. Waloff N., Jervis M.A., 1987: Communities of parasitoids associated with leafhoppers and planthoppers in Europe. Adv.Ecol.Res., 17: 281-402. Tab. 1: Cicadellidae collected on conifers and brambles in the biennium 1993-1994. Cicadellidae Conifers Brambles m. f. m. f. Stenidiocerus poecilus 40 45 0 0 Empoasca spp. 0 0 0 2 Empoasca decipiens 1 0 4 0 Empoasca vitis 32 132 6 53 Ribautiana spp. 0 0 0 8 Zyginella pulchra 21 13 1 0 Zygina spp. 1 1 0 0 Zygina augusta 0 0 2 6 Zygina flammigera 2 3 20 34 Zygina rhamni 2 5 3 3 Zygina tithide 6 9 2 1 Arboridia spp. 0 1 0 4 Arboridia versuta 1 0 1 0 Frutioidia bisignata 0 0 0 3 49 ©Slovenian Entomological Society, download unter www.biologieAaftliii«Sit>mologica sloveilica, 10 (1). 2002 Table 2: Parasitoid activity of Dryinidae on Cicadellidae. Host plant No. Parasitized Burrowed Emerged Cicadellids Dryinids Dryinids (1) (2) Acer campestre 2 Alebra spp. 1 0 0 Pirus mal lis 5 Eclwardsiana rosae 1 1 0 Salix sp. 1 Macropsis sp. 0 0 0 2 Metidiocerus elegans 2 0 1 1 Edwardsiana frustrator 1 0 0 Populus nigra 1 Macropsis gramínea 0 0 0 239" Rhytidodus decimusquartus 184 69 5 73 Tremulicerus vitreus 55 15 4 Populus trémula 34 Populicerus spp. 26 0 0 Populus alba 8 Populicerus albicans 0 0 0 2 Edwardsiana candidula 2 1 0 Ulmus campestris 1 lassus scutellaris 1 0 1 Betula péndula 19 Oncopsis flavicollis 13 0 0 Alnus glutinosa 3 Oncopsis alni 1 0 0 1 Edwardsiana frustrator 1 0 0 Carpinus betulus 43 Oncopsis carpini 25 0 0 1 Typhlocyba bifasciata 0 0 0 3 Alnetoidia alneti 3 0 0 2 Arboridia ribauti 2 2 0 Corylus avellana 68 Alebra coryli 1 1 0 20 Edwardsiana avellanae 15 4 4 4 Edwardsiana staminata 3 2 0 3 Alnetoidia alneti 2 0 0 1 Arboridia parvula 0 0 0 Quercus robur 6 Alebra albostriella 6 0 0 3 Fagocyba carri 2 0 0 4 Edwardsiana flavescens 3 1 0 1 Eclwardsiana rosae 1 0 0 9 Typhlocyba quercus 7 3 0 6 Arboridia versuta 5 4 0 Castanea sativa 1 Alebra wahlbergi 1 0 0 Fagus sylvatica 83 Fagocyba cruenta 47 14 7 3 Eclwardsiana flavescens 2 0 0 1 Edwardsiana staminata 0 0 0 Dryinids emerged in the year of cocooning (1) or in the following year (2). 50 V Giordano. A. Alma & A. Arzone: The interspecific relationships between plants, cicatiellids, and dryinids Table 3: Dead Dryinidae found in the ground at the end of rearings. Host plant Cicadellidae Burrowed dryinids not emerged Dead dryinids Without cocoon Inside cocoon L P A Acer campestre Alebra sp. 1 1 0 0 0 Salix sp. Meticliocerus elegans 1 0 0 0 0 Eclwardsiana frustrator 1 0 0 0 1 Populus nigra Rhytidodus decimusquartus 110 2 15 5 47 Tremulicerus vitreus 36 1 5 2 14 Populus trémula Populicerus spp. 26 1 8 0 5 Populus alba Eclwardsiana candidula 1 0 1 0 0 Betula péndula Oncopsis flavicollis 13 1 5 0 3 Alnus glutinosa Oncopsis al ni 1 0 1 0 0 Eclwardsiana frustrator 1 0 1 0 0 Carpinus betulus Oncopsis carpini 25 20 0 0 1 Alnetoiclia alneti 3 1 2 0 0 Corylus avellana Alebra coryli 67 9 32 3 2 Eclwardsiana avellanae 7 3 1 0 1 Eclwardsiana staminata 1 0 1 0 0 Alnetoiclia alneti 2 0 1 0 0 Quercus robur Alebra albostriella 6 0 5 0 0 Fagocyba carri 2 0 1 0 0 Eclwardsiana flavescens 2 0 0 0 1 Eclwardsiana rosae 1 0 1 0 0 Typhlocyba quercus 4 0 2 0 0 Arboridia versuta 1 1 0 0 0 Castanea sativa Alebra wahlbergi 1 0 1 0 0 Fagus sy Iva tica Fagocyba cruenta 26 2 8 1 4 Eclwardsiana flavescens 2 0 1 0 1 L larva, P pupa, A adult. 51 ©Slovenian Entomological Society, download unterwww.biologie^rtfitLffmtamoIogica sloveilica, 10 (1), 2002 30 5 25 c §20 Q. -u 15 :=10 i 5 Q. 0 Trent u lice rus vitreas Populas nigra □ 1993 □ 1994 I 20 I 15 D_ I 10 :| 5 o. 0 Populicerus spp. Populas trémula n. □ o — — O — — := 4 2 2 S. o Onco-psis carpini. Carpinus betulus n □ 19941 □ 1995; 70 c 60 1 50 Q. 40 -o 30 20 ra 10 0 Rhytidodus deciinusquaitus Populas nigra □ 1993 □ 1994 □ 1995 I 6 o. | 4 N 1 2 D. Q Oncopsis flavicollis Betula péndula II o — — □ 1994 ILJ1 ■S 30 o. i20 N i 10 c3 0 Fagocyba cruenta Fagus sylvatica □ 1993 □ 1994 JL Fig. 1: Capture dates of parasitized specimens and parasitization rate in different plants and years. 52 ©Slovenian Entomological Society, download unter www.biologiezentrum.at V Giordano. A. Alma & A. Arzone: The interspecific relationships between plants, cicadellids, and dryinids Table 4: Host plant-cicadellid-dryinid associations. Host plant Cicadellidae Dryinidae Pints malus — Salix sp. - Populus nigra Populus trémula Populus alba Ulmus campestris Betula pendula — Carpinus betulus Coiylus avellana Quercus robur - Edwardsiana rosae— ■ Metidiocerus elegans-Rhytidodus decimusquartus Tremulicerus vitreus-Populicerus spp. — Populicerus albicans — -Edwardsiana candidida Iassus scutellaris - Oncopsis flavicollis — Oncopsis carpini - -Arboridia ribauti - A lebra coryli - Fagus sy Iva tica Edwardsiana avellanae Edwardsiana staminata Edwardsiana flavescens Typhlocyba quercus Arboridia versuta Fagocyba cruenta Aphelopus melaleucus -Anteon flavicome Anteon arcuatum Anteon flavicome Anteon flavicome Anteon flavicome Aphelopus melaleucus Anteon infectum Anteon jurineanum Anteon jurineanum Aphelopus serratus Aphelopus melaleucus Aphelopus atratus Aphelopus serratus Aphelopus melaleucus Aphelopus nigriceps Aphelopus querceus Aphelopus melaleucus Received / Prejeto: 26. 9. 2001 53