1. Biological invasions of exotic species pose a major threat to native biodiversity. Invaders are known to have direct impacts on native species; however, less well studied are the indirect impacts mediated through the integration of invaders into trophically linked communities.2. A survey of the chalcid wasp parasitoid community attacking the chestnut gallwasp Dryocosmus kuriphilus was carried out over a 5-year period at 26 sites in northwestern Italy. More than 415 000 galls were collected and more than 10 000 parasitoid specimens emerged. Twenty-seven parasitoid species belonging to six families (Eurytomidae, Pteromalidae, Torymidae, Eupelmidae, Ormyridae, Eulophidae) were identified using morphological and molecular methods; seventeen are new records for the parasitoid community associated with D. kuriphilus in Italy. The morphospecies complexes Megastigmus dorsalis, Eupelmus urozonus, E. annulatus, and Eurytoma pistaciae were the dominant species; another six morphospecies were encountered regularly but at low frequency; and 13 species were recorded only occasionally. The attack rate of any individual parasitoid species was low, although the more common species appeared to be increasing their use of this novel host.3. Biases observed in the sex ratios of parasitoids emerging from D. kuriphilus galls suggest that parasitoid individuals are making life-history decisions to take advantage of the high abundance of this host. Overall, these patterns imply that there is an ongoing transfer of parasitoids between oak and chestnut galls, and hence a high potential for this invading species to have a major impact on native oak gall communities via indirect competition mediated through shared parasitoids.

Tracking the movement dispersion of Scaphoideus titanusThe movement dispersion of Scaphoideus titanus Ball adults from wild to cultivated 8 grapevine was studied with a novel mark-capture techniqueapplying. aA water solution of 9 cow milk (marker: casein) or chicken egg whites (marker: albumin) was applied directly onto 10 the canopy of wild grapevine more or less in close proximity (5-350 m) to at a distance from 11 vineyards ranging from 5 to 330 m.; Yyellow sticky traps were placed on the canopy of 12 grapes, and captured S. titanus adultsinsects were analyzed via an indirect ELISA for 13 markers' identification. Data were subject to exponential regression as a function of distance 14 from wild grapevine, and to spatial interpolation analyses (Inverse Distance Weighted and 15Kernel interpolation with barriers) were performedusing ArcGIS Desktop 10.1 software.; Tthe 16 influence of rainfall and time elapsed after marking on markers' effectiveness, and the 17 different dispersal patternsdispersion of males and females were also studied with regression 18 analyses. Of a total of 5417 insects analyzed for egg, 43% were positive to egg; whereas 18% 19 of 536 tested were milk-resulted marked with milkpositive. No influence of rainfall or time 20 since the marker's applicationelapsed was observed for egg-marked specimens, whereas milk-21 Introduction 33The nearctic leafhopper Scaphoideus titanus Ball (Hemiptera: Cicadellidae) was introduced 34into Europe in the late 1950s (Bonfils & Schvester, 1960) and is now widespread in many 35European countries from Portugal to Bulgaria (COST Action FA0807). This species is a 36 grapevine specialist, and develops on both wild and cultivated grapevine (Vitis spp.). It is 37 univoltine and overwinters in the egg stage, which is laid under the bark of wood 2-yrs of age 38 or more (Vidano, 1964); eggs start to hatch in the middle of May and nymphs (which include 39 five instars) are present until the end of July, whereas adults usually appear at the beginning 40 of July and are observed up to the middle of October (Vidano, 1964). S. titanus is an 41 important pest, as it is the main vector of grapevine's Flavescence dorée (FD), a disease 42 caused by 16SrV phytoplasmas (subgroups C and D) (Malembic-Maher et al., 2011). Nymphs 43 from the 3 rd instar on acquire phytoplasmas by feeding on infected plants (acquisition access 44 period, AAP), and following a latency access period (LAP) of 4-5 weeks they become adults 45 and able to transmit FD to healthy plants (IAP) (Bressan et al., 2005). Since FD is a cause of 46 great economic losses, insecticidal sprays against S. titanus are mandatory in Italy: active 47 ingredients include neonichotinoids, organophosphates, etofenprox, and natural pyrethrum, 48 the latter in organic farming (Lessio et al., 2011a Marking methods used in entomology include fluorescent dusts (Garcia-Salazar & Landis, 55 1997; Takken et al., 1998; Skovgard, 2002), radioisotopes (Hagler & Jackson, 2001), and 56immunomarking (Hagler & Jackson, 2001; Jones et al.,...

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Hawthorn (Crataegus monogyna Jacquin) is one of the natural hosts of Cacopsylla melanoneura (Förster), the acknowledged vector of "Candidatus Phytoplasma mali", the causal agent of Apple Proliferation (AP) disease, a serious and growing problem for apple production in Europe, particularly in Northern Italy. Wild plants could be important sources of both insects and phytoplasmas, but their role in the epidemiology of phytoplasma diseases and their insect vectors has never been thoroughly examined. C. melanoneura's primary host is hawthorn, a plant closely related to apple which often grows wild near orchards. Other psyllid species feed on hawthorn, but no data are available on their possible role as phytoplasma vectors. We investigated the hawthorn's psyllid fauna in northwestern Italy using yellow sticky traps, beat trays, and molecular analyses from [2003][2004][2005], to study the relationship between hawthorn, the phytoplasma and the insect vector.Population dynamics were monitored, and insects and hawthorn samples were analysed by PCR, RFLP, and DNA sequencing for the presence of phytoplasmas. C. melanoneura was the dominant psyllid species, followed by C. peregrina, C. affinis and C. crataegi. PCR and RFLP analyses revealed the presence of different fruit tree phytoplasmas in hawthorn plants, and in all four psyllid species .

The leafhopper Scaphoideus titanus is able to transmit 16SrV phytoplasmas agents of grapevine's flavescence dorée (FD) within 30–45 days, following an acquisition access period (AAP) of a few days feeding on infected plants as a nymph, a latency period (LP) of 3–5 weeks becoming meanwhile an adult, and an inoculation access period (IAP) of a few days on healthy plants. However, several aspects of FD epidemiology suggest how the whole transmission process may take less time, and may start directly with adults of the insect vector. Transmission experiments have been set up under lab condition. Phytoplasma‐free S. titanus adults were placed on broad bean (BB) plants (Vicia faba) infected by FD‐C (16SrV‐C) phytoplasmas for an AAP = 7 days. Afterwards, they were immediately moved onto healthy BB for IAP, which were changed every 7 days, obtaining three timings of inoculation: IAP 1, IAP 2 and IAP 3, lasting 7, 14 and 21 days from the end of AAP, respectively. DNA was extracted from plants and insects, and PCR tests were performed to identify FD phytoplasmas. Insects were dissected and fluorescence in situ hybridisation was made to detect the presence of phytoplasmas in midguts and salivary glands. The rate of infection in insects ranged 46–68% without significant differences among IAPs. Inoculation in plants succeeded in all IAPs, at a rate of 16–23% (no significant differences). Phytoplasma load was significantly higher in IAP 3 than IAP 1–2 for both plants and insects. Phytoplasmas were identified both in midgut and salivary glands of S. titanus at all IAP times. The possible implications of these results in the epidemiology of flavescence dorée are discussed.