1,720,974 research outputs found
Dati preliminari sul controllo biologico di Ophelimus maskelli (Ashmead) (Hymenoptera: Eulophidae) in Campania a seguito dell'introduzione del suo antagonista Closterocerus chamaeleon (Girault) (Hymenoptera: Eulophidae)
No full textVengono forniti i dati preliminari relativi al controllo di Ophelimus maskelli (Ashmead) a seguito dell'introduzione dell'antagonista naturale Closterocerus chamaeleon (Girault
Gli stadi giovanili del parassitoide Closterocerus Chamaeleon (Girault) (Hymenoptera: Eulophidae) e il loro sviluppo in rapporto all'eulofide galligeno Ophelimus maskelli (Ashmead)
No full textSono descritti ed illustrati gli stadi giovanili di Closterocerus camaeleon (Girault) e la modalità di sviluppo in relazione agli stadi giovanili dell'ospite Ophelimus maskelli (Ashmead). Il parassitoide, di origine australiana è stato introdotto in Italia e in diversi altri Paesi del Bacino del Mediterraneo. Lo studio ha permesso di evidenziare le caratteristiche morfologiche larvali dell'Eulofide, utili per lo studio bio-ecologico e per la valutazione della sua attività antagonista
SULLA INTRODUZIONE DI CLOSTEROCERUS SP. (HYMENOPTERA: EULOPHIDAE) PER IL CONTROLLO DELL� EULOFIDE GALLIGENO DELL�EUCALIPTO OPHELIMUS MASKELLI (ASHMEAD) IN CAMPANIA
No full textSi descrive l'attività parassitaria a carico di Ophelimus maskell
Modalità di svernamento e di parassitizzazione di Closterocerus chamaeleon (Girault) (Hymenoptera: Eulophidae), parassitoide dell'Eulofide galligeno dell'eucalipto Ophelimus maskelli (Ashmead) in Campania
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Ridurre gli input chimici ed energetici in agricoltura mediante tecniche agronomiche innovative
Full text linkThe complex of parasitoids associated with the invasive leafminer Coptodisca lucifluella: indigenous species and a case of host-tracking
No full textCoptodisca lucifluella is a leafminer native to North Eastern America that has been recently recorded in Italy. Whereas in the native range it is detrimental to pecan-trees, the invasive populations attack black and common walnut trees in Italy. A high larval mortality has been previously reported, partially due to the activity of parasitoids.
To assess if the complex of parasitoids associated to this alien pest is affected by the protocol of defence against the key walnut pest Rhagoletis completa and by the agricultural management (specialized walnut or promiscuous), three fields were chosen in the same area: two specialized walnut orchards (organic and conventional) and an organic promiscuous orchard.
Percentage of parasitization was evaluated by weekly collecting samples of leaves over two years, from the earliest emergence of adults up to the last recorded larva, and parasitoids were isolated and identified.
We show that several species of indigenous parasitoids have quickly adapted to this invasive pest, and that there are significant differences in the parasitization rates and in the composition of parasitoids among the three orchards. Chrysocharis spp., Neochrysocharis sp. and one species of the Pnigalio soemius complex (Hymenoptera: Eulophidae) are the most abundant parasitoids. We also collected another eulophid, Cirrospilus coptodiscae, a parasitoid native to North America that has likely host-tracked C. lucifluella. Hitherto, this parasitoid had been reared on three host species including Coptodisca splendoriferella, a closely related species often confused with C. lucifluella, parasitizing larvae in leaf mines and in host cocoons. The parasitization of the latter host stage has probably favoured the host-tracking process.
Lastly, adults of C. coptodiscae showed high colour plasticity associated to different times of emergence, with lighter specimens emerging over summer and darker specimens emerging in spring
Evidence that Rickettsia manipulate the reproduction of Quadrastichus mendeli, a parasitoid of the Eucalyptus invasive pest Leptocybe invasa recently recorded in Italy
No full textThe blue-gum chalcid Leptocybe invasa is a pest of Eucalyptus, likely native to Australia that over the past 15 years has invaded 39 countries on all continents where eucalypts are grown. A recent survey in Australia pointed out three species of parasitoids, the most promising of which, Quadrastichus mendeli, has been released into some Mediterranean countries. At present, the Italian legislation forbids the release of non-native parasitoids; nevertheless in 2014 Q. mendeli was recorded in Southern Italy, probably due to its release in neighbouring countries. After just one year, Q. mendeli has showed a strong impact on Italian populations of L. invasa causing, in some areas, the almost complete disappearance of galls. Q. mendeli is uniparental like its host. As we have recently shown that the thelytokous reproduction of its host (L. invasa) is due to a Rickettsia symbiont, we hypothesised that Rickettsia could be involved also in the thelytoky of Q. mendeli, which may have acquired this symbiont by horizontal transmission.
We found evidences that a Parthenogenesis-Inducing (PI) Rickettsia is involved in Q. mendeli’s thelytoky, that is, the symbiont is densely present in the reproductive apparatus and is vertically transmitted. However, despite the close contact inside the gall and a presumably long coevolutionary history due to the parasitoid’s host specificity, host and parasitoid do not share the same Rickettsia. Indeed, phylogenetic analyses of three regions (16S-rRNA, gltA and rpmE-tRNAfMet) showed that Q. mendeli harbours a Rickettsia belonging to the ancestral group, subgroup limoniae. This is the first finding of a PI Rickettsia of this clade infecting a hymenopteran, and represents the fourth instance of PI Rickettsia. Remarkably, all PI Rickettsia discovered so far infect wasps of the hymenopteran family Eulophidae, and belong to three different phylogenetic groups, suggesting multiple independent evolution of the PI phenotype in the genus Rickettsia
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