1,720,967 research outputs found
Centrodora livens (Walker), afelinide parassitoide di uova di Metcalfa pruinosa (Say) in Italia
No full text
The community composition of ladybirds (Coccinellidae) occurring in three vineyards in Tuscany (Italy)
No full textThe ladybird communities were investigated in three differently managed vineyards of the province of Pisa (Tuscany, Italy), two of which were organic. A total of 4,057 specimens were captured in 2012 and 866 in 2013, all belonging to the subfamilies of Scymninae, Coccinellinae, Coccidulinae and Chilocorinae. The ladybird community was analysed on the base of the simple species composition as well as of the trophic guild to whom they belonged. Scymninae and Coccinellinae were the most represented subfamilies. Aphidophagous components of the community were the highest everywhere, followed by the species feeding on coccids, fungi and mites. The analysis based on the community functional biodiversity was better in discriminating different vineyards then the one based on species diversity. The two organic vineyards showed a higher potentiality to host a high number of species and a complex community structure. Coccid predators were predominant in the conventional vineyard
PROVE PRELIMINARI SULLA MORTALITÀ INDOTTA DA ALCUNI AGROFARMACI NEI CONFRONTI DI SCYMNUS APETZI (COLEOPTERA,COCCINELLIDAE)
No full textL’attività di predazione svolta da gran parte dei Coccinellidi riveste un ruolo di grande importanza all’interno degli ecosistemi. Tuttavia, la posizione di tali predatori nelle catene trofiche li rende molto sensibili ai disturbi antropici che, soprattutto negli agroecosistemi, vengono causati dalle operazioni colturali e, in particolare, dall’utilizzo dei prodotti fitosanitari. In questo lavoro si è inteso indagare i possibili effetti di agrofarmaci diversi sulla mortalità di Scymnus apetzi Mulsant, predatore afidifago diffuso in numerosi ambienti coltivati e incolti. A tale scopo, su individui adulti di circa 10 giorni di età, sono stati eseguiti biosaggi per contatto, utilizzando cinque prodotti commerciali ad azione insetticida (aventi come p.a. Deltametrina, Imidacloprid, Thiamethoxam, Abamectina ed Esaflumuron), tre fungicidi ad azione antioidica (contenenti Zolfo, Penconazolo, Difenoconazolo), un erbicida (p.a. Glyphosate) e un acaricida (p.a. Dicofol). Inoltre, sono stati indagati gli effetti dell’Imidacloprid, molecola caratterizzata da un’elevata sistemicità, sullo sviluppo di larve neonate del Coccinellide alimentate con prede (Aphis craccivora Koch) che avevano subito un trattamento a dosi subletali. I biosaggi effettuati con i diversi agrofarmaci hanno mostrato come gli insetticidi possano causare mortalità nel Coccinellide anche a dosi di parecchie volte più basse rispetto a quelle di etichetta mentre, tra gli altri prodotti saggiati, soltanto l’erbicida Glyphosate ha mostrato elevata tossicità nei confronti dell’entomofago. La prova condotta con Imidacloprid ha mostrato come la mortalità delle larve di S. apetzi si concentri nella prima decade, proseguendo più lentamente per tutto l’arco della prova, consentendo di raggiungere lo stadio adulto solo a una ridottissima percentuale di esemplari. La sensibilità dimostrata da S. apetzi nei confronti degli agrofarmaci saggiati (specialmente quelli ad azione insetticida) ha confermato la necessità di un’attenta valutazione degli effetti di questi prodotti sulle specie non target presenti in un agroecosistema, mettendo in evidenza come anche le dosi subletali e l’assunzione indiretta dei principi attivi possano indurre mortalità significative nei confronti di entomofagi
Prey selection behaviour in the multicoloured asian ladybird, Harmonia axyridis (Coleoptera: Coccinellidae)
No full textThe multicoloured Asian ladybird, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) is a generalist predator of aphids and other soft-bodied insects. Its diet leads to negative impacts on non-target species, despite its beneficial effects offered as biocontrol agent. Herein, we evaluated prey preferences and predation success of H. axyridis adults and 4th instar larvae exposed to binary prey combinations of insects commonly found in Italian vineyards. These binary combinations included a classic prey, Aphis craccivora (Hemiptera: Aphididae) and an alternative prey, i.e., first instar larvae of the European grapevine moth Lobesia botrana (Lepidoptera: Tortricidae), second instar larvae of H. axyridis, to evaluate cannibalistic behaviour of H. axyridis, fourth instar larvae of the non-target ladybird Scymnus apetzi (Coleoptera: Coccinellidae), to evaluate intra-guild predation. Results showed that H. axyridis larvae and adults can act as potential predators of the moth pest L. botrana. They were also able to predate the non-target coccinellid species S. apetzi, thus adversely affecting aphidophagous guilds. Harmonia axyridis larvae did not significantly prefer to predate A. craccivora over the other tested preys. Harmonia axyridis adults did not show significant preferences on A. craccivora over S. apetzi larvae, whereas they prefer A. craccivora over L. botrana and H. axyridis larvae. As a general trend, the prey selection time was shorter in H. axyridis larvae, if compared to adults. Overall, our study adds basic knowledge to the prey location behaviour of H. axyridis larvae and adults, showing main differences in predation parameters of larvae and adults of this species evaluating selected binary combinations of potential preys
Influenza di differenti modalità di gestione agronomica sulla coleotterofauna del suolo. Un caso studio in provincia di Pisa
No full textLeptoconops (Holoconops) kerteszi (Diptera Ceratopogonidae) in the coastal area of Grosseto: eco-ethological aspects
No full textMulti-year observations on the life-cycle of Leptoconops (Holoconops) kerteszi Kieffer (Diptera Ceratopogonidae) were carried
out in the coastal areas of Grosseto (Italy). In the studied environment, most of the populations complete two generations within a
year. Overwintering is assured by the larvae. Using a simple and functional sampling technique of preimaginal stages, we obtained
a general overview of L. (H.) kerteszi breeding sites. L. (H.) kerteszi is generally found in coastal swampy areas, where the
species colonizes a sandy shore that is devoid of vegetation and remains constantly damp as saltwater ascends by capillarity. Larvae
living in the first centimeter of the shallow sandy layer. Such sites occur in interdunal sandy areas bordering the ponds closest
to the seashore and also in tongues of sand along the edges of the ponds beyond the dunes, a little further inland
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
- …
