Search results for "nez"

Leaf epicuticular waxes effects egg parasitoid’s response to host adult footprint contact kairomone

2009

Chemical footprints left behind by true bugs are perceived as a contact kairomones by scelionid egg parasitoids. In the system Nezara viridula and its egg parasitoid Trissolcus basalis, previous studies have shown that the kairomone mediating such behavior is part of N. viridula’s cuticular hydrocarbons. In this study, the effect of epicuticular waxes of leaves of broad bean, Vicia faba, on wasp response to footprints of N. viridula females are investigated. Plants with intact waxes layer were used (1) without host chemical contamination, or (2) contaminated by host female footprints. Mechanically de-waxed plants were tested (3) without host chemical contamination, or (4) de-waxed a few min…

Plant surface mediates interaction between true bug chemical footprints and scelionid egg parasitoids

2009

Chemical footprints left behind by true bugs act as contact kairomones inducing an arrestment response in scelionid egg parasitoids. Once in contact with contaminated substrates, female wasps display a characteristic arrestment posture followed by an increase of the host searching time. Previous studies were conducted on artificial substrates as filter papers, so that little is known about the effects of natural substrates on behavioural response by wasps. In field, the substrate where these interactions occur, i.e. the surface of plants, is covered by wax layers that can have a role in trophic interactions between insects. In this study, we investigated the influence of plant surfaces on a…

I semiochimici utilizzati nella localizzazione dell’ospite da parte del parassitoide oofago Ooencyrtus telenomicida

2009

Ooencyrtus telenomicida (Vassiliev) (Hymenoptera: Encyrtidae) è un parassitoide oofago di Nezara viridula (L.) (Heteroptera: Pentatomidae) di origine paleartica frequentemente diffuso in Sicilia. Scopo del presente lavoro è stato quello di investigare il processo di localizzazione dell’ospite nel sistema tritrofico Solanum lycopersicum L. – N. viridula – O. telenomicida. In particolare sono stati condotti esperimenti in olfattometro a Y, per valutare il ruolo attrattivo dei composti volatili emessi sia dalle piante, sia dagli adulti della cimice verde, e in arena aperta, per biosaggiare. la risposta delle femmine del parassitoide alle tracce lasciate sul substrato dagli adulti di N. viridul…

Intraguild interactions between two egg parasitoids of a true bug: from laboratory to field investigations

2011

Intraguild interactions can play a role in species coexistence and in sizing and shaping community structures. In addition, understanding how competitive interactions between parasitoid guilds can affect pest suppression may improve biological control. Interspecific competitive effects can be divided in “extrinsic competition”, the indirect interactions between adult females searching for or exploiting hosts, and “intrinsic competition”, the competition that occurs between larvae developing in the same host. In this work we performed both laboratory and field investigations to address on intraguild interactions occurring between Trissolcus basalis (Hymenoptera: Scelionidae) and Ooencyrtus t…

Outcomes of intraguild interactions between two egg parasitoids in field and semi-field conditions

2012

Intraguild interactions between two egg parasitoids, Trissolcus basalis (Wollaston) and Ooencyrtus telenomicida (Vassiliev) exploring egg masses of the Southern Green Stink Bug Nezara viridula (L.) were investigated in field and semi-field conditions. Field trials were conducted in tomato fields by using sentinel and naturally laid egg masses in 2010 and 2011. Egg parasitoids monitoring, by sentinel egg masses placed weekly on plants during the tomato growing season and recollected one week later, showed that T. basalis occurs from June to October, whereas O. telenomicida occurs mainly in July and August. In the same fields, collections of naturally laid egg masses display different types o…

Endogenous and exogenous factors affecting host chemical footprint exploitation by a hymenopterous egg parasitoid

2014

During the host location process, parasitoids encounter and explore a great variety of volatile and contact semiochemicals from the host-plant complex. In the system Nezara viridula and its egg parasitoid Trissolcus basalis, when wasps land on a plant, they can taste chemical footprints left by walking adult hosts. These cues represent a set of indirect host-related contact kairomones that induce arrestment and motivated searching behavior, as they drive wasps in an area where there is a high probability of finding hosts but are not able to “promise” the presence of the suitable host stage. Patch time allocation is strongly modified by experience gained during foraging on host traces. In fa…

Sintesi di 1,2,4-ossadiazoli fluorurati analoghi del Linezolid come potenziali anti-batterici

2009

L'aumentata multidrug resistance tra i batteri patogeni Gram-positivi ha riacceso l'interesse verso la ricerca di nuove classi strutturali di antibiotici attivi nei confronti di batteri multiresistenti.1 Il Linezolid, appartenente alla classe degli ossazolidinoni, è il capostipite di una nuova generazione di anti-batterici di sintesi attivi contro patogeni Gram-positivi.2 La ricerca di nuovi analoghi del Linezolid risulta quanto mai attuale dato il recente riscontro di fenomeni di resistenza batterica a tale farmaco.3 In questo contesto, verranno presentati alcuni risultati preliminari relativi allo sviluppo di nuove metodologie di sintesi per l’ottenimento di composti eterociclici fluorura…

Sintesi e valutazione biologica di 1,2,4-ossadiazoli analoghi del Linezolid

2011

Risonanza stocastica nel riconoscimento e nel corteggiamento di specie di Nezara viridula

2011

Mito e archetipi

2015

Dal mito emergono e si attualizzano degli archetipi, che sono delle forme costanti, delle possibilità di rappresentazioni; sono dei principi formali che sembrano prendere avvio da un mitico inizio genetico nel quale ogni evento e ogni fenomeno trae origine; forme da assumere come modello, unità di misura per ogni valutazione, termine di confronto assoluto. Parlare di archetipi originari, dunque di miti, serve a mettere in luce le pratiche analitiche e congetturali di senso archeologico. Proprio l’archeologia vede nel mito la proiezione collettiva, poetica, esagerata e affabulante di asciutte e incontrovertibili verità. Palermo, con i suoi simboli ed emblemi utilizzati come sineddoche, è spe…