La localizzazione dell'ospite nei parassitoidi oofagi: il ruolo delle cere epicuticolari delle piante.

Stefano Colazza, Ezio Peri, Daniela Lo Giudice, Mauro Lo Bue

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[automatically translated] The host location in parasitoids oofagi is the result of a complex foraging behavior influenced mainly by the physical and chemical stimuli. The chemical signals (semiochemicals) may result from the interaction between the plant and the host egg (sinomoni induced dall'ovideposizione), from egg such (direct kairomones) and / or from different stages from the egg, such as for example the adult (indirect kairomones). The sinomoni induced by oviposition, which attract parasitoids of eggs even before the pest can cause damage, are an effective example of the involvement "Direct" in the plant host localization process by parasitoids oofagi. The plant may also affect "indirectly" the research activity of these parasitoids thanks to their chemical-physical characteristics. A good example is the role they can play the epicuticulari waxes, non-polar molecules (hydrocarbons, ketones, alcohols, aldehydes, esters, fatty acids, etc.) that cover the surface of the aerial parts of higher plants. The epicuticulari waxes represent an interface between the plant and the outside and have important functional and physiological roles. In this presentation we review studies related to the influence of these waxes on the effectiveness of parasitoids oofagi. They will also be provided, for two tri-trophic systems, experimental data on the role that the waxes have in influencing the perception of sinomoni induced dall'ovideposizione [Brassica oleracea L. var. Savoy - Murgantia histrionica Hahn - Trissolcus brochymenae (Ashmead)] and the contact kairomones issued by adult bedbugs [Vicia faba var. luz de otoño and Brassica oleracea L. var. marathon - Nezara viridula (L.) - Trissolcus basalis (Wollaston)] as part of their primary parasitoids oofagi. The tests were conducted with in vivo bioassays, while the epicuticulari waxes were studied morphologically, with the aid of a scanning electron microscope (SEM), and chemically, by means of mechanical removal, extraction in chloroform or solid phase microextraction (SPME ), and subsequent analysis in gas chromatography coupled to mass spectrometry (GC-MS). The results have revealed the important role of waxes in modulating the foraging behavior of parasitoids, interfering on the release of induced sinomoni and adsorbing the cairomonali compounds produced by the guests, thus performing a "bridge" between pest and antagonist. In the discussion we will analyze the possible contributions that this knowledge can play in enhancing the effectiveness of biological control programs using ooparassitoidi.
Original languageItalian
Number of pages1
Publication statusPublished - 2009

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