L’orientamento guidato da semiochimici di contatto in imenotteri parassitoidi

Stefano Colazza, Ezio Peri, Daniela Lo Giudice

Research output: Contribution to conferenceOther


[automatically translated] The chemo-orientation in the Hymenoptera parasitoids, and more generally in insects, is manifested by movements in time and space led by chemical information in different degree of volatility. In the case of contact semiochemicals, the reception is entrusted to each and gustatory sensilla multiporo and manifests itself with a period of immobility, during which the antennas are kept adhering to the examined surface. Subsequently we can generally distinguish two types of behavior: random search and executive search. The random search is characterized by a decrease of the linear velocity of locomotion and by an increase of the angular velocity, in such a way parasitoids tend to intensify the exploration activities in the area where the resource is potentially present. The directional search, instead, It is oriented along a chemical trail to the source of emission. The parasitoids following a contact semiochimico maintain their body near the central axis of the track exhibiting a pace to "zig-zag". Both the search methods, random and directional, they can be induced by allelochemicals with kairomonal function and / or semiochemicals with pheromonal function. It is reported here, an extensive series of locomotor responses of parasitoid wasps into contact semiochemicals, with a focus on two case studies, Trissolcus basalis (Wollaston) and Metaphycus luteolus Timberlake, which represent, respectively, an example of searching motivated towards cairomonali stimuli and an oriented research pheromonal stimuli. The females of the egg parasitoid T. basalis use, the guest research, semiochemicals indirectly associated with the target stage, such as the traces left by the adults of Nezara viridula (L.), which induce the parasitoid a random search in an area where more could be the presence of egg masses. In M. luteolus, the traces left by the females in the male lead a directional movement along the pheromonal traces, which then mediate the encounter between the sexes.
Original languageItalian
Number of pages1
Publication statusPublished - 2009

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