Role of volatile semiochemicals in host location by the egg parasitoid Anagrus breviphragma |
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Authors: | Elisabetta Chiappini Gianandrea Salerno Alessia Berzolla Alessia Iacovone Maria Cristina Reguzzi Eric Conti |
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Affiliation: | 1. Istituto di Entomologia e Patologia vegetale, Università Cattolica del Sacro Cuore, , 29122 Piacenza, Italy;2. Dipartimento di Scienze Agrarie e Ambientali, Università degli Studi di Perugia, , 06121 Perugia, Italy |
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Abstract: | Recent investigations conducted on several tritrophic systems have demonstrated that egg parasitoids, when searching for host eggs, may exploit plant synomones that have been induced as a consequence of host oviposition. In this article we show that, in a system characterized by host eggs embedded in the plant tissue, naïve females of the egg parasitoid Anagrus breviphragma Soyka (Hymenoptera: Mymaridae) responded in a Y‐tube olfactometer to volatiles from leaves of Carex riparia Curtis (Cyperaceae) containing eggs of one of its hosts, Cicadella viridis (L.) (Hemiptera: Cicadellidae). The wasp did not respond to host eggs or to clean leaves from non‐infested plants compared with clean air, whereas it showed a strong preference for the olfactometer arm containing volatiles of leaves with embedded host eggs, compared with the arm containing volatiles of leaves from a non‐infested plant or host eggs extracted from the plant. When the eggs were removed from an infested leaf, the parasitoid preference was observed only if eggs were added aside, suggesting a synergistic effect of a local plant synomone and an egg kairomone. The parasitoid also responded to clean leaves from an egg‐infested plant when compared with leaves from a non‐infested plant, indicating a systemic effect of volatile induction. |
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Keywords: | induced synomones indirect plant defences VOCs host selection behaviour oviposition Hymenoptera Mymaridae Carex riparia Cyperaceae Cicadella viridis Hemiptera Cicadellidae |
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