Oviposition behaviour in Lygus rugulipennis: a morpho-functional study |
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Authors: | Roberto Romani Gianandrea Salerno Francesca Frati Eric Conti Nunzio Isidoro & Ferdinando Bin |
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Institution: | Dipartimento di Scienze Agrarie ed Ambientali-Entomologia, Faculty of Agriculture, University of Perugia, Borgo XX Giugno 74, 06121 Perugia, Italy;;Dipartimento di Biologia, Difesa e Biotecnologie Agro-forestali, Faculty of Agriculture, University of Basilicata, Macchia Romana, 85100 Potenza, Italy;;Dipartimento di Scienze Ambientali e delle Produzioni Vegetali, Faculty of Agriculture, Politechnic University of Marche, Via Brecce Bianche, 60131 Ancona, Italy |
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Abstract: | Before oviposition, a Lygus rugulipennis (Poppius) (Heteroptera: Miridae) female explores the substrate with her mouthparts, performing ‘probing’ behaviour which eventually leads to a choice of oviposition site. In this study, morphological and behavioural observations were carried out in order to define the mechanisms through which female bugs recognise suitable oviposition sites. The morphological study was conducted using electron‐microscopy techniques, while the behavioural experiments aimed at the temporary (using ZnSO4) or permanent (i.e., cauterization of the rostrum and ablation of both stylets and labium) inactivation of sensory structures located in the labium tip and in the stylets, which are probably involved in oviposition site selection. The tip of the labium of L. rugulipennis females is characterised by the presence of 11–12 uniporous gustatory sensilla which are innervated by 3–6 sensory neurones. One aporous mechanoreceptor is located ventrally on both areas of the labium tip. Other aporous mechanosensilla are found more proximally on the labium. ZnSO4 labium tip treatment did not affect oviposition site selection, while stylet amputations, as well as rostrum cauterisations, resulted in almost complete oviposition failure. Labium tip‐ablated females oviposited similarly to control females. These results suggest that the sensory neurones associated with the stylets are involved in the location of the oviposition site. Uniporous gustatory sensilla on the labium tip are not involved in the final steps of the oviposition behaviour. However, they seem to play a role in assessing the suitability of the substrate as a food source. |
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Keywords: | Miridae Heteroptera uniporous gustatory sensilla host-plant recognition mouthparts ultrastructure bioassays |
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