RESUMEN
The strawberry blossom weevil (SBW), Anthonomus rubi, is a major pest in strawberry fields throughout Europe. Traps baited with aggregation pheromone are used for pest monitoring. However, a more effective lure is needed. For a number of pests, it has been shown that the attractiveness of a pheromone can be enhanced by host plant volatiles. The goal of this study was to explore floral volatile blends of different strawberry species (Fragaria x ananassa and Fragaria vesca) to identify compounds that might be used to improve the attractiveness of existing lures for SBW. Floral emissions of F. x a. varieties Sonata, Beltran, Korona, and of F. vesca, were collected by both solid-phase microextraction (SPME) and dynamic headspace sampling on Tenax. Analysis by gas chromatography/mass spectrometry showed the floral volatiles of F. x ananassa. and F. vesca were dominated by aromatic compounds and terpenoids, with 4-methoxybenzaldehyde (p-anisaldehyde) and α-muurolene the major compounds produced by the two species, respectively. Multi-dimensional scaling analyses separated the blends of the two species and explained differences between F. vesca genotypes and, to some degree, variation between F. x ananassa varieties In two-choice behavioral tests, SBW preferred odors of flowering strawberry plants to those of non-flowering plants, but weevils did not discriminate between odors from F. x ananassa and F. vesca flowering plants. Adding blends of six synthetic flower volatiles to non-flowering plants of both species increased the preference of SBW for these over the plants alone. When added individually to non-flowering plants, none of the components increased the preference of SBW, indicating a synergistic effect. However, SBW responded to 1,4-dimethoxybenzene, a major component of volatiles from F. viridis, previously found to synergize the attractiveness of the SBW aggregation pheromone in field studies.
Asunto(s)
Benzaldehídos/química , Fragaria/química , Terpenos/química , Compuestos Orgánicos Volátiles/química , Gorgojos/efectos de los fármacos , Animales , Conducta Animal , Benzaldehídos/metabolismo , Flores/química , Flores/metabolismo , Fragaria/metabolismo , Cromatografía de Gases y Espectrometría de Masas , Odorantes/análisis , Feromonas/análisis , Extractos Vegetales/química , Extractos Vegetales/metabolismo , Análisis de Componente Principal , Microextracción en Fase Sólida , Terpenos/metabolismo , Compuestos Orgánicos Volátiles/metabolismoRESUMEN
In identifying the volatiles that insects use to locate suitable host plants, electrophysiological recordings of olfactory responses to plant volatiles may give important information. However, divergent results may be obtained with different recording techniques. To illustrate these differences, the results of a previous investigation using single cell recordings linked to a gas chromatograph (SCR-GC) are compared with the results obtained with an electroantennogram linked to a gas chromatograph (EAG-GC). Testing insects of the same species (Hylobius abietis) for the same test sample, 30 potent volatile compounds were identified by SCR-GC and 18 by EAG-GC. Of the 34 different compounds, 14 were identified by both techniques. Furthermore, when the same compound elicited detectable responses by both techniques, the response strength was usually not the same relative to the strongest response recorded by each technique. This shows that both EAG-GC and SCR-GC are important techniques in the identification of potent plant volatiles for insects. However, by using SCR-GC more information was obtained, information that can be crucial for understanding the insect-plant relationship.
