Analytical studies of Spodoptera littoralis sex pheromone components by electroantennography and coupled gas chromatography-electroantennographic detection

Citation
Ea. Malo et al., Analytical studies of Spodoptera littoralis sex pheromone components by electroantennography and coupled gas chromatography-electroantennographic detection, TALANTA, 52(3), 2000, pp. 525-532
Citations number
31
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Spectroscopy /Instrumentation/Analytical Sciences
Journal title
TALANTA
ISSN journal
0039-9140 → ACNP
Volume
52
Issue
3
Year of publication
2000
Pages
525 - 532
Database
ISI
SICI code
0039-9140(20000630)52:3<525:ASOSLS>2.0.ZU;2-#
Abstract
In this paper we present analytical studies of the sex pheromone components of the Egyptian armyworm Spodoptera littoralis (Lepidoptera, Noctuidae) by electroantennography (EAG) and coupled gas chromatography-electroantennogr aphic detection (GC-EAD). EAG responses in three different preparations, us ing an insect's head, an excised antenna and a live insect, have been recor ded. EAG depolarizations of live insects were significantly higher than tho se elicited by the insect's head or the excised antenna. The responses were dose-dependent. Live insects also allowed regular pheromone stimulations f or 40 min with only 38% decrease of the EAG initial depolarization. The syn thetic pheromone blend elicited the highest EAG activity (2.0 +/- 0.3 mV), followed by the major compound (Z,E)-9,11-tetradecadienyl acetate (I) (1.54 +/- 0.1mV), and the minor components (Z)-9-tetradecenyl acetate (II), (E)- 11-tetradecenyl acetate (III), tetradecyl acetate (IV) and (Z)-11-tetradece nyl acetate (V) (1.21-1.32 mV range). (Z,E)-9,12-tetradecadienyl acetate (V I), although not present in the pheromone blend of our strain, also showed an EAG activity (1.32 +/- 0.09 mV) similar to that of the monoenic componen ts. GC-EAD responses confirmed the composition of the sex pheromone blend, the major response being elicited by the main component I followed by the o ther minor compounds II-V. The new dienic compound found in the female pher omone gland, (E,E)-10,12-tetradecadienyl acetate (VII), was not electrophys iologically active. Regarding sensitivity, the minimum amount detectable to elicit an antennal response in our GC-EAD system was 15 pg of the major co mponent. In our system, which was built with cheap and easily available mat erials, no cooling of the effluent at the outlet of the chromatographic col umn is required. (C) 2000 Elsevier Science B.V. All rights reserved.