Identification of female-produced sex pheromone of the honey locust gall midge, Dasineura gleditchiae

• Published in: Journal of Chemical Ecology
• Main Authors: Molnár, Béla, Kárpáti, Zsolt, Szőcs, Gábor, Hall, David R.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Springer-Verlag 2009
• Subjects: S Agriculture (General); SF Animal culture; SB Plant culture; Antarc*; Antarctica
• Online Access: http://gala.gre.ac.uk/id/eprint/2060/; https://doi.org/10.1007/s10886-009-9641-5

The honey locust gall midge, Dasineura gleditchiae Osten Sacken 1866 (Diptera: Cecidomyiidae) is the main pest of ornamental varieties of the honey locust tree, Gleditsia triacanthos L., in North America, and is now becoming a pest of concern in Europe. Female midges were observed to emerge in the early morning with their ovipositor extended until they mated. Volatiles were collected from virgin females in a closed-loop stripping apparatus and analyzed by gas chromatography (GC) coupled to electroantennographic (EAG) recording from the antenna of a male midge. A single EAG response was observed, which was assumed to be to the major component of the female sex pheromone. This was identified as (Z)-2-acetoxy-8-heptadecene by comparison of its mass spectrum and GC retention times on different columns with those of synthetic standards and by micro-analytical reactions. This compound was synthesized, and the individual enantiomers were produced by kinetic resolution with lipase from Candida antarctica. Analysis of the naturally-produced compound on a cyclodextrin GC column indicated it was the (R)-enantiomer. In EAG dose-response measurements, the (R)-enantiomer alone or in the racemic mixture evoked significant responses from the antennae of male D. gleditchiae, whereas the (S)-enantiomer did not. In field trapping tests, the (R)-enantiomer attracted male D. gleditchiae. The racemic compound was equally attractive, but the (S)-enantiomer was not attractive. Both the pure (R)-enantiomer or racemic (Z)-2-acetoxy-8-heptadecene, applied to red rubber septa in a dose range of 3–30 μg, constitute a strongly attractive bait in sticky traps for monitoring the flight of D. gleditchiae.