The European corn borer moth, (ECB), Ostrinia nubilalis
(Lepidoptera: Crambidae, Pyraustinae) is one of the most destructive pests of
maize worldwide. ECB has two pheromone-strains, separated by specific ratios of
isomers of E- and Z11-tetradecenyl acetates (E11- and Z11-14Ac), but appearing
morphologically identical. Accordingly, E- and Z-ECB pheromone traps are
available for the respective populations for practical monitoring of the flight,
however, traps for Z-strain are unreliable for practical usage in some parts of
Central-Europe. E- and Z-ECB populations occur in sympatry in some areas, while
in allelopatry in other areas. Determining the strains before the flight of
adults, when difference in the composition of their respective pheromones is
manifested, would be of practical interest for early warning. In addition to the
known fatty-acyl-reductase (FAR) marker, further markers would allow more
comprehensive studies. We screened the following common markers for
mitochondrial and nuclear DNA regions: partial cytochrome c oxidase I (COI),
cytochrome B (CytB), the second spacer of the internal transcribed spacer
(ITS2), Elongation factor 1a (EF1a) and actin gene (Act). In addition, a marker
of the Δ11-desaturase gene (11desat), linked to biosynthesis of female-produced
sex pheromone, was also included, because we reported earlier a differential
expression for this site. Three Z-ECB populations locating at distant sites
within Hungary, an area where only Z-strain occurs, and an E-ECB population in
Slovenia, known as the closest-occurring E-strain, were included into the study.
Separate laboratory colonies were established from each population, and
F1 generations were sampled to verify the identity of pheromone
strains, by analysing the composition of sex pheromone by gas chromatography
linked to an electroantennographic detector (GC-EAD). Molecular studies were
conducted using specimens taken from the F2 generations. Results of
genetic studies showed that there were no differences between the Z and E
populations for the common markers. In contrast to this, several nucleic acid
changes (11 nt in 4 positions) were found between the three Z-populations
(Hungary) and the E-population (Slovenia) in the desaturase marker. Further
study is required to reveal whether the differences found in this study are
consistent across E-populations, thus making these markers suitable for
diagnostic purposes.
Erratum: Screening some common molecular markers and a desaturase marker, linked to sex pheromone biosynthesis, in three Z-strain and an E-strain populations of the European Corn Borer, Ostrinia nubilalis, occurring in Central Europe
