Evaluating the induced-odour emission of a Bt maize and its attractiveness to parasitic wasps
Ted Turlings, Philippe Jeanbourquin, Matthias Held & Thomas Degen
| Résumé |
The current discussion on the safety of transgenic crops includes
their effects on beneficial insects, such as parasitoids and
predators of pest insects. One important plant trait to consider in
this context is the emission of volatiles in response to herbivory.
Natural enemies use the odours that result from these emissions as
cues to locate their herbivorous prey and any significant change in
these plant-provided signals may disrupt their search efficiency.
There is a need for practical and reliable methods to evaluate
transgenic crops for this and other important plant traits.
Moreover, it is imperative that such evaluations are done in the
context of variability for these traits among conventional
genotypes of a crop. For maize and the induction of volatile
emissions by caterpillar feeding this variability is known and
realistic comparisons can therefore be made. Here we used a six-arm
olfactometer that permits the simultaneous collection of volatiles
emitted by multiple plants and testing of their attractiveness to
insects. With this apparatus we measured the induced odour
emissions of Bt maize (Bt11, N4640Bt) and its near-isogenic line
(N4640) and the attractiveness of these odours to Cotesia
marginiventris and Microplitis rufiventris, two important larval
parasitoids of common lepidopteran pests. Both parasitoid species
were strongly attracted to induced maize odour and neither wasp
distinguished between the odours of the transgenic and the isogenic
line. Also wasps that had previously experienced one of the odours
during a successful oviposition divided their choices equally
between the two odours. However, chemical analyses of collected
odours revealed significant quantitative differences. The same 11
compounds dominated the blends of both genotypes, but the isogenic
line released a larger amount of most of these. These differences
may be due to altered resource allocation in the transgenic line,
but it had no measurable effect on the wasps' behaviour. All
compounds identified here had been previously reported for maize
and the differential quantities in which they were released fall
well within the range of variability observed for other maize
genotypes. |
| Mots-clés |
Bacillus thuringiensis, maize, parasitoids, tritrophic interactions, Zea mays, FIELD CONDITIONS, PLANT-GENOTYPE, CORN POLLEN, HERBIVORE, PERFORMANCE, PREFERENCE, BEHAVIOR, MONARCH, QUALITY, OVIPOSITION |
| Citation | Turlings, T., Jeanbourquin, P., Held, M., & Degen, T. (2005). Evaluating the induced-odour emission of a Bt maize and its attractiveness to parasitic wasps. Transgenic Research, 14(6), 807-816. |
| Type | Article de périodique (Anglais) |
| Date de publication | 2005 |
| Nom du périodique | Transgenic Research |
| Volume | 14 |
| Numéro | 6 |
| Pages | 807-816 |