Compatibility of transgenic legumes and parasitoids to control bruchids (Coleoptera: Chrysomelidae)
A powerful approach to control also such tolerant species might be the combination of αAI-1 transgenic seeds with hymenopteran parasitoids.
To assess the impact of αAI-transgenic legumes to bruchid parasitoids, we have thus assessed (i) whether bruchid parasitoids rely on α-amylases for carbohydrate digestion and whether their α-amylases are inhibited by αAI-1; (ii) whether parasitoids ingest harmful amounts of the inhibitor, (iii) whether parasitoids are adversely affected when feeding on larvae of αAI-1 tolerant bruchids developing in αAI-1 transgenic seeds.
Our results for five parasitoid species from 3 families indicate that both females and larvae possess α-amylase activity and thus appear to rely on α-amylases for carbohydrate digestion. In vitro inhibition studies have confirmed that α-amylases of both larvae and females of all parasitic wasps were strongly inhibited by αAI-1. We could, however, not detect an adverse effect on the parasitoid Dinarmus basalis when attacking larvae of the αAI-1 tolerant bruchid Z. subfasciatus developing in αAI-1 transgenic cowpea seeds. This appears to be due to the low level of exposure to the insecticidal factor.
Thus, αAI-1-transgenic legumes appear to be compatible with parasitoids to control bruchid pests.
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