Does host-feeding on GNA-intoxicated aphids by Aphelinus abdominalis affect their longevity and/or fecundity?

Transgenic potatoes have been transformed with a gene coding the snowdrop lectin Galanthus nivalis agglutinin (GNA) and they have been shown to be partially resistant to aphids. GNA binds to insect gut cells, including those of aphids, consequently inducing disruption of nutrient assimilation. Aphid parasitoids are important natural biocontrol agents of aphids and some species such as Aphelinus abdominalis are commercially available. Aphid parasitoids are endoparasitoids during their larval stages and free-living insects as adults. They could be directly or indirectly affected by GNA during both these stages, In this work, we present data on the potential direct and indirect effects of GNA on adult A. abdominalis. Aphelinus abdominalis is a synovigenic species (eggs are matured throughout the adult life) which needs a diet relatively rich in proteins and amino-acids to produce anhydropic eggs (large, yolk-rich eggs that do not expand in the host during embryonic stages). Adult A. abdominalis females feed on aphid haemolymph and they may be directly exposed to the entomotoxin or indirectly affected by a change in aphid haemolymph quality due to intoxication by GNA. We conducted a first tier experiment to investigate this potential risk. A. abdominalis females were offered either aphids reared on control diet or aphids reared on GNA 0.1% diet as hosts (i.e., as food and oviposition sites). No trace of GNA was found in females fed with GNA-aphids but no GNA could be detected in the haemolymph of aphids fed a 0.1% GNA diet. Longevity and fecundity were not affected suggesting that the quality of the haemolymph necessary for A. abdominalis egg maturation and production was not significantly altered.