Effect of black legume aphid Aphis craccivora honeydew on survival of the parasitoid Microctonus aethiopoides

摘要

The introduced parasitoid Microctonus aethiopoides (Hymenoptera: Braconidae) appears to be an effective biocontrol agent for clover root weevil Sitona lepidus Gyllenhal (Coleoptera: Curculionidae) in New Zealand pastures. As these pastures lack accessible nectar sources, hemipteran honeydew may be the most readily available energy source for the parasitoid. Experiments were undertaken to compare longevity of newly emerged M. aethiopoides adults caged on white clover, firstly with and without black legume aphid Aphis craccivora Kock (Hemiptera: Aphididae) and then with additional water and sucrose solution treatments. Parasitoids with access to aphid honeydew lived significantly longer (mean longevity 8.1 days) than those with water or no liquid (both 6.8 days) but not as long as those fed sucrose solution (10.9 days). Therefore the abundance of aphids commonly present on clovers may enhance M, aethiopoides longevity and therefore efficacy, in the field, especially in mid spring when host availability is very low.