The goal is to provide a brief overview of the hypothesis that the presence of nectar-producing plants can improve biological control by supplying parasitoids with sugar. The presentation will propose that the evidence supporting this hypothesis is largely circumstantial. Data will be provided showing that the parasitoid Macrocentrus grandii does not utilize the nectar from buckwheat flowers in the field. This is despite the fact that M. grandii feeds on buckwheat nectar in the laboratory and that this nectar increases M. grandii longevity. One explanation for the observation of no nectar feeding is that M. grandii females may be able to compensate for a lack of sugar by increasing their reproductive rate. Laboratory studies indicated that sugar (and nectar) feeding led to decreased rates of egg maturation and increased pre-oviposition periods. These adjustments led to fecundities in (shorter-lived) starved females that were very similar to those of (longer-lived) nectar-fed females.
Species 1: Hymenoptera Braconidae Macrocentrus grandii
Species 2: Lepidoptera Crambidae Ostrinia nubilalis (European corn borer)
Keywords: nectar, parasitoid
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