Many adult parasitic Hymenoptera consume floral nectar and honeydew, although the latter is in most cases a 'bad meal' compared to floral nectars. Parasitoids of aphids, however, may be well-adapted to consuming honeydew when it is produced by their hosts. The nutritional value of honeydew for this group of parasitoids has often been tested against that of synthetic feeding solutions, but rarely against floral nectar. In the present work, the relative nutritional values of honeydew from the aphid Myzus persicae (Sulzer), nectar from two cultivars of oilseed rape (OSR) and nectars from four 'companion' plant species were assessed by testing their effect on the longevity of Diaeretiella rapae (McIntosh) Hymenoptera: Braconidae. Parasitoids fed on nectar from OSR lived longer than those fed on nectars of companion plants, or on water only. Diaeretiella rapae also lived longer when fed OSR nectar than when fed honeydew from M. persicae.
展开▼
