[The suitability of Megoura viciae(Buckt.) (aphid.) for larvae and adult females of Aphelinus asychis walker (Aphelin.)].

In the laboratory, the females of the polyphagous aphid parasite Aphelinus asychis accepted vetch aphids (Megoura viciae on Vicia faba) for oviposition and host feeding as readily as peach aphids (Myzus persicae on Brassica oleracea var. gongylodes) of the same size. However, the vetch aphids defended themselves less often; consequently, they were parasitized more frequently.With very few exceptions, all parasite larvae in the vetch aphids died after some days. Blood reactions were scarcely notized. In the peach aphids, development went on normally.After one day with Me. viciae, fecundity of Aphelinus females was reduced during the next day with My. persicae. At room temperature, the average longevity of the adult females was 3.0 days with Me. viciae but 15.2 days with My. persicae. Additional supply with glucose solution extended the life span in both cases.If honeydew from My. persicae (without aphids) or glucose solution was offered to the females they lived for about one month, whereas they died after 3-4 days without any nutrition. With honeydew from Me. viciae they reached a medium life span of 6.7 days. Peach aphids which were cemented each morning to the bottom of the vial for host feeding and (to a lesser degree) oviposition (nearly without honeydew) sustained the life of Aphelinus females for 2 weeks; cemented vetch aphids, however, reduced the longevity significantly when offered alone or in addition to glucose solution or cemented peach aphids.Consequently, Me. viciae is unsuitable not only for the development of the larvae but also for the permanent nutrition of the adult females of A. asychis. This applies to the hemolymph as well as to the honeydew of that species.