FORTSCHRITTE AUF DEM GEBIET DER HONIGTAU-FORSCHUNG

Abstract

In central Europe bees collect the honeydew from only few (58 known) species of Sternorrhyncha (coccids, aphids, psyllids) (Table 1). This collecting it favored by an aggregation near the floral parts, in roll galls, and at the peripheral branches of trees combined with less visitation by ants. But 72.4 % of all species possess a filter chamber. As a consequence, these aphids secret 2-3 times more honeydew with 25-40%dry weight sucrose (from coccids and aphids) instead of less than 1 % sucrose found from aphids without a filter - gut. The appearance of other types of carbohydrates is discussed. Trehalose seems to occur in every honey-dew. Since raffinose is known to be widespread as a constituent of phloem sap, its occurence in honeydew is also discussed. Not all the aphids can assimilate raffinose as seen from the artificial diet studies. The honeydew from M. persicae is collected by bees, and, on the other hand, these aphids can be reared on artificial diet well. As a model their nutritional physiology can be well studied, and some results are reviewed. At the end, significance of host phants is shown to the following items summer depression in aphid populations, the analysis of phloem sap, influence of saliva in nutrition.