Sambucus nigra L. as a reservoir of beneficial insects (Diptera, Syrphidae)

Black elder (Sambucus nigra L.) commonly occurs throughout the country – it can be found in forests, thickets, parks, balks or in home gardens. It is a valuable reservoir of food for beneficial insects and a place of refuge or wintering. Almost every part of the elderberry plant has some uses: the fruits, flowers, leaves, roots, pith and bark. Its fruits and flowers are used in herbal medicine and in the kitchen. S. nigra is a primary host of Aphis sambuci L. feeding, which weakens plant growth, reduces flowering and fruiting, and decreases the ornamental value of these shrubs. Aphid populations are limited by a group of predatory and parasitic organisms, among which an important role is played by predatory Syrphidae. Observations were conducted in the years 2009 and 2010 in Krakow (south Poland, 19°57'E, 50°03'N). Significantly more numerous A. sambuci colonies were observed in 2009 – in the maximum of their abundance, 960 specimens per shoot were noted. Seven syrphid species were noted in A. sambuci colonies: Episyrphus balteatus (Deg.), Epistrophe eligans (Harr.), Sphaerophoria scripta (L.), Syrphus ribesii (L.), Syrphus vitripennis Meig., Scaeva pyrastri (L.) and Eupeodes corollae (Fabr.). E. balteatus dominated in both years of research. Research on the effectiveness of Syrphidae was performed on four commonly occurring species – the most voracious were Epistrophe eligans (Harr.) larvae, eating up to 676 A. sambuci aphids during their development.