Changes in the fauna of zoophagous hoverflies (Syrphidae, Diptera) of green urban environments of Poznań in the light of multi-year observations

Observations of zoophagous hoverflies communities were carried out in 2006–2015 in the study area which covers the Botanical Garden of the Adam Mickiewicz University, Poznań, and the adjacent collection of decorative plants of the Faculty of Horticulture and Landscape Architecture of the Poznań University of Life Sciences. The insects were caught in Moericke’s yellow traps. The study yielded the occurrence of 42 zoophagous hoverflies species of 22 genera, which constitutes about 25% of predatory Syrphidae in Poland. The largest numbers of individuals were recorded in 2008, 2013 and 2015. The highest species diversity was observed in 2015, namely 21 species of zoophagous Syrphidae. Episyrphus balteatus (De Geer, 1776) was the only species reported in each study year and also caught in the highest numbers. The resulting 336 individuals of E. balteatus constituted 49% of the collected material. The abundance of this species in each study year helped to classify it as a eudominant. Depending on the year the group also comprised: Epistrophe eligans (Harris, 1780), Eupeodes corollae (Fabricius, 1794), Melangyna pavlovskyi Violovitsh, 1956, M. quadrimaculata Verrall, 1873, Parasyrphus punctulatus (Verrall, 1873), Pipizella viduata (Linnaeus, 1758), Syrphus torvus Osten-Sacken, 1875 and S. vitripennis Meigen, 1822.