Selectivity in the exploitation of floral resources by hoverflies (Diptera: Syrphinae)

Adults of the Syrphinae subfamily display no strong flower preferences but exploit pollen and nectar produced by native plants having large infloresce nces and flat corollae (e.g. Apiaceae, Asteraceae, Ranunculaceae and Rosace ae). Seven foraging guilds are defined according to the dietary patterns of hoverflies, reflecting mainly a sequential exploitation of flowers at diff erent times of the year and in different habitats. The majority of species live in forests where they form highly diversified communities. Few Syrphinae colonize successfully open and anthropogenic hab itats, such as field margins and fallow areas. Episyrphus balteatus. Melano stoma mellinum, Eupeodes corollae. Sphaerophoria scripta and Plutycheirus s pp. are dominant in the communities of Syrphinae from open habitats, all ov er western Europe. These species are highly polyphagous and characterized b y elongated mouthparts as well as a long and slender body. They have access to pollen and nectar in flowers with small and tubular corollae. It is sug gested that their polyphagy is an important asset for colonizing open and e phemeral habitats.