New records, distribution and phenology of hoverflies (Diptera: Syrphidae) in semi-arid habitats in northeastern Algeria

Hoverflies (Diptera: Syrphidae) pollinate plants, predate other insects, and feed on vegetal and decay materials, being used as bioindicators of different ecosystem conditions and processes. The main aim is to enhance the bioindicator potential of hoverflies in Algeria by increasing our knowledge on the hoverfly communities of different environments in the semi-arid Northeast of Algeria: unpolluted riverbank, plant nursery, polluted riverbank, olive orchard (Olea europaea), prickly pear plantations (Opuntia ficus-indica), and a cypress hedge (Cupressus sempervirens). With an entomological net, hoverflies were sampled fortnightly from December 2016 to November 2017. In total 37 species were identified. The unpolluted and polluted riverbanks and the plant nursery had the highest species richness with 26, 24, and 23 species respectively, whereas, the lowest species numbers were detected in the prickly pear plantations, the cypress hedge and the olive orchard with 16, 14, and 10 species respectively. One species was new to North Africa (Eumerus etnensis), whereas four species were recorded for the first time in Algeria (Eumerus obliquus, Eupeodes nuba, Paragus vandergootiandPlatycheirus ambiguus). Examined material also contributes to better understand each species phenology in Algeria.