No abstract

A survey of the hoverfly fauna of northeastern Algeria was carried out in 1991 and 1992, and seventy-three species recorded. Four species are new for Algeria: Dasysyrphus albostriatus, Chamaesyrphus lusitanicus, Brachypalpus laphriformis and Spilomyia maroccana. The genera Dasysyrphus, Chamaesyrphus and Brachypalpus are new for Algeria. Data on the distribution and the seasonal pattern of each species are provided. Species richness was found highest amongst wetlands (up to 38) and forested hills (up to 29). In contrast, degraded sites held the lowest numbers of hoverflies. Species such as Episyrphus balteatus, Sphaerophoria scripta, Syritta pipiens and Eristalis tenax were widespread and abundant, whereas others were rare (Platycheirus albimanus) or confined to forested hills, such as the North African endemic Volucella liquida. A good knowledge of the Syrphidae will pave the way to a close monitoring of global changes affecting the region and the conservation of an important but much neglected group in one of the foremost biodiversity hotspots of the Maghreb.

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 of the present paper is to enhance the bioindicator potential of hoverflies in Algeria (North Africa) by studying the hoverfly communities of six sites with different vegetation and conditions, 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, predominating by the subfamily Erisalinae. 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) and other three species new to Algeria (Eupeodes nuba, Paragus vandergooti and Eumerus obliquus). The results of the present paper suggest the need for further hoverfly surveys in other unexplored regions and habitats of Algeria.