Species composition and diversity of Culicoides biting midges (Diptera: Ceratopogonidae) in Algeria

Culicoides biting midges (Diptera: Ceratopogonidae) transmit various protozoa, bacteria, and viruses to both animals and humans. In Algeria, the most serious illness affecting sheep is bluetongue. This study compared the abundance and species composition of Culicoides across biotopes (peri‑urban and rural), elevation ranges, and various bioclimatic zones (humid, sub-humid, and semi-arid). The collection of Culicoides was accomplished from February to October for two subsequent years (2023 and 2024) utilizing CDC light traps positioned in 18 locations throughout three provinces. In total, 922 specimens (855 females and 67 males) belonging to nine subgenera and 23 species. The species Culicoides brunnicans (Edward, 1939) was documented for the first time in Algeria and North Africa. Across all the surveyed sites, Culicoides imicola showed the highest prevalence (23.96 %), followed by Culicoides obsoletus complex (19.52 %), and Culicoides punctatus (13.77 %). Of the Culicoides collected, these three species constitute 57 %. Similarity analysis based on Venn diagrams and diversity indices revealed a considerable overlap of Culicoides species between peri‑urban and rural areas, with several species shared across both landscapes. However, rural sites harbored the highest number of exclusive species, highlighting their greater contribution to overall species richness. Culicoides total abundance showed negative correlations with elevation. Culicoides community composition presented no significant correlation with the climatic factors (precipitation, mean temperature, and relative humidity). However, when examined at the provincial scale, significant correlations emerged in one province, where Culicoides composition was associated with temperature and humidity. The findings of this study help to understand the relation between environmental factors and the abundance, diversity and distribution of Culicoides, and create strategies for vector control in all three provinces and throughout Algeria.