Biodiversity and seasonal fluctuation of aquatic and semiaquatic insects in Rashid stream, kafr El Zayat (Gharbyia governorate)

摘要: Rashid branch of Nile River is a principle stream in Kafr El Zayat (Gharbyia governorate) for drinking and irrigation to different essential crops. Five stations were selected seasonal collection, resulted 539 specimens, belonging 7 orders 22 families 31 species. The total population density was higher during Spring (41.9%), then Summer (25.1). Order Diptera the most abundant (33.8%), represented by 5 (Chironomidae, Culicidae, Ephydridae, Tabanidae & Stratiomyiidae) with highest value season; order Hemiptera (19.5%), (Blestomatidae, Croxidae, Mesovillidae, Villidae Notonectidae) also followed Coleoptera (16.9%) 6 (Hydrophylidae, Dytiscidae, Noteridae, Hydranaeidae, Curculionidae Staphylinidae), representation Odonata (16.7%), 2 (Libellulidae Coenagrionidae) , Spring; Ephemeroptera (9.5%), ( Baetidae Caenidae), lastly Trichoptera Orthoptera each one family Winter respectively. Family Tridactylidae Staphylinidae are collected first time from streams Egypt. Tables, Figures, Keys, diagnosis notes on habitat, addition detailed colored photographs diagnostic features all species introduced facilitate correct identification that permits utilization these aquatic insects as bioindicators monitoring programs reflecting ecological contents pollution level ecosystem along this stream.