Abundance and fluctuations of insect population of order Diptera at Al-Arish region, North of Sinai

An ultraviolet light trap was used to survey and study dipterous insects in Al-Arish city. North Sinai province, Egypt, from October 1994 to September 1996. Twenty-eight species from 21 genera belonging to 15 families were identified with a total annual number of 3598 flies caught in the first year and 2083 flies caught in the second. The majority and highest numbers of Diptera were trapped during April-October, with peaks during September in both years. Fewer Diptera were trapped during winter months. Syrphidae, Tachinidae, Tabanidae and Muscidae were more abundant than other families and constituted 20.2, 14.7, 12.2 and 13.1% of the total catch in the first year, and 14.5, 17.0, 15.6 and 11.7% in the second year, respectively. Individuals of Syrphus corollae [Eupeodes corollae] and Sarcophaga carnaria were the most active and abundant of all species, and numbers of both peaked during September in both years.