Abundance and population fluctuations of syrphid flies (Diptera: Syrphidae) in altitudinal gradient in Sari, Iran

This study was carried out to evaluate distribution and abundance of Syrphid flies population in Sari-Kiasar forest Region. Data collection was done in five stations including Alikola (1640 metres above sea level, m.a.s.l.), Haftkhal (855 m.a.s.l.), Alamdardeh (396 m.a.s.l.), Pahnekola (175 m.a.s.l.) and one station in Dasht-e-naz region (20 m.a.s.l.). The samples of syrphid flies were collected by set of Malaise trap, window trap, yellow pan trap and white pan trap in each station. The data collection was done every two weeks during spring and summer. Seven species were identified in the study site. The most abundant species was Melanostomamellinum (L.) followed by Sphaerophoriascripta (L.) which was 43.54% and 33.39%, respectively. Results showed that altitudinal gradient affected the species abundance. For example M. mellinum was the most abundant in habitat with altitude 1640m and 855m, S. scripta was the most abundant species in habitat with altitude of 855m, Sphaerophoriarueppellii (Wiedemann) was the most abundant in habitat with altitude 20m, Eupeodescorollae (Fabricius) was the most abundant species in habitat with altitude of 855m and Merodonavidus (Rossi) was the most abundant species in habitat with altitude of 1640m. Also results showed that peak of maximum abundance in studied sites occurred in May.