Predator beetles (Coleoptera) and their population fluctuation in rice fields of Mazandaran

The rice fields consist of diverse fauna of Arthropoda because of both subterranean and aquatic ecosystems. In this research، the fauna of predator beetles including Carabidae، Coccinellidae، Staphylinidae، Malachiidae، and their population fluctuation were studied in Mazandaran province during 2002-2006. A number of 13 carabid species، one staphylinid species، six coccinellid species، and two species of Malachiidae were collected from different rice fields of Mazandaran. Out of wich، 10 carabid and two malachiid species are new records for Iranian fauna. The density of these beneficial beetles increase since May until July and the highest density was obtained in the late of July. The highest density of predator beetles was observed on the rice variety of Fajr. The results of biomass-percent comparison between predator beetles with predator bugs (Heteroptera)، spiders (Araneae) and other predators of rice fields indicated that the biomass-percentage were 38. 2 (Coleoptera)، 10. 8 (Heteroptera)، 26. 2 (Araneae)، and 24. 9 (Others)، respectively. Therefore، the predator beetles had the highest biomass-percent because of high density of Paederus fuscipes in all rice fields of Mazandaran.