Diversity of Predators'insects on Organic Rice Field and Conserved Areas,in Viamão,Rs,Brazil

Abstract

Predator's appearance in eco-systems is fundamental to regulate phytophagous insect population. Knowledge about associate's species in every system is very important to understand the dynamic events and to help the management of possible pests. The predator diversity of an irrigated rice organical production agroecosystem (AO) and a preserved area, Refúgio de Vida Silvestre Banhado dos Pachecos (RBP), both located in Viamão country, RS, Brazil, was studied and compared between out fauna index monthly catches were taken from May/2011 to April 2012, with Malaise, Moericke and Pitfall traps, for 24 hours every time. Were colected in AO 355 predators, identificated in 26 morphotypes and distributes in four orders and 11 families. The RBP group found 653 individuals of 50 morphotypes, belonged to six orders and 13 families. The richness estimators, Chao 1, Chao 2 and Bootstrap, indicate from 29 to 35 species richness in the AO and 59 to 71 in the RBP group. RBP present more diversity according diversity index (P = 0,01) than AO. Seasonal variation had influence in differences, to the richness and the abundance of species, in both areas. January was the month with more abundance of individuals in both areas. Considering the composition of the species, 18 morphotypes were shared in between two ambient, unless little structural complexity available in the rice area, which indicate that RBP can serve as a predators species reservoir.