Seasonal distribution of Ochetina uniformis (Pascoe, 1881) adults in flooded rice

Abstract

A Ochetina uniformis (Pascoe, 1881) (Coleoptera: Erirhinidae) populational survey was performed in the country of Santa Maria, Rio Grande do Sul State, in a commercial flooded rice field, from June 2005 to July 2006. A stratified sampling was used, with 90 sampling units of 0.25 m x 0.25 m, recorded every other week at the time of sampling. The reduction of the population of O. uniformis was observed from July to January. There were some areas without insects, and areas with a high populational density; with species occurring aggregated. Adults of O. uniformis remain concentrated on the levees of the field, representing 44% of the total collected. The remaining population is distributed from the levees inwards, reaching values between 12.9 and 15.1%. There were no adults of O. uniformis outside the cultivated area.