Berlese vs Winkler: Assessing the relative effectiveness of two methods used to extract arthropods from organic litter samples

Studies of forest litter arthropod communities are important in understanding forest ecology, diversity, and species distributions. Two methods utilized for the extraction of arthropods from litter samples are Winkler extractors and Berlese funnels. But, debates exist about the relative efficacy of these methods, and detailed studies addressing this question have not been published. Recovery rates of litter-dwelling Coleoptera were compared for both methods for two samples, one from the Ouachita National Forest in Arkansas and another from the Tunica Hills region of Louisiana. Samples were divided into two portions and recovery trials were performed using four Winkler extractors and four Berlese funnels per trial. Organisms were recovered at timed intervals until recovery dropped to near zero. Coleoptera were sorted and identified to species or morphospecies. Numbers and diversity of taxa recovered for each interval were compared for both methods and species accumulation curves were generated. Data indicate that for short term recovery, Berlese funnels are superior to Winklers, but differences across all taxa where not observed by the ends of runs. Recovery rates for individual taxa varied greatly. Our study provides insight into the selection of one method over the other depending on laboratory and field conditions and targeted taxa.